feat(cache): add warnings when using sync methods with async-only Redis client

[Shades-en]

What is happening?

When below conditions are met -

1. I Initialise EmbeddingCache with async_redis_client only.
2. I then use get method of EmbeddingCache - cache.get(text=text, model_name=model_name)

It defaults to using local redis client instead of the supplied async_redis_client without any warnings. Which in turn results to empty cache always.

It gets worse when we use SemanticCache and use EmbeddingCache with async_redis_client in its vectorizer

Since SemanticCache only accepts synchronous redis_client we may tend to use check method or store method instead of astore or acheck method, which in turn again calls cache.get(text=text, model_name=model_name) and it return EMPTY CACHE

Hence warning logs become neccessary.

What is done?

I have added some warning logs in case if developer supplies async_redis_client but uses get/ mget/set/mset methods.

[bsbodden]

Suggested Improvements

I've reviewed this PR and have some suggestions to improve the warning messages and prevent log spam:

1. Add a class-level warning flag

Add this after line 14 (class definition):

class EmbeddingsCache(BaseCache):
    """Embeddings Cache for storing embedding vectors with exact key matching."""

    _warning_shown: bool = False  # Class-level flag to prevent warning spam

2. Improve warning messages

Replace the warning blocks in all four methods with cleaner, spam-prevented versions:

In get_by_key method (around line 170):

if self._owns_redis_client is False and self._redis_client is None:
    if not EmbeddingsCache._warning_shown:
        logger.warning(
            "EmbeddingsCache initialized with async_redis_client only. "
            "Use async methods (aget_by_key) instead of sync methods (get_by_key)."
        )
        EmbeddingsCache._warning_shown = True

In mget_by_keys method (around line 205):

if self._owns_redis_client is False and self._redis_client is None:
    if not EmbeddingsCache._warning_shown:
        logger.warning(
            "EmbeddingsCache initialized with async_redis_client only. "
            "Use async methods (amget_by_keys) instead of sync methods (mget_by_keys)."
        )
        EmbeddingsCache._warning_shown = True

In set method (around line 286):

if self._owns_redis_client is False and self._redis_client is None:
    if not EmbeddingsCache._warning_shown:
        logger.warning(
            "EmbeddingsCache initialized with async_redis_client only. "
            "Use async methods (aset) instead of sync methods (set)."
        )
        EmbeddingsCache._warning_shown = True

In mset method (around line 336):

if self._owns_redis_client is False and self._redis_client is None:
    if not EmbeddingsCache._warning_shown:
        logger.warning(
            "EmbeddingsCache initialized with async_redis_client only. "
            "Use async methods (amset) instead of sync methods (mset)."
        )
        EmbeddingsCache._warning_shown = True

Benefits of these changes:

1. Clearer messages - Directly tell users which async method to use
2. No log spam - Warning only shows once per session
3. Better DX - More actionable guidance for developers

Test Coverage

Consider adding tests to verify:

• Warnings appear when using sync methods with async-only client
• Warning only shows once (no spam)
• No warnings when using correct client types

I have a complete test file ready if you'd like to add test coverage for this feature.

[bsbodden]

See comments on the PR conversation, also rebase against main. Thank you!

[bsbodden]

@Shades-en I'm closing this one and replacing with a rebased version and an extra test #390 - you'll be acknowledge in the release notes, thank you for the contribution!

[Shades-en]

@Shades-en I'm closing this one and replacing with a rebased version and an extra test #390 - you'll be acknowledge in the release notes, thank you for the contribution!

Thank you @bsbodden sure that would be great! You can acknowledge this account itself!