MetricProducer.Produce can include a Resource parameter (#3636)

CHANGELOG.md

@@ -15,6 +15,8 @@ release.
 
 - Increase metric name maximum length from 63 to 255 characters.
   ([#3648](https://github.com/open-telemetry/opentelemetry-specification/pull/3648))
+- MetricReader.Collect ignores Resource from MetricProducer.Produce.
+  ([#3636](https://github.com/open-telemetry/opentelemetry-specification/pull/3636))
 
 ### Logs
 

specification/metrics/sdk.md

@@ -1141,6 +1141,12 @@ SDK](../overview.md#sdk) authors MAY choose to add parameters (e.g. callback,
 filter, timeout). [OpenTelemetry SDK](../overview.md#sdk) authors MAY choose the
 return value type, or do not return anything.
 
+`Collect` SHOULD invoke [Produce](#produce-batch) on registered
+[MetricProducers](#metricproducer). If the batch of metric points from
+`Produce` includes [Resource](../resource/sdk.md) information, `Collect` MAY
+replace the `Resource` from the MetricProducer with the `Resource` provided
+when constructing the MeterProvider instead.
+
 Note: it is expected that the `MetricReader.Collect` implementations will be
 provided by the SDK, so it is RECOMMENDED to prevent the user from accidentally
 overriding it, if possible (e.g. `final` in C++ and Java, `sealed` in C#).
@@ -1431,10 +1437,6 @@ in-memory state MAY implement the `MetricProducer` interface for convenience.
 `AggregationTemporality` of produced metrics. SDK authors MAY provide utility
 libraries to facilitate conversion between delta and cumulative temporalities.
 
-If the batch of [Metric points](./data-model.md#metric-points) returned by
-`Produce()` includes a [Resource](../resource/sdk.md), the `MetricProducer` MUST
-accept configuration for the [Resource](../resource/sdk.md).
-
 ```text
 +-----------------+            +--------------+
 |                 | Metrics... |              |
@@ -1457,7 +1459,9 @@ A `MetricProducer` MUST support the following functions:
 
 `Produce` provides metrics from the MetricProducer to the caller. `Produce`
 MUST return a batch of [Metric points](./data-model.md#metric-points).
-`Produce` does not have any required parameters, however, [OpenTelemetry
+If the batch of [Metric points](./data-model.md#metric-points) includes
+resource information, `Produce` SHOULD require a resource as a parameter.
+`Produce` does not have any other required parameters, however, [OpenTelemetry
 SDK](../overview.md#sdk) authors MAY choose to add required or optional
 parameters (e.g. timeout).