feat: add experimental view_matching_mode to meter provider by dashpole · Pull Request #666 · open-telemetry/opentelemetry-configuration

dashpole · 2026-06-23T18:42:28Z

Implements composable View matching configuration in support of open-telemetry/opentelemetry-specification#5173.

Adds experimental meter_provider.view_matching_mode/development enum property, with ['independent' default, 'composable'] as values

Copilot

Pull request overview

Adds an experimental meter_provider.view_matching_mode/development configuration option to support composable View matching (per spec work), and propagates it through the schema outputs, docs, and language support metadata.

Changes:

Add view_matching_mode/development to the MeterProvider schema (enum values: independent, composable) and regenerate JSON schema + docs.
Update per-language support metadata to mark the new property as not_implemented.
Add a validator shelltest for invalid values and update an example configuration to demonstrate usage.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
validator/shelltests/invalid_view_matching_mode.yaml	New negative test input using an invalid `view_matching_mode/development` value.
validator/shelltests/invalid_view_matching_mode.test	Expected validator output for the invalid value case.
schema/meter_provider.yaml	Introduces `view_matching_mode/development` on MeterProvider.
schema/meta_schema_language_php.yaml	Marks the new MeterProvider property as `not_implemented` for PHP.
schema/meta_schema_language_js.yaml	Marks the new MeterProvider property as `not_implemented` for JS.
schema/meta_schema_language_java.yaml	Marks the new MeterProvider property as `not_implemented` for Java.
schema/meta_schema_language_go.yaml	Marks the new MeterProvider property as `not_implemented` for Go.
schema/meta_schema_language_cpp.yaml	Marks the new MeterProvider property as `not_implemented` for C++.
schema-docs.md	Documents the new property and its language support status (generated).
opentelemetry_configuration.json	Adds the generated JSON schema for the new property.
language-support-status.md	Updates generated language support tables to include the new property.
examples/otel-sdk-config.yaml	Demonstrates `view_matching_mode/development: composable` plus views.
CHANGELOG.md	Notes the new property in Unreleased.

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jack-berg

Content looks good. Still need to fix schema-docs.md, mark "ready for review", and get more approvals on the spec PR. But setting aside that, the schema changes look good here.

Fixes open-telemetry#5013 Following-up after this came up in the spec SIG meeting on 6/23. ### Summary Introduces an opt-in `view_matching_mode` configuration parameter on `MeterProvider` to support merging multiple Views that match the same Instrument. ### API * Adds `view_matching_mode` to `MeterProvider` with two modes: * `independent`: (Default) Maintains existing behavior where matching Views create separate streams independently. * `composable`: Merges matching Views into a single stream unless they configure different stream `name`s. ### Composable merge rules * For `name`, `description`, `aggregation`, `exemplar_reservoir`, and `aggregation_cardinality_limit`, **last-wins precedence** applies based on View registration order. * `attribute_keys`' `included` and `excluded` sets are merged. * `include` keeps only keys present in **all include-lists** (set intersection). * `exclude` drops keys listed in **any of the exclude-lists** (set union). ### Declarative Config example ```yaml meter_provider: view_matching_mode: composable views: # 1. Specific override: Rename histogram and use sum aggregation - selector: meter_name: go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp instrument_name: http.client.request.duration stream: name: http.client.latency aggregation: sum: {} # 2. Scope policy: Drop status code from all metrics in otelhttp scope - selector: meter_name: go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp stream: attribute_keys: exclude: - http.response.status_code ``` ### Alternatives Considered * Considered a boolean (`composable_views_enabled: true`) or alternative naming (`composable_views`), but opted for an explicit enum (`view_matching_mode`) to support future extensibility. * Considered **first-wins** ordering because first-wins is used more often in the specification, but aligned on **last-wins** to match reviewer intuition for how it should work. * Considered atomic whole-field last-wins for `attribute_keys`, but opted for set composition so global governance policies (e.g., dropping sensitive PII) layer safely with specific View overrides. * Other alternatives are listed in open-telemetry#5013 ### Checklist * [x] Related issues # * [x] Related [OTEP(s)](https://github.com/open-telemetry/oteps) # * [x] Links to the prototypes (when adding or changing features): open-telemetry/opentelemetry-go#8510 * [x] [`CHANGELOG.md`](https://github.com/open-telemetry/opentelemetry-specification/blob/main/CHANGELOG.md) file updated for non-trivial changes * For trivial changes, include `[chore]` in the PR title to skip the changelog check * [x] [Spec compliance matrix](https://github.com/open-telemetry/opentelemetry-specification/blob/main/spec-compliance-matrix/template.yaml) updated if necessary: * [x] [Declarative config data model](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/configuration/data-model.md#overview) is updated if SDK config surface is changed: open-telemetry/opentelemetry-configuration#666 @open-telemetry/specs-metrics-approvers --------- Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

…property Implements composable View matching configuration in support of open-telemetry/opentelemetry-specification#5173. - Adds experimental meter_provider.view_matching_mode/development property ('independent' default, 'composable') - Marks view_matching_mode/development as not_implemented in language support status matrix - Updates existing otel-sdk-config.yaml example and adds validator shelltest edge case

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dashpole requested a review from Copilot June 23, 2026 18:42

dashpole mentioned this pull request Jun 23, 2026

Add composable views matching mode open-telemetry/opentelemetry-specification#5173

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Copilot started reviewing on behalf of dashpole June 23, 2026 18:43 View session

Copilot AI reviewed Jun 23, 2026

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Comment thread schema/meter_provider.yaml Outdated

Comment thread opentelemetry_configuration.json Outdated

Comment thread schema-docs.md Outdated

Comment thread schema-docs.md Outdated

Comment thread CHANGELOG.md Outdated

dashpole force-pushed the add-view-matching-mode branch from 5225b23 to 0e8eb3d Compare June 23, 2026 18:51

dashpole changed the title ~~feat: add experimental view_matching mode to meter provider~~ feat: add experimental view_matching_mode to meter provider Jun 23, 2026

jack-berg reviewed Jul 23, 2026

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Comment thread examples/otel-sdk-config.yaml Outdated

Comment thread schema/meter_provider.yaml Outdated

dashpole force-pushed the add-view-matching-mode branch from 0e8eb3d to fb9dda0 Compare July 23, 2026 15:40

jack-berg reviewed Jul 23, 2026

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Comment thread schema-docs.md

jack-berg reviewed Jul 23, 2026

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dashpole added 5 commits August 13, 2026 18:54

Address review comments for view_matching_mode enum and snippet

bcfd1fc

Move experimental view matching mode property to bottom of list

148c035

Update validator shelltest for view_matching_mode enum ref

5fe30c1

Address review comment: revert schema-docs.md changes after documenta…

0f7a679

…tion move

dashpole force-pushed the add-view-matching-mode branch from acb8776 to 0f7a679 Compare August 13, 2026 18:59

dashpole marked this pull request as ready for review August 13, 2026 19:27

dashpole requested a review from a team as a code owner August 13, 2026 19:27

jack-berg reviewed Aug 13, 2026

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Comment thread snippets/MeterProvider_composable_views.yaml

jack-berg approved these changes Aug 13, 2026

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Address review comment: add explanation comments to composable views …

32f537e

…snippet

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