litellm/litellm/caching
devin-ai-integration[bot] ae01882535
feat(proxy): offload spend tracking to a pod-local collector sidecar (#40545)
* feat(proxy): offload spend tracking to a pod-local spend worker sidecar

py-spy on the gateway showed the post-response _PROXY_track_cost_callback,
spend-log and DBSpendUpdateWriter work running on the inference workers'
event loop, so a DB or Redis stall backed up the request path.

When LITELLM_SPEND_WORKER_ENABLED=true, _ProxyDBLogger serializes one compact
typed SpendEvent per success and hands it to a SpendEventProducer that ships
it over a unix socket (default) or loopback-only TCP to a sidecar started as
`python -m gateway.spend_worker`. The sidecar runs the unchanged
_ProxyDBLogger pipeline against the pod's PgBouncer (pooled_database_url).
When the sidecar is unreachable, the buffer is full, or the gateway shuts
down with events still queued or in flight, the producer applies
LITELLM_SPEND_WORKER_ON_UNAVAILABLE (fallback in-process, or drop). The
sidecar half-closes producers on SIGTERM and drains, the producer treats
EOF as unavailable, and the gateway flushes buffered spend counters on
shutdown. The sidecar honors LITELLM_LOG so its writes are visible in its
own process log.

Helm: both charts gain an opt-in spend-worker sidecar container sharing an
emptyDir socket dir, and the componentized chart's HPA uses a
ContainerResource CPU metric scoped to the gateway container so sidecar
CPU does not drive inference scaling.

* feat(terraform): opt-in spend-worker sidecar for the AWS and GCP gateway stacks

Adds spend_worker_* inputs to both modules. On ECS Fargate the sidecar is a second, non-essential container in the gateway task; on Cloud Run it is a second container in the gateway service. Both listen on loopback TCP, share the gateway's DB/Redis/secret env, and set LITELLM_JOB_ROLE=spend_worker. Disabled by default. Plan-only tests cover both, and the terraform CI workflow now runs the gcp module too

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* test(proxy): retrieve a completed batch in the in-process spend path test

The base now defers cost tracking for batches that are still in flight, so an in_progress batch never reaches update_database

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* refactor(proxy): rename the spend worker sidecar to collector

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* fix(proxy): run the collector from the installed litellm package and finish in-flight fallbacks on shutdown

The sidecar command becomes python -m litellm.proxy.collector so the classic image, whose runtime
stage copies only the installed package, can run it. The module now assembles DATABASE_URL and the
pod-local pgbouncer URL itself, replacing gateway/collector.py

The componentized collector sidecar inherits gateway.volumeMounts so custom CA mounts reach it.
SpendEventProducer shields an in-progress fallback from the writer task cancellation so close()
no longer loses an event already handed to the in-process pipeline

Helpers used across modules (address_argument, should_store_prompts_and_responses_in_spend_logs,
flush_spend_counters_on_shutdown) become public so the change adds no reportPrivateUsage errors

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* ci(terraform): drop the gcp job duplicated by the aws/gcp matrix

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* fix(collector): keep metrics env off the classic sidecar and reject shared loopback ports

The classic chart no longer hands PROMETHEUS_METRICS_PORT and the billing metrics env to the collector container, and gives it the same /.npm scratch mount as the proxy on a read-only root. AWS and GCP now refuse a plan where the spend collector and the metrics sidecar bind the same loopback port. A regression test drives a sidecar crash mid-stream on asyncio and uvloop and checks no event is billed by both the sidecar and the in-process fallback; the producer docstring spells out why a failed drain() cannot double count

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* style(proxy): format pooled_database_url after the pgbouncer rebase

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* fix(proxy): keep the cache-hit preset key and survive dead producers on collector drain

Cache hits updated the logging object after the early return, so the offloaded spend event carried
preset_cache_key=None and the collector re-hashed reconstructed kwargs. Also guard write_eof() against
producer transports uvloop already closed so one dead connection cannot abort the drain

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* fix(terraform): keep the gcp collector port off the metrics sidecar health port

