Merge branch 'main' into cijothomas/metric-doc2

Author: cijothomas

.github/workflows/ci.yml

@@ -72,7 +72,7 @@ jobs:
       with:
         toolchain: stable
         components: rustfmt, clippy
-    - uses: taiki-e/install-action@33734a118689b0b418824fb78ea2bf18e970b43b # v2.50.4
+    - uses: taiki-e/install-action@735e5933943122c5ac182670a935f54a949265c1 # v2.52.4
       with:
           tool: cargo-hack
     - uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # v3.0.0
@@ -100,7 +100,7 @@ jobs:
           # https://github.com/awslabs/cargo-check-external-types/releases
           toolchain: nightly-2025-05-04
           components: rustfmt
-      - uses: taiki-e/install-action@33734a118689b0b418824fb78ea2bf18e970b43b # v2.50.4
+      - uses: taiki-e/install-action@735e5933943122c5ac182670a935f54a949265c1 # v2.52.4
         with:
           tool: [email protected]
       - name: external-type-check
@@ -124,7 +124,7 @@ jobs:
       - uses: dtolnay/rust-toolchain@b3b07ba8b418998c39fb20f53e8b695cdcc8de1b
         with:
           toolchain: stable
-      - uses: taiki-e/install-action@33734a118689b0b418824fb78ea2bf18e970b43b # v2.50.4
+      - uses: taiki-e/install-action@735e5933943122c5ac182670a935f54a949265c1 # v2.52.4
         with:
           tool: cargo-msrv
       - uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # v3.0.0
@@ -206,7 +206,7 @@ jobs:
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
       - name: Install cargo-llvm-cov
-        uses: taiki-e/install-action@33734a118689b0b418824fb78ea2bf18e970b43b # v2.50.4
+        uses: taiki-e/install-action@735e5933943122c5ac182670a935f54a949265c1 # v2.52.4
         with:
           tool: cargo-llvm-cov
       - name: cargo generate-lockfile
@@ -215,7 +215,7 @@ jobs:
       - name: cargo llvm-cov
         run: cargo llvm-cov --locked --all-features --workspace --lcov --lib --output-path lcov.info
       - name: Upload to codecov.io
-        uses: codecov/codecov-action@ad3126e916f78f00edff4ed0317cf185271ccc2d # v5.4.2
+        uses: codecov/codecov-action@18283e04ce6e62d37312384ff67231eb8fd56d24 # v5.4.3
         env:
           CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
         with:
@@ -224,8 +224,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-      - uses: dtolnay/rust-toolchain@4305c38b25d97ef35a8ad1f985ccf2d2242004f2 # stable
+      - uses: dtolnay/rust-toolchain@b3b07ba8b418998c39fb20f53e8b695cdcc8de1b # stable
         with:
+          toolchain: stable
           components: rustfmt
       - uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # v3.0.0
         with:
@@ -253,7 +254,7 @@ jobs:
       - uses: dtolnay/rust-toolchain@b3b07ba8b418998c39fb20f53e8b695cdcc8de1b
         with:
           toolchain: stable
-      - uses: taiki-e/install-action@33734a118689b0b418824fb78ea2bf18e970b43b # v2.50.4
+      - uses: taiki-e/install-action@735e5933943122c5ac182670a935f54a949265c1 # v2.52.4
         with:
           tool: cargo-machete
       - name: cargo machete

.github/workflows/fossa.yml

@@ -19,7 +19,7 @@ jobs:
 
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
 
-      - uses: fossas/fossa-action@c0a7d013f84c8ee5e910593186598625513cc1e4 # v1.6.0
+      - uses: fossas/fossa-action@3ebcea1862c6ffbd5cf1b4d0bd6b3fe7bd6f2cac # v1.7.0
         with:
           api-key: ${{secrets.FOSSA_API_KEY}}
           team: OpenTelemetry

