Added

• opentelemetry-exporter-prometheus: add support to configure Resource attributes as metric labels (#5122)
• infra: add renovate (#5202)
• opentelemetry-api, opentelemetry-sdk: add support for extended attribute values everywhere. (#5266)
• opentelemetry-sdk: wire the top-level log_level field in declarative configuration — when set, maps the OTel SeverityNumber value to a Python logging level and applies it to the opentelemetry logger so SDK internal diagnostics respect the configured severity. (#5351)
• opentelemetry-sdk: add the new stable AlwaysRecordSampler (#5354)
• opentelemetry-configuration, opentelemetry-sdk: wire top-level attribute_limits into per-signal providers via declarative config; add log_record_limits support to LoggerProvider (#5365)
• opentelemetry-exporter-otlp-json-http: add OTLP JSON HTTP exporter package (#5374)
• opentelemetry-api, opentelemetry-sdk: add enabled() support to the Logger API, SDK, and LogRecordProcessor to let instrumentation skip expensive work when logging is disabled (#5380)
• opentelemetry-exporter-otlp-json-file: add OTLP JSON file Docker tests (#5412)
• opentelemetry-configuration: wire the experimental tracer_configurator/development, meter_configurator/development and logger_configurator/development fields into create_tracer_provider, create_meter_provider and create_logger_provider, so per-instrumentation-scope enabled overrides declared in the config file are applied to the provider (previously these fields were parsed but silently discarded). The logger minimum_severity/trace_based fields are not supported by the Python SDK and are ignored with a warning. (#5418)
• docs/examples: add example on how to manually setup the SDK to get SDK metrics (#5449)
• opentelemetry-docker-tests: add Prometheus exporter docker tests (#5457)
• opentelemetry-sdk: count records dropped after shutdown on otel.sdk.processor.{span,log}.processed with error.type=already_shutdown (batch span/log and simple log processors), which the semantic conventions define as a valid value for this metric. (#5509)
• opentelemetry-semantic-conventions: update semantic conventions to v1.44.0 (#5511)
• opentelemetry-sdk: add host.id to the host resource detector (#5653)
• opentelemetry-test-utils: add CapturingSampler to record what samplers receive in instrumentation tests (#5681)

Changed

• Enable PIE (flake8-pie) ruff rule and fix all violations (#5150)
• The public opentelemetry.util.types.AttributeValue type in package opentelemetry-api is being expanded to include None, heterogeneous sequences of primitive types (and nested sequences) as opposed to only homogeneous primitive sequences, and Mappings of strings to any primitive types or sequences/mappings (which themselves must only contain primitive types or sequences/mappings validated the same way). If a bytes type is set as an attribute value in the SDK, it will no longer be utf-8 decoded to a string, instead it will be passed along as is in accordance with the OTEL spec, since bytes is a valid type in the OTLP proto. (#5266)
• opentelemetry-exporter-otlp-proto-http: add a max_request_size argument to the OTLP HTTP exporters (traces, logs, metrics); serialized requests larger than the limit are dropped before sending, measured before compression. Defaults to 64 MiB (enabled); set to 0 to disable. Mirrors opentelemetry-go#8157. (#5369)
• [BREAKING] opentelemetry-api: subclasses of Logger need to implement the enabled method (#5380)
• opentelemetry-exporter-otlp-proto-http: refactor to use shared opentelemetry-exporter-otlp-common and opentelemetry-exporter-http-transport packages and switch default HTTP backend to urllib3 (#5389)
• opentelemetry-sdk: unify logging force_flush timeout defaults to 30000ms (#5438)
• opentelemetry-python: enable Ruff default ruleset and fix auto-fixable lint issues (#5491)
• opentelemetry-sdk: SimpleSpanProcessor now drops spans ended after shutdown() instead of passing them to the exporter, and counts them on otel.sdk.processor.span.processed with error.type=already_shutdown. (#5512)
• Bump pytest to 9.0.3 (#5518)
• opentelemetry-exporter-otlp-proto-http: clarify that the endpoint= kwarg requires the full signal path (#5633)
• opentelemetry-sdk: fix typos in SpanLimits docstring (#5658)

