Working on tests.

Sources/Bootstrap/Bootstrap.swift

@@ -120,7 +120,7 @@ extension EventLoopFuture where Value == (EnvVars, Topics) {
       map { envVars, topics in
         let nioClient = MQTTClient(envVars: envVars, eventLoopGroup: eventLoopGroup, logger: logger)
         return DewPointEnvironment.init(
-          mqttClient: .live(client: nioClient),
+          mqttClient: .live(client: nioClient, topics: topics),
           envVars: envVars,
           nioClient: nioClient,
           topics: topics
@@ -148,7 +148,7 @@ extension EventLoopFuture where Value == DewPointEnvironment {
   }
 }
 
-extension MQTTClient {
+extension MQTTNIO.MQTTClient {
   
   fileprivate convenience init(envVars: EnvVars, eventLoopGroup: EventLoopGroup, logger: Logger?) {
     self.init(

Sources/Client/Interface.swift

@@ -9,15 +9,18 @@ import Psychrometrics
 ///
 /// This is an abstraction around the ``MQTTNIO.MQTTClient``.
 public struct MQTTClient {
-  
+    
   /// Retrieve the humidity from the MQTT Broker.
   public var fetchHumidity: (Sensor<RelativeHumidity>) -> EventLoopFuture<RelativeHumidity>
   
+  /// Retrieve a set point from the MQTT Broker.
+  public var fetchSetPoint: (KeyPath<Topics.SetPoints, String>) -> EventLoopFuture<Double>
+  
   /// Retrieve the temperature from the MQTT Broker.
   public var fetchTemperature: (Sensor<Temperature>, PsychrometricEnvironment.Units?) -> EventLoopFuture<Temperature>
   
   /// Publish a change of state message for a relay.
-  public var setRelay: (Relay, Relay.State) -> EventLoopFuture<Void>
+  public var setRelay: (KeyPath<Topics.Commands.Relays, String>, Relay.State) -> EventLoopFuture<Void>
   
   /// Disconnect and close the connection to the MQTT Broker.
   public var shutdown: () -> EventLoopFuture<Void>
@@ -27,12 +30,14 @@ public struct MQTTClient {
   
   public init(
     fetchHumidity: @escaping (Sensor<RelativeHumidity>) -> EventLoopFuture<RelativeHumidity>,
+    fetchSetPoint: @escaping (KeyPath<Topics.SetPoints, String>) -> EventLoopFuture<Double>,
     fetchTemperature: @escaping (Sensor<Temperature>, PsychrometricEnvironment.Units?) -> EventLoopFuture<Temperature>,
-    setRelay: @escaping (Relay, Relay.State) -> EventLoopFuture<Void>,
+    setRelay: @escaping (KeyPath<Topics.Commands.Relays, String>, Relay.State) -> EventLoopFuture<Void>,
     shutdown: @escaping () -> EventLoopFuture<Void>,
     publishDewPoint: @escaping (DewPoint, String) -> EventLoopFuture<Void>
   ) {
     self.fetchHumidity = fetchHumidity
+    self.fetchSetPoint = fetchSetPoint
     self.fetchTemperature = fetchTemperature
     self.setRelay = setRelay
     self.shutdown = shutdown
@@ -60,7 +65,7 @@ public struct MQTTClient {
   /// - Parameters:
   ///   - relay: The relay to send the message to.
   ///   - state: The state to change the relay to.
-  public func `set`(relay: Relay, to state: Relay.State) -> EventLoopFuture<Void> {
+  public func `set`(relay: KeyPath<Topics.Commands.Relays, String>, to state: Relay.State) -> EventLoopFuture<Void> {
     setRelay(relay, state)
   }
   

Sources/ClientLive/Helpers.swift

@@ -43,8 +43,55 @@ enum MQTTError: Error {
   case relay(reason: String, error: Error?)
 }
 
+protocol FetchableTopic {
+  associatedtype Value: BufferInitalizable
+  var topic: String { get }
+}
+
+extension Double: BufferInitalizable {
+  
+  init?(buffer: inout ByteBuffer) {
+    guard let string = buffer.readString(length: buffer.readableBytes) else {
+      return nil
+    }
+    self.init(string)
+  }
+}
+
+//extension SetPoint: FetchableTopic {
+//  typealias Value = Double
+//}
+
+extension Sensor: FetchableTopic where Reading: BufferInitalizable {
+  typealias Value = Reading
+}
+
 extension MQTTNIO.MQTTClient {
   
