Mark Metrics SDK as Mixed/Stable

CHANGELOG.md

@@ -19,6 +19,9 @@ release.
   ([#2131](https://github.com/open-telemetry/opentelemetry-specification/pull/2131))
 - Remove the concept of supported temporality, keep preferred.
   ([#2154](https://github.com/open-telemetry/opentelemetry-specification/pull/2154))
+- Mark Metrics SDK spec as Mixed, with `MeterProvider`, `MetricReader` and
+  `MetricExporter` marked as Stable.
+  ([#2150](https://github.com/open-telemetry/opentelemetry-specification/pull/2150))
 
 ### Logs
 

specification/metrics/sdk.md

@@ -1,6 +1,6 @@
 # Metrics SDK
 
-**Status**: [Feature-freeze](../document-status.md)
+**Status**: [Mixed](../document-status.md)
 
 <details>
 <summary>Table of Contents</summary>
@@ -47,6 +47,8 @@
 
 ## MeterProvider
 
+**Status**: [Stable](../document-status.md)
+
 A `MeterProvider` MUST provide a way to allow a [Resource](../resource/sdk.md) to
 be specified. If a `Resource` is specified, it SHOULD be associated with all the
 metrics produced by any `Meter` from the `MeterProvider`. The [tracing SDK
@@ -180,17 +182,19 @@ are the inputs:
     not in the list will be ignored. If not provided, all the attribute keys
     will be used by default (TODO: once the Hint API is available, the default
     behavior should respect the Hint if it is available).
-  * The `extra dimensions` which come from Baggage/Context (optional). If not
-    provided, no extra dimension will be used. Please note that this only
-    applies to [synchronous Instruments](./api.md#synchronous-instrument).
+  * **Status**: [Experimental](../document-status.md) - the `extra dimensions`
+    which come from Baggage/Context (optional). If not provided, no extra
+    dimension will be used. Please note that this only applies to [synchronous
+    Instruments](./api.md#synchronous-instrument).
   * The `aggregation` (optional) to be used. If not provided, the SDK MUST
     apply a [default aggregation](#default-aggregation). If the aggregation
     outputs metric points that use aggregation temporality (e.g. Histogram,
     Sum), the SDK SHOULD handle the aggregation temporality based on the
     temporality of each [MetricReader](#metricreader) instance.
-  * The `exemplar_reservoir` (optional) to use for storing exemplars.
-    This should be a factory or callback similar to aggregation which allows
-    different reservoirs to be chosen by the aggregation.
+  * **Status**: [Experimental](../document-status.md) - the `exemplar_reservoir`
+    (optional) to use for storing exemplars. This should be a factory or
+    callback similar to aggregation which allows different reservoirs to be
+    chosen by the aggregation.
 
 The SDK SHOULD use the following logic to determine how to process Measurements
 made with an Instrument:
@@ -422,13 +426,17 @@ This Aggregation informs the SDK to collect:
 
 ## Attribute limits
 
+**Status**: [Stable](../document-status.md)
+
 Attributes which belong to Metrics are exempt from the
 [common rules of attribute limits](../common/common.md#attribute-limits) at this
 time. Attribute truncation or deletion could affect identitity of metric time
 series and it requires further analysis.
 
 ## Exemplar
 
+**Status**: [Experimental](../document-status.md)
+
 An [Exemplar](./datamodel.md#exemplars) is a recorded
 [Measurement](./api.md#measurement) that exposes the following pieces of
 information:
@@ -554,6 +562,8 @@ measurements using the equivalent of the following naive algorithm:
 
 ## MetricReader
 
+**Status**: [Stable](../document-status.md)
+
 `MetricReader` is an interface which provides the following capabilities:
 
 * Collecting metrics from the SDK.
@@ -657,6 +667,8 @@ Configurable parameters:
 
 ## MetricExporter
 
+**Status**: [Stable](../document-status.md)
+
 `MetricExporter` defines the interface that protocol-specific exporters MUST
 implement so that they can be plugged into OpenTelemetry SDK and support sending
 of telemetry data.
@@ -876,6 +888,8 @@ errors/exceptions are taken care of.
 
 ## Compatibility requirements
 
+**Status**: [Stable](../document-status.md)
+
 All the metrics components SHOULD allow new methods to be added to existing
 components without introducing breaking changes.
 
@@ -884,6 +898,8 @@ existing methods without introducing breaking changes, if possible.
 
 ## Concurrency requirements
 
+**Status**: [Stable](../document-status.md)
+
 For languages which support concurrent execution the Metrics SDKs provide
 specific guarantees and safeties.