.github/workflows/ossf-scorecard.yml

@@ -29,7 +29,7 @@ jobs:
         with:
           persist-credentials: false
 
-      - uses: ossf/scorecard-action@f49aabe0b5af0936a0987cfb85d86b75731b0186 # v2.4.1
+      - uses: ossf/scorecard-action@05b42c624433fc40578a4040d5cf5e36ddca8cde # v2.4.2
         with:
           results_file: results.sarif
           results_format: sarif

Cargo.toml

@@ -74,7 +74,7 @@ sysinfo = "0.32"
 tempfile = "3.3.0"
 testcontainers = "0.23.1"
 tracing-log = "0.2"
-tracing-opentelemetry = "0.30"
+tracing-opentelemetry = "0.31"
 typed-builder = "0.20"
 uuid = "1.3"
 

README.md

@@ -35,11 +35,11 @@ documentation.
 | Baggage               | RC                 |
 | Propagators           | Beta               |
 | Logs-API              | Stable*            |
-| Logs-SDK              | Stable              |
+| Logs-SDK              | Stable             |
 | Logs-OTLP Exporter    | RC                 |
 | Logs-Appender-Tracing | Stable             |
 | Metrics-API           | Stable             |
-| Metrics-SDK           | RC                 |
+| Metrics-SDK           | Stable             |
 | Metrics-OTLP Exporter | RC                 |
 | Traces-API            | Beta               |
 | Traces-SDK            | Beta               |

docs/release_0.30.md

@@ -0,0 +1,68 @@
+# Release Notes 0.30
+
+OpenTelemetry Rust 0.30 introduces a few breaking changes to the
+`opentelemetry_sdk` crate in the `metrics` feature. These changes were essential
+to drive the Metrics SDK towards stability. With this release, the Metrics SDK
+is officially declared stable. The Metrics API was declared stable last year,
+and previously, the Logs API, SDK, and OTel-Appender-Tracing were also marked
+stable. Importantly, no breaking changes have been introduced to components
+already marked as stable.
+
+It is worth noting that the `opentelemetry-otlp` crate remains in a
+Release-Candidate state and is not yet considered stable. With the API and SDK
+for Logs and Metrics now stable, the focus will shift towards further refining
+and stabilizing the OTLP Exporters in upcoming releases. Additionally,
+Distributed Tracing is expected to progress towards stability, addressing key
+interoperability challenges.
+
+For detailed changelogs of individual crates, please refer to their respective
+changelog files. This document serves as a summary of the main changes.
+
+## Key Changes
+
+### Metrics SDK Improvements
+
+1. **Stabilized "view" features**: Previously under an experimental feature
+   flag, views can now be used to modify the name, unit, description, and
+   cardinality limit of a metric. Advanced view capabilities, such as changing
+   aggregation or dropping attributes, remain under the experimental feature
+   flag.
+
+2. **Cardinality capping**: Introduced the ability to cap cardinality and
+   configure limits using views.
+
+3. **Polished public API**: Refined the public API to hide implementation
+   details from exporters, enabling future internal optimizations and ensuring
+   consistency. Some APIs related to authoring custom metric readers have been
+   moved behind experimental feature flags. These advanced use cases require
+   more time to finalize the API surface before being included in the stable
+   release.
+
+### Context-Based Suppression
+
+Added the ability to suppress telemetry based on Context. This feature prevents
+telemetry-induced-telemetry scenarios and addresses a long-standing issue. Note
+that suppression relies on proper context propagation. Certain libraries used in
+OTLP Exporters utilize `tracing` but do not adopt OpenTelemetry's context
+propagation. As a result, not all telemetry is automatically suppressed with
+this feature. Improvements in this area are expected in future releases.
+
+## Next Release
+
+In the [next
+release](https://github.com/open-telemetry/opentelemetry-rust/milestone/22), the
+focus will shift to OTLP Exporters and Distributed Tracing, specifically
+resolving
+[interoperability](https://github.com/open-telemetry/opentelemetry-rust/issues/2420)
+issues with `tokio-tracing` and other fixes required to drive Distributed
+Tracing towards stability.
+
+## Acknowledgments
+
+Thank you to everyone who contributed to this milestone. We welcome your
+feedback through GitHub issues or discussions in the OTel-Rust Slack channel
+[here](https://cloud-native.slack.com/archives/C03GDP0H023).
+
+We are also excited to announce that [Anton Grübel](https://github.com/gruebel)
+and [Björn Antonsson](https://github.com/bantonsson) have joined the OTel Rust
+project as Approvers.

