Introduce LangCacheSemanticCache as a caching option

[abrookins]

Introduces a semantic cache backend for the Redis LangCache service.

Usage example

Instantiate with the required LangCache cache_id and api_key. Optionally set name/prefix.

from langchain_redis import LangCacheSemanticCache


cache = LangCacheSemanticCache(
    embeddings=embedding_client,
    cache_id="your-langcache-cache-id",
    api_key="your-langcache-api-key",
    prefix="tenant-a",  # optional
)

[Copilot]

Pull Request Overview

This PR introduces LangCacheSemanticCache as a new semantic caching backend that leverages Redis's managed LangCache service, providing an alternative to the existing self-hosted RedisSemanticCache implementation.

Key changes:

• Adds LangCacheSemanticCache class that wraps RedisVL's LangCache client for managed semantic caching
• Introduces optional langcache dependency with extras support for installation flexibility
• Updates dependencies to require redisvl>=0.11.0 and python>=3.9.2 to support the new LangCache integration

Reviewed Changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
libs/redis/langchain_redis/cache.py	Implements the new LangCacheSemanticCache class with sync/async methods for lookup, update, and clear operations, plus name/prefix mapping logic
libs/redis/langchain_redis/init.py	Exports the new LangCacheSemanticCache class for public API access
libs/redis/tests/unit_tests/test_langcache_semantic_cache.py	Adds unit tests for basic cache operations and name/prefix parameter combinations using a mock implementation
libs/redis/tests/unit_tests/test_imports.py	Updates expected imports list to include LangCacheSemanticCache
libs/redis/pyproject.toml	Adds optional langcache>=0.9.0 dependency, updates redisvl to >=0.11.0, bumps minimum Python to 3.9.2, and adds mypy exclusion for virtual environments
libs/redis/poetry.lock	Updates lock file with langcache 0.10.1 package and redisvl git dependency, reflects Poetry version change from 2.0.1 to 1.7.1
libs/redis/Makefile	Adds poetry check command to lint targets for validating pyproject.toml correctness
CLAUDE.md	Documents virtual environment setup and Poetry usage patterns for development

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[Copilot]

Pull Request Overview

Copilot reviewed 7 out of 8 changed files in this pull request and generated 7 comments.

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[Copilot]

Pull Request Overview

Copilot reviewed 7 out of 8 changed files in this pull request and generated 7 comments.

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[Copilot]

Pull Request Overview

Copilot reviewed 7 out of 8 changed files in this pull request and generated 2 comments.

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[tylerhutcherson]

Looks great -- left a note about the prefix arg. Should we require the args that langcache doesn't actually need or use here (embeddings and prefix for example).

Also, we need an update to the README and to one of the user guides. Also need to make sure this gets updated within langcache docs so it's listed with a link to sign up for the service on redis cloud!

[abrookins]

Ah, a hiccup. LangChain uses model parameters as a filter, so it expects caching to be specific to a model+params combo, which makes sense. LangCache's "attributes" is the feature that should allow us to filter. However, attributes don't support commas, which it appears the model+params string from LangChain includes (llm_string):

BadRequestErrorResponseContent: {"detail":"attributes: (llm_string: Cannot contain commas ','.).","status":400,"title":"Invalid Request","type":"/errors/invalid-data"}

I will have to follow up with this next week!

[bsbodden]

Looks great! Ship it!

[bjh3311]

I have a question bout this. I thought langchain-redis package already had RedisSemanticCache. Is RedisSemanticCache different from Redis LangCache?