fix: exhaust MovingWindowCallRatePolicy bucket when API reports 0 available calls

[devin-ai-integration]

Overview

👉 TL;DR: When an API tells the connector it has no calls left, the moving-window rate limiter was only recording a single extra call instead of marking the whole window as used, so connectors kept sending requests and hit HTTP 429s. Specifically, MovingWindowCallRatePolicy.update(available_calls=0, call_reset_ts=None) now fills the InMemoryBucket up to the strictest configured Rate via a new _get_available_calls(now) helper.

Resolves https://github.com/airbytehq/airbyte-internal-issues/issues/17242:

• https://github.com/airbytehq/airbyte-internal-issues/issues/17242

Changes

• update() previously computed items_to_add = self._bucket.count() < rates[0].limit (a bool) and passed it as RateItem.weight; InMemoryBucket.put() does items.extend(weight * [item]), so True added exactly one entry. It now computes an integer weight:

  min(rate.limit - count(items with timestamp >= now - rate.interval) for rate in bucket.rates)

  which mirrors the per-rate window check inside put(), so the put fills the tightest window exactly (no-op when already full) and is accepted for multi-rate buckets. bucket.count() was also wrong because it includes entries outside the shortest window (leak() only drops entries older than the longest window).
• The bool return of bucket.put() is now checked; a warning is logged if the sync fails.
• No behavior change for available_calls > 0 or when call_reset_ts is provided.

Review Spotlight

Reviewers with limited time, please review first:

• call_rate.py#L485-L511: the new weight computation

Test plan

• New freezegun-based tests in TestMovingWindowCallRatePolicy: 3-of-10 acquired then update(0, None) blocks the next call and unblocks after the window expires; already-full bucket is a no-op; expired-but-not-leaked entries with two rates; three-rate bucket; positive available_calls / provided call_reset_ts remain no-ops.
• test_update_available_calls_zero_exhausts_bucket fails on main (assert 4 == 10) and passes with the fix.
• poetry run pytest unit_tests/sources/streams/test_call_rate.py -q (43 passed), poetry run ruff check ., poetry run ruff format ., poetry run mypy --config-file mypy.ini airbyte_cdk/sources/streams/call_rate.py all pass.

Requested via the /ai-fix workflow on the linked issue.

Link to Devin session: https://app.devin.ai/sessions/7f1fa151fe884f51a6fdadf484f8048f
Open in Devin Desktop: https://app.devin.ai/desktop/session/7f1fa151fe884f51a6fdadf484f8048f?variant=devin

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment, CI, and merge conflict monitoring

[github-actions]

👋 Greetings, Airbyte Team Member!

Here are some helpful tips and reminders for your convenience.

💡 Show Tips and Tricks

Testing This CDK Version

You can test this version of the CDK using the following:

# Run the CLI from this branch:
uvx 'git+https://github.com/airbytehq/airbyte-python-cdk.git@devin/1789428944-fix-moving-window-update#egg=airbyte-python-cdk[dev]' --help

# Update a connector to use the CDK from this branch ref:
cd airbyte-integrations/connectors/source-example
poe use-cdk-branch devin/1789428944-fix-moving-window-update

PR Slash Commands

Airbyte Maintainers can execute the following slash commands on your PR:

• /autofix - Fixes most formatting and linting issues
• /poetry-lock - Updates poetry.lock file
• /test - Runs connector tests with the updated CDK
• /prerelease - Triggers a prerelease publish with default arguments
• /poe build - Regenerate git-committed build artifacts, such as the pydantic models which are generated from the manifest JSON schema in YAML.
• /poe <command> - Runs any poe command in the CDK environment

📚 Show Repo Guidance

Helpful Resources

• CDK API Reference

📝 Edit this welcome message.

[Copilot]

🟢 Approval recommended

No unresolved review issues remain.

Pull request overview

Fixes moving-window rate-limit synchronization when an API reports zero available calls.

Changes:

• Exhausts the bucket across configured rate windows.
• Logs failed bucket synchronization.
• Adds regression coverage for exhaustion and edge cases.

File summaries

File	Description
unit_tests/sources/streams/test_call_rate.py	Adds coverage for zero-call updates and edge cases.
airbyte_cdk/sources/streams/call_rate.py	Implements capacity calculation and bucket exhaustion.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 0
• Review effort level: Lite

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[github-actions]

PyTest Results (Fast)

4 393 tests  +5   4 381 ✅ +5   9m 37s ⏱️ -1s
    1 suites ±0      12 💤 ±0 
    1 files   ±0       0 ❌ ±0 

Results for commit d2ef79a. ± Comparison against base commit 96a7c0a.

[github-actions]

PyTest Results (Full)

4 396 tests  +5   4 384 ✅ +5   14m 4s ⏱️ +3s
    1 suites ±0      12 💤 ±0 
    1 files   ±0       0 ❌ ±0 

Results for commit d2ef79a. ± Comparison against base commit 96a7c0a.