make device stop suspended to properly await for lifecycle event.

Add capabilities to Constructor

build.gradle.kts

@@ -8,7 +8,7 @@ plugins {
 
 allprojects {
     group = "space.kscience"
-    version = "0.3.1-dev-1"
+    version = "0.4.0-dev-1"
     repositories{
         maven("https://maven.pkg.jetbrains.space/spc/p/sci/dev")
     }

controls-constructor/build.gradle.kts

@@ -10,9 +10,14 @@ description = """
 kscience{
     jvm()
     js()
-    dependencies {
+    useCoroutines()
+    commonMain {
         api(projects.controlsCore)
     }
+
+    commonTest{
+        implementation(spclibs.logback.classic)
+    }
 }
 
 readme{

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/ConstructorBinding.kt

@@ -0,0 +1,26 @@
+package space.kscience.controls.constructor
+
+import space.kscience.controls.api.Device
+
+public sealed interface ConstructorBinding
+
+/**
+ * A binding that exposes device property as read-only state
+ */
+public class PropertyBinding<T>(
+    public val device: Device,
+    public val propertyName: String,
+    public val state: DeviceState<T>,
+) : ConstructorBinding
+
+/**
+ * A binding for independent state like a timer
+ */
+public class StateBinding<T>(
+    public val state: DeviceState<T>
+) : ConstructorBinding
+
+public class ActionBinding(
+    public val reads: Collection<DeviceState<*>>,
+    public val writes: Collection<DeviceState<*>>
+): ConstructorBinding

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/DeviceConstructor.kt

@@ -1,9 +1,16 @@
 package space.kscience.controls.constructor
 
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
 import space.kscience.controls.api.Device
 import space.kscience.controls.api.PropertyDescriptor
+import space.kscience.controls.manager.ClockManager
+import space.kscience.controls.spec.DevicePropertySpec
+import space.kscience.controls.spec.MutableDevicePropertySpec
 import space.kscience.dataforge.context.Context
 import space.kscience.dataforge.context.Factory
+import space.kscience.dataforge.context.request
 import space.kscience.dataforge.meta.Meta
 import space.kscience.dataforge.meta.MetaConverter
 import space.kscience.dataforge.names.Name
@@ -14,105 +21,154 @@ import kotlin.reflect.KProperty
 import kotlin.time.Duration
 
 /**
- * A base for strongly typed device constructor blocks. Has additional delegates for type-safe devices
+ * A base for strongly typed device constructor block. Has additional delegates for type-safe devices
  */
 public abstract class DeviceConstructor(
     context: Context,
-    meta: Meta,
+    meta: Meta = Meta.EMPTY,
 ) : DeviceGroup(context, meta) {
+    private val _bindings: MutableList<ConstructorBinding> = mutableListOf()
+    public val bindings: List<ConstructorBinding> get() = _bindings
+
+    public fun registerBinding(binding: ConstructorBinding) {
+        _bindings.add(binding)
+    }
+
+    override fun registerProperty(descriptor: PropertyDescriptor, state: DeviceState<*>) {
+        super.registerProperty(descriptor, state)
+        registerBinding(PropertyBinding(this, descriptor.name, state))
+    }
 
     /**
-     * Register a device, provided by a given [factory] and
+     * Create and register a timer. Timer is not counted as a device property.
      */
-    public fun <D : Device> device(
+    public fun timer(tick: Duration): TimerState = TimerState(context.request(ClockManager), tick)
-        factory: Factory<D>,
+        .also { registerBinding(StateBinding(it)) }
-        meta: Meta? = null,
-        nameOverride: Name? = null,
-        metaLocation: Name? = null,
-    ): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, D>> =
-        PropertyDelegateProvider { _: DeviceConstructor, property: KProperty<*> ->
-            val name = nameOverride ?: property.name.asName()
-            val device = install(name, factory, meta, metaLocation ?: name)
-            ReadOnlyProperty { _: DeviceConstructor, _ ->
-                device
-            }
-        }
-
-    public fun <D : Device> device(
-        device: D,
-        nameOverride: Name? = null,
-    ): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, D>> =
-        PropertyDelegateProvider { _: DeviceConstructor, property: KProperty<*> ->
-            val name = nameOverride ?: property.name.asName()
-            install(name, device)
-            ReadOnlyProperty { _: DeviceConstructor, _ ->
-                device
-            }
-        }
-
 
     /**
-     * Register a property and provide a direct reader for it
+     * Launch action that is performed on each [DeviceState] value change.
+     *
+     * Optionally provide [writes] - a set of states that this change affects.
      */
-    public fun <T, S: DeviceState<T>> property(
+    public fun <T> DeviceState<T>.onChange(
-        state: S,
+        vararg writes: DeviceState<*>,
-        descriptorBuilder: PropertyDescriptor.() -> Unit = {},
+        reads: Collection<DeviceState<*>>,
-        nameOverride: String? = null,
+        onChange: suspend (T) -> Unit,
-    ): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, S>> =
+    ): Job = valueFlow.onEach(onChange).launchIn(this@DeviceConstructor).also {
-        PropertyDelegateProvider { _: DeviceConstructor, property ->
+        registerBinding(ActionBinding(setOf(this, *reads.toTypedArray()), setOf(*writes)))
-            val name = nameOverride ?: property.name
+    }
-            val descriptor = PropertyDescriptor(name).apply(descriptorBuilder)
-            registerProperty(descriptor, state)
-            ReadOnlyProperty { _: DeviceConstructor, _ ->
-                state
-            }
-        }
-
-    /**
-     * Register external state as a property
-     */
-    public fun <T : Any> property(
-        metaConverter: MetaConverter<T>,
-        reader: suspend () -> T,
-        readInterval: Duration,
-        initialState: T,
-        descriptorBuilder: PropertyDescriptor.() -> Unit = {},
-        nameOverride: String? = null,
-    ): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, DeviceState<T>>> = property(
-        DeviceState.external(this, metaConverter, readInterval, initialState, reader),
-        descriptorBuilder,
-        nameOverride,
-    )
-
-    /**
-     * Register a mutable external state as a property
-     */
-    public fun <T : Any> mutableProperty(
-        metaConverter: MetaConverter<T>,
-        reader: suspend () -> T,
-        writer: suspend (T) -> Unit,
-        readInterval: Duration,
-        initialState: T,
-        descriptorBuilder: PropertyDescriptor.() -> Unit = {},
-        nameOverride: String? = null,
-    ): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, MutableDeviceState<T>>> = property(
-        DeviceState.external(this, metaConverter, readInterval, initialState, reader, writer),
-        descriptorBuilder,
-        nameOverride,
-    )
-
-    /**
-     * Create and register a virtual mutable property with optional [callback]
-     */
-    public fun <T> virtualProperty(
-        metaConverter: MetaConverter<T>,
-        initialState: T,
-        descriptorBuilder: PropertyDescriptor.() -> Unit = {},
-        nameOverride: String? = null,
-        callback: (T) -> Unit = {},
-    ): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, MutableDeviceState<T>>> = property(
-        DeviceState.virtual(metaConverter, initialState, callback),
-        descriptorBuilder,
-        nameOverride,
-    )
 }
+
+/**
+ * Register a device, provided by a given [factory] and
+ */
+public fun <D : Device> DeviceConstructor.device(
+    factory: Factory<D>,
+    meta: Meta? = null,
+    nameOverride: Name? = null,
+    metaLocation: Name? = null,
+): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, D>> =
+    PropertyDelegateProvider { _: DeviceConstructor, property: KProperty<*> ->
+        val name = nameOverride ?: property.name.asName()
+        val device = install(name, factory, meta, metaLocation ?: name)
+        ReadOnlyProperty { _: DeviceConstructor, _ ->
+            device
+        }
+    }
+
+public fun <D : Device> DeviceConstructor.device(
+    device: D,
+    nameOverride: Name? = null,
+): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, D>> =
+    PropertyDelegateProvider { _: DeviceConstructor, property: KProperty<*> ->
+        val name = nameOverride ?: property.name.asName()
+        install(name, device)
+        ReadOnlyProperty { _: DeviceConstructor, _ ->
+            device
+        }
+    }
+
+/**
+ * Register a property and provide a direct reader for it
+ */
+public fun <T, S : DeviceState<T>> DeviceConstructor.property(
+    state: S,
+    descriptorBuilder: PropertyDescriptor.() -> Unit = {},
+    nameOverride: String? = null,
+): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, S>> =
+    PropertyDelegateProvider { _: DeviceConstructor, property ->
+        val name = nameOverride ?: property.name
+        val descriptor = PropertyDescriptor(name).apply(descriptorBuilder)
+        registerProperty(descriptor, state)
+        ReadOnlyProperty { _: DeviceConstructor, _ ->
+            state
+        }
+    }
+
+/**
+ * Register external state as a property
+ */
+public fun <T : Any> DeviceConstructor.property(
+    metaConverter: MetaConverter<T>,
+    reader: suspend () -> T,
+    readInterval: Duration,
+    initialState: T,
+    descriptorBuilder: PropertyDescriptor.() -> Unit = {},
+    nameOverride: String? = null,
+): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, DeviceState<T>>> = property(
+    DeviceState.external(this, metaConverter, readInterval, initialState, reader),
+    descriptorBuilder,
+    nameOverride,
+)
+
+/**
+ * Register a mutable external state as a property
+ */
+public fun <T : Any> DeviceConstructor.mutableProperty(
+    metaConverter: MetaConverter<T>,
+    reader: suspend () -> T,
+    writer: suspend (T) -> Unit,
+    readInterval: Duration,
+    initialState: T,
+    descriptorBuilder: PropertyDescriptor.() -> Unit = {},
+    nameOverride: String? = null,
+): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, MutableDeviceState<T>>> = property(
+    DeviceState.external(this, metaConverter, readInterval, initialState, reader, writer),
+    descriptorBuilder,
+    nameOverride,
+)
+
+/**
+ * Create and register a virtual mutable property with optional [callback]
+ */
+public fun <T> DeviceConstructor.virtualProperty(
+    metaConverter: MetaConverter<T>,
+    initialState: T,
+    descriptorBuilder: PropertyDescriptor.() -> Unit = {},
+    nameOverride: String? = null,
+    callback: (T) -> Unit = {},
+): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, MutableDeviceState<T>>> = property(
+    DeviceState.internal(metaConverter, initialState, callback),
+    descriptorBuilder,
+    nameOverride,
+)
+
+/**
+ * Bind existing property provided by specification to this device
+ */
+public fun <T, D : Device> DeviceConstructor.deviceProperty(
+    device: D,
+    property: DevicePropertySpec<D, T>,
+    initialValue: T,
+): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, DeviceState<T>>> =
+    property(device.propertyAsState(property, initialValue))
+
+/**
+ * Bind existing property provided by specification to this device
+ */
+public fun <T, D : Device> DeviceConstructor.deviceProperty(
+    device: D,
+    property: MutableDevicePropertySpec<D, T>,
+    initialValue: T,
+): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, MutableDeviceState<T>>> =
+    property(device.mutablePropertyAsState(property, initialValue))

