Sandbox::https://github.com/deepset-ai/haystack/pull/12987

Mariam-Amin12 · 2026-09-27T14:32:12Z

fixes Add TTL / expiration support to CacheChecker #12967

Proposed Changes:

Added optional TTL support to CacheChecker to allow cached documents to expire.

Added an optional ttl parameter.
Added a configurable time_field parameter for the cache timestamp.
A cache entry is considered a hit only when its timestamp is within the configured TTL.
Missing, malformed, or invalid timestamps are treated as cache misses when TTL is enabled.
Preserved the existing behavior when ttl=None.
Added support for both synchronous and asynchronous cache checking.

How did you test it?

Added and ran unit tests covering:

Fresh cache entries within the TTL
Expired cache entries
Missing timestamp fields
ISO timestamp strings
Naive datetime timestamps (no tzinfo)
Malformed timestamp strings
Non-datetime timestamp values
Numeric TTL values (seconds, not just timedelta)
Serialization/deserialization round-tripping with ttl and time_field set
Behavior when TTL is not configured (backward compatibility)
Async CacheChecker behavior with TTL (fresh + expired)

Ran:

hatch run test:unit test/components/caching/

Result: 26 passed

Notes for the reviewer

The existing behavior is preserved when ttl=None. TTL validation is only applied when TTL is configured.

Checklist

I have read the [contributors guidelines](https://github.com/deepset-ai/haystack/blob/main/CONTRIBUTING.md) and the [code of conduct](https://github.com/deepset-ai/haystack/blob/main/code_of_conduct.txt).
I have updated the related issue with new insights and changes.
I have added unit tests and updated the docstrings.
I've used one of the [conventional commit types](https://www.conventionalcommits.org/en/v1.0.0/) for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test: and added ! in case the PR includes breaking changes.
I have documented my code.
I have added a release note file, following the [contributors guidelines](https://github.com/deepset-ai/haystack/blob/main/CONTRIBUTING.md#release-notes).
I have run [pre-commit hooks](https://github.com/deepset-ai/haystack/blob/main/CONTRIBUTING.md#setting-up-your-development-environment) and fixed any issue.

vercel · 2026-09-27T14:32:21Z

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github-actions · 2026-09-27T14:32:24Z

Hi @Mariam-Amin12, thanks for your interest in contributing to Haystack! 🙏

⚠️ Issue #12967 is already being addressed by open pull request(s) #12979. Before opening a PR for an issue, please check whether a PR is already linked to it, and consider contributing to the existing PR instead. We may close duplicate PRs to keep the review queue manageable.

This is an automated message to help us keep the review queue healthy.

github-actions · 2026-10-06T10:01:47Z

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
haystack/components/agents
agent.py
haystack/components/builders
chat_prompt_builder.py
haystack/components/caching
cache_checker.py
haystack/components/converters
csv.py
docx.py
json.py
xlsx.py
haystack/components/generators/chat
azure.py
openai.py
openai_responses.py
haystack/components/joiners
branch.py
haystack/components/preprocessors
recursive_splitter.py
haystack/components/rankers
meta_field.py
haystack/components/retrievers
sentence_window_retriever.py
haystack/components/validators
json_schema.py
haystack/dataclasses
chat_message.py
haystack/document_stores/in_memory
document_store.py
haystack/hooks/compaction
hooks.py
haystack/tools
component_tool.py
searchable_toolset.py
tool.py
toolset.py
utils.py
haystack/tools/skills
skill_toolset.py
haystack/utils
misc.py
Project Total

The report is truncated to 25 files out of 31. To see the full report, please visit the workflow summary page.

_{This report was generated by python-coverage-comment-action}

CLAassistant · 2026-11-05T08:24:27Z

All committers have signed the CLA.

HaystackBot · 2026-11-05T08:53:11Z

Hi @Mariam-Amin12, thanks a lot for your contribution! 🙏

We noticed that the Contributor License Agreement (CLA) check (license/cla) hasn't passed yet, so we've temporarily moved this PR to draft and paused the review assignment.

