# Changelog

## vNext

## 0.33.0

Released 2026-Sep-18

- Exporter builder usage and environment configuration are unchanged.
  **Breaking for callers parsing compression strings:** `Compression::from_str`
  (including `.parse::<Compression>()`) now returns the opaque `ParseConfigError`
  instead of `ExporterBuildError`. Update explicit result types and error handling
  that expects `ExporterBuildError::UnsupportedCompressionAlgorithm`. The new error
  implements `Display` and `std::error::Error`; its message is for diagnostics.
  Accepted strings and parsing behavior are unchanged.

  ```rust
  // Before:
  let result: Result<Compression, ExporterBuildError> = value.parse();

  // After:
  let result: Result<Compression, ParseConfigError> = value.parse();
  if let Err(error) = result {
      eprintln!("invalid compression configuration: {error}");
  }
  ```

- Interpret protocol, compression, and metrics temporality environment values
  case-insensitively. Treat empty values as unset, and warn and ignore invalid,
  non-Unicode, or feature-unavailable enum values so resolution can continue
  to the next environment variable or default. Compression `none` explicitly
  disables compression, including when a generic compression value is set.
  Programmatic configuration remains strict.

### Retry

- Retries are now enabled by default for OTLP/HTTP and OTLP/gRPC. The default
  policy uses exponential backoff and jitter with up to 3 retries (4 attempts
  total). Use `.with_retry_policy(RetryPolicy::disabled())` to disable retries,
  or provide a custom `RetryPolicy` to change the behavior.
- **Migration for users of the experimental retry features:** If your
  `Cargo.toml` enables `experimental-grpc-retry` or
  `experimental-http-retry`, remove those feature flags. No migration action is
  required for users who did not enable them.
  [#3621](https://github.com/open-telemetry/opentelemetry-rust/pull/3621)
- **Breaking** Make the `retry` and `retry_classification` modules crate-private,
  removing their retry engine, error type, and protocol classifiers from the
  public API. `RetryPolicy` remains available from the crate root with private
  fields and fluent configuration methods. Replace imports from
  `opentelemetry_otlp::retry` with `opentelemetry_otlp::RetryPolicy`, and replace
  struct literals with its `with_*` methods.
  [#3672](https://github.com/open-telemetry/opentelemetry-rust/pull/3672)

#### Retry fixes

The following fixes apply to retry behavior that was experimental before this
release:

- Retry only HTTP status codes 429, 502, 503, and 504, as required by the OTLP
  specification. The exporter now also honors `Retry-After` on 503 responses.
- Honor positive gRPC `RetryInfo` delays returned with `Unavailable` responses.
- Continue exponential backoff from server-provided `RetryInfo` and
  `Retry-After` delays when subsequent export attempts fail.

### Other changes

- Exporter compression configuration and behavior are unchanged; users of
  `.with_compression(...)` need no changes. **Breaking only for direct conversion
  callers:** removed `TryFrom<Compression>` for
  `tonic::codec::CompressionEncoding`. Code explicitly converting between these
  enums must map the variants itself.

- Return an exporter build error when construction of a built-in reqwest HTTP
  client fails instead of silently falling back to a client without the
  exporter-configured timeout. Failure to spawn the blocking client's setup
  thread, or a panic in that thread, is also returned instead of panicking.