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/DeviceGroup.kt

@@ -9,9 +9,7 @@ import space.kscience.controls.api.*
 import space.kscience.controls.api.DeviceLifecycleState.*
 import space.kscience.controls.manager.DeviceManager
 import space.kscience.controls.manager.install
-import space.kscience.dataforge.context.Context
+import space.kscience.dataforge.context.*
-import space.kscience.dataforge.context.Factory
-import space.kscience.dataforge.context.request
 import space.kscience.dataforge.meta.*
 import space.kscience.dataforge.misc.DFExperimental
 import space.kscience.dataforge.names.*
@@ -57,6 +55,7 @@ public open class DeviceGroup(
                             )
                         )
                     }
+                    logger.error(throwable) { "Exception in device $id" }
                 }
     )
 
@@ -69,7 +68,7 @@ public open class DeviceGroup(
      * Register and initialize (synchronize child's lifecycle state with group state) a new device in this group
      */
     @OptIn(DFExperimental::class)
-    public fun <D : Device> install(token: NameToken, device: D): D {
+    public open fun <D : Device> install(token: NameToken, device: D): D {
         require(_devices[token] == null) { "A child device with name $token already exists" }
         //start the child device if needed
         if (lifecycleState == STARTED || lifecycleState == STARTING) launch { device.start() }
@@ -82,7 +81,7 @@ public open class DeviceGroup(
     /**
      * Register a new property based on [DeviceState]. Properties could be modified dynamically
      */
-    public fun registerProperty(descriptor: PropertyDescriptor, state: DeviceState<*>) {
+    public open fun registerProperty(descriptor: PropertyDescriptor, state: DeviceState<*>) {
         val name = descriptor.name.parseAsName()
         require(properties[name] == null) { "Can't add property with name $name. It already exists." }
         properties[name] = Property(state, descriptor)
@@ -126,37 +125,33 @@ public open class DeviceGroup(
         return action.invoke(argument)
     }
 
-    @DFExperimental
+    final override var lifecycleState: DeviceLifecycleState = DeviceLifecycleState.STOPPED
-    override var lifecycleState: DeviceLifecycleState = STOPPED
+        private set
-        protected set(value) {
+
-            if (field != value) {
+
-                launch {
+    private suspend fun setLifecycleState(lifecycleState: DeviceLifecycleState) {
-                    sharedMessageFlow.emit(
+        this.lifecycleState = lifecycleState
-                        DeviceLifeCycleMessage(value)
+        sharedMessageFlow.emit(
-                    )
+            DeviceLifeCycleMessage(lifecycleState)
-                }
+        )
-            }
+    }
-            field = value
-        }
 
 
-    @OptIn(DFExperimental::class)
     override suspend fun start() {
-        lifecycleState = STARTING
+        setLifecycleState(STARTING)
         super.start()
         devices.values.forEach {
             it.start()
         }
-        lifecycleState = STARTED
+        setLifecycleState(STARTED)
     }
 
-    @OptIn(DFExperimental::class)
+    override suspend fun stop() {
-    override fun stop() {
         devices.values.forEach {
             it.stop()
         }
+        setLifecycleState(STOPPED)
         super.stop()
-        lifecycleState = STOPPED
     }
 
     public companion object {
@@ -210,13 +205,9 @@ public fun <D : Device> DeviceGroup.install(name: Name, device: D): D {
     }
 }
 
-public fun <D : Device> DeviceGroup.install(name: String, device: D): D =
+public fun <D : Device> DeviceGroup.install(name: String, device: D): D = install(name.parseAsName(), device)
-    install(name.parseAsName(), device)
 
-public fun <D : Device> DeviceGroup.install(device: D): D =
+public fun <D : Device> DeviceGroup.install(device: D): D = install(device.id, device)
-    install(device.id, device)
-
-public fun <D : Device> Context.install(name: String, device: D): D = request(DeviceManager).install(name, device)
 
 /**
  * Add a device creating intermediate groups if necessary. If device with given [name] already exists, throws an error.
@@ -292,7 +283,7 @@ public fun <T : Any> DeviceGroup.registerVirtualProperty(
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     callback: (T) -> Unit = {},
 ): MutableDeviceState<T> {
-    val state = DeviceState.virtual<T>(converter, initialValue, callback)
+    val state = DeviceState.internal<T>(converter, initialValue, callback)
     registerMutableProperty(name, state, descriptorBuilder)
     return state
 }

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/DeviceState.kt

@@ -2,18 +2,13 @@ package space.kscience.controls.constructor
 
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
-import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.flow.launchIn
-import kotlinx.coroutines.launch
+import kotlinx.coroutines.flow.map
-import space.kscience.controls.api.Device
+import kotlinx.coroutines.flow.onEach
-import space.kscience.controls.api.PropertyChangedMessage
-import space.kscience.controls.spec.DevicePropertySpec
-import space.kscience.controls.spec.MutableDevicePropertySpec
-import space.kscience.controls.spec.name
 import space.kscience.dataforge.meta.Meta
 import space.kscience.dataforge.meta.MetaConverter
 import kotlin.reflect.KProperty
-import kotlin.time.Duration
 
 /**
  * An observable state of a device
@@ -24,6 +19,8 @@ public interface DeviceState<T> {
 
     public val valueFlow: Flow<T>
 
+    override fun toString(): String
+
     public companion object
 }
 
@@ -36,7 +33,7 @@ public operator fun <T> DeviceState<T>.getValue(thisRef: Any?, property: KProper
 /**
  * Collect values in a given [scope]
  */
-public fun <T> DeviceState<T>.collectValuesIn(scope: CoroutineScope, block: suspend (T)->Unit): Job =
+public fun <T> DeviceState<T>.collectValuesIn(scope: CoroutineScope, block: suspend (T) -> Unit): Job =
     valueFlow.onEach(block).launchIn(scope)
 
 /**
@@ -57,186 +54,46 @@ public var <T> MutableDeviceState<T>.valueAsMeta: Meta
     }
 