+  func mqttSubscription(topic: String, qos: MQTTQoS = .atLeastOnce, retainAsPublished: Bool = true, retainHandling: MQTTSubscribeInfoV5.RetainHandling = .sendAlways)  -> MQTTSubscribeInfoV5 {
+    .init(topicFilter: topic, qos: qos, retainAsPublished: retainAsPublished, retainHandling: retainHandling)
+  }
+  
+  func fetch<Value>(
+    _ subscription: MQTTSubscribeInfoV5
+  ) -> EventLoopFuture<Value> where Value: BufferInitalizable {
+    logger.debug("Fetching data for: \(subscription.topicFilter)")
+    return v5.subscribe(to: [subscription])
+      .flatMap { _ in
+        let promise = self.eventLoopGroup.next().makePromise(of: Value.self)
+        self.addPublishListener(named: subscription.topicFilter + "-listener") { result in
+          
+          result.mapBuffer(to: Value.self)
+            .unwrap(or: MQTTError.sensor(reason: "Invalid sensor reading", error: nil))
+            .fullfill(promise: promise)
+          
+          self.logger.debug("Done fetching data for: \(subscription.topicFilter)")
+        }
+        
+        return promise.futureResult
+      }
+  }
+  
   /// Fetch a sensor state and convert it appropriately, when the sensor type is ``BufferInitializable``.
   ///
   /// - Parameters:
@@ -52,32 +99,17 @@ extension MQTTNIO.MQTTClient {
   func fetch<S>(
     sensor: Sensor<S>
   ) -> EventLoopFuture<S> where S: BufferInitalizable {
-    logger.debug("Fetching data for sensor: \(sensor.topic)")
-    let subscription = MQTTSubscribeInfoV5.init(
-      topicFilter: sensor.topic,
-      qos: .atLeastOnce,
-      retainAsPublished: false,
-      retainHandling: .sendAlways
-    )
-    return v5.subscribe(to: [subscription])
-      .flatMap { _ in
-        let promise = self.eventLoopGroup.next().makePromise(of: S.self)
-        self.addPublishListener(named: sensor.topic) { result in
-          
-          result.mapBuffer(to: S.self)
-            .unwrap(or: MQTTError.sensor(reason: "Invalid sensor reading", error: nil))
-            .fullfill(promise: promise)
-          
-          self.logger.debug("Done fetching data for sensor: \(sensor.topic)")
-        }
-        
-        return promise.futureResult
-      }
+    return fetch(mqttSubscription(topic: sensor.topic))
   }
   
-  func `set`(relay: Relay, to state: Relay.State, qos: MQTTQoS = .atLeastOnce) -> EventLoopFuture<Void> {
+  func fetch(setPoint: KeyPath<Topics.SetPoints, String>, setPoints: Topics.SetPoints) -> EventLoopFuture<Double> {
+//    logger.debug("Fetching data for set point: \(setPoint.topic)")
+    return fetch(mqttSubscription(topic: setPoints[keyPath: setPoint]))
+  }
+  
+  func `set`(relay relayTopic: String, to state: Relay.State, qos: MQTTQoS = .atLeastOnce) -> EventLoopFuture<Void> {
     publish(
-      to: relay.topic,
+      to: relayTopic,
       payload: ByteBufferAllocator().buffer(string: state.rawValue),
       qos: qos
     )

Sources/ClientLive/Live.swift

@@ -1,5 +1,5 @@
 import Foundation
-import Client
+@_exported import Client
 import CoreUnitTypes
 import Models
 import MQTTNIO
@@ -11,20 +11,24 @@ extension Client.MQTTClient {
   ///
   /// - Parameters:
   ///   - client: The ``MQTTNIO.MQTTClient`` used to send and recieve messages from the MQTT Broker.
-  public static func live(client: MQTTNIO.MQTTClient) -> Self {
+  public static func live(client: MQTTNIO.MQTTClient, topics: Topics) -> Self {
     .init(
       fetchHumidity: { sensor in
         client.fetch(sensor: sensor)
           .debug(logger: client.logger)
       },
+      fetchSetPoint: { setPointKeyPath in
+        client.fetch(client.mqttSubscription(topic: topics.setPoints[keyPath: setPointKeyPath]))
+          .debug(logger: client.logger)
+      },
       fetchTemperature: { sensor, units in
         client.fetch(sensor: sensor)
           .debug(logger: client.logger)
           .convertIfNeeded(to: units)
           .debug(logger: client.logger)
       },
-      setRelay: { relay, state in
-        client.set(relay: relay, to: state)
+      setRelay: { relayKeyPath, state in
+        client.set(relay: topics.commands.relays[keyPath: relayKeyPath], to: state)
       },
       shutdown: {
         client.disconnect()

Sources/Models/Topics.swift

@@ -5,7 +5,7 @@ public struct Topics: Codable, Equatable {
   /// The command topics the application can publish to.
   public var commands: Commands
   
-  /// The sensor topics the application can read sensor values from.
+  /// The sensor topics the application can read from / write to.
   public var sensors: Sensors
   
   /// The set point topics the application can read set point values from.

Sources/dewPoint-controller/main.swift

@@ -34,7 +34,11 @@ defer {
 while true {
 //  let temp = try environment.mqttClient.fetchTemperature(tempSensor, .imperial).wait()
 //  logger.debug("Temp: \(temp.rawValue)")
-  
+//
+//  logger.debug("Fetching set-point...")
+//  let sp = try environment.mqttClient.fetchSetPoint(\.dehumidify.highDewPoint).wait()
+//  logger.debug("Set point: \(sp)")
+//
   logger.debug("Fetching dew point...")
 
   let dp = try environment.mqttClient.currentDewPoint(