- **Breaking** Removed `Default` from the `TonicExporterBuilderSet` and
  `HttpExporterBuilderSet` typestate markers. This also removes `Default` from
  the transport-selected exporter builders (e.g.
  `SpanExporterBuilder<TonicExporterBuilderSet>`). Use the intended builder
  flow instead:
  ```rust
  // Before (no longer compiles):
  let exporter = SpanExporterBuilder::<TonicExporterBuilderSet>::default().build()?;

  // After (use the builder entry point):
  let exporter = SpanExporter::builder().with_tonic().build()?;
  ```
  Also removed the unused `#[doc(hidden)]` `NoExporterConfig` type.
- **Breaking** Mark `Protocol` and `Compression` as non-exhaustive so new OTLP
  protocols, encodings, and compression algorithms can be added without
  breaking downstream users. External exhaustive matches must add a wildcard
  arm. Constructing existing variants and passing them to exporter builders is
  unchanged.
  ```rust
  let protocol_name = match protocol {
      Protocol::Grpc => "grpc",
      Protocol::HttpBinary => "http/protobuf",
      Protocol::HttpJson => "http/json",
      _ => "unknown", // Required because Protocol is non-exhaustive.
  };
  ```
- **Breaking** Make `Protocol::from_env()` crate-private. Exporter builders
  already resolve `OTEL_EXPORTER_OTLP_PROTOCOL` when built; applications that
  need to inspect the raw environment setting should read the variable
  directly.
- **Breaking** Remove `OTEL_EXPORTER_OTLP_ENDPOINT_DEFAULT`, which always held
  the HTTP default (`http://localhost:4318`) despite gRPC using
  `http://localhost:4317`. Omit `.with_endpoint(...)` to let the selected
  transport use its correct default, or provide the appropriate URL explicitly.
  [#3690](https://github.com/open-telemetry/opentelemetry-rust/issues/3690)
- **Breaking** Restrict `MetricExporterBuilder::with_http()` and `with_tonic()`
  to builders where no transport has been selected, matching the span and log
  exporter builders. Select a transport once; `with_temporality()` remains
  available before or after transport selection.
- **Breaking** Remove the public `HttpExporterBuilder` and
  `TonicExporterBuilder` transport-first APIs. Configure transports through the
  signal builders instead:
  - Replace `HttpExporterBuilder::default()` with the corresponding signal
    exporter builder followed by `.with_http()`, then replace
    `.build_span_exporter()` or `.build_log_exporter()` with `.build()`.
  - Replace `.build_metrics_exporter(temporality)` with
    `.with_temporality(temporality).build()`.
  - Replace `TonicExporterBuilder::default()` with the corresponding signal
    exporter builder followed by `.with_tonic()`.
  Transport-specific configuration methods remain available after
  `.with_http()` or `.with_tonic()`.
- **Breaking** Removed the deprecated `tls` feature alias. Replace `tls` with
  `tls-ring`, or select `tls-aws-lc` or `tls-provider-agnostic` explicitly.
- Exporter builder usage is unchanged. **Breaking for code matching or constructing
  removed error variants:** Simplified `ExporterBuildError` to the exhaustive
  `InvalidConfiguration(String)` and `InternalFailure(String)` variants.
  The enum is no longer marked `#[non_exhaustive]`.
  Configuration errors such as invalid endpoints, missing HTTP clients,
  transport/protocol mismatches, and missing compression features now use
  `InvalidConfiguration`. Replace implementation-specific, non-exhaustive
  matches such as:
  ```rust
  match error {
      ExporterBuildError::InvalidUri(_, _)
      | ExporterBuildError::InvalidConfig { .. }
      | ExporterBuildError::NoHttpClient => {
          eprintln!("fix the exporter configuration");
      }
      ExporterBuildError::InternalFailure(message) => {
          eprintln!("exporter initialization failed: {message}");
      }
      _ => {}
  }
  ```
  with an exhaustive match over the two stable categories:
  ```rust
  match error {
      ExporterBuildError::InvalidConfiguration(message) => {
