fix(auth): use asyncio.to_thread for credential resolution in signing hook#270
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nix-tkobayashi wants to merge 3 commits into
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fix(auth): use asyncio.to_thread for credential resolution in signing hook#270nix-tkobayashi wants to merge 3 commits into
nix-tkobayashi wants to merge 3 commits into
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… hook `_sign_request_hook` is an async httpx event hook, but it calls `session_holder.session.get_credentials()` and `session_holder.refresh_if_needed()` synchronously. For profiles that use assumed IAM roles (chained credentials), `get_credentials()` triggers a blocking STS `AssumeRole` call that stalls the event loop and causes connection timeouts (~60 s). Add `SessionHolder.async_get_credentials()` and `SessionHolder.async_refresh_if_needed()` which delegate to `asyncio.to_thread`, keeping the event loop responsive. Update `_sign_request_hook` to call the async variants. Fixes aws#176 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2 tasks
Address review feedback: - Clarify that get_credentials() is the primary blocking path; async_refresh_if_needed() is a defensive measure - Replace timeout-based non-blocking test with ticker coroutine that proves the event loop stays responsive during credential resolution Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
Changes
_sign_request_hookis an async httpx event hook, but it callssession_holder.session.get_credentials()andsession_holder.refresh_if_needed()synchronously. For AWS profiles that use assumed IAM roles (chained credentials),get_credentials()triggers a blocking STSAssumeRolecall that stalls the asyncio event loop, causing ~60 second connection timeouts.This PR:
SessionHolder.async_get_credentials()andSessionHolder.async_refresh_if_needed()which delegate blocking botocore calls toasyncio.to_thread()_sign_request_hookto use the async variantsUser experience
Before: Using an AWS profile backed by an assumed IAM role (chained credentials) causes the MCP proxy connection to time out after ~60 seconds:
After: The connection succeeds normally. The STS
AssumeRolecall runs in a worker thread, keeping the event loop responsive.Checklist
Is this a breaking change? (Y/N)
Please add details about how this change was tested.
Acknowledgment
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Fixes #176