[SDK] Additional committed metrics

[lenny-goodell]

Decided on the following committed list for SDK in 5/31/22 WG Meeting

• Size of data exported via HTTP
• Size of data exported via MQTT
• Number of invalid messages received (i.e. error decoding)
• Number of errors that terminate a pipeline (per pipeline)

Use separate PRs for each of above and check them off once complete.

Background Info

The Metrics ADR has this potential list for App Services not completed in Kamakura:

• DB access times
  • Only use DB for S&F (Store & Forward). Value of this?
• How often are we failing export to be sent to db to be retried at a later time
  • Again, only S&F. How does this diffed than the next one.
• What is the current store and forward queue size
  • This is interesting since this would be hard to monitor off box is system not connected, i.e. utilizing S&F... ;-)
  • Collection continues and but reporting would only be available for when system is on-line. I.e collector could use S7F w/o collecting metrics on itself...
• How much data (size in KBs or MBs) of packaged sensor data is being sent to an endpoint (or volume)
  • This would be in the HTTP and MQTT exports. Two separate metrics?
• Number of invalid messages that triggered pipeline
  • This allows monitoring is App Service is operational wrt processing incoming message, i.e. TargetType may not match the incoming data.

Completed in Kamakura:

• Processing time for a pipeline (PipelineMessageProcessingTime)
  • latency (measure of time) an event takes to get through an application service pipeline
  • This is per pipeline now since a service can have multiple pipelines. The metric gets reported for each pipeline with the pipeline ID as the tag.
• Number of events processed by each pipeline (PipelineMessagesProcessed )
  • This is per pipeline now since a service can have multiple pipelines. The metric gets reported for each pipeline with the pipeline ID as the tag.
• Number of events processed by the service (MessagesReceived)

Decided on the following list for SDK:

• Size of data exported (HTTP and MQTT)
  • Requires Meter metric type to be added.
• Number of invalid messages received (i.e. error decoding)
• Number of errors that terminate a pipeline (per pipeline)
• What is the current store and forward queue size (stretch)
• Message latency for received from MessageBus to hand off to Pipeline (stretch)