Log more metrics

Sources/App/DeviceManager.swift

@@ -1,6 +1,7 @@
 import Foundation
 import WebSocketKit
 import Vapor
+import Clairvoyant
 
 final class DeviceManager {
 
@@ -19,6 +20,10 @@ final class DeviceManager {
     private var isOpeningNewConnection = false
 
     private let deviceTimeout: Int64
+
+    private let deviceConnectedMetric: Metric<Bool>
+
+    private let messagesToDeviceMetric: Metric<Int>
     
     /// Indicator for device availability
     var deviceIsConnected: Bool {
@@ -32,6 +37,23 @@ final class DeviceManager {
         self.deviceKey = deviceKey
         self.remoteKey = remoteKey
         self.deviceTimeout = deviceTimeout
+        self.deviceConnectedMetric = .init(
+            "sesame.connected",
+            name: "Device connected",
+            description: "Shows if the device is connected via WebSocket")
+        self.messagesToDeviceMetric = .init(
+            "sesame.messages",
+            name: "Forwarded Messages",
+            description: "The number of messages transmitted to the device")
+    }
+
+    private func updateDeviceConnectionMetric() {
+        deviceConnectedMetric.update(deviceIsConnected)
+    }
+
+    private func updateMessageCountMetric() {
+        let lastValue = messagesToDeviceMetric.lastValue()?.value ?? 0
+        messagesToDeviceMetric.update(lastValue + 1)
     }
     
     // MARK: API
@@ -50,6 +72,7 @@ final class DeviceManager {
         }
         requestInProgress = eventLoop.makePromise(of: DeviceResponse.self)
         socket.send(message.bytes, promise: nil)
+        updateMessageCountMetric()
         eventLoop.scheduleTask(in: .seconds(deviceTimeout)) { [weak self] in
             guard let promise = self?.requestInProgress else {
                 return
@@ -61,6 +84,7 @@ final class DeviceManager {
     }
     
     func authenticateDevice(hash: String) {
+        defer { updateDeviceConnectionMetric() }
         guard let key = Data(fromHexEncodedString: hash),
               SHA256.hash(data: key) == self.deviceKey else {
             log("Invalid device key")
@@ -86,6 +110,7 @@ final class DeviceManager {
     }
     
     func didCloseDeviceSocket() {
+        defer { updateDeviceConnectionMetric() }
         guard !isOpeningNewConnection else {
             return
         }
@@ -99,6 +124,7 @@ final class DeviceManager {
     }
     
     func removeDeviceConnection() {
+        defer { updateDeviceConnectionMetric() }
         deviceIsAuthenticated = false
         guard let socket = connection else {
             return
@@ -109,6 +135,7 @@ final class DeviceManager {
     }
     
     func createNewDeviceConnection(_ socket: WebSocket) {
+        defer { updateDeviceConnectionMetric() }
         isOpeningNewConnection = true
         removeDeviceConnection()
         connection = socket