 /**
- * A [MutableDeviceState] that does not correspond to a physical state
+ * Device state with a value that depends on other device states
- *
- * @param callback a synchronous callback that could be used without a scope
  */
-private class VirtualDeviceState<T>(
+public interface DeviceStateWithDependencies<T> : DeviceState<T> {
-    override val converter: MetaConverter<T>,
+    public val dependencies: Collection<DeviceState<*>>
-    initialValue: T,
-    private val callback: (T) -> Unit = {},
-) : MutableDeviceState<T> {
-    private val flow = MutableStateFlow(initialValue)
-    override val valueFlow: Flow<T> get() = flow
-
-    override var value: T
-        get() = flow.value
-        set(value) {
-            flow.value = value
-            callback(value)
-        }
-}
-
-
-/**
- * A [MutableDeviceState] that does not correspond to a physical state
- *
- * @param callback a synchronous callback that could be used without a scope
- */
-public fun <T> DeviceState.Companion.virtual(
-    converter: MetaConverter<T>,
-    initialValue: T,
-    callback: (T) -> Unit = {},
-): MutableDeviceState<T> = VirtualDeviceState(converter, initialValue, callback)
-
-private class StateFlowAsState<T>(
-    override val converter: MetaConverter<T>,
-    val flow: MutableStateFlow<T>,
-) : MutableDeviceState<T> {
-    override var value: T by flow::value
-    override val valueFlow: Flow<T> get() = flow
-}
-
-public fun <T> MutableStateFlow<T>.asDeviceState(converter: MetaConverter<T>): DeviceState<T> =
-    StateFlowAsState(converter, this)
-
-
-private open class BoundDeviceState<T>(
-    override val converter: MetaConverter<T>,
-    val device: Device,
-    val propertyName: String,
-    initialValue: T,
-) : DeviceState<T> {
-
-    override val valueFlow: StateFlow<T> = device.messageFlow.filterIsInstance<PropertyChangedMessage>().filter {
-        it.property == propertyName
-    }.mapNotNull {
-        converter.read(it.value)
-    }.stateIn(device.context, SharingStarted.Eagerly, initialValue)
-
-    override val value: T get() = valueFlow.value
 }
 
 /**
- * Bind a read-only [DeviceState] to a [Device] property
+ * Create a new read-only [DeviceState] that mirrors receiver state by mapping the value with [mapper].
  */
-public suspend fun <T> Device.propertyAsState(
-    propertyName: String,
-    metaConverter: MetaConverter<T>,
-): DeviceState<T> {
-    val initialValue = metaConverter.readOrNull(readProperty(propertyName)) ?: error("Conversion of property failed")
-    return BoundDeviceState(metaConverter, this, propertyName, initialValue)
-}
-
-public suspend fun <D : Device, T> D.propertyAsState(
-    propertySpec: DevicePropertySpec<D, T>,
-): DeviceState<T> = propertyAsState(propertySpec.name, propertySpec.converter)
-
 public fun <T, R> DeviceState<T>.map(
     converter: MetaConverter<R>, mapper: (T) -> R,
-): DeviceState<R> = object : DeviceState<R> {
+): DeviceStateWithDependencies<R> = object : DeviceStateWithDependencies<R> {
+    override val dependencies = listOf(this)
+
     override val converter: MetaConverter<R> = converter
+
     override val value: R
         get() = mapper(this@map.value)
 
     override val valueFlow: Flow<R> = this@map.valueFlow.map(mapper)
-}
 
-private class MutableBoundDeviceState<T>(
+    override fun toString(): String = "DeviceState.map(arg=${this@map}, converter=$converter)"
-    converter: MetaConverter<T>,
-    device: Device,
-    propertyName: String,
-    initialValue: T,
-) : BoundDeviceState<T>(converter, device, propertyName, initialValue), MutableDeviceState<T> {
-
-    override var value: T
-        get() = valueFlow.value
-        set(newValue) {
-            device.launch {
-                device.writeProperty(propertyName, converter.convert(newValue))
-            }
-        }
-}
-
-public fun <T> Device.mutablePropertyAsState(
-    propertyName: String,
-    metaConverter: MetaConverter<T>,
-    initialValue: T,
-): MutableDeviceState<T> = MutableBoundDeviceState(metaConverter, this, propertyName, initialValue)
-
-public suspend fun <T> Device.mutablePropertyAsState(
-    propertyName: String,
-    metaConverter: MetaConverter<T>,
-): MutableDeviceState<T> {
-    val initialValue = metaConverter.readOrNull(readProperty(propertyName)) ?: error("Conversion of property failed")
-    return mutablePropertyAsState(propertyName, metaConverter, initialValue)
-}
-
-public suspend fun <D : Device, T> D.mutablePropertyAsState(
-    propertySpec: MutableDevicePropertySpec<D, T>,
-): MutableDeviceState<T> = mutablePropertyAsState(propertySpec.name, propertySpec.converter)
-
-public fun <D : Device, T> D.mutablePropertyAsState(
-    propertySpec: MutableDevicePropertySpec<D, T>,
-    initialValue: T,
-): MutableDeviceState<T> = mutablePropertyAsState(propertySpec.name, propertySpec.converter, initialValue)
-
-
-private open class ExternalState<T>(
-    val scope: CoroutineScope,
-    override val converter: MetaConverter<T>,
-    val readInterval: Duration,
-    initialValue: T,
-    val reader: suspend () -> T,
-) : DeviceState<T> {
-
-    protected val flow: StateFlow<T> = flow {
-        while (true) {
-            delay(readInterval)
-            emit(reader())
-        }
-    }.stateIn(scope, SharingStarted.Eagerly, initialValue)
-
-    override val value: T get() = flow.value
-    override val valueFlow: Flow<T> get() = flow
 }
 
 /**
- * Create a [DeviceState] which is constructed by periodically reading external value
+ * Combine two device states into one read-only [DeviceState]. Only the latest value of each state is used.
  */
-public fun <T> DeviceState.Companion.external(
+public fun <T1, T2, R> combine(
-    scope: CoroutineScope,
+    state1: DeviceState<T1>,
-    converter: MetaConverter<T>,
+    state2: DeviceState<T2>,
-    readInterval: Duration,
+    converter: MetaConverter<R>,
-    initialValue: T,
+    mapper: (T1, T2) -> R,
-    reader: suspend () -> T,
+): DeviceStateWithDependencies<R> = object : DeviceStateWithDependencies<R> {
-): DeviceState<T> = ExternalState(scope, converter, readInterval, initialValue, reader)
+    override val dependencies = listOf(state1, state2)
 
-private class MutableExternalState<T>(
+    override val converter: MetaConverter<R> = converter
-    scope: CoroutineScope,
+
-    converter: MetaConverter<T>,
+    override val value: R get() = mapper(state1.value, state2.value)
-    readInterval: Duration,
+
-    initialValue: T,
+    override val valueFlow: Flow<R> = kotlinx.coroutines.flow.combine(state1.valueFlow, state2.valueFlow, mapper)
-    reader: suspend () -> T,
+
-    val writer: suspend (T) -> Unit,
+    override fun toString(): String = "DeviceState.combine(state1=$state1, state2=$state2)"
-) : ExternalState<T>(scope, converter, readInterval, initialValue, reader), MutableDeviceState<T> {
-    override var value: T
-        get() = super.value
-        set(value) {
-            scope.launch {
-                writer(value)
-            }
-        }
 }
-
-/**
- * Create a [DeviceState] that regularly reads and caches an external value
- */
-public fun <T> DeviceState.Companion.external(
-    scope: CoroutineScope,
-    converter: MetaConverter<T>,
-    readInterval: Duration,
-    initialValue: T,
-    reader: suspend () -> T,
-    writer: suspend (T) -> Unit,
-): MutableDeviceState<T> = MutableExternalState(scope, converter, readInterval, initialValue, reader, writer)

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/TimerState.kt

@@ -0,0 +1,41 @@
+package space.kscience.controls.constructor
+
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
+import kotlinx.datetime.Instant
+import space.kscience.controls.manager.ClockManager
+import space.kscience.controls.spec.instant
+import space.kscience.dataforge.meta.MetaConverter
+import kotlin.time.Duration
+
+/**
+ * A dedicated [DeviceState] that operates with time.
+ * The state changes with [tick] interval and always shows the time of the last update.
+ *
+ * Both [tick] and current time are computed by [clockManager] enabling time manipulation.
+ *
+ * The timer runs indefinitely until the parent context is closed
+ */
+public class TimerState(
+    public val clockManager: ClockManager,
+    public val tick: Duration,
+) : DeviceState<Instant> {
+    override val converter: MetaConverter<Instant> get() = MetaConverter.instant
+
+    private val clock = MutableStateFlow(clockManager.clock.now())
+
+    private val updateJob = clockManager.context.launch {
+        while (isActive) {
+            clockManager.delay(tick)
+            clock.value = clockManager.clock.now()
+        }
+    }
+
+    override val valueFlow: Flow<Instant> get() = clock
+
+    override val value: Instant get() = clock.value
+
+    override fun toString(): String = "TimerState(tick=$tick)"
+}

