Monitor topics and event subscriptions

Event Grid on Edge exposes a number of metrics for topics and event subscriptions in the Prometheus exposition format. This article describes the available metrics and how to enable them.

Important

On March 31, 2023, Event Grid on Azure IoT Edge support will be retired, so make sure to transition to IoT Edge native capabilities prior to that date. For more information, see Transition from Event Grid on Azure IoT Edge to Azure IoT Edge.

Enable metrics

Configure the module to emit metrics by setting the metrics__reporterType environment variable to prometheus in the container create options:

       {
         "Env": [
           "metrics__reporterType=prometheus"
         ],
         "HostConfig": {
           "PortBindings": {
             "4438/tcp": [
               {
                   "HostPort": "4438"
               }
             ]
           }
         }
       }

Metrics will be available at 5888/metrics of the module for http and 4438/metrics for https. For example, http://<modulename>:5888/metrics?api-version=2019-01-01-preview for http. At this point, a metrics module can poll the endpoint to collect metrics as in this example architecture.

Available metrics

Both topics and event subscriptions emit metrics to give you insights into event delivery and module performance.

Topic metrics

Metric	Description
EventsReceived	Number of events published to the topic
UnmatchedEvents	Number of events published to the topic that do not match an Event Subscription and are dropped
SuccessRequests	Number of inbound publish requests received by the topic
SystemErrorRequests	Number of inbound publish requests failed due to an internal system error
UserErrorRequests	Number on inbound publish requests failed due to user error such as malformed JSON
SuccessRequestLatencyMs	Publish request response latency in milliseconds

Event subscription metrics

Metric	Description
DeliverySuccessCounts	Number of events successfully delivered to the configured endpoint
DeliveryFailureCounts	Number of events that failed to be delivered to the configured endpoint
DeliverySuccessLatencyMs	Latency of events successfully delivered in milliseconds
DeliveryFailureLatencyMs	Latency of events delivery failures in milliseconds
SystemDelayForFirstAttemptMs	System delay of events before first delivery attempt in milliseconds
DeliveryAttemptsCount	Number of event delivery attempts - success and failure
ExpiredCounts	Number of events that expired and were not delivered to the configured endpoint