fix(task-sdk): set default Content-Type header on execution API client by YoannAbriel · Pull Request #63215 · apache/airflow

YoannAbriel · 2026-03-09T20:03:11Z

Problem

Task subprocesses get killed with SIGKILL immediately after starting. The API server returns 422 on PATCH /execution/task-instances/{id}/run because the request body is received as a raw string instead of parsed JSON.

Root Cause

client.py uses httpx's content=body.model_dump_json() to send requests. The content= parameter sets the raw body but does not set a Content-Type header — so the API server (cadwyn/FastAPI) can't identify the payload as JSON, passes it to Pydantic as a plain string, and rejects it with a model_attributes_type validation error.

Fix

Added content-type: application/json to the default headers in Client.__init__(). This covers all call sites that use content= (start, heartbeat, state transitions, etc.) without touching each one individually.

Added a test that verifies the header is present on outgoing requests.

Closes: #63209

Was generative AI tooling used to co-author this PR?

Yes — Claude Code

Generated-by: Claude Code following the guidelines

Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
When adding dependency, check compliance with the ASF 3rd Party License Policy.
For significant user-facing changes create newsfragment: {pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.

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The task SDK client sends JSON payloads via httpx's content= parameter, which doesn't set Content-Type automatically. Without it, the API server can't parse the body and returns 422, causing the supervisor to SIGKILL the task subprocess. Add 'content-type: application/json' to the default client headers so all requests are properly identified as JSON. Closes: apache#63209

amoghrajesh

The fix is redundant. The request() method override added by #57377 and #59676 already handles this exact scenario

amoghrajesh · 2026-04-14T13:45:11Z

Closing the PR with above comment.

YoannAbriel · 2026-03-09T20:03:11Z

Problem

Task subprocesses get killed with SIGKILL immediately after starting. The API server returns 422 on PATCH /execution/task-instances/{id}/run because the request body is received as a raw string instead of parsed JSON.

Root Cause

client.py uses httpx's content=body.model_dump_json() to send requests. The content= parameter sets the raw body but does not set a Content-Type header — so the API server (cadwyn/FastAPI) can't identify the payload as JSON, passes it to Pydantic as a plain string, and rejects it with a model_attributes_type validation error.

Fix

Added content-type: application/json to the default headers in Client.__init__(). This covers all call sites that use content= (start, heartbeat, state transitions, etc.) without touching each one individually.

Added a test that verifies the header is present on outgoing requests.

Closes: #63209

Was generative AI tooling used to co-author this PR?

Yes — Claude Code

Generated-by: Claude Code following the guidelines

Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
When adding dependency, check compliance with the ASF 3rd Party License Policy.
For significant user-facing changes create newsfragment: {pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.

Copilot

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

The task SDK client sends JSON payloads via httpx's content= parameter, which doesn't set Content-Type automatically. Without it, the API server can't parse the body and returns 422, causing the supervisor to SIGKILL the task subprocess. Add 'content-type: application/json' to the default client headers so all requests are properly identified as JSON. Closes: apache#63209

amoghrajesh

The fix is redundant. The request() method override added by #57377 and #59676 already handles this exact scenario

amoghrajesh · 2026-04-14T13:45:11Z

Closing the PR with above comment.

YoannAbriel · 2026-03-09T20:03:11Z

Problem

Task subprocesses get killed with SIGKILL immediately after starting. The API server returns 422 on PATCH /execution/task-instances/{id}/run because the request body is received as a raw string instead of parsed JSON.

Root Cause

client.py uses httpx's content=body.model_dump_json() to send requests. The content= parameter sets the raw body but does not set a Content-Type header — so the API server (cadwyn/FastAPI) can't identify the payload as JSON, passes it to Pydantic as a plain string, and rejects it with a model_attributes_type validation error.

Fix

Added content-type: application/json to the default headers in Client.__init__(). This covers all call sites that use content= (start, heartbeat, state transitions, etc.) without touching each one individually.

Added a test that verifies the header is present on outgoing requests.

Closes: #63209

Was generative AI tooling used to co-author this PR?

