Record event on server unavailable error

glean/metrics.yaml

@@ -18,7 +18,6 @@
 $schema: moz://mozilla.org/schemas/glean/metrics/2-0-0
 
 sample:
-
   addon_state_changed:
     type: event
     lifetime: ping
@@ -71,7 +70,6 @@ sample:
           Received, Notified, Read, or Dismissed
         type: string
 
-
   addon_cta_clicked:
     type: event
     lifetime: ping
@@ -566,7 +564,6 @@ sample:
       - amarchesini@mozilla.com
     expires: never
 
-
   connection_health_no_signal:
     type: event
     lifetime: ping
@@ -1047,6 +1044,23 @@ sample:
         description: The Host network type (i.e wifi or 4g)
         type: string
 
+  server_unavailable_error:
+    type: event
+    lifetime: ping
+    send_in_pings:
+      - main
+    description: |
+      A "Server unavailable" error has occured.
+    bugs:
+      - https://github.com/mozilla-mobile/mozilla-vpn-client/issues/4589
+    data_reviews:
+      - TODO
+    data_sensitivity:
+      - technical
+    notification_emails:
+      - brizental@mozilla.com
+    expires: never
+
   app_step:
     type: event
     lifetime: ping

src/controller.cpp

@@ -608,6 +608,7 @@ bool Controller::processNextStep() {
 
   if (nextStep == ServerUnavailable) {
     logger.info() << "Server Unavailable - Ping succeeded: " << m_ping_received;
+
     emit readyToServerUnavailable(m_ping_received);
     return true;
   }

src/telemetry.cpp

@@ -75,6 +75,13 @@ void Telemetry::initialize() {
       emit vpn->recordGleanEvent(GleanSample::controllerStateOff);
     }
   });
+
+  connect(controller, &Controller::readyToServerUnavailable, this, [this]() {
+    MozillaVPN* vpn = MozillaVPN::instance();
+    Q_ASSERT(vpn);
+
+    emit vpn->recordGleanEvent(GleanSample::serverUnavailableError);
+  });
 }
 
 void Telemetry::connectionStabilityEvent() {