Verify compliant metric SDK specification implementation: MetricProducer

[MrAlias]

• Identify all the normative requirements, recommendations, and options the specification defines as comments to this issue
• Ensure the current metric SDK implementation is compliant with these normative requirements, recommendations, and options in those comments.

[MadVikingGod]

Requirements from reading the Metric Producer Section of the spec.

• MetricProducer is an open interface that can be implemented outside the SDK.

  MetricProducer defines the interface which bridges to third-party metric sources MUST implement so they can be plugged into an OpenTelemetry MetricReader as a source of aggregated metric data.

• The SDK's in-memory state MAY implement the MetricProducer interface for convenience.

• SDK authors MAY provide utility libraries to facilitate conversion between delta and cumulative temporalities.

• If the batch of Metric points returned by Produce() includes a Resource, the MetricProducer MUST accept configuration for the Resource.

• The MetricProducer Interface must have the following defined:
  • Produce

    • Produce MUST return a batch of Metric points.

    • Produce does not have any required parameters... SDK authors MAY choose to add parameters

    • Produce SHOULD provide a way to let the caller know whether it succeeded, failed or timed out.

    • When the Produce operation fails, the MetricProducer MAY return successfully collected results and a failed reasons list to the caller.

    • If a batch of Metric points can include InstrumentationScope information, Produce SHOULD include a single InstrumentationScope which identifies the MetricProducer.

[damemi]

@MrAlias can you assign this to me?

[damemi]

Requirements from reading the Metric Producer Section of the spec.

• MetricProducer is an open interface that can be implemented outside the SDK.

  MetricProducer defines the interface which bridges to third-party metric sources MUST implement so they can be plugged into an OpenTelemetry MetricReader as a source of aggregated metric data.

• The SDK's in-memory state MAY implement the MetricProducer interface for convenience.

I didn't find any implementations of this in the in-memory state

SDK authors MAY provide utility libraries to facilitate conversion between delta and cumulative temporalities.

Didn't see any

If the batch of Metric points returned by Produce() includes a Resource, the MetricProducer MUST accept configuration for the Resource.

Produce() (ScopeMetrics) does not include a Resource

The MetricProducer Interface must have the following defined:

• Produce

It does

Produce MUST return a batch of Metric points.

Produce() returns []metricdata.ScopeMetrics.

Produce does not have any required parameters... SDK authors MAY choose to add parameters

Produce() requires a Go context. It's unclear whether the specification means that Produce "MUST" not have any required parameters (and authors may add optional parameters), or if authors may add required parameters.

Produce SHOULD provide a way to let the caller know whether it succeeded, failed or timed out.

Produce() returns a Go error (along with the batch of data points)

When the Produce operation fails, the MetricProducer MAY return successfully collected results and a failed reasons list to the caller.

This is up to each Producer's implementation, but for example the opencensus bridge will return successful results and an aggregated error (from internal.ConvertMetrics())

If a batch of Metric points can include InstrumentationScope information, Produce SHOULD include a single InstrumentationScope which identifies the MetricProducer.

ScopeMetrics includes a single InstrumentationScope

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I think the only action item from this would be to clarify the intent of Produce does not have any required parameters... SDK authors MAY choose to add parameters

[MrAlias]

The MetricProducer specification needs to be stabilized before we can release our implementation of it stabilly.

[MrAlias]

I think the only action item from this would be to clarify the intent of Produce does not have any required parameters... SDK authors MAY choose to add parameters

@damemi do you plan to open a spec issue/PR for this?

[MrAlias]

The MetricProducer specification needs to be stabilized before we can release our implementation of it stabilly.

open-telemetry/opentelemetry-specification#3599

[MrAlias]

TODO:

• Stabilize the MetricProducer opentelemetry-specification#3599
• Clarify MetricProducer "Produce() does not have any required parameters" opentelemetry-specification#3601

[damemi]

I think the only action item from this would be to clarify the intent of Produce does not have any required parameters... SDK authors MAY choose to add parameters

@damemi do you plan to open a spec issue/PR for this?

Opened open-telemetry/opentelemetry-specification#3601 for this question

[arminru]

Clarified that the required context parameter is fine: open-telemetry/opentelemetry-specification@15df460

[dashpole]

I believe this can be closed now.