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/boundState.kt

@@ -0,0 +1,103 @@
+package space.kscience.controls.constructor
+
+import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.launch
+import space.kscience.controls.api.Device
+import space.kscience.controls.api.PropertyChangedMessage
+import space.kscience.controls.api.id
+import space.kscience.controls.spec.DevicePropertySpec
+import space.kscience.controls.spec.MutableDevicePropertySpec
+import space.kscience.controls.spec.name
+import space.kscience.dataforge.meta.MetaConverter
+
+
+/**
+ * A copy-free [DeviceState] bound to a device property
+ */
+private open class BoundDeviceState<T>(
+    override val converter: MetaConverter<T>,
+    val device: Device,
+    val propertyName: String,
+    initialValue: T,
+) : DeviceState<T> {
+
+    override val valueFlow: StateFlow<T> = device.messageFlow.filterIsInstance<PropertyChangedMessage>().filter {
+        it.property == propertyName
+    }.mapNotNull {
+        converter.read(it.value)
+    }.stateIn(device.context, SharingStarted.Eagerly, initialValue)
+
+    override val value: T get() = valueFlow.value
+    override fun toString(): String =
+        "BoundDeviceState(converter=$converter, device=${device.id}, propertyName='$propertyName')"
+
+
+}
+
+public fun <T> Device.propertyAsState(
+    propertyName: String,
+    metaConverter: MetaConverter<T>,
+    initialValue: T,
+): DeviceState<T> = BoundDeviceState(metaConverter, this, propertyName, initialValue)
+
+/**
+ * Bind a read-only [DeviceState] to a [Device] property
+ */
+public suspend fun <T> Device.propertyAsState(
+    propertyName: String,
+    metaConverter: MetaConverter<T>,
+): DeviceState<T> = propertyAsState(
+    propertyName,
+    metaConverter,
+    metaConverter.readOrNull(readProperty(propertyName)) ?: error("Conversion of property failed")
+)
+
+public suspend fun <D : Device, T> D.propertyAsState(
+    propertySpec: DevicePropertySpec<D, T>,
+): DeviceState<T> = propertyAsState(propertySpec.name, propertySpec.converter)
+
+public fun <D : Device, T> D.propertyAsState(
+    propertySpec: DevicePropertySpec<D, T>,
+    initialValue: T,
+): DeviceState<T> = propertyAsState(propertySpec.name, propertySpec.converter, initialValue)
+
+
+private class MutableBoundDeviceState<T>(
+    converter: MetaConverter<T>,
+    device: Device,
+    propertyName: String,
+    initialValue: T,
+) : BoundDeviceState<T>(converter, device, propertyName, initialValue), MutableDeviceState<T> {
+
+    override var value: T
+        get() = valueFlow.value
+        set(newValue) {
+            device.launch {
+                device.writeProperty(propertyName, converter.convert(newValue))
+            }
+        }
+}
+
+public fun <T> Device.mutablePropertyAsState(
+    propertyName: String,
+    metaConverter: MetaConverter<T>,
+    initialValue: T,
+): MutableDeviceState<T> = MutableBoundDeviceState(metaConverter, this, propertyName, initialValue)
+
+public suspend fun <T> Device.mutablePropertyAsState(
+    propertyName: String,
+    metaConverter: MetaConverter<T>,
+): MutableDeviceState<T> {
+    val initialValue = metaConverter.readOrNull(readProperty(propertyName)) ?: error("Conversion of property failed")
+    return mutablePropertyAsState(propertyName, metaConverter, initialValue)
+}
+
+public suspend fun <D : Device, T> D.mutablePropertyAsState(
+    propertySpec: MutableDevicePropertySpec<D, T>,
+): MutableDeviceState<T> = mutablePropertyAsState(propertySpec.name, propertySpec.converter)
+
+public fun <D : Device, T> D.mutablePropertyAsState(
+    propertySpec: MutableDevicePropertySpec<D, T>,
+    initialValue: T,
+): MutableDeviceState<T> = mutablePropertyAsState(propertySpec.name, propertySpec.converter, initialValue)
+

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/customState.kt

@@ -38,6 +38,10 @@ public class DoubleRangeState(
      * A state showing that the range is on its higher boundary
      */
     public val atEndState: DeviceState<Boolean> = map(MetaConverter.boolean) { it >= range.endInclusive }
+
+    override fun toString(): String = "DoubleRangeState(range=$range, converter=$converter)"
+
+
 }
 
 @Suppress("UnusedReceiverParameter")

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/externalState.kt

@@ -0,0 +1,70 @@
+package space.kscience.controls.constructor
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.launch
+import space.kscience.dataforge.meta.MetaConverter
+import kotlin.time.Duration
+
+
+private open class ExternalState<T>(
+    val scope: CoroutineScope,
+    override val converter: MetaConverter<T>,
+    val readInterval: Duration,
+    initialValue: T,
+    val reader: suspend () -> T,
+) : DeviceState<T> {
+
+    protected val flow: StateFlow<T> = flow {
+        while (true) {
+            delay(readInterval)
+            emit(reader())
+        }
+    }.stateIn(scope, SharingStarted.Eagerly, initialValue)
+
+    override val value: T get() = flow.value
+    override val valueFlow: Flow<T> get() = flow
+
+    override fun toString(): String  = "ExternalState(converter=$converter)"
+}
+
+/**
+ * Create a [DeviceState] which is constructed by regularly reading external value
+ */
+public fun <T> DeviceState.Companion.external(
+    scope: CoroutineScope,
+    converter: MetaConverter<T>,
+    readInterval: Duration,
+    initialValue: T,
+    reader: suspend () -> T,
+): DeviceState<T> = ExternalState(scope, converter, readInterval, initialValue, reader)
+
+private class MutableExternalState<T>(
+    scope: CoroutineScope,
+    converter: MetaConverter<T>,
+    readInterval: Duration,
+    initialValue: T,
+    reader: suspend () -> T,
+    val writer: suspend (T) -> Unit,
+) : ExternalState<T>(scope, converter, readInterval, initialValue, reader), MutableDeviceState<T> {
+    override var value: T
+        get() = super.value
+        set(value) {
+            scope.launch {
+                writer(value)
+            }
+        }
+}
+
+/**
+ * Create a [MutableDeviceState] which is constructed by regularly reading external value and allows writing
+ */
+public fun <T> DeviceState.Companion.external(
+    scope: CoroutineScope,
+    converter: MetaConverter<T>,
+    readInterval: Duration,
+    initialValue: T,
+    reader: suspend () -> T,
+    writer: suspend (T) -> Unit,
+): MutableDeviceState<T> = MutableExternalState(scope, converter, readInterval, initialValue, reader, writer)

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/flowState.kt

@@ -0,0 +1,23 @@
+package space.kscience.controls.constructor
+
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import space.kscience.dataforge.meta.MetaConverter
+
+
+private class StateFlowAsState<T>(
+    override val converter: MetaConverter<T>,
+    val flow: MutableStateFlow<T>,
+) : MutableDeviceState<T> {
+    override var value: T by flow::value
+    override val valueFlow: Flow<T> get() = flow
+
+    override fun toString(): String = "FlowAsState(converter=$converter)"
+}
+
+/**
+ * Create a read-only [DeviceState] that wraps [MutableStateFlow].
+ * No data copy is performed.
+ */
+public fun <T> MutableStateFlow<T>.asDeviceState(converter: MetaConverter<T>): DeviceState<T> =
+    StateFlowAsState(converter, this)

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/internalState.kt

@@ -0,0 +1,42 @@
+package space.kscience.controls.constructor
+
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import space.kscience.dataforge.meta.MetaConverter
+
+/**
+ * A [MutableDeviceState] that does not correspond to a physical state
+ *
+ * @param callback a synchronous callback that could be used without a scope
+ */
+private class VirtualDeviceState<T>(
+    override val converter: MetaConverter<T>,
+    initialValue: T,
+    private val callback: (T) -> Unit = {},
+) : MutableDeviceState<T> {
+    private val flow = MutableStateFlow(initialValue)
+    override val valueFlow: Flow<T> get() = flow
+
+    override var value: T
+        get() = flow.value
+        set(value) {
+            flow.value = value
+            callback(value)
+        }
+
+    override fun toString(): String = "VirtualDeviceState(converter=$converter)"
+
+
+}
+
+
+/**
+ * A [MutableDeviceState] that does not correspond to a physical state
+ *
+ * @param callback a synchronous callback that could be used without a scope
+ */
+public fun <T> DeviceState.Companion.internal(
+    converter: MetaConverter<T>,
+    initialValue: T,
+    callback: (T) -> Unit = {},
+): MutableDeviceState<T> = VirtualDeviceState(converter, initialValue, callback)

