server: add new metric for event trigger observability

PR-URL: https://github.com/hasura/graphql-engine-mono/pull/8380
Co-authored-by: Rob Dominguez <24390149+robertjdominguez@users.noreply.github.com>
GitOrigin-RevId: df7d5c53668fc84e7d70d471e29774136f5d560a

docs/docs/enterprise/metrics.mdx

@@ -122,6 +122,20 @@ curl 'http://127.0.0.1:8080/v1/metrics' -H 'Authorization: Bearer <secret>'
     <td>none</td>
     <td>Compare this number to the <a href="/latest/deployment/graphql-engine-flags/reference/#events-http-pool-size">HTTP pool size</a>. Consider increasing it if the metric is near the current configured value.</td>
   </tr>
+  <tr>
+    <td><code>hasura_event_processed_total</code></td>
+    <td>Total number of events processed</td>
+    <td>Counter</td>
+    <td>&#8226; "status": success|failed</td>
+    <td>Represents the Event Trigger egress.</td>
+  </tr>
+  <tr>
+    <td><code>hasura_event_invocations_total</code></td>
+    <td>Total number of events invoked</td>
+    <td>Counter</td>
+    <td>&#8226; "status": success|failed</td>
+    <td>Represents the Event Trigger webhook HTTP requests made.</td>
+  </tr>
   <tr>
     <td><code>hasura_postgres_connections</code></td>
     <td>Current number of active PostgreSQL connections</td>

server/src-lib/Hasura/Eventing/EventTrigger.hs

@@ -554,9 +554,15 @@ processEventQueue logger statsLogger httpMgr getSchemaCache getEventEngineCtx ac
                     Prometheus.Histogram.observe (eventWebhookProcessingTime eventTriggerMetrics) eventWebhookProcessingTime'
                     EKG.Distribution.add (smEventProcessingTime serverMetrics) eventProcessingTime'
                     Prometheus.Histogram.observe (eventProcessingTime eventTriggerMetrics) eventProcessingTime'
-                Left (HTTPError reqBody err) ->
+                    Prometheus.Counter.inc (eventProcessedTotalSuccess eventTriggerMetrics)
-                  processError @b sourceConfig e retryConf logHeaders reqBody maintenanceModeVersion err >>= flip onLeft logQErr
+                    Prometheus.Counter.inc (eventInvocationTotalSuccess eventTriggerMetrics)
-                Left (TransformationError _ err) -> do
+                Left eventError -> do
+                  -- TODO (paritosh): We can also add a label to the metric to indicate the type of error
+                  liftIO $ Prometheus.Counter.inc (eventInvocationTotalFailure eventTriggerMetrics)
+                  case eventError of
+                    (HTTPError reqBody err) ->
+                      processError @b sourceConfig e retryConf logHeaders reqBody maintenanceModeVersion eventTriggerMetrics err >>= flip onLeft logQErr
+                    (TransformationError _ err) -> do
                       L.unLogger logger $ L.UnstructuredLog L.LevelError (SB.fromLBS $ J.encode err)
 
                       -- Record an Event Error
@@ -608,9 +614,10 @@ processError ::
   [HeaderConf] ->
   J.Value ->
   MaintenanceMode MaintenanceModeVersion ->
+  EventTriggerMetrics ->
   HTTPErr a ->
   m (Either QErr ())
-processError sourceConfig e retryConf reqHeaders ep maintenanceModeVersion err = do
+processError sourceConfig e retryConf reqHeaders ep maintenanceModeVersion eventTriggerMetrics err = do
   let invocation = case err of
         HClient httpException ->
           let statusMaybe = getHTTPExceptionStatus httpException
@@ -623,16 +630,17 @@ processError sourceConfig e retryConf reqHeaders ep maintenanceModeVersion err =
         HOther detail -> do
           let errMsg = SB.fromLBS $ J.encode detail
           mkInvocation (eId e) ep (Just 500) reqHeaders errMsg []
-  retryOrError <- retryOrSetError e retryConf err
+  retryOrError <- retryOrSetError e retryConf eventTriggerMetrics err
   recordError @b sourceConfig e invocation retryOrError maintenanceModeVersion
 
 retryOrSetError ::
   MonadIO m =>
   Event b ->
   RetryConf ->
+  EventTriggerMetrics ->
   HTTPErr a ->
   m ProcessEventError
-retryOrSetError e retryConf err = do
+retryOrSetError e retryConf eventTriggerMetrics err = do
   let mretryHeader = getRetryAfterHeaderFromError err
       tries = eTries e
       mretryHeaderSeconds = mretryHeader >>= parseRetryHeader
@@ -640,7 +648,9 @@ retryOrSetError e retryConf err = do
       noRetryHeader = isNothing mretryHeaderSeconds
   -- current_try = tries + 1 , allowed_total_tries = rcNumRetries retryConf + 1
   if triesExhausted && noRetryHeader
-    then pure PESetError
+    then do
+      liftIO $ Prometheus.Counter.inc (eventProcessedTotalFailure eventTriggerMetrics)
+      pure PESetError
     else do
       currentTime <- liftIO getCurrentTime
       let delay = fromMaybe (rcIntervalSec retryConf) mretryHeaderSeconds

server/src-lib/Hasura/Server/Prometheus.hs

@@ -60,7 +60,11 @@ data EventTriggerMetrics = EventTriggerMetrics
     eventWebhookProcessingTime :: Histogram,
     eventProcessingTime :: Histogram,
     eventTriggerBytesReceived :: Counter,
-    eventTriggerBytesSent :: Counter
+    eventTriggerBytesSent :: Counter,
+    eventProcessedTotalSuccess :: Counter,
+    eventProcessedTotalFailure :: Counter,
+    eventInvocationTotalSuccess :: Counter,
+    eventInvocationTotalFailure :: Counter
   }
 
 -- | Create dummy mutable references without associating them to a metrics
@@ -99,6 +103,10 @@ makeDummyEventTriggerMetrics = do
   eventProcessingTime <- Histogram.new []
   eventTriggerBytesReceived <- Counter.new
   eventTriggerBytesSent <- Counter.new
+  eventProcessedTotalSuccess <- Counter.new
+  eventProcessedTotalFailure <- Counter.new
+  eventInvocationTotalSuccess <- Counter.new
+  eventInvocationTotalFailure <- Counter.new
   pure EventTriggerMetrics {..}
 
 --------------------------------------------------------------------------------