          eprintln!("fix the exporter configuration: {message}");
      }
      ExporterBuildError::InternalFailure(message) => {
          eprintln!("exporter initialization failed: {message}");
      }
  }
  ```
  Code that propagates build errors with `?` without inspecting their variants
  needs no changes.
  Tonic endpoint errors identify the originating environment variable when
  validating the URI or reporting endpoint-related TLS setup failures.
  [#3691](https://github.com/open-telemetry/opentelemetry-rust/issues/3691)
- Return an exporter build error for invalid OTLP/HTTP endpoint environment
  variables instead of silently falling back to another endpoint or localhost.
  Empty endpoint environment variables are now treated as unset.
- Return an exporter build error for invalid OTLP/gRPC endpoint environment
  variables instead of silently falling back to another endpoint or localhost.
  Empty endpoint environment variables are now treated as unset.
- Add `WithHttpConfig::with_max_request_body_size` to configure the HTTP request
  body limit. OTLP/HTTP request bodies are now limited to 64 MiB by default, before and
  after compression; oversized requests are discarded without being sent or
  retried.
- **Breaking** Seal `WithExportConfig`, `WithHttpConfig`, and
  `WithTonicConfig`. These traits remain public for calling configuration
  methods on OTLP builders, but can no longer be implemented for external
  types.
- Add support for INSECURE environment variables for gRPC (env-var-only, no builder method, per spec):
  `OTEL_EXPORTER_OTLP_INSECURE` (generic), `OTEL_EXPORTER_OTLP_TRACES_INSECURE`,
  `OTEL_EXPORTER_OTLP_METRICS_INSECURE`, `OTEL_EXPORTER_OTLP_LOGS_INSECURE`.
  Per the spec, these only apply to gRPC connections. When an endpoint has no explicit scheme,
  `INSECURE=true` uses `http://`, `INSECURE=false` (default) uses `https://` with auto-TLS.
  **Breaking:** Schemeless endpoints (e.g., `collector.example.com:4317`) now default to `https://`  
  instead of being passed as-is. Set `OTEL_EXPORTER_OTLP_INSECURE=true` for plaintext connections.
  Endpoints with an explicit scheme (e.g., `http://`, `https://`, `unix://`) are unaffected.
  [#774](https://github.com/open-telemetry/opentelemetry-rust/issues/774)
  [#984](https://github.com/open-telemetry/opentelemetry-rust/issues/984)
- **Breaking** Removed the `serialize` feature flag and its implicit `serde`
  dependency. This feature gated `Serialize`/`Deserialize` derives on
  `Protocol` and `Compression`, but the derived representations were incorrect
  (Rust variant names instead of spec values) and the feature only covered
  these two enums. The equivalent feature was removed from the core
  `opentelemetry` crate in 2022.
  **Migration**: Remove `serialize` (and `serde`, if listed) from your feature
  list. If these values are part of serialisable app config, define a local
  config enum or wrapper and convert it to `Protocol` or `Compression` when
  building the exporter.
  [#3711](https://github.com/open-telemetry/opentelemetry-rust/pull/3711)
- **Breaking** Removed `reqwest-rustls-webpki-roots` feature. The `webpki-roots` cargo feature was
  removed from `reqwest` in v0.13.0, making this feature broken for anyone resolving `reqwest >= 0.13.0`.
  **Migration**: Use `reqwest-rustls` instead (now correctly uses `reqwest/rustls` with platform native
  trust roots). If you specifically need Mozilla's embedded CA bundle, construct a custom client:
  ```rust
  let root_store = rustls::RootCertStore::from_iter(
      webpki_roots::TLS_SERVER_ROOTS.iter().cloned(),
  );
  let tls_config = rustls::ClientConfig::builder()
      .with_root_certificates(root_store)
      .with_no_client_auth();
  let client = reqwest::Client::builder()
      .tls_backend_preconfigured(tls_config)
      .build()?;
  exporter_builder.with_http_client(client)
  ```
- Allow to provide http client wrapped in Arc when configuring HTTP exporter. [3468](https://github.com/open-telemetry/opentelemetry-rust/pull/3468)

