feat: Adds MQTTConnectionService

Package.swift

@@ -2,6 +2,10 @@
 
 import PackageDescription
 
+let swiftSettings: [SwiftSetting] = [
+  .enableExperimentalFeature("StrictConcurrency")
+]
+
 let package = Package(
   name: "dewPoint-controller",
   platforms: [
@@ -47,7 +51,8 @@ let package = Package(
         "Models",
         .product(name: "MQTTNIO", package: "mqtt-nio"),
         .product(name: "NIO", package: "swift-nio")
-      ]
+      ],
+      swiftSettings: swiftSettings
     ),
     .target(
       name: "DewPointEnvironment",
@@ -56,17 +61,20 @@ let package = Package(
         "Client",
         "Models",
         .product(name: "MQTTNIO", package: "mqtt-nio")
-      ]
+      ],
+      swiftSettings: swiftSettings
     ),
     .target(
       name: "EnvVars",
-      dependencies: []
+      dependencies: [],
+      swiftSettings: swiftSettings
     ),
     .target(
       name: "Models",
       dependencies: [
         .product(name: "Psychrometrics", package: "swift-psychrometrics")
-      ]
+      ],
+      swiftSettings: swiftSettings
     ),
     .target(
       name: "Client",
@@ -75,7 +83,8 @@ let package = Package(
         .product(name: "CoreUnitTypes", package: "swift-psychrometrics"),
         .product(name: "NIO", package: "swift-nio"),
         .product(name: "Psychrometrics", package: "swift-psychrometrics")
-      ]
+      ],
+      swiftSettings: swiftSettings
     ),
     .target(
       name: "ClientLive",
@@ -84,7 +93,8 @@ let package = Package(
         "EnvVars",
         .product(name: "MQTTNIO", package: "mqtt-nio"),
         .product(name: "ServiceLifecycle", package: "swift-service-lifecycle")
-      ]
+      ],
+      swiftSettings: swiftSettings
     ),
     .testTarget(
       name: "ClientTests",
@@ -94,10 +104,13 @@ let package = Package(
       ]
     ),
     .target(
-      name: "TopicsLive",
+      name: "MQTTConnectionService",
       dependencies: [
-        "Models"
+        "EnvVars",
-      ]
+        .product(name: "MQTTNIO", package: "mqtt-nio"),
+        .product(name: "ServiceLifecycle", package: "swift-service-lifecycle")
+      ],
+      swiftSettings: swiftSettings
     ),
     .target(
       name: "SensorsService",
@@ -105,7 +118,8 @@ let package = Package(
         "Models",
         .product(name: "MQTTNIO", package: "mqtt-nio"),
         .product(name: "ServiceLifecycle", package: "swift-service-lifecycle")
-      ]
+      ],
+      swiftSettings: swiftSettings
     ),
     .testTarget(
       name: "SensorsServiceTests",
@@ -114,6 +128,13 @@ let package = Package(
         // TODO: Remove.
         "ClientLive"
       ]
+    ),
+    .target(
+      name: "TopicsLive",
+      dependencies: [
+        "Models"
+      ],
+      swiftSettings: swiftSettings
     )
   ]
 )

Sources/MQTTConnectionService/MQTTConnectionService.swift

@@ -0,0 +1,56 @@
+import EnvVars
+import Logging
+import MQTTNIO
+import NIO
+import ServiceLifecycle
+
+/// Manages the MQTT broker connection.
+public actor MQTTConnectionService: Service {
+  private let cleanSession: Bool
+  public let client: MQTTClient
+  private var shuttingDown = false
+  var logger: Logger { client.logger }
+
+  public init(
+    cleanSession: Bool = true,
+    client: MQTTClient
+  ) {
+    self.cleanSession = cleanSession
+    self.client = client
+  }
+
+  /// The entry-point of the service.
+  ///
+  /// This method connects to the MQTT broker and manages the connection.
+  /// It will attempt to gracefully shutdown the connection upon receiving
+  /// `sigterm` signals.
+  public func run() async throws {
+    await withGracefulShutdownHandler {
+      await self.connect()
+    } onGracefulShutdown: {
+      Task { await self.shutdown() }
+    }
+  }
+
+  private func shutdown() async {
+    shuttingDown = true
+    try? await client.disconnect()
+    try? await client.shutdown()
+  }
+
+  private func connect() async {
+    do {
+      try await client.connect(cleanSession: cleanSession)
+      client.addCloseListener(named: "SensorsClient") { [self] _ in
+        Task {
+          self.logger.debug("Connection closed.")
+          self.logger.debug("Reconnecting...")
+          await self.connect()
+        }
+      }
+      logger.debug("Connection successful.")
+    } catch {
+      logger.trace("Connection Failed.\n\(error)")
+    }
+  }
+}