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/library/Drive.kt

@@ -1,10 +1,12 @@
-package space.kscience.controls.constructor
+package space.kscience.controls.constructor.library
 
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
 import space.kscience.controls.api.Device
+import space.kscience.controls.constructor.MutableDeviceState
+import space.kscience.controls.constructor.mutablePropertyAsState
 import space.kscience.controls.manager.clock
 import space.kscience.controls.spec.*
 import space.kscience.dataforge.context.Context
@@ -49,7 +51,7 @@ public class VirtualDrive(
     public val positionState: MutableDeviceState<Double>,
 ) : Drive, DeviceBySpec<Drive>(Drive, context) {
 
-    private val dt = meta["time.step"].double?.milliseconds ?: 1.milliseconds
+    private val dt = meta["time.step"].double?.milliseconds ?: 5.milliseconds
     private val clock = context.clock
 
     override var force: Double = 0.0
@@ -82,7 +84,7 @@ public class VirtualDrive(
         }
     }
 
-    override fun onStop() {
+    override suspend fun onStop() {
         updateJob?.cancel()
     }
 

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/library/LimitSwitch.kt

@@ -1,8 +1,9 @@
-package space.kscience.controls.constructor
+package space.kscience.controls.constructor.library
 
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 import space.kscience.controls.api.Device
+import space.kscience.controls.constructor.DeviceState
 import space.kscience.controls.spec.DeviceBySpec
 import space.kscience.controls.spec.DevicePropertySpec
 import space.kscience.controls.spec.DeviceSpec
@@ -20,7 +21,7 @@ public interface LimitSwitch : Device {
 
     public companion object : DeviceSpec<LimitSwitch>() {
         public val locked: DevicePropertySpec<LimitSwitch, Boolean> by booleanProperty { locked }
-        public fun factory(lockedState: DeviceState<Boolean>): Factory<LimitSwitch> = Factory { context, _ ->
+        public operator fun invoke(lockedState: DeviceState<Boolean>): Factory<LimitSwitch> = Factory { context, _ ->
             VirtualLimitSwitch(context, lockedState)
         }
     }

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/library/PidRegulator.kt

@@ -1,4 +1,4 @@
-package space.kscience.controls.constructor
+package space.kscience.controls.constructor.library
 
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
@@ -7,8 +7,11 @@ import kotlinx.coroutines.launch
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
 import kotlinx.datetime.Instant
+import space.kscience.controls.constructor.DeviceGroup
+import space.kscience.controls.constructor.install
 import space.kscience.controls.manager.clock
 import space.kscience.controls.spec.DeviceBySpec
+import space.kscience.controls.spec.write
 import kotlin.time.Duration
 import kotlin.time.Duration.Companion.milliseconds
 import kotlin.time.DurationUnit
@@ -71,15 +74,17 @@ public class PidRegulator(
                     lastTime = realTime
                     lastPosition = drive.position
 
-                    drive.force = pidParameters.kp * delta + pidParameters.ki * integral + pidParameters.kd * derivative
+                    drive.write(Drive.force,pidParameters.kp * delta + pidParameters.ki * integral + pidParameters.kd * derivative)
+                    //drive.force = pidParameters.kp * delta + pidParameters.ki * integral + pidParameters.kd * derivative
                     propertyChanged(Regulator.position, drive.position)
                 }
             }
         }
     }
 
-    override fun onStop() {
+    override suspend fun onStop() {
         updateJob?.cancel()
+        drive.stop()
     }
 
     override val position: Double get() = drive.position

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/library/Regulator.kt

@@ -1,4 +1,4 @@
-package space.kscience.controls.constructor
+package space.kscience.controls.constructor.library
 
 import space.kscience.controls.api.Device
 import space.kscience.controls.spec.*

controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/DeviceGroupTest.kt

@@ -0,0 +1,43 @@
+package space.kscience.controls.constructor
+
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.test.runTest
+import space.kscience.controls.api.Device
+import space.kscience.controls.api.DeviceLifeCycleMessage
+import space.kscience.controls.api.DeviceLifecycleState
+import space.kscience.controls.manager.DeviceManager
+import space.kscience.controls.manager.install
+import space.kscience.controls.spec.doRecurring
+import space.kscience.dataforge.context.Context
+import space.kscience.dataforge.context.Factory
+import space.kscience.dataforge.context.Global
+import space.kscience.dataforge.context.request
+import space.kscience.dataforge.meta.Meta
+import kotlin.test.Test
+import kotlin.time.Duration.Companion.milliseconds
+
+class DeviceGroupTest {
+
+    class TestDevice(context: Context) : DeviceConstructor(context) {
+
+        companion object : Factory<Device> {
+            override fun build(context: Context, meta: Meta): Device = TestDevice(context)
+        }
+    }
+
+    @Test
+    fun testRecurringRead() = runTest {
+        var counter = 10
+        val testDevice = Global.request(DeviceManager).install("test", TestDevice)
+        testDevice.doRecurring(1.milliseconds) {
+            counter--
+            println(counter)
+            if (counter <= 0) {
+                testDevice.stop()
+            }
+            error("Error!")
+        }
+        testDevice.messageFlow.first { it is DeviceLifeCycleMessage && it.state == DeviceLifecycleState.STOPPED }
+        println("stopped")
+    }
+}

controls-constructor/src/commonTest/kotlin/space/kscience/controls/constructor/TimerTest.kt

@@ -0,0 +1,22 @@
+package space.kscience.controls.constructor
+
+import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.flow.take
+import kotlinx.coroutines.test.runTest
+import space.kscience.controls.manager.ClockManager
+import space.kscience.dataforge.context.Global
+import space.kscience.dataforge.context.request
+import kotlin.test.Test
+import kotlin.time.Duration.Companion.milliseconds
+
+class TimerTest {
+
+    @Test
+    fun timer() = runTest {
+        val timer = TimerState(Global.request(ClockManager), 10.milliseconds)
+        timer.valueFlow.take(10).onEach {
+            println(it)
+        }.collect()
+    }
+}

controls-core/src/commonMain/kotlin/space/kscience/controls/api/Device.kt

@@ -12,7 +12,6 @@ import space.kscience.dataforge.context.logger
 import space.kscience.dataforge.meta.Meta
 import space.kscience.dataforge.meta.get
 import space.kscience.dataforge.meta.string
-import space.kscience.dataforge.misc.DFExperimental
 import space.kscience.dataforge.misc.DfType
 import space.kscience.dataforge.names.parseAsName
 
@@ -100,12 +99,11 @@ public interface Device : ContextAware, CoroutineScope {
     /**
      * Close and terminate the device. This function does not wait for the device to be closed.
      */
-    public fun stop() {
+    public suspend fun stop() {
         logger.info { "Device $this is closed" }
         cancel("The device is closed")
     }
 
-    @DFExperimental
     public val lifecycleState: DeviceLifecycleState
 
     public companion object {

controls-core/src/commonMain/kotlin/space/kscience/controls/api/descriptors.kt

@@ -15,18 +15,23 @@ public class PropertyDescriptor(
     public var description: String? = null,
     public var metaDescriptor: MetaDescriptor = MetaDescriptor(),
     public var readable: Boolean = true,
-    public var mutable: Boolean = false
+    public var mutable: Boolean = false,
 )
 
-public fun PropertyDescriptor.metaDescriptor(block: MetaDescriptorBuilder.()->Unit){
+public fun PropertyDescriptor.metaDescriptor(block: MetaDescriptorBuilder.() -> Unit) {
-    metaDescriptor = MetaDescriptor(block)
+    metaDescriptor = MetaDescriptor {
+        from(metaDescriptor)
+        block()
+    }
 }
 
 /**
  * A descriptor for property
  */
 @Serializable
-public class ActionDescriptor(public val name: String) {
+public class ActionDescriptor(
-    public var description: String? = null
+    public val name: String,
-}
+    public var description: String? = null,
-
+    public var inputMetaDescriptor: MetaDescriptor = MetaDescriptor(),
+    public var outputMetaDescriptor: MetaDescriptor = MetaDescriptor()
+)

controls-core/src/commonMain/kotlin/space/kscience/controls/manager/ClockManager.kt

