feat: add enrichment of StartRequest with OS, device ID, version (#123)

Enriches `StartRequest` protocol message with device ID, OS, and version, for Coder Desktop telemetry.

Author: spikecurtis

Diff for: Coder-Desktop/VPN/Manager.swift

@@ -6,6 +6,7 @@ import VPNLib
 actor Manager {
     let ptp: PacketTunnelProvider
     let cfg: ManagerConfig
+    let telemetryEnricher: TelemetryEnricher
 
     let tunnelHandle: TunnelHandle
     let speaker: Speaker<Vpn_ManagerMessage, Vpn_TunnelMessage>
@@ -19,6 +20,7 @@ actor Manager {
     init(with: PacketTunnelProvider, cfg: ManagerConfig) async throws(ManagerError) {
         ptp = with
         self.cfg = cfg
+        telemetryEnricher = TelemetryEnricher()
         #if arch(arm64)
             let dylibPath = cfg.serverUrl.appending(path: "bin/coder-vpn-darwin-arm64.dylib")
         #elseif arch(x86_64)
@@ -176,6 +178,7 @@ actor Manager {
                                 req.value = header.value
                             }
                         }
+                        req = telemetryEnricher.enrich(req)
                     }
                 })
         } catch {

Diff for: Coder-Desktop/VPNLib/Speaker.swift

@@ -88,8 +88,11 @@ public actor Speaker<SendMsg: RPCMessage & Message, RecvMsg: RPCMessage & Messag
 
     /// Does the VPN Protocol handshake and validates the result
     public func handshake() async throws(HandshakeError) {
-        let hndsh = Handshaker(writeFD: writeFD, dispatch: dispatch, queue: queue, role: role)
-        // ignore the version for now because we know it can only be 1.0
+        let hndsh = Handshaker(writeFD: writeFD, dispatch: dispatch, queue: queue, role: role,
+                               versions: [ProtoVersion(1, 1)])
+        // ignore the version for now because we know it can only be 1.0 or 1.1.
+        // 1.1 adds support for telemetry to StartRequest, but since setting these
+        // fields won't adversely affect a 1.0 speaker, we set them regardless.
         try _ = await hndsh.handshake()
     }
 

Diff for: Coder-Desktop/VPNLib/TelemetryEnricher.swift

@@ -0,0 +1,31 @@
+import Foundation
+
+public struct TelemetryEnricher {
+    private let deviceID: String
+    private let version: String?
+
+    public init() {
+        version = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String
+
+        let userDefaults = UserDefaults.standard
+        let key = "deviceID"
+
+        if let existingID = userDefaults.string(forKey: key) {
+            deviceID = existingID
+        } else {
+            let newID = UUID().uuidString
+            userDefaults.set(newID, forKey: key)
+            deviceID = newID
+        }
+    }
+
+    public func enrich(_ original: Vpn_StartRequest) -> Vpn_StartRequest {
+        var req = original
+        req.deviceOs = "macOS"
+        req.deviceID = deviceID
+        if let version {
+            req.coderDesktopVersion = version
+        }
+        return req
+    }
+}