adjust faas metrics

Author: skonto

specification/metrics/semantic_conventions/faas-metrics.md

@@ -1,48 +1,49 @@
 # General
 
-The conventions described in this section are FaaS (function as a service) specific. When FaaS operations occur,
-metric events about those operations will be generated and reported to provide insight into the
-operations. By adding FaaS labels to metric events it allows for finely tuned filtering.
+The conventions described in this section aim both Functions running as a service (FaaS) and on-premise setups. When Functions are operated, metric events about those operations will be generated and reported to provide insight into the
+operations. By adding Functions dedicated labels to metric events it allows for finely tuned filtering.
 
-**Disclaimer:** These are initial FaaS metric instruments and labels but more may be added in the future.
+**Disclaimer:** These are initial Function metric instruments and labels but more may be added in the future. Not all instruments
+apply to all environments.
 
 ## Metric Instruments
 
-The following metric instruments MUST be used to describe FaaS operations. They MUST be of the specified
+The following metric instruments MUST be used to describe Function operations. They MUST be of the specified
 type and units.
 
-### FaaS Invocations
+### Function Invocations
 
-Below is a table of FaaS invocation metric instruments.
+Below is a table of Function invocation metric instruments.
 
 | Name | Instrument | Units | Description |
-|------|------------|----|--|-------------|
-| `faas.invoke_duration` | ValueRecorder | milliseconds | Measures the duration of the invocation |
-| `faas.init_duration` | ValueRecorder | milliseconds | Measures the duration of the function's initialization, such as a cold start |
-| `faas.coldstarts` | Counter | number of cold starts | Number of invocation cold starts. |
-| `faas.errors` | Counter | number of errors | Number of invocation errors. |
-| `faas.executions` | counter | number of invocations | number of successful invocations. |
-| `faas.timeouts` | counter | number of timeouts | number of invocation timeouts. |
+|------|------------|-------|-------------|
+| `func.invoke_duration` | ValueRecorder | milliseconds | Measures the duration of the invocation where real work is being done.  |
+| `func.init_duration` | ValueRecorder | milliseconds | Measures the duration of the function's initialization, such as a cold start |
+| `func.coldstarts` | Counter | number of cold starts | Number of invocation cold starts. |
+| `func.errors` | Counter | number of errors | Number of invocation errors. |
+| `func.executions` | Counter | number of invocations | number of successful invocations. |
+| `func.timeouts` | Counter | number of timeouts | number of invocation timeouts. |
 
 ## Labels
 
-Below is a table of the labels that SHOULD be included on FaaS metric events.
+Below is a table of the labels that SHOULD be included on Func metric events if applicable.
 
 | Name | Recommended | Notes and examples |
 |------|-------------|--------------------|
-| `faas.trigger` | Yes | Type of the trigger on which the function is invoked. SHOULD be one of: `datasource`, `http`, `pubsub`, `timer`, `other` |
-| `faas.invoked_name` | Yes | Name of the invoked function. Example: `my-function` |
-| `faas.invoked_provider` | Yes | Cloud provider of the invoked function. Corresponds to the resource `cloud.provider`. Example: `aws` |
-| `faas.invoked_region` | Yes | Cloud provider region of invoked function. Corresponds to resource `cloud.region`. Example: `us-east-1` |
+| `func.trigger` | Yes | Type of the trigger on which the function is invoked. SHOULD be one of: `datasource`, `http`, `pubsub`, `timer`, `other` |
+| `func.invoked_name` | Yes | Name of the invoked function. Example: `my-function` |
+| `func.invoked_provider` | Yes | Cloud provider of the invoked function. Corresponds to the resource `cloud.provider`. Example: `aws` |
+| `func.invoked_region` | Yes | Cloud provider region of invoked function. Corresponds to resource `cloud.region`. Example: `us-east-1` |
 
 ## References
 
 ### Metric Reference
 
 Below are links to documentation regarding metrics that are available with different
-FaaS providers. This list is not exhaustive.
+FaaS providers and other vendors. This list is not exhaustive.
 
 * [AWS Lambda Metrics](https://docs.aws.amazon.com/lambda/latest/dg/monitoring-metrics.html)
 * [Azure Functions Metrics](https://docs.microsoft.com/en-us/azure/azure-monitor/platform/metrics-supported)
 * [Google CloudFunctions Metrics](https://cloud.google.com/monitoring/api/metrics_gcp#gcp-cloudfunctions)
 * [OpenFaas Metrics](https://docs.openfaas.com/architecture/metrics/)
+* [Openwhisk Metrics](https://github.com/apache/openwhisk/blob/master/docs/metrics.md)