@@ -6,15 +6,21 @@ import space.kscience.dataforge.context.Context
 import space.kscience.dataforge.context.PluginFactory
 import space.kscience.dataforge.context.PluginTag
 import space.kscience.dataforge.meta.Meta
+import kotlin.time.Duration
 
 public class ClockManager : AbstractPlugin() {
-    override val tag: PluginTag get() = DeviceManager.tag
+    override val tag: PluginTag get() = Companion.tag
 
     public val clock: Clock by lazy {
         //TODO add clock customization
         Clock.System
     }
 
+    public suspend fun delay(duration: Duration) {
+        //TODO add time compression
+        kotlinx.coroutines.delay(duration)
+    }
+
     public companion object : PluginFactory<ClockManager> {
         override val tag: PluginTag = PluginTag("clock", group = PluginTag.DATAFORGE_GROUP)
 

controls-core/src/commonMain/kotlin/space/kscience/controls/manager/DeviceManager.kt

@@ -49,6 +49,10 @@ public fun <D : Device> DeviceManager.install(name: String, device: D): D {
 public fun <D : Device> DeviceManager.install(device: D): D = install(device.id, device)
 
 
+public fun <D : Device> Context.install(name: String, device: D): D = request(DeviceManager).install(name, device)
+
+public fun <D : Device> Context.install(device: D): D = request(DeviceManager).install(device.id, device)
+
 /**
  * Register and start a device built by [factory] with current [Context] and [meta].
  */
@@ -76,4 +80,3 @@ public inline fun <D : Device> DeviceManager.installing(
         }
     }
 }
-

controls-core/src/commonMain/kotlin/space/kscience/controls/spec/DeviceBase.kt

@@ -9,11 +9,11 @@ import kotlinx.coroutines.sync.withLock
 import space.kscience.controls.api.*
 import space.kscience.dataforge.context.Context
 import space.kscience.dataforge.context.debug
+import space.kscience.dataforge.context.error
 import space.kscience.dataforge.context.logger
 import space.kscience.dataforge.meta.Meta
 import space.kscience.dataforge.meta.get
 import space.kscience.dataforge.meta.int
-import space.kscience.dataforge.misc.DFExperimental
 import kotlin.coroutines.CoroutineContext
 
 /**
@@ -72,10 +72,10 @@ public abstract class DeviceBase<D : Device>(
         onBufferOverflow = BufferOverflow.DROP_OLDEST
     )
 
-    @OptIn(kotlinx.coroutines.ExperimentalCoroutinesApi::class)
+    @OptIn(ExperimentalCoroutinesApi::class)
     override val coroutineContext: CoroutineContext = context.newCoroutineContext(
         SupervisorJob(context.coroutineContext[Job]) +
-                CoroutineName("Device $this") +
+                CoroutineName("Device $id") +
                 CoroutineExceptionHandler { _, throwable ->
                     launch {
                         sharedMessageFlow.emit(
@@ -86,6 +86,7 @@ public abstract class DeviceBase<D : Device>(
                             )
                         )
                     }
+                    logger.error(throwable) { "Exception in device $id" }
                 }
     )
 
@@ -187,43 +188,39 @@ public abstract class DeviceBase<D : Device>(
         return spec.executeWithMeta(self, argument ?: Meta.EMPTY)
     }
 
-    @DFExperimental
     final override var lifecycleState: DeviceLifecycleState = DeviceLifecycleState.STOPPED
-        private set(value) {
+        private set
-            if (field != value) {
+
-                launch {
+
-                    sharedMessageFlow.emit(
+    private suspend fun setLifecycleState(lifecycleState: DeviceLifecycleState) {
-                        DeviceLifeCycleMessage(value)
+        this.lifecycleState = lifecycleState
-                    )
+        sharedMessageFlow.emit(
-                }
+            DeviceLifeCycleMessage(lifecycleState)
-            }
+        )
-            field = value
+    }
-        }
 
     protected open suspend fun onStart() {
 
     }
 
-    @OptIn(DFExperimental::class)
     final override suspend fun start() {
         if (lifecycleState == DeviceLifecycleState.STOPPED) {
             super.start()
-            lifecycleState = DeviceLifecycleState.STARTING
+            setLifecycleState(DeviceLifecycleState.STARTING)
             onStart()
-            lifecycleState = DeviceLifecycleState.STARTED
+            setLifecycleState(DeviceLifecycleState.STARTED)
         } else {
             logger.debug { "Device $this is already started" }
         }
     }
 
-    protected open fun onStop() {
+    protected open suspend fun onStop() {
 
     }
 
-    @OptIn(DFExperimental::class)
+    final override suspend fun stop() {
-    final override fun stop() {
         onStop()
-        lifecycleState = DeviceLifecycleState.STOPPED
+        setLifecycleState(DeviceLifecycleState.STOPPED)
         super.stop()
     }
 

controls-core/src/commonMain/kotlin/space/kscience/controls/spec/DeviceBySpec.kt

@@ -20,7 +20,7 @@ public open class DeviceBySpec<D : Device>(
         self.onOpen()
     }
 
-    override fun onStop(): Unit = with(spec){
+    override suspend fun onStop(): Unit = with(spec){
         self.onClose()
     }
 

controls-core/src/commonMain/kotlin/space/kscience/controls/spec/DeviceSpec.kt

@@ -4,8 +4,10 @@ import kotlinx.coroutines.withContext
 import space.kscience.controls.api.ActionDescriptor
 import space.kscience.controls.api.Device
 import space.kscience.controls.api.PropertyDescriptor
+import space.kscience.controls.api.metaDescriptor
 import space.kscience.dataforge.meta.Meta
 import space.kscience.dataforge.meta.MetaConverter
+import space.kscience.dataforge.meta.descriptors.MetaDescriptor
 import kotlin.properties.PropertyDelegateProvider
 import kotlin.properties.ReadOnlyProperty
 import kotlin.reflect.KProperty
@@ -54,6 +56,11 @@ public abstract class DeviceSpec<D : Device> {
             val deviceProperty = object : DevicePropertySpec<D, T> {
 
                 override val descriptor: PropertyDescriptor = PropertyDescriptor(propertyName).apply {
+                    converter.descriptor?.let { converterDescriptor ->
+                        metaDescriptor {
+                            from(converterDescriptor)
+                        }
+                    }
                     fromSpec(property)
                     descriptorBuilder()
                 }
@@ -83,6 +90,11 @@ public abstract class DeviceSpec<D : Device> {
                     propertyName,
                     mutable = true
                 ).apply {
+                    converter.descriptor?.let { converterDescriptor ->
+                        metaDescriptor {
+                            from(converterDescriptor)
+                        }
+                    }
                     fromSpec(property)
                     descriptorBuilder()
                 }
@@ -118,6 +130,19 @@ public abstract class DeviceSpec<D : Device> {
             val actionName = name ?: property.name
             val deviceAction = object : DeviceActionSpec<D, I, O> {
                 override val descriptor: ActionDescriptor = ActionDescriptor(actionName).apply {
+                    inputConverter.descriptor?.let { converterDescriptor ->
+                        inputMetaDescriptor = MetaDescriptor {
+                            from(converterDescriptor)
+                            from(inputMetaDescriptor)
+                        }
+                    }
+                    outputConverter.descriptor?.let { converterDescriptor ->
+                        outputMetaDescriptor = MetaDescriptor {
+                            from(converterDescriptor)
+                            from(outputMetaDescriptor)
+                        }
+                    }
+
                     fromSpec(property)
                     descriptorBuilder()
                 }

controls-core/src/commonMain/kotlin/space/kscience/controls/spec/converters.kt

@@ -0,0 +1,41 @@
+package space.kscience.controls.spec
+
+import kotlinx.datetime.Instant
+import space.kscience.dataforge.meta.*
+import kotlin.time.Duration
+import kotlin.time.DurationUnit
+import kotlin.time.toDuration
+
+public fun Double.asMeta(): Meta = Meta(asValue())
+
+/**
+ * Generate a nullable [MetaConverter] from non-nullable one
+ */
+public fun <T : Any> MetaConverter<T>.nullable(): MetaConverter<T?> = object : MetaConverter<T?> {
+    override fun convert(obj: T?): Meta  = obj?.let { this@nullable.convert(it) }?: Meta(Null)
+
+    override fun readOrNull(source: Meta): T? = if(source.value == Null) null else this@nullable.readOrNull(source)
+
+}
+
+//TODO to be moved to DF
+private object DurationConverter : MetaConverter<Duration> {
+    override fun readOrNull(source: Meta): Duration = source.value?.double?.toDuration(DurationUnit.SECONDS)
+        ?: run {
+            val unit: DurationUnit = source["unit"].enum<DurationUnit>() ?: DurationUnit.SECONDS
+            val value = source[Meta.VALUE_KEY].double ?: error("No value present for Duration")
+            return@run value.toDuration(unit)
+        }
+
+    override fun convert(obj: Duration): Meta = obj.toDouble(DurationUnit.SECONDS).asMeta()
+}
+
+public val MetaConverter.Companion.duration: MetaConverter<Duration> get() = DurationConverter
+
+
+private object InstantConverter : MetaConverter<Instant> {
+    override fun readOrNull(source: Meta): Instant? = source.string?.let { Instant.parse(it) }
+    override fun convert(obj: Instant): Meta = Meta(obj.toString())
+}
+
+public val MetaConverter.Companion.instant: MetaConverter<Instant> get() = InstantConverter

controls-core/src/commonMain/kotlin/space/kscience/controls/spec/deviceExtensions.kt