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* fix(proxy): collector connects to Postgres directly under IAM or Entra token auth

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* fix(proxy): mark the collector's DATABASE_URL as pooled when it uses the pod's pgbouncer

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

---------

Co-authored-by: yassin <yassin@berri.ai>
Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
2026-09-10 17:14:13 -07:00
..
__init__.py refactor(lint): apply every safe ruff autofix and zero 28 strict-rule budgets 2026-08-01 15:43:29 -07:00
_embedding_router.py fix(caching): bound the semantic cache embedding lookup 2026-08-20 16:09:30 -07:00
_internal_lru_cache.py feat(lint): enforce Final on locals and freeze function parameters (LIT010, LIT011) 2026-08-04 12:54:39 -07:00
azure_blob_cache.py feat(lint): enforce Final on locals and freeze function parameters (LIT010, LIT011) 2026-08-04 12:54:39 -07:00
base_cache.py chore(lint): clear grandfathered over-limit lint drift and ratchet budgets down 2026-08-05 12:18:13 -07:00
caching.py fix(redis): log an open circuit breaker once instead of a traceback per request and count sync timeouts as timeouts 2026-09-10 13:50:34 -07:00
caching_handler.py feat(proxy): offload spend tracking to a pod-local collector sidecar (#40545) 2026-09-10 17:14:13 -07:00
disk_cache.py chore(lint): clear grandfathered over-limit lint drift and ratchet budgets down 2026-08-05 12:18:13 -07:00
dual_cache.py fix(redis): quiet every per-request Redis fallback while the breaker is open 2026-09-10 14:18:53 -07:00
evicted_client_closer.py fix(caching): clear strict-lint budget breaches in re-landed closer code 2026-08-05 11:08:19 -07:00
gcs_cache.py feat(lint): enforce Final on locals and freeze function parameters (LIT010, LIT011) 2026-08-04 12:54:39 -07:00
in_memory_cache.py feat(lint): enforce Final on locals and freeze function parameters (LIT010, LIT011) 2026-08-04 12:54:39 -07:00
llm_caching_handler.py fix(caching): clear strict-lint budget breaches in re-landed closer code 2026-08-05 11:08:19 -07:00
qdrant_semantic_cache.py refactor(types): replace Any with precise types across 73 modules 2026-09-01 11:05:02 +00:00
Readme.md add azure blob cache support (#12587) 2025-07-15 11:47:38 -07:00
redis_cache.py refactor(redis): drop the narrative docstrings on the breaker helper and its tests 2026-09-10 14:31:48 -07:00
redis_cluster_cache.py fix(redis): support credential providers across clients 2026-08-24 19:07:13 -04:00
redis_cluster_node_isolation.py fix(caching): keep a node timeout from forcing a cluster-wide topology reinit on redis-py 8.x (#39349) 2026-09-03 17:31:58 -07:00
redis_semantic_cache.py refactor(typing): replace Any with proven types in 65 backend files 2026-09-02 09:11:36 +00:00
s3_cache.py chore(lint): strip inert type: ignore comments and zero LIT009, LIT010, LIT011 headroom 2026-08-05 02:37:24 -07:00
valkey_semantic_cache.py chore(lint): fix post-merge type regressions and ratchet lint budgets 2026-08-29 20:16:04 +00:00

Caching on LiteLLM

LiteLLM supports multiple caching mechanisms. This allows users to choose the most suitable caching solution for their use case.

The following caching mechanisms are supported:

  1. RedisCache
  2. RedisSemanticCache
  3. QdrantSemanticCache
  4. InMemoryCache
  5. DiskCache
  6. S3Cache
  7. AzureBlobCache
  8. DualCache (updates both Redis and an in-memory cache simultaneously)

Folder Structure

litellm/caching/
├── base_cache.py
├── caching.py
├── caching_handler.py
├── disk_cache.py
├── dual_cache.py
├── in_memory_cache.py
├── qdrant_semantic_cache.py
├── redis_cache.py
├── redis_semantic_cache.py
├── s3_cache.py

Documentation