Fixed

• opentelemetry-configuration: perform environment variable substitution on scalar values after parsing the configuration file, so ${VAR} references inside comments and mapping keys are no longer substituted and undefined references in comments no longer abort loading (#5407)
• opentelemetry-configuration: declarative config environment variable substitution now replaces an unset variable that has no default with an empty value instead of raising an error, per the configuration spec. Resource attributes whose value resolves to null (an unset ${VAR} with no default) are skipped with a warning instead of being inserted as a null value. (#5408)
• 'scripts/build.sh: add opentelemetry-configurationandopentelemetry-proto-json` to the package to release (#5425)
• opentelemetry-sdk: fix View instrument-name matching so a view configured with an instrument's real (mixed-case) name is applied; matching is now case-insensitive and platform-independent instead of relying on fnmatch's OS-dependent case handling (#5430)
• opentelemetry-sdk: fix missing f-prefix in exponential histogram error messages (#5434)
• opentelemetry-configuration: resolve false-positive warning logs for newer schema minor version (#5436)
• opentelemetry-sdk: make methods on FixedSizeExemplarReservoirABC thread safe (#5437)
• opentelemetry-propagator-jaeger: fix typing issues and enable pyright typechecking for the package opentelemetry-propagator-jaeger: skip uberctx- baggage headers with an empty value on extraction instead of raising TypeError (#5440)
• opentelemetry-sdk: fix TypeError when instantiating a _BaseConfigurator subclass whose __init__ takes arguments (#5441)
• opentelemetry-sdk: fix TypeError in os.fork() when a BatchProcessor or PeriodicExportingMetricReader is garbage collected (#5453)
• opentelemetry-configuration: a declarative config key present with an empty (null) value on an object-typed node (e.g. always_on:, a - service: detector, or a metric console: exporter) is now treated the same as an explicit empty config (always_on: {}) instead of failing type dispatch or silently skipping the node. Both dict-typed nodes and dataclasses constructible with no arguments are covered. (#5454)
• opentelemetry-api: fix copy-pasted log message in SpanContext.__delattr__ (#5455)
• opentelemetry-sdk: reject views with ExponentialBucketHistogramAggregation for asynchronous instruments instead of silently producing no data (#5461)
• opentelemetry-sdk: fill every bucket of SimpleFixedSizeExemplarReservoir before random sampling (#5462)
• opentelemetry-sdk: Import code_attributes from stable semconv package (#5465)
• opentelemetry-sdk: for both the simple and batch span/log processors, count otel.sdk.processor.{span,log}.processed when the processor submits records to the exporter instead of after export completes, and stop stamping exporter failures onto this metric as error.type (#5472)
• opentelemetry-sdk: fix misleading instrument name validation error message (name max length is 255, not 63). (#5513)
• opentelemetry-configuration: add missing process executable name to default service name when available in resource attributes (#5534)
• opentelemetry-sdk: fix values for process.executable.name and process.executable.path to match semantic conventions. (#5535)
• opentelemetry-api: fix TraceState.update dropping all entries when adding a new key at the 32-key limit (#5543)
• opentelemetry-sdk: bound get_aggregated_resources() wait to the timeout (#5545)
• opentelemetry-sdk: don't read process.executable.name resource attribute when building default service.name (#5547)
• opentelemetry-propagator-jaeger: enforce baggage limits on both uberctx- extract and inject, borrowing the same limits (180 entries, 4096 bytes per entry, 8192 bytes total) the package's core W3CBaggagePropagator already uses, so neither an inbound carrier nor an in-process baggage map can produce unbounded work or headers. (#5556)
• opentelemetry-sdk: keep metric attribute values that Python considers equal but the data model does not, such as True, 1 and 1.0, in separate metric streams (#5573)
• opentelemetry-sdk: keep Resource hashable and serialisable when an attribute value is bytes, instead of raising TypeError from every OTLP encoder (#5577)
• opentelemetry-sdk: fix instrumentation scope name matching in the tracer, meter and logger configurators so it is case-sensitive on every platform instead of relying on fnmatch's OS-dependent case handling (#5584)
• opentelemetry-sdk: fix TracerProvider() raising ValueError when OTEL_TRACES_SAMPLER_ARG is a syntactically valid number outside the [0.0, 1.0] range, instead of logging a warning and falling back like other invalid values (#5594)
• opentelemetry-sdk: retain values from synchronous instruments using last-value aggregation across cumulative collections (#5637)
• opentelemetry-api: Added guard for negative value on max_value_len (#5647)
• opentelemetry-sdk: fix overriding of the service.instance.id which has been populated from the user provided values through the resource detectors (#5660)
• opentelemetry-exporter-otlp-proto-grpc: Fix incorrect default port for OTLP gRPC exporter self-metrics (#5668)
• opentelemetry-api: update W3CBaggagePropagator to properly handle whitespace (#5680)

