v4.5.0rc4

Estimated end-of-life date, accurate to within three months: 05-2027 See the support level definitions for more information.

Upgrade Notes

• dynamic instrumentation
  • log probes now use the debugger intake track. This requires Datadog agent version 7.49.0 or above.
• CI Visibility
  • Official release of the new version of the pytest plugin, with architectural improvements. This new version uses an independent span writer for Test Optimization (similar to the DD_CIVISIBILITY_USE_BETA_WRITER option), and also contains performance and memory usage improvements. A beta version of the plugin had been available since v4.2.0, and could be enabled via the DD_PYTEST_USE_NEW_PLUGIN environment variable. This new version is now the default, and the environment variable can be used to revert to the previous plugin if used with false or 0 values.

Deprecation Notes

• tracing

  • DD_TRACE_128_BIT_TRACEID_GENERATION_ENABLED is deprecated and will be removed in version 5.0.0. 128-bit trace ID generation will become mandatory.

• The tracer parameter is deprecated in the following functions and class methods and will be removed in version 5.0.0:

  • aiohttp: trace_app
  • asgi: TraceMiddleware.__init__
  • bottle: TracePlugin.__init__
  • cherrypy: TraceMiddleware.__init__
  • falcon: TraceMiddleware.__init__
  • flask_cache: get_traced_cache
  • sqlalchemy: trace_engine
  • wsgi: WSGIMiddleware.__init__

  The ddtrace.trace.tracer singleton is always used.

New Features

• profiling
  • It is now possible to profile applications using uvloop with asyncio.
• pymongo
  • Adds support for tracing pymongo 4.12+ AsyncMongoClient operations. The integration now automatically instruments both synchronous and asynchronous clients when using pymongo >= 4.12.
• Code Security (IAST)
  • This introduces support for Python 3.14 template strings (PEP-750). Template strings (t-strings) are now tracked for taint propagation, enabling detection of security vulnerabilities when user input is embedded in template strings.
• claude_agent_sdk
  • Introduces tracing support for the Claude Agent SDK's query, ClaudeSDKClient.query, and ClaudeSDKClient.receive_messages methods. See the docs for more information.
• opentelemetry: Adds support for the start_as_current_span decorator on asynchronous functions. Requires opentelemetry-api>=1.24.
• LLM Observability
  • Adds LLM Observability tracing support for Claude Agent SDK requests.
  • Adds Azure OpenAI as a supported provider for the LLM Judge evaluator.
  • Adds Vertex AI as a supported provider for the LLM Judge evaluator.
  • Introduces the LLMObs.async_experiment() method for running experiments with async task functions and mixed sync/async evaluators.
  • Adds built-in evaluators for common evaluation tasks. The following evaluators are now available:
    • StringCheckEvaluator: Performs string comparison operations (equals, not equals, contains, case-insensitive contains).
    • RegexMatchEvaluator: Validates output against regex patterns with search, match, or fullmatch modes.
    • LengthEvaluator: Validates output length constraints by characters, words, or lines.
    • JSONEvaluator: Validates JSON syntax and optionally checks for required keys.
    • SemanticSimilarityEvaluator: Measures semantic similarity between output and expected output using embedding vectors.
  • Adds support for json metric type in evaluation metrics. Users can now submit dict values as evaluation metrics using LLMObs.submit_evaluation() with metric_type="json". Additionally, experiment evaluators that return dict values are automatically detected as json metric type.
  • Adds LLMJudge evaluator for automated evaluation of LLM outputs using another LLM as the judge. Supports OpenAI and Anthropic providers with boolean, score, categorical, and custom JSON schema output formats.
  • Adds AWS Bedrock as a supported provider for the LLM Judge evaluator.

Bug Fixes

• lib injection
  • the injected site-packages directory is now added as the last entry in the PYTHONPATH environment variable (it previously was added before the last entry).
• profiling
  • A race condition that could lead to out-of-bounds access in the Profiler was fixed.
  • A bug where the Stack Profiler could loop infinitely (and allocate large amounts of memory, leading to crashes) when sampling asyncio Tasks has been fixed.
  • Fixes crashes in the memory profiler caused by re-entering the Python interpreter from inside CPython's allocator hook.
  • This fix resolves an issue where stack profiler could hold frame references to greenlets, which could have already completed. This could delay garbage collecting local variables from the greenlet.
  • A bug where corrupted or circular stack chunk linked lists on Python 3.11+ could cause infinite recursion during stack unwinding was fixed.
  • This fix resolves an issue where the dropped frames indicator frame could be added multiple times when exporting the same sample repeatedly, resulting in duplicate "<N frame(s) omitted>" entries in profiling data and unbounded memory growth in the memory profiler.
• internal
  • This fix resolves an issue where ddtrace ignored the uwsgi --skip-atexit flag and registered Python atexit handlers regardless. This caused profiler cleanup code to run during process shutdown even when --skip-atexit was set, leading to crashes and hangs in uwsgi workers.
• tracing
  • This fix resolves an issue where traces may not be flushed during the handling of SIGTERM or SIGINT signals.
• telemetry
  • This fix resolves an issue where telemetry events may not be flushed during the handling of SIGTERM or SIGINT signals.
  • handle closed logging streams in writer background threads
• AAP
  • Add the noopener and noreferrer link tags in the Datadog link in the footer of the App and API Protection HTML blocking response template. This could previously trigger a "reverse tabnabbing" vulnerability finding from other security analysis tools.
• DSM
  • This fix resolves an issue where malformed DSM payloads prevented data from being reported when DD_EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED was enabled.