examples/metrics-advanced/README.md

@@ -12,6 +12,3 @@ Run the following, and the Metrics will be written out to stdout.
 ```shell
 $ cargo run
 ```
-
-
-

examples/metrics-advanced/src/main.rs

@@ -85,15 +85,23 @@ async fn main() -> Result<(), Box<dyn Error + Send + Sync + 'static>> {
         .with_description("My histogram example description")
         .build();
 
-    // Record measurements using the histogram instrument.
-    // This metric will have a cardinality limit of 2,
-    // as set in the view. Because of this, only the first two
-    // measurements will be recorded, and the rest will be folded
-    // into the overflow attribute.
+    // Record measurements using the histogram instrument. This metric will have
+    // a cardinality limit of 2, as set in the view. Because of this, only the
+    // first two distinct attribute combinations will be recorded, and the rest
+    // will be folded into the overflow attribute. Any number of measurements
+    // can be recorded as long as they use the same or already-seen attribute
+    // combinations.
     histogram2.record(1.5, &[KeyValue::new("mykey1", "v1")]);
-
     histogram2.record(1.2, &[KeyValue::new("mykey1", "v2")]);
 
+    // Repeatedly emitting measurements for "v1" and "v2" will not
+    // trigger overflow, as they are already seen attribute combinations.
+    histogram2.record(1.7, &[KeyValue::new("mykey1", "v1")]);
+    histogram2.record(1.8, &[KeyValue::new("mykey1", "v2")]);
+
+    // Emitting measurements for new attribute combinations will trigger
+    // overflow, as the cardinality limit of 2 has been reached.
+    // All the below measurements will be folded into the overflow attribute.
     histogram2.record(1.23, &[KeyValue::new("mykey1", "v3")]);
 
     histogram2.record(1.4, &[KeyValue::new("mykey1", "v4")]);
@@ -104,9 +112,9 @@ async fn main() -> Result<(), Box<dyn Error + Send + Sync + 'static>> {
 
     histogram2.record(1.8, &[KeyValue::new("mykey1", "v7")]);
 
-    // Metrics are exported by default every 30 seconds when using stdout exporter,
+    // Metrics are exported by default every 60 seconds when using stdout exporter,
     // however shutting down the MeterProvider here instantly flushes
-    // the metrics, instead of waiting for the 30 sec interval.
+    // the metrics, instead of waiting for the 60 sec interval.
     meter_provider.shutdown()?;
     Ok(())
 }

examples/metrics-basic/README.md

@@ -11,6 +11,3 @@ Run the following, and the Metrics will be written out to stdout.
 ```shell
 $ cargo run
 ```
-
-
-

examples/metrics-basic/src/main.rs

@@ -136,9 +136,9 @@ async fn main() -> Result<(), Box<dyn Error>> {
         })
         .build();
 
-    // Metrics are exported by default every 30 seconds when using stdout
+    // Metrics are exported by default every 60 seconds when using stdout
     // exporter, however shutting down the MeterProvider here instantly flushes
-    // the metrics, instead of waiting for the 30 sec interval. Shutdown returns
+    // the metrics, instead of waiting for the 60 sec interval. Shutdown returns
     // a result, which is bubbled up to the caller The commented code below
     // demonstrates handling the shutdown result, instead of bubbling up the
     // error.