Added

• opentelemetry-docker-tests: Refactor Docker tests to properly validate contents of exported telemetry (#5220)
• opentelemetry-exporter-otlp-common: add shared package for common OTLP utilities (#5252)
• opentelemetry-sdk: add MissingDependencyError exception for declarative configuration and use it for missing optional dependency errors (#5265)
• opentelemetry-sdk: Add ability to refresh process dependent Resource attributes (#5280)
• opentelemetry-sdk: add force_flush method to LogRecordExporter ABC (#5294)
• opentelemetry-sdk: Make it possible to limit the size of stored spans in InMemorySpanExporter (#5296)
• opentelemetry-sdk: add log record limits environment variables OTEL_LOGRECORD_ATTRIBUTE_COUNT_LIMIT and OTEL_LOGRECORD_ATTRIBUTE_VALUE_LENGTH_LIMIT (#5300)
• opentelemetry-sdk: add support for file exporter with declarative config (#5311)
• opentelemetry-sdk: expose SynchronousMultiLogRecordProcessor and ConcurrentMultiLogRecordProcessor publicly (#5327)
• opentelemetry-sdk: point the declarative configuration package README at the shared language support status matrix in the opentelemetry-configuration repo, so Python conformance status lives alongside the other languages instead of being duplicated per language SDK. (#5347)
• opentelemetry-sdk: document that Python-implementation extensions (OTEL_PYTHON_* variables) are bypassed when OTEL_CONFIG_FILE is set. The env-var initialisation path is skipped entirely in favour of the declarative file; honouring these alongside a config file is tracked as a follow-up. (#5353)
• opentelemetry-sdk: wire id_generator from declarative configuration to TracerProvider (#5363)
• opentelemetry-sdk: Add support for activating instrumentors from a declarative configuration file via the instrumentation/development.python section. Instrumentors can declare a configuration attribute to have their options validated through the same type-coercion pipeline used for SDK component configuration. (#5372)
• opentelemetry-sdk: add record_min_max option to ExponentialBucketHistogramAggregation, matching the option already available on ExplicitBucketHistogramAggregation and required by the specification (#5377)

Changed

• opentelemetry-sdk: revert BoundedAttributes RLock back to Lock (#5329)
• docs: update logs example to use opentelemetry-instrumentation-logging (#5344)
• opentelemetry-sdk: bump declarative configuration schema to v1.1.0 (#5345)
• opentelemetry-configuration: declarative configuration moves from opentelemetry.sdk._configuration into the new public opentelemetry-configuration package (opentelemetry.configuration namespace), published experimentally. opentelemetry-sdk[file-configuration] continues to work as an alias that installs opentelemetry-configuration alongside the SDK. (#5356)
• opentelemetry-api: remove env carrier environment snapshot caching, you now have to pass explicitly the mapping where to get the environment variables from as the EnvironmentGetter.get first argument. (#5366)
• opentelemetry-semantic-conventions: bump to 1.42.0 (#5410)
• opentelemetry-semantic-conventions: bump to 1.43.0 (#5413)

Removed

• opentelemetry-api, opentelemetry-sdk: Removed deprecated Events API/SDK. Use LogRecord with the event_name field set instead. (#5293)

Fixed

• opentelemetry-sdk: Optimize LogRecord memory in BatchLogRecordProcessor by clearing the Context object before buffering. This is a potentially breaking change for custom log exporters that access context from the exported ReadableLogRecord, as the context will now be an empty Context() instead of the original. (#4977)
• opentelemetry-sdk: drop non-finite measurements (NaN and Inf) at the instrument level to prevent permanent aggregation poisoning (#5336)
• opentelemetry-sdk: raise ValueError when ExplicitBucketHistogramAggregation boundaries are not strictly increasing or finite (#5340)
• opentelemetry-sdk: ProcessResourceDetector no longer collects or emits process.command_args and process.command_line by default since the values are not sanitized and may contain sensitive information. Users who depend on these resource attributes must pass include_command_args=True. (#5364)
• opentelemetry-exporter-otlp-proto-http: fix the OTLP HTTP metric exporter self-observability metrics over-counting data points when max_export_batch_size splits a batch; each split now reports its own data-point count instead of the whole-batch count. (#5370)
• opentelemetry-api: Prevent in-place mutation of Context via inherited dict methods (#5399)