feat(tools): expose httpx_client_factory on RestApiTool and OpenAPITo… by darshil3011 · Pull Request #5715 · google/adk-python

darshil3011 · 2026-05-15T23:23:14Z

…olset

Mirror the pattern merged for MCP in #2997 (StreamableHTTPConnectionParams. httpx_client_factory) on the OpenAPI tool surface.

Adds an optional httpx_client_factory parameter to:

RestApiTool.init
RestApiTool.from_parsed_operation
OpenAPIToolset.init

OpenAPIToolset forwards the factory to every generated RestApiTool the same way ssl_verify and header_provider are already forwarded. When provided, the factory's client is used to issue each API call; when None (default), the existing httpx.AsyncClient(verify=..., timeout=None) construction is preserved exactly. This unlocks httpx.AsyncClient knobs that the narrower ssl_verify parameter can't reach: proxies, HTTP/2, custom transports (e.g. request signing), and shared connection pools.

Closes #5681

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google-cla · 2026-05-15T23:23:25Z

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rohityan · 2026-05-18T19:14:03Z

Hi @darshil3011 , Thank you for your contribution! We appreciate you taking the time to submit this pull request. Your PR has been received by the team and is currently under review. We will provide feedback as soon as we have an update to share.

rohityan · 2026-05-18T19:14:16Z

Hi @xuanyang15 , can you please review this.

darshil3011 · 2026-05-19T03:11:31Z

Thanks, looking forward to feedbacks.

xuanyang15 · 2026-05-21T20:34:30Z

@darshil3011 Thanks for creating this PR! ADK has upgraded to 2.0, could you please help rebase the PR?

darshil3011 · 2026-05-21T20:40:05Z

Sure, let me check and update you @xuanyang15

…olset Mirror the pattern merged for MCP in google#2997 (StreamableHTTPConnectionParams. httpx_client_factory) on the OpenAPI tool surface. Adds an optional httpx_client_factory parameter to: - RestApiTool.__init__ - RestApiTool.from_parsed_operation - OpenAPIToolset.__init__ OpenAPIToolset forwards the factory to every generated RestApiTool the same way ssl_verify and header_provider are already forwarded. When provided, the factory's client is used to issue each API call; when None (default), the existing httpx.AsyncClient(verify=..., timeout=None) construction is preserved exactly. This unlocks httpx.AsyncClient knobs that the narrower ssl_verify parameter can't reach: proxies, HTTP/2, custom transports (e.g. request signing), and shared connection pools. Closes google#5681

darshil3011 · 2026-05-21T21:00:28Z

I rebased onto current main (ADK 2.0). The feature is purely additive and did not touch openapi_tool/openapi_spec_parser/*, so no API migration was needed

darshil3011 · 2026-05-26T17:27:49Z

@xuanyang15 did you get a chance to review this ?

xuanyang15 · 2026-05-27T17:26:49Z

Thank you @darshil3011! I left some comments. Could you please also help fix the failed checks above?

darshil3011 · 2026-05-27T19:57:35Z

Hi @xuanyang15 I couldnt find your comments ? did you actually publish it or still drafting ? I am working on the failed checks though

…px-client-factory

xuanyang15 · 2026-05-27T17:21:18Z

          an argument, allowing dynamic header generation based on the current
          context. Useful for adding custom headers like correlation IDs,
          authentication tokens, or other request metadata.
+        httpx_client_factory: Optional zero-argument callable returning an


This docstring says "zero-argument callable", but the HttpxClientFactory is defined as Callable[..., httpx.AsyncClient], which takes any arguments, is this inconsistency intended?

xuanyang15 · 2026-05-27T17:23:54Z

+) -> httpx.Response:
+  verify = request_params.pop("verify", True)
+  if httpx_client_factory is not None:
+    async with httpx_client_factory() as client:


With async with, will the client being closed automatically after it is being used in line 615? Is this intended? Should we point this out clearly in the docstring?

Yes, intentional — the client is used as an async context manager and closed after the request, mirroring the default branch. I've documented this in the docstrings (factory must return a fresh client per call) and dropped the inaccurate "shared connection pools" wording. Reusing a pooled client would require holding a persistent client on the tool, which I think is best as a separate change — happy to follow up if you'd prefer that.

xuanyang15 · 2026-05-27T20:08:26Z

@darshil3011 I forgot to submit the comments, could you please check again?

darshil3011 · 2026-05-27T20:09:11Z

Thanks @xuanyang15 ! I merged the latest main on top of your merge commit, the pre-commit check is green now. It had been failing on main-authored files that pre-commit run --all-files flags; that was fixed upstream in #af8bfe08, which is now in the branch.

The remaining red check, check-file-contents → "Check for hardcoded googleapis.com endpoints", is flagging test_openapi_toolset.py and test_rest_api_tool.py — but only because of pre-existing fixtures, not anything this PR adds. That step scans all changed .py files, whereas its sibling steps in the same workflow already exclude tests/ . Could you either waive it here or add the same tests/ exclusion to that step? My added source and tests don't introduce any new endpoints.

…lifecycle - Tighten HttpxClientFactory to Callable[[], httpx.AsyncClient] to match the zero-arg call site. - Document per-request client lifecycle (closed after each request); drop the inaccurate "shared connection pools" claim.

xuanyang15 · 2026-05-27T20:27:48Z

+        request signing). The returned client is used as an async context
+        manager and closed after each request, so the factory must return a
+        fresh client on every call. Defaults to ``None``, which preserves
+        today's behaviour. Mirrors the pattern exposed for MCP by


nit: "today's behaviour" sounds unclear once the code is submitted. Can we remove this sentence or make it more clear, e.g. something like "which preserves the behavior when httpx_client_factory is not set".

- Replace vague "today's behaviour"/"unchanged" with a concrete description of what None does.

darshil3011 · 2026-05-27T20:44:31Z

I think the only thing left is hardcoded googleapis.com endpoints which is beyond this PR's scope. Can you please waive this off ?

xuanyang15 · 2026-05-27T20:55:57Z

Thanks you @darshil3011 for addressing the comments so quickly! This PR is now waiting for ADK team internal review. I will merge it as soon as it is approved by the team.

rohityan self-assigned this May 18, 2026

rohityan added tools [Component] This issue is related to tools needs review [Status] The PR/issue is awaiting review from the maintainer labels May 18, 2026

rohityan requested a review from xuanyang15 May 18, 2026 19:13

xuanyang15 self-assigned this May 18, 2026

darshil3011 force-pushed the feat/openapi-tool-httpx-client-factory branch from ba2c37e to 3074cd8 Compare May 21, 2026 20:58

Merge branch 'main' into feat/openapi-tool-httpx-client-factory

11f22b8

Merge remote-tracking branch 'origin/main' into feat/openapi-tool-htt…

be08e06

…px-client-factory

xuanyang15 reviewed May 27, 2026

View reviewed changes

darshil3011 and others added 2 commits May 27, 2026 13:33

docs(tools): clarify default httpx client behavior in factory docstrings

70210dd

- Replace vague "today's behaviour"/"unchanged" with a concrete description of what None does.

Merge branch 'main' into feat/openapi-tool-httpx-client-factory

f6f83bc

xuanyang15 approved these changes May 27, 2026

View reviewed changes

xuanyang15 added the ready to pull [Status] This PR is ready to be imported back to Google label May 27, 2026

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darshil3011 commented May 15, 2026

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