## 0.32.0

Released 2026-May-08

- Add `tls-provider-agnostic` feature flag for environments that require a custom crypto backend (e.g., OpenSSL for FIPS compliance). Enables TLS code paths without bundling `ring` or `aws-lc-rs`.
- Add `build()` directly on `SpanExporterBuilder`, `MetricExporterBuilder`, and `LogExporterBuilder`
  (before selecting a transport), which auto-selects the transport based on the
  `OTEL_EXPORTER_OTLP_PROTOCOL` environment variable or enabled features.
  [#3394](https://github.com/open-telemetry/opentelemetry-rust/pull/3394)
- **Breaking** Removed `ExportConfig`, `HasExportConfig`, `with_export_config()`, `HasTonicConfig`, `HasHttpConfig`, `TonicConfig`, and `HttpConfig` from public API.
  Use the public `WithExportConfig`, `WithTonicConfig`, and `WithHttpConfig` trait methods instead, which remain unchanged.
- The gRPC/tonic OTLP exporter's build method now returns an error for all signals (traces, metrics, logs) when
  an `https://` endpoint is configured but no TLS feature (`tls-ring` or `tls-aws-lc`) is enabled, instead of
  silently sending unencrypted traffic. When a TLS feature is enabled and an `https://` endpoint is used without
  an explicit `.with_tls_config()`, a default `ClientTlsConfig` is automatically applied.
  [#3182](https://github.com/open-telemetry/opentelemetry-rust/issues/3182)
- Prevent auth tokens from leaking in export error messages. gRPC and HTTP
  exporter errors no longer include potentially sensitive server responses
  (e.g., authentication tokens echoed back). Error messages returned to SDK
  processors contain only the gRPC status code or HTTP status code. Full
  details are logged at DEBUG level only.
  [#3021](https://github.com/open-telemetry/opentelemetry-rust/issues/3021)
- Surface pre-flight transport error details at ERROR level when `grpc-tonic`
  OTLP export fails due to a local misconfiguration. When the returned
  `tonic::Status` wraps a local transport error (invalid URL, connect failure,
  DNS), its source chain (e.g., `"transport error: invalid URI"`) is appended
  to the returned error so SDK processors surface it at ERROR without
  requiring DEBUG logging. Server-returned gRPC status messages remain
  DEBUG-only to preserve the auth-token leak safeguards from
  [#3021](https://github.com/open-telemetry/opentelemetry-rust/issues/3021).
  [#3331](https://github.com/open-telemetry/opentelemetry-rust/issues/3331)
- Add support for per-signal protocol environment variables:
  `OTEL_EXPORTER_OTLP_TRACES_PROTOCOL`, `OTEL_EXPORTER_OTLP_METRICS_PROTOCOL`,
  `OTEL_EXPORTER_OTLP_LOGS_PROTOCOL`. These allow configuring different transport protocols
  per signal type. Signal-specific vars take precedence over generic `OTEL_EXPORTER_OTLP_PROTOCOL`.
  The auto-select `build()` method on each exporter builder now respects the full priority chain:
  signal-specific env var > generic env var > feature-based default.
- Transport/protocol mismatch validation: HTTP transport returns `InvalidConfig` when gRPC protocol
  is requested; gRPC transport returns `InvalidConfig` when an HTTP protocol is requested.
- **Breaking**: `Protocol::default()` no longer consults the `OTEL_EXPORTER_OTLP_PROTOCOL`
  environment variable. It now returns only the feature-based default (http-json > http-proto >
  grpc-tonic). Protocol resolution from environment variables is handled internally by the
  exporter builders. Users who relied on `Protocol::default()` to read env vars should use
  `Protocol::from_env()` instead.
- Add support for `OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE` environment variable
  to configure metrics temporality. Accepted values: `cumulative` (default), `delta`,
  `lowmemory` (case-insensitive). Programmatic `.with_temporality()` overrides the env var.
- Fix `NoHttpClient` error when multiple HTTP client features are enabled by using priority-based selection (`reqwest-client` > `hyper-client` > `reqwest-blocking-client`). [#2994](https://github.com/open-telemetry/opentelemetry-rust/issues/2994)
- Add partial success response handling for OTLP exporters (traces, metrics, logs) per OTLP spec. Exporters now log warnings when the server returns partial success responses with rejected items and error messages. [#865](https://github.com/open-telemetry/opentelemetry-rust/issues/865)
- Refactor `internal-logs` feature in `opentelemetry-otlp` to reduce unnecessary dependencies[3191](https://github.com/open-telemetry/opentelemetry-rust/pull/3192)
- Fixed [#2777](https://github.com/open-telemetry/opentelemetry rust/issues/2777)  to properly handle `shutdown_with_timeout()` when using `grpc-tonic`.
- Deprecate `tls` feature in favor of explicit `tls-ring` and `tls-aws-lc` features.
  **Migration**: Replace `tls` with `tls-ring` (or `tls-aws-lc`). Users of `tls-roots` or `tls-webpki-roots` must now also enable one of these.
- Prevent logging of header values in OTLP tonic exporter [#3465](https://github.com/open-telemetry/opentelemetry-rust/pull/3465)

## 0.31.0

Released 2025-Sep-25

- Update `opentelemetry-proto` and `opentelemetry-http` dependency version to 0.31.0
- Add HTTP compression support with `gzip-http` and `zstd-http` feature flags
- Add retry with exponential backoff and throttling support for HTTP and gRPC exporters
  This behaviour is opt in via the `experimental-grpc-retry` and `experimental-http-retry` flags on this crate. You can customize the retry policy using the `with_retry_policy` on the exporter builders.

## 0.30.0

Released 2025-May-23

- Update `opentelemetry` dependency version to 0.30
- Update `opentelemetry_sdk` dependency version to 0.30
- Update `opentelemetry-http` dependency version to 0.30
- Update `opentelemetry-proto` dependency version to 0.30
- Update `tonic` dependency version to 0.13
- Re-export `tonic` types under `tonic_types`
  [2898](https://github.com/open-telemetry/opentelemetry-rust/pull/2898)
- Publicly re-exported `MetricExporterBuilder`, `SpanExporterBuilder`, and
  `LogExporterBuilder` types, enabling users to directly reference and use these
  builder types for metrics, traces, and logs exporters.
  [2966](https://github.com/open-telemetry/opentelemetry-rust/pull/2966)

## 0.29.0

Released 2025-Mar-21

- Update `opentelemetry` dependency version to 0.29
- Update `opentelemetry_sdk` dependency version to 0.29
- Update `opentelemetry-http` dependency version to 0.29
- Update `opentelemetry-proto` dependency version to 0.29