Yes — Claude Code

Generated-by: Claude Code following the guidelines

Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
When adding dependency, check compliance with the ASF 3rd Party License Policy.
For significant user-facing changes create newsfragment: {pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.

Copilot

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

The task SDK client sends JSON payloads via httpx's content= parameter, which doesn't set Content-Type automatically. Without it, the API server can't parse the body and returns 422, causing the supervisor to SIGKILL the task subprocess. Add 'content-type: application/json' to the default client headers so all requests are properly identified as JSON. Closes: apache#63209

amoghrajesh

The fix is redundant. The request() method override added by #57377 and #59676 already handles this exact scenario

amoghrajesh · 2026-04-14T13:45:11Z

Closing the PR with above comment.

YoannAbriel · 2026-03-09T20:03:11Z

Problem

Task subprocesses get killed with SIGKILL immediately after starting. The API server returns 422 on PATCH /execution/task-instances/{id}/run because the request body is received as a raw string instead of parsed JSON.

Root Cause

client.py uses httpx's content=body.model_dump_json() to send requests. The content= parameter sets the raw body but does not set a Content-Type header — so the API server (cadwyn/FastAPI) can't identify the payload as JSON, passes it to Pydantic as a plain string, and rejects it with a model_attributes_type validation error.

Fix

Added content-type: application/json to the default headers in Client.__init__(). This covers all call sites that use content= (start, heartbeat, state transitions, etc.) without touching each one individually.

Added a test that verifies the header is present on outgoing requests.

Closes: #63209

Was generative AI tooling used to co-author this PR?

Yes — Claude Code

Generated-by: Claude Code following the guidelines

Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
When adding dependency, check compliance with the ASF 3rd Party License Policy.
For significant user-facing changes create newsfragment: {pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.

Copilot

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

The task SDK client sends JSON payloads via httpx's content= parameter, which doesn't set Content-Type automatically. Without it, the API server can't parse the body and returns 422, causing the supervisor to SIGKILL the task subprocess. Add 'content-type: application/json' to the default client headers so all requests are properly identified as JSON. Closes: apache#63209

amoghrajesh

The fix is redundant. The request() method override added by #57377 and #59676 already handles this exact scenario

amoghrajesh · 2026-04-14T13:45:11Z

Closing the PR with above comment.

YoannAbriel · 2026-03-09T20:03:11Z

Problem

Task subprocesses get killed with SIGKILL immediately after starting. The API server returns 422 on PATCH /execution/task-instances/{id}/run because the request body is received as a raw string instead of parsed JSON.

Root Cause

client.py uses httpx's content=body.model_dump_json() to send requests. The content= parameter sets the raw body but does not set a Content-Type header — so the API server (cadwyn/FastAPI) can't identify the payload as JSON, passes it to Pydantic as a plain string, and rejects it with a model_attributes_type validation error.

Fix

Added content-type: application/json to the default headers in Client.__init__(). This covers all call sites that use content= (start, heartbeat, state transitions, etc.) without touching each one individually.

Added a test that verifies the header is present on outgoing requests.

Closes: #63209

Was generative AI tooling used to co-author this PR?

Yes — Claude Code

Generated-by: Claude Code following the guidelines

Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
When adding dependency, check compliance with the ASF 3rd Party License Policy.
For significant user-facing changes create newsfragment: {pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.

Copilot

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

The task SDK client sends JSON payloads via httpx's content= parameter, which doesn't set Content-Type automatically. Without it, the API server can't parse the body and returns 422, causing the supervisor to SIGKILL the task subprocess. Add 'content-type: application/json' to the default client headers so all requests are properly identified as JSON. Closes: apache#63209

amoghrajesh

The fix is redundant. The request() method override added by #57377 and #59676 already handles this exact scenario

amoghrajesh · 2026-04-14T13:45:11Z

Closing the PR with above comment.

YoannAbriel · 2026-03-09T20:03:11Z

Problem

Task subprocesses get killed with SIGKILL immediately after starting. The API server returns 422 on PATCH /execution/task-instances/{id}/run because the request body is received as a raw string instead of parsed JSON.