To get your PR reviewed, please sign the CLA via the link in the license/cla check below (or in the CLA bot comment). As soon as the check turns green, this PR will automatically be marked ready for review again and a reviewer will be re-assigned.

HaystackBot · 2026-11-05T09:24:28Z

Thanks for signing the CLA, @Mariam-Amin12! 🎉 This PR is now ready for review again and the reviewer has been re-assigned.

bogdankostic

Thanks for working on this @Mariam-Amin12! Keeping ttl optional and storing it as seconds looks good. The main things to fix are naive timestamps being treated as UTC and time_field not accepting the meta. prefix.

bogdankostic · 2026-11-09T15:29:53Z

            found = self.document_store.filter_documents(filters=filters)
-            if found:
-                found_documents.extend(found)
+            fresh = [doc for doc in found if self._is_fresh(doc)]


I'm wondering if we could push the cutoff into the filter instead of checking each document in Python:

cutoff = datetime.now(UTC) - self.ttl filters = { "operator": "AND", "conditions": [ {"field": self.cache_field, "operator": "==", "value": item}, {"field": self.time_field, "operator": ">=", "value": cutoff.isoformat()}, ], }

The store would only return fresh documents and we wouldn't need our own timestamp parsing. It would also help with stale copies: a new cached_at changes the document ID, so re-caching an item writes a second document instead of overwriting the old one, and right now every check fetches all of them. The trade-off is that time_field would need to be stored in a format the store can range-filter on. What do you think?

I'd prefer to include this optimization in the current PR if possible. Can we handle invalid timestamps safely while keeping compatibility across the supported DocumentStores and preserving the existing behavior (invalid or missing timestamps result in cache misses)?

…Mariam-Amin12/haystack into add-TTL-support-to-CacheChecker

Mariam-Amin12 · 2026-11-13T10:11:01Z

@bogdankostic I've addressed the review feedback and pushed the latest changes. The implementation and tests have been updated accordingly. Ready for another review. Thanks!

feat: add ttl and time_field support to CacheChecker

49923cb

Mariam-Amin12 requested a review from a team as a code owner September 27, 2026 14:32

Mariam-Amin12 requested review from bogdankostic and removed request for a team September 27, 2026 14:32

github-actions Bot added the topic:tests label Sep 27, 2026

julian-risch mentioned this pull request Oct 1, 2026

feat: add TTL support to CacheChecker #12979

Closed

github-actions Bot added the type:documentation Improvements on the docs label Oct 6, 2026

github-actions Bot added the P3 Low priority, leave it in the backlog label Oct 8, 2026

HaystackBot removed the request for review from bogdankostic November 5, 2026 08:53

HaystackBot added the cla-pending PR is in draft until the contributor signs the CLA label Nov 5, 2026

HaystackBot marked this pull request as draft November 5, 2026 08:53

HaystackBot marked this pull request as ready for review November 5, 2026 09:24

HaystackBot requested a review from bogdankostic November 5, 2026 09:24

HaystackBot removed the cla-pending PR is in draft until the contributor signs the CLA label Nov 5, 2026

Mariam-Amin12 and others added 2 commits November 8, 2026 21:41

Merge branch 'main' into add-TTL-support-to-CacheChecker

656eecf

Merge branch 'main' into add-TTL-support-to-CacheChecker

d4ff51c

bogdankostic requested changes Nov 9, 2026

View reviewed changes

Mariam-Amin12 added 2 commits November 13, 2026 12:06

Add TTL support to CacheChecker

850515a

Merge branch 'add-TTL-support-to-CacheChecker' of https://github.com/…

089621c

…Mariam-Amin12/haystack into add-TTL-support-to-CacheChecker

Conversation

Mariam-Amin12 commented Sep 27, 2026

Proposed Changes:

How did you test it?

Notes for the reviewer

Checklist

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github-actions Bot commented Oct 6, 2026

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Mariam-Amin12 commented Nov 13, 2026

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