- The `OTEL_EXPORTER_OTLP_TIMEOUT`, `OTEL_EXPORTER_OTLP_TRACES_TIMEOUT`, `OTEL_EXPORTER_OTLP_METRICS_TIMEOUT` and `OTEL_EXPORTER_OTLP_LOGS_TIMEOUT` are changed from seconds to milliseconds.
- Fixed `.with_headers()` in `HttpExporterBuilder` to correctly support multiple key/value pairs. [#2699](https://github.com/open-telemetry/opentelemetry-rust/pull/2699)
- Fixed
  [#2770](https://github.com/open-telemetry/opentelemetry-rust/issues/2770)
  partially to properly handle `shutdown()` when using `http`. (`tonic` still
  does not do proper shutdown)
- *Breaking*
 ExporterBuilder's build() method now Result with `ExporterBuildError` being the
 Error variant. Previously it returned signal specific errors like `LogError`
 from the `opentelemetry_sdk`, which are no longer part of the sdk. No changes
 required if you were using unwrap/expect. If you were matching on the returning
 Error enum, replace with the enum `ExporterBuildError`. Unlike the previous
 `Error` which contained many variants unrelated to building an exporter, the
 new one returns specific variants applicable to building an exporter. Some
 variants might be applicable only on select features.
 Also, now unused `Error` enum is removed.
- **Breaking** `ExportConfig`'s `timeout` field is now optional(`Option<Duration>`)
- **Breaking** Export configuration done via code is final. ENV variables cannot be used to override the code config.
  Do not use code based config, if there is desire to control the settings via ENV variables.
  List of ENV variables and corresponding setting being affected by this change.
  - `OTEL_EXPORTER_OTLP_ENDPOINT` -> `ExportConfig.endpoint`
  - `OTEL_EXPORTER_OTLP_TIMEOUT` -> `ExportConfig.timeout`

## 0.28.0

Released 2025-Feb-10

- Update `opentelemetry` dependency version to 0.28.
- Update `opentelemetry_sdk` dependency version to 0.28.
- Update `opentelemetry-http` dependency version to 0.28.
- Update `opentelemetry-proto` dependency version to 0.28.
- Bump msrv to 1.75.0.
- Feature flag "populate-logs-event-name" is removed as no longer relevant.
  LogRecord's `event_name()` is now automatically populated on the newly added
  "event_name" field in LogRecord proto definition.
- Remove "grpc-tonic" feature from default, and instead add "http-proto" and
  "reqwest-blocking-client" features as default, to align with the
  specification.
  [2516](https://github.com/open-telemetry/opentelemetry-rust/pull/2516)
- Remove unnecessarily public trait `opentelemetry_otlp::metrics::MetricsClient`
  and `MetricExporter::new(..)` method. Use
  `MetricExporter::builder()...build()` to obtain `MetricExporter`.
- The HTTP clients (reqwest, reqwest-blocking, hyper) now support the
  export timeout interval configured in below order
  - Signal specific env variable `OTEL_EXPORTER_OTLP_TRACES_TIMEOUT`,
  `OTEL_EXPORTER_OTLP_LOGS_TIMEOUT` or `OTEL_EXPORTER_OTLP_TIMEOUT`.
  - `OTEL_EXPORTER_OTLP_TIMEOUT` env variable.
  - `with_http().with_timeout()` API method of
`LogExporterBuilder` and `SpanExporterBuilder` and `MetricsExporterBuilder`.
  - The default interval of 10 seconds is used if none is configured.

## 0.27.0

Released 2024-Nov-11

- Update `opentelemetry` dependency version to 0.27
- Update `opentelemetry_sdk` dependency version to 0.27
- Update `opentelemetry-http` dependency version to 0.27
- Update `opentelemetry-proto` dependency version to 0.27

- **BREAKING**:
  - ([#2217](https://github.com/open-telemetry/opentelemetry-rust/pull/2217)) **Replaced**: The `MetricsExporterBuilder` interface is modified from `with_temporality_selector` to `with_temporality` example can be seen below:
    Previous Signature:
    ```rust
    MetricsExporterBuilder::default().with_temporality_selector(DeltaTemporalitySelector::new())
    ```
    Updated Signature:
    ```rust
    MetricsExporterBuilder::default().with_temporality(opentelemetry_sdk::metrics::Temporality::Delta)
    ```
  - ([#2221](https://github.com/open-telemetry/opentelemetry-rust/pull/2221)) **Replaced**:
    - The `opentelemetry_otlp::new_pipeline().{trace,logging,metrics}()` interface is now replaced with `{TracerProvider,SdkMeterProvider,LoggerProvider}::builder()`.
    - The `opentelemetry_otlp::new_exporter()` interface is now replaced with `{SpanExporter,MetricsExporter,LogExporter}::builder()`.