Sources/Models/TemperatureAndHumiditySensor.swift

@@ -3,6 +3,7 @@
 /// Represents a temperature and humidity sensor that can be used to derive
 /// the dew-point temperature and enthalpy values.
 ///
+/// > Note: Temperature values are received in `celsius`.
 public struct TemperatureAndHumiditySensor: Equatable, Hashable, Identifiable, @unchecked Sendable {
 
   /// The identifier of the sensor, same as the location.
@@ -25,9 +26,6 @@ public struct TemperatureAndHumiditySensor: Equatable, Hashable, Identifiable, @
   /// The topics to listen for updated sensor values.
   public let topics: Topics
 
-  /// The psychrometric units of the sensor.
-  public let units: PsychrometricEnvironment.Units
-
   /// Create a new temperature and humidity sensor.
   ///
   /// - Parameters:
@@ -36,21 +34,18 @@ public struct TemperatureAndHumiditySensor: Equatable, Hashable, Identifiable, @
   ///   - temperature: The current temperature value of the sensor.
   ///   - humidity: The current relative humidity value of the sensor.
   ///   - needsProcessed: If the sensor needs to be processed.
-  ///   - units: The unit of measure for the sensor.
   public init(
     location: Location,
     altitude: Length = .feet(800.0),
     temperature: Temperature? = nil,
     humidity: RelativeHumidity? = nil,
     needsProcessed: Bool = false,
-    units: PsychrometricEnvironment.Units = .imperial,
     topics: Topics? = nil
   ) {
     self.altitude = altitude
     self.location = location
     self._temperature = TrackedChanges(wrappedValue: temperature, needsProcessed: needsProcessed)
     self._humidity = TrackedChanges(wrappedValue: humidity, needsProcessed: needsProcessed)
-    self.units = units
     self.topics = topics ?? .init(location: location)
   }
 
@@ -61,7 +56,7 @@ public struct TemperatureAndHumiditySensor: Equatable, Hashable, Identifiable, @
           !temperature.rawValue.isNaN,
           !humidity.rawValue.isNaN
     else { return nil }
-    return .init(dryBulb: temperature, humidity: humidity, units: units)
+    return .init(dryBulb: temperature, humidity: humidity)
   }
 
   /// The calculated enthalpy of the sensor.
@@ -71,7 +66,7 @@ public struct TemperatureAndHumiditySensor: Equatable, Hashable, Identifiable, @
           !temperature.rawValue.isNaN,
           !humidity.rawValue.isNaN
     else { return nil }
-    return .init(dryBulb: temperature, humidity: humidity, altitude: altitude, units: units)
+    return .init(dryBulb: temperature, humidity: humidity, altitude: altitude)
   }
 
   /// Check whether any of the sensor values have changed and need processed.

Sources/SensorsService/SensorsService.swift

@@ -1,6 +1,6 @@
 import Foundation
 import Logging
-@preconcurrency import Models
+import Models
 @preconcurrency import MQTTNIO
 import NIO
 import Psychrometrics
@@ -102,13 +102,12 @@ public actor SensorsService: Service {
 // MARK: - Errors
 
 struct DecodingError: Error {}
+struct MQTTClientNotConnected: Error {}
 struct NotFoundError: Error {}
 struct SensorExists: Error {}
 
 // MARK: - Helpers
 
-struct MQTTClientNotConnected: Error {}
-
 private extension TemperatureAndHumiditySensor.Topics {
   func contains(_ topic: String) -> Bool {
     temperature == topic || humidity == topic