@@ -1,14 +1,31 @@
 package space.kscience.controls.spec
 
-import kotlinx.coroutines.Job
+import kotlinx.coroutines.*
-import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flow
-import kotlinx.coroutines.isActive
-import kotlinx.coroutines.launch
 import space.kscience.controls.api.Device
 import kotlin.time.Duration
 
+/**
+ * Do a recurring (with a fixed delay) task on a device.
+ */
+public fun <D : Device> D.doRecurring(
+    interval: Duration,
+    debugTaskName: String? = null,
+    task: suspend D.() -> Unit,
+): Job {
+    val taskName = debugTaskName ?: "task[${task.hashCode().toString(16)}]"
+    return launch(CoroutineName(taskName)) {
+        while (isActive) {
+            delay(interval)
+            //launch in parent scope to properly evaluate exceptions
+            this@doRecurring.launch {
+                task()
+            }
+        }
+    }
+}
+
 /**
  * Perform a recurring asynchronous read action and return a flow of results.
  * The flow is lazy, so action is not performed unless flow is consumed.
@@ -16,23 +33,12 @@ import kotlin.time.Duration
  *
  * The flow is canceled when the device scope is canceled
  */
-public fun <D : Device, R> D.readRecurring(interval: Duration, reader: suspend D.() -> R): Flow<R> = flow {
+public fun <D : Device, R> D.readRecurring(
-    while (isActive) {
+    interval: Duration,
-        delay(interval)
+    debugTaskName: String? = null,
-        launch {
+    reader: suspend D.() -> R,
-            emit(reader())
+): Flow<R> = flow {
-        }
+    doRecurring(interval, debugTaskName) {
-    }
+        emit(reader())
-}
-
-/**
- * Do a recurring (with a fixed delay) task on a device.
- */
-public fun <D : Device> D.doRecurring(interval: Duration, task: suspend D.() -> Unit): Job = launch {
-    while (isActive) {
-        delay(interval)
-        launch {
-            task()
-        }
     }
 }

controls-core/src/commonMain/kotlin/space/kscience/controls/spec/fromSpec.kt

@@ -4,8 +4,6 @@ import space.kscience.controls.api.ActionDescriptor
 import space.kscience.controls.api.PropertyDescriptor
 import kotlin.reflect.KProperty
 
-@Target(AnnotationTarget.CLASS, AnnotationTarget.PROPERTY, AnnotationTarget.FIELD)
-public annotation class Description(val content: String)
 
 internal expect fun PropertyDescriptor.fromSpec(property: KProperty<*>)
 

controls-core/src/commonMain/kotlin/space/kscience/controls/spec/misc.kt

@@ -1,22 +0,0 @@
-package space.kscience.controls.spec
-
-import space.kscience.dataforge.meta.*
-import kotlin.time.Duration
-import kotlin.time.DurationUnit
-import kotlin.time.toDuration
-
-public fun Double.asMeta(): Meta = Meta(asValue())
-
-//TODO to be moved to DF
-public object DurationConverter : MetaConverter<Duration> {
-    override fun readOrNull(source: Meta): Duration = source.value?.double?.toDuration(DurationUnit.SECONDS)
-        ?: run {
-            val unit: DurationUnit = source["unit"].enum<DurationUnit>() ?: DurationUnit.SECONDS
-            val value = source[Meta.VALUE_KEY].double ?: error("No value present for Duration")
-            return@run value.toDuration(unit)
-        }
-
-    override fun convert(obj: Duration): Meta = obj.toDouble(DurationUnit.SECONDS).asMeta()
-}
-
-public val MetaConverter.Companion.duration: MetaConverter<Duration> get() = DurationConverter

controls-core/src/jvmMain/kotlin/space/kscience/controls/spec/fromSpec.jvm.kt

@@ -2,17 +2,18 @@ package space.kscience.controls.spec
 
 import space.kscience.controls.api.ActionDescriptor
 import space.kscience.controls.api.PropertyDescriptor
+import space.kscience.dataforge.descriptors.Description
 import kotlin.reflect.KProperty
 import kotlin.reflect.full.findAnnotation
 
 internal actual fun PropertyDescriptor.fromSpec(property: KProperty<*>) {
     property.findAnnotation<Description>()?.let {
-        description = it.content
+        description = it.value
     }
 }
 
 internal actual fun ActionDescriptor.fromSpec(property: KProperty<*>){
     property.findAnnotation<Description>()?.let {
-        description = it.content
+        description = it.value
     }
 }

controls-modbus/build.gradle.kts

@@ -1,7 +1,7 @@
 import space.kscience.gradle.Maturity
 
 plugins {
-    id("space.kscience.gradle.jvm")
+    id("space.kscience.gradle.mpp")
     `maven-publish`
 }
 
@@ -9,10 +9,12 @@ description = """
     A plugin for Controls-kt device server on top of modbus-rtu/modbus-tcp protocols
 """.trimIndent()
 
-
+kscience {
-dependencies {
+    jvm()
-    api(projects.controlsCore)
+    jvmMain {
-    api(libs.j2mod)
+        api(projects.controlsCore)
+        api(libs.j2mod)
+    }
 }
 
 readme{

controls-modbus/src/jvmMain/kotlin/space/kscience/controls/modbus/ModbusDeviceBySpec.kt

@@ -24,7 +24,7 @@ public open class ModbusDeviceBySpec<D: Device>(
         master.connect()
     }
 
-    override fun onStop() {
+    override suspend fun onStop() {
         if(disposeMasterOnClose){
             master.disconnect()
         }

controls-opcua/src/main/kotlin/space/kscience/controls/opcua/client/OpcUaDeviceBySpec.kt

@@ -63,7 +63,7 @@ public open class OpcUaDeviceBySpec<D : Device>(
         }
     }
 
-    override fun onStop() {
+    override suspend fun onStop() {
         client.disconnect()
     }
 }

controls-pi/build.gradle.kts

@@ -1,5 +1,5 @@
 plugins {
-    id("space.kscience.gradle.jvm")
+    id("space.kscience.gradle.mpp")
     `maven-publish`
 }
 
@@ -7,10 +7,15 @@ description = """
     Utils to work with controls-kt on Raspberry pi
 """.trimIndent()
 
-dependencies{
+kscience {
-    api(project(":controls-core"))
+    jvm()
-    api(libs.pi4j.ktx) // Kotlin DSL
+
-    api(libs.pi4j.core)
+
-    api(libs.pi4j.plugin.raspberrypi)
+    jvmMain {
-    api(libs.pi4j.plugin.pigpio)
+        api(project(":controls-core"))
+        api(libs.pi4j.ktx) // Kotlin DSL
+        api(libs.pi4j.core)
+        api(libs.pi4j.plugin.raspberrypi)
+        api(libs.pi4j.plugin.pigpio)
+    }
 }

controls-ports-ktor/build.gradle.kts

@@ -1,7 +1,7 @@
 import space.kscience.gradle.Maturity
 
 plugins {
-    id("space.kscience.gradle.jvm")
+    id("space.kscience.gradle.mpp")
     `maven-publish`
 }
 
@@ -9,9 +9,12 @@ description = """
     Implementation of byte ports on top os ktor-io asynchronous API
 """.trimIndent()
 