    Pull request [#2221](https://github.com/open-telemetry/opentelemetry-rust/pull/2221) has a detailed migration guide in the description. See example below,
    and [basic-otlp](https://github.com/open-telemetry/opentelemetry-rust/blob/main/opentelemetry-otlp/examples/basic-otlp/src/main.rs) for more details:

    Previous Signature:
    ```rust
    let logger_provider: LoggerProvider = opentelemetry_otlp::new_pipeline()
      .logging()
      .with_resource(RESOURCE.clone())
      .with_exporter(
          opentelemetry_otlp::new_exporter()
              .tonic()
              .with_endpoint("http://localhost:4317")
      )
      .install_batch(runtime::Tokio)?;
    ```
    Updated Signature:
    ```rust
    let exporter = LogExporter::builder()
        .with_tonic()
        .with_endpoint("http://localhost:4317")
        .build()?;

    Ok(LoggerProvider::builder()
        .with_resource(RESOURCE.clone())
        .with_batch_exporter(exporter, runtime::Tokio)
        .build())
    ```
  - **Renamed**
    - ([#2255](https://github.com/open-telemetry/opentelemetry-rust/pull/2255)): de-pluralize Metric types.
      - `MetricsExporter` -> `MetricExporter`
      - `MetricsExporterBuilder` -> `MetricExporterBuilder`

  - [#2263](https://github.com/open-telemetry/opentelemetry-rust/pull/2263)
  Support `hyper` client for opentelemetry-otlp. This can be enabled using flag `hyper-client`.
  Refer example: https://github.com/open-telemetry/opentelemetry-rust/tree/main/opentelemetry-otlp/examples/basic-otlp-http

## v0.26.0
Released 2024-Sep-30

- Update `opentelemetry` dependency version to 0.26
- Update `opentelemetry_sdk` dependency version to 0.26
- Update `opentelemetry-http` dependency version to 0.26
- Update `opentelemetry-proto` dependency version to 0.26
- Bump MSRV to 1.71.1 [2140](https://github.com/open-telemetry/opentelemetry-rust/pull/2140)

## v0.25.0

- Update `opentelemetry` dependency version to 0.25
- Update `opentelemetry_sdk` dependency version to 0.25
- Update `opentelemetry-http` dependency version to 0.25
- Update `opentelemetry-proto` dependency version to 0.25
- Starting with this version, this crate will align with `opentelemetry` crate
  on major,minor versions.
- **Breaking**
The logrecord event-name is added as an attribute only if the feature flag
`populate-logs-event-name` is enabled. The name of the attribute is changed from
"name" to "event.name".
[1994](https://github.com/open-telemetry/opentelemetry-rust/pull/1994),
[2050](https://github.com/open-telemetry/opentelemetry-rust/pull/2050)

## v0.17.0

- Add "metrics", "logs" to default features. With this, default feature list is
  "trace", "metrics" and "logs".
- **Breaking** `OtlpMetricPipeline.build()` no longer invoke the
  `global::set_meter_provider`. User who setup the pipeline must do it
  themselves using `global::set_meter_provider(meter_provider.clone());`.
- Add `with_resource` on `OtlpLogPipeline`, replacing the `with_config` method.
Instead of using
`.with_config(Config::default().with_resource(RESOURCE::default()))` users must
now use `.with_resource(RESOURCE::default())` to configure Resource when using
`OtlpLogPipeline`.
- **Breaking** The methods `OtlpTracePipeline::install_simple()` and `OtlpTracePipeline::install_batch()` would now return `TracerProvider` instead of `Tracer`.
  These methods would also no longer set the global tracer provider. It would now be the responsibility of users to set it by calling `global::set_tracer_provider(tracer_provider.clone());`. Refer to the [basic-otlp](https://github.com/open-telemetry/opentelemetry-rust/blob/main/opentelemetry-otlp/examples/basic-otlp/src/main.rs) and [basic-otlp-http](https://github.com/open-telemetry/opentelemetry-rust/blob/main/opentelemetry-otlp/examples/basic-otlp-http/src/main.rs) examples on how to initialize OTLP Trace Exporter.
- **Breaking** Correct the misspelling of "webkpi" to "webpki" in features [#1842](https://github.com/open-telemetry/opentelemetry-rust/pull/1842)
- Bump MSRV to 1.70 [#1840](https://github.com/open-telemetry/opentelemetry-rust/pull/1840)
- Fixing the OTLP HTTP/JSON exporter. [#1882](https://github.com/open-telemetry/opentelemetry-rust/pull/1882) - The exporter was broken in the
  previous release.
- **Breaking** [1869](https://github.com/open-telemetry/opentelemetry-rust/pull/1869) The OTLP logs exporter now overrides the [InstrumentationScope::name](https://github.com/open-telemetry/opentelemetry-proto/blob/b3060d2104df364136d75a35779e6bd48bac449a/opentelemetry/proto/common/v1/common.proto#L73) field with the `target` from `LogRecord`, if target is populated.
- Groups batch of `LogRecord` and `Span` by their resource and instrumentation scope before exporting, for better efficiency [#1873](https://github.com/open-telemetry/opentelemetry-rust/pull/1873).
- **Breaking** Update to `http` v1 and `tonic` v0.12 [#1674](https://github.com/open-telemetry/opentelemetry-rust/pull/1674)
- Update `opentelemetry` dependency version to 0.24
- Update `opentelemetry_sdk` dependency version to 0.24
- Update `opentelemetry-http` dependency version to 0.13
- Update `opentelemetry-proto` dependency version to 0.7

