[Cosmos] [Embedding V0] Diagnostics: cosmos.embedding_generation OpenTelemetry span

[ananth7592]

Diagnostics: OpenTelemetry span cosmos.embedding_generation

Parent: 46729
Depends on: 46732

Goal

Surface embedding-generation latency, count, and generator type as a first-class telemetry item, so customers and support can see the new step in distributed traces.

Scope

1. Inside _resolve_embeddings (and async sibling), wrap the call to generator.generate_embeddings(...) in:

   from azure.core.settings import settings
   
   tracer = settings.tracing_implementation()
   if tracer is not None:
       with tracer.span(name="cosmos.embedding_generation") as span:
           span.add_attribute("cosmos.embedding.count", len(texts))
           span.add_attribute("cosmos.embedding.generator_type", type(generator).__name__)
           start = time.perf_counter()
           vectors = generator.generate_embeddings(list(texts))
           span.add_attribute("cosmos.embedding.latency_ms",
                              int((time.perf_counter() - start) * 1000))
   else:
       start = time.perf_counter()
       vectors = generator.generate_embeddings(list(texts))
       _logger.info(
           "embedding_generation count=%d generator_type=%s latency_ms=%d",
           len(texts), type(generator).__name__,
           int((time.perf_counter() - start) * 1000),
       )

2. Mirror in async aggregator (await the call inside the span).
3. Privacy:
   • Never log raw input strings.
   • Never log returned vectors.
   • It is OK to log the parameter key names (e.g. @documentdb-hybridsearchquery-embedding-0) — they are not customer data.
4. If a tracer is configured, also record an event on the span when an exception is raised by the generator (so failures show up in traces, not just logs).

Non-goals

• Do NOT introduce a new logger — reuse the package logger (logging.getLogger("azure.cosmos")).
• Do NOT add new public diagnostics types (no Python equivalent of .NET's EmbeddingGenerationDatum).

Files touched

• sdk/cosmos/azure-cosmos/azure/cosmos/_execution_context/hybrid_search_aggregator.py
• sdk/cosmos/azure-cosmos/azure/cosmos/_execution_context/aio/hybrid_search_aggregator.py

Acceptance

• With an OpenTelemetry tracer configured, a query that triggers embedding generation produces a child span named cosmos.embedding_generation with the three documented attributes.
• Without a tracer configured, an INFO-level log line is produced.
• Tests assert raw text / vectors do not appear in span attributes or log output.