-dependencies {
+kscience {
-    api(projects.controlsCore)
+    jvm()
-    api(spclibs.ktor.network)
+    jvmMain {
+        api(projects.controlsCore)
+        api(spclibs.ktor.network)
+    }
 }
 
 readme{

controls-serial/build.gradle.kts

@@ -1,15 +1,18 @@
 import space.kscience.gradle.Maturity
 
 plugins {
-    id("space.kscience.gradle.jvm")
+    id("space.kscience.gradle.mpp")
     `maven-publish`
 }
 
 description = "Implementation of direct serial port communication with JSerialComm"
 
-dependencies{
+kscience {
-    api(project(":controls-core"))
+    jvm()
-    implementation(libs.jSerialComm)
+    jvmMain {
+        api(project(":controls-core"))
+        implementation(libs.jSerialComm)
+    }
 }
 
 readme{

controls-storage/controls-xodus/build.gradle.kts

@@ -1,5 +1,5 @@
 plugins {
-    id("space.kscience.gradle.jvm")
+    id("space.kscience.gradle.mpp")
     `maven-publish`
 }
 
@@ -7,13 +7,18 @@ description = """
     An implementation of controls-storage on top of JetBrains Xodus.
 """.trimIndent()
 
-dependencies {
+kscience {
-    api(projects.controlsStorage)
+    jvm()
-    implementation(libs.xodus.entity.store)
+    jvmMain {
+        api(projects.controlsStorage)
+        implementation(libs.xodus.entity.store)
 //    implementation("org.jetbrains.xodus:xodus-environment:$xodusVersion")
 //    implementation("org.jetbrains.xodus:xodus-vfs:$xodusVersion")
 
-    testImplementation(spclibs.kotlinx.coroutines.test)
+    }
+    jvmTest{
+        implementation(spclibs.kotlinx.coroutines.test)
+    }
 }
 
 readme{

demo/all-things/src/main/kotlin/space/kscience/controls/demo/DemoControllerView.kt

@@ -8,6 +8,7 @@ import javafx.stage.Stage
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.runBlocking
 import kotlinx.serialization.json.Json
 import org.eclipse.milo.opcua.sdk.server.OpcUaServer
 import org.eclipse.milo.opcua.stack.core.types.builtin.LocalizedText
@@ -91,7 +92,7 @@ class DemoController : Controller(), ContextAware {
         }
     }
 
-    fun shutdown() {
+    suspend fun shutdown() {
         logger.info { "Shutting down..." }
         opcUaServer.shutdown()
         logger.info { "OpcUa server stopped" }
@@ -179,7 +180,9 @@ class DemoControllerApp : App(DemoControllerView::class) {
     }
 
     override fun stop() {
-        controller.shutdown()
+        runBlocking {
+            controller.shutdown()
+        }
         super.stop()
     }
 }

demo/car/src/main/kotlin/space/kscience/controls/demo/car/VirtualCarController.kt

@@ -8,6 +8,7 @@ import javafx.scene.layout.Priority
 import javafx.stage.Stage
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.runBlocking
 import space.kscience.controls.client.launchMagixService
 import space.kscience.controls.demo.car.IVirtualCar.Companion.acceleration
 import space.kscience.controls.manager.DeviceManager
@@ -67,7 +68,7 @@ class VirtualCarController : Controller(), ContextAware {
         }
     }
 
-    fun shutdown() {
+    suspend fun shutdown() {
         logger.info { "Shutting down..." }
         magixServer?.stop(1000, 5000)
         logger.info { "Magix server stopped" }
@@ -137,7 +138,9 @@ class VirtualCarControllerApp : App(VirtualCarControllerView::class) {
     }
 
     override fun stop() {
-        controller.shutdown()
+        runBlocking {
+            controller.shutdown()
+        }
         super.stop()
     }
 }

demo/constructor/src/jvmMain/kotlin/main.kt

@@ -16,9 +16,11 @@ import androidx.compose.ui.window.Window
 import androidx.compose.ui.window.application
 import kotlinx.coroutines.launch
 import space.kscience.controls.constructor.*
+import space.kscience.controls.constructor.library.*
 import space.kscience.controls.manager.ClockManager
 import space.kscience.controls.manager.DeviceManager
 import space.kscience.controls.manager.clock
+import space.kscience.controls.manager.install
 import space.kscience.controls.spec.doRecurring
 import space.kscience.controls.spec.name
 import space.kscience.controls.vision.plot
@@ -48,13 +50,14 @@ class LinearDrive(
     val drive by device(VirtualDrive.factory(mass, state))
     val pid by device(PidRegulator(drive, pidParameters))
 
-    val start by device(LimitSwitch.factory(state.atStartState))
+    val start by device(LimitSwitch(state.atStartState))
-    val end by device(LimitSwitch.factory(state.atEndState))
+    val end by device(LimitSwitch(state.atEndState))
 
 
     val positionState: DoubleRangeState by property(state)
-    private val targetState: MutableDeviceState<Double> by property(pid.mutablePropertyAsState(Regulator.target, 0.0))
+
-    var target by targetState
+    private val targetState: MutableDeviceState<Double> by deviceProperty(pid, Regulator.target, 0.0)
+    var target: Double by targetState
 }
 
 
@@ -73,7 +76,6 @@ private fun Context.launchPidDevice(
             val timeFromStart = clock.now() - clockStart
             val t = timeFromStart.toDouble(DurationUnit.SECONDS)
             val freq = 0.1
-
             target = 5 * sin(2.0 * PI * freq * t) +
                     sin(2 * PI * 21 * freq * t + 0.02 * (timeFromStart / pidParameters.timeStep))
         }
@@ -150,7 +152,7 @@ fun main() = application {
                 Row {
                     Text("kp:", Modifier.align(Alignment.CenterVertically).width(50.dp).padding(5.dp))
                     TextField(
-                        String.format("%.2f",pidParameters.kp),
+                        String.format("%.2f", pidParameters.kp),
                         { pidParameters.kp = it.toDouble() },
                         Modifier.width(100.dp),
                         enabled = false
@@ -165,7 +167,7 @@ fun main() = application {
                 Row {
                     Text("ki:", Modifier.align(Alignment.CenterVertically).width(50.dp).padding(5.dp))
                     TextField(
-                        String.format("%.2f",pidParameters.ki),
+                        String.format("%.2f", pidParameters.ki),
                         { pidParameters.ki = it.toDouble() },
                         Modifier.width(100.dp),
                         enabled = false
@@ -181,7 +183,7 @@ fun main() = application {
                 Row {
                     Text("kd:", Modifier.align(Alignment.CenterVertically).width(50.dp).padding(5.dp))
                     TextField(
-                        String.format("%.2f",pidParameters.kd),
+                        String.format("%.2f", pidParameters.kd),
                         { pidParameters.kd = it.toDouble() },
                         Modifier.width(100.dp),
                         enabled = false

magix/magix-server/build.gradle.kts

@@ -1,36 +1,38 @@
 import space.kscience.gradle.Maturity
 
 plugins {
-    id("space.kscience.gradle.jvm")
+    id("space.kscience.gradle.mpp")
     `maven-publish`
-    application
 }
 
 description = """
     A magix event loop implementation in Kotlin. Includes HTTP/SSE and RSocket routes.
 """.trimIndent()
 
-kscience {
-    useSerialization{
-        json()
-    }
-}
-
 val dataforgeVersion: String by rootProject.extra
 val ktorVersion: String  = space.kscience.gradle.KScienceVersions.ktorVersion
 
-dependencies{
+kscience {
-    api(projects.magix.magixApi)
+    jvm()
-    api("io.ktor:ktor-server-cio:$ktorVersion")
+    useSerialization{
-    api("io.ktor:ktor-server-websockets:$ktorVersion")
+        json()
-    api("io.ktor:ktor-server-content-negotiation:$ktorVersion")
+    }
-    api("io.ktor:ktor-serialization-kotlinx-json:$ktorVersion")
+
-    api("io.ktor:ktor-server-html-builder:$ktorVersion")
+    jvmMain{
+        api(projects.magix.magixApi)
+        api("io.ktor:ktor-server-cio:$ktorVersion")
+        api("io.ktor:ktor-server-websockets:$ktorVersion")
+        api("io.ktor:ktor-server-content-negotiation:$ktorVersion")
+        api("io.ktor:ktor-serialization-kotlinx-json:$ktorVersion")
+        api("io.ktor:ktor-server-html-builder:$ktorVersion")
+
+        api(libs.rsocket.ktor.server)
+        api(libs.rsocket.transport.ktor.tcp)
+    }
 
-    api(libs.rsocket.ktor.server)
-    api(libs.rsocket.transport.ktor.tcp)
 }
 
+
 readme{
     maturity = Maturity.EXPERIMENTAL
 }