## v0.16.0

### Fixed

- URL encoded values in `OTEL_EXPORTER_OTLP_HEADERS` are now correctly decoded. [#1578](https://github.com/open-telemetry/opentelemetry-rust/pull/1578)
- OTLP exporter will not change the URL added through `ExportConfig` [#1706](https://github.com/open-telemetry/opentelemetry-rust/pull/1706)
- Default grpc endpoint will not have path based on signal(e.g `/v1/traces`) [#1706](https://github.com/open-telemetry/opentelemetry-rust/pull/1706)
- Fix feature flags for `OTEL_EXPORTER_OTLP_PROTOCOL_DEFAULT` [#1746](https://github.com/open-telemetry/opentelemetry-rust/pull/1746)

### Added

- Added `DeltaTemporalitySelector` ([#1568])
- Add `webpki-roots` features to `reqwest` and `tonic` backends

[#1568]: https://github.com/open-telemetry/opentelemetry-rust/pull/1568

### Changed
 - **Breaking** Remove global provider for Logs [#1691](https://github.com/open-telemetry/opentelemetry-rust/pull/1691/)
      - The method OtlpLogPipeline::install_simple() and OtlpLogPipeline::install_batch() now return `LoggerProvider` instead of
      `Logger`. Refer to the [basic-otlp](https://github.com/open-telemetry/opentelemetry-rust/blob/main/opentelemetry-otlp/examples/basic-otlp/src/main.rs) and [basic-otlp-http](https://github.com/open-telemetry/opentelemetry-rust/blob/main/opentelemetry-otlp/examples/basic-otlp-http/src/main.rs) examples for how to initialize OTLP Log Exporter to use with OpenTelemetryLogBridge and OpenTelemetryTracingBridge respectively.
- Update `opentelemetry` dependency version to 0.23
- Update `opentelemetry_sdk` dependency version to 0.23
- Update `opentelemetry-http` dependency version to 0.12
- Update `opentelemetry-proto` dependency version to 0.6

## v0.15.0

### Added

- Support custom channels in topic exporters  [#1335](https://github.com/open-telemetry/opentelemetry-rust/pull/1335)
- Allow specifying OTLP Tonic metadata from env variable [#1377](https://github.com/open-telemetry/opentelemetry-rust/pull/1377)

### Changed
- Update to tonic 0.11 and prost 0.12 [#1536](https://github.com/open-telemetry/opentelemetry-rust/pull/1536)

### Fixed
- Fix `tonic()` to the use correct port. [#1556](https://github.com/open-telemetry/opentelemetry-rust/pull/1556)

### Removed
- **Breaking** Remove support for surf HTTP client [#1537](https://github.com/open-telemetry/opentelemetry-rust/pull/1537)
- **Breaking** Remove support for grpcio transport [#1534](https://github.com/open-telemetry/opentelemetry-rust/pull/1534)

## v0.14.0

### Added

- Add `build_{signal}_exporter` methods to client builders [#1187](https://github.com/open-telemetry/opentelemetry-rust/pull/1187)
- Add `grpcio` metrics exporter [#1202](https://github.com/open-telemetry/opentelemetry-rust/pull/1202)
- Allow specifying OTLP HTTP headers from env variable [#1290](https://github.com/open-telemetry/opentelemetry-rust/pull/1290)

### Changed

- Bump MSRV to 1.65 [#1318](https://github.com/open-telemetry/opentelemetry-rust/pull/1318)
- Bump MSRV to 1.64 [#1203](https://github.com/open-telemetry/opentelemetry-rust/pull/1203)
- Changed dependency from `opentelemetry_api` to `opentelemetry` as the latter
  is now the API crate. [#1226](https://github.com/open-telemetry/opentelemetry-rust/pull/1226)
- Make `NoExporterBuilder` a compiling time error [#1272](https://github.com/open-telemetry/opentelemetry-rust/pull/1272)

## v0.13.0

### Added

- Add OTLP HTTP Metrics Exporter [#1020](https://github.com/open-telemetry/opentelemetry-rust/pull/1020).
- Add tonic compression support [#1165](https://github.com/open-telemetry/opentelemetry-rust/pull/1165).

### Changed

- make the tonic/transport feature optional #985
- update to opentelemetry-api v0.20.0

### Fixed

- Fix a missing import when http-proto is enabled without grpc-sys #1081

## v0.12.0

### Added

- Add batch config for otlp pipeline [#979](https://github.com/open-telemetry/opentelemetry-rust/pull/979).
- Add tonic interceptor [#901](https://github.com/open-telemetry/opentelemetry-rust/pull/901).

### Changed

- Update `opentelemetry` to 0.19.
- Update `opentelemetry-semantic-conventions` to 0.11.
- Update `opentelemetry-http` to 0.8.
- Bump MSRV to 1.57 [#953](https://github.com/open-telemetry/opentelemetry-rust/pull/953).
- Add `User-Agent` header on all exporters [#896](https://github.com/open-telemetry/opentelemetry-rust/pull/896).
- Improve OTLP exporter environment variable handling [#912](https://github.com/open-telemetry/opentelemetry-rust/pull/912).
- Fix the issue where tonic exporter builder ignored provided metadata [#937](https://github.com/open-telemetry/opentelemetry-rust/pull/937).
- Export `MetricsExporterBuilder` [#943](https://github.com/open-telemetry/opentelemetry-rust/pull/943).
- Report OTLP http export errors [#945](https://github.com/open-telemetry/opentelemetry-rust/pull/945).
- Change to export using v0.19.0 protobuf definitions. [#989](https://github.com/open-telemetry/opentelemetry-rust/pull/989).
- Update dependencies and bump MSRV to 1.60 [#969](https://github.com/open-telemetry/opentelemetry-rust/pull/969).


## v0.11.0

### Changed

- reduce `tokio` feature requirements #750
- Update to opentelemetry v0.18.0
- Update to opentelemetry-http v0.7.0
- Update `tonic` to 0.7 #783
- Automatically add traces / metrics paths #806

## v0.10.0

### Changed

- Update to opentelemetry v0.17.0
- Update to opentelemetry-http v0.6.0
- Update `tonic` to 0.6 #660

## v0.9.0

### Changed

- Merge metrics and tracing pipeline #585
- Update to opentelemetry v0.16.0

### Fixed

- `MetricsExporterBuilder` drops `exporter_pipeline` #590
- Improve error messages #603
- Upgrade `tonic` to `0.5.x` #597

## v0.8.0

### Changed

- Update grpcio version and add the coverage badge #556
- Update to opentelemetry v0.15.0

## v0.7.0

### Added

- adding otlp http transport, using proto binary #516

### Fixed

- docs cannot compile #507
- exporter cannot merge IntSum correctly. #518
- update metrics proto and metric transformation #535

### Changed

- Allow users to bring their own tonic channel  #515
- Remove default surf features #546
- Update to opentelemetry v0.14.0

### v0.6.0

### Added
- Examples on how to connect to an external otlp using tonic, tls and tokio #449
- Examples on how to connect to an external otlp using grpcio and tls #450
- `with_env` method for `OtlpPipelineBuilder` to use environment variables to config otlp pipeline #451
- Update `tracing-grpc` example to include extractors and injectors #464
- Mentioned `service.name` resource in README #476

### Changed
- Update to opentelemetry v0.13.0
- Update `tonic-build` dependency to 0.4 #463
- Update the opentelemetry pipeline to use API to choose grpc layer instead of feature #467
- Rename trace config with_default_sampler to with_sampler #482

### Removed
- Removed `from_env` and use environment variables to initialize the configurations by default #459
- Removed support for running tonic without tokio runtime #483

## v0.5.0

### Added

- Otlp metric exporter #402
- Otlp exporter integration test #424

### Changed

- Update to opentelemetry v0.12.0
- Update tokio to v1 #421

## v0.4.0

### Added

- Tonic support #352
- Add openssl feature flags for grpcio #367

### Changed

- Update to opentelemetry v0.11.0
- Update default otlp port to `4317` #388

### Fixed

- Propagate `Resource` information #366
- Propagate `Resource` in tonic as well #390

## v0.3.0

### Changed

- Update to opentelemetry v0.10.0

## v0.2.0

### Changed

- Update to opentelemetry v0.9.0
- Add exporter pipeline #210

## v0.1.0

### Added

- Initial Alpha implementation