Root Cause

client.py uses httpx's content=body.model_dump_json() to send requests. The content= parameter sets the raw body but does not set a Content-Type header — so the API server (cadwyn/FastAPI) can't identify the payload as JSON, passes it to Pydantic as a plain string, and rejects it with a model_attributes_type validation error.

Fix

Added content-type: application/json to the default headers in Client.__init__(). This covers all call sites that use content= (start, heartbeat, state transitions, etc.) without touching each one individually.

Added a test that verifies the header is present on outgoing requests.

Closes: #63209

Was generative AI tooling used to co-author this PR?

Yes — Claude Code

Generated-by: Claude Code following the guidelines

Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
When adding dependency, check compliance with the ASF 3rd Party License Policy.
For significant user-facing changes create newsfragment: {pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.

Copilot

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

The task SDK client sends JSON payloads via httpx's content= parameter, which doesn't set Content-Type automatically. Without it, the API server can't parse the body and returns 422, causing the supervisor to SIGKILL the task subprocess. Add 'content-type: application/json' to the default client headers so all requests are properly identified as JSON. Closes: apache#63209

amoghrajesh

The fix is redundant. The request() method override added by #57377 and #59676 already handles this exact scenario

amoghrajesh · 2026-04-14T13:45:11Z

Closing the PR with above comment.

YoannAbriel · 2026-03-09T20:03:11Z

Problem

Task subprocesses get killed with SIGKILL immediately after starting. The API server returns 422 on PATCH /execution/task-instances/{id}/run because the request body is received as a raw string instead of parsed JSON.

Root Cause

client.py uses httpx's content=body.model_dump_json() to send requests. The content= parameter sets the raw body but does not set a Content-Type header — so the API server (cadwyn/FastAPI) can't identify the payload as JSON, passes it to Pydantic as a plain string, and rejects it with a model_attributes_type validation error.

Fix

Added content-type: application/json to the default headers in Client.__init__(). This covers all call sites that use content= (start, heartbeat, state transitions, etc.) without touching each one individually.

Added a test that verifies the header is present on outgoing requests.

Closes: #63209

Was generative AI tooling used to co-author this PR?

Yes — Claude Code

Generated-by: Claude Code following the guidelines

Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
When adding dependency, check compliance with the ASF 3rd Party License Policy.
For significant user-facing changes create newsfragment: {pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.

Copilot

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

The task SDK client sends JSON payloads via httpx's content= parameter, which doesn't set Content-Type automatically. Without it, the API server can't parse the body and returns 422, causing the supervisor to SIGKILL the task subprocess. Add 'content-type: application/json' to the default client headers so all requests are properly identified as JSON. Closes: apache#63209

amoghrajesh

The fix is redundant. The request() method override added by #57377 and #59676 already handles this exact scenario

amoghrajesh · 2026-04-14T13:45:11Z

Closing the PR with above comment.

YoannAbriel · 2026-03-09T20:03:11Z

Problem

Task subprocesses get killed with SIGKILL immediately after starting. The API server returns 422 on PATCH /execution/task-instances/{id}/run because the request body is received as a raw string instead of parsed JSON.

Root Cause

client.py uses httpx's content=body.model_dump_json() to send requests. The content= parameter sets the raw body but does not set a Content-Type header — so the API server (cadwyn/FastAPI) can't identify the payload as JSON, passes it to Pydantic as a plain string, and rejects it with a model_attributes_type validation error.

Fix

Added content-type: application/json to the default headers in Client.__init__(). This covers all call sites that use content= (start, heartbeat, state transitions, etc.) without touching each one individually.

Added a test that verifies the header is present on outgoing requests.

Closes: #63209

Was generative AI tooling used to co-author this PR?

Yes — Claude Code

Generated-by: Claude Code following the guidelines

Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
When adding dependency, check compliance with the ASF 3rd Party License Policy.
For significant user-facing changes create newsfragment: {pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.

Copilot

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

The task SDK client sends JSON payloads via httpx's content= parameter, which doesn't set Content-Type automatically. Without it, the API server can't parse the body and returns 422, causing the supervisor to SIGKILL the task subprocess. Add 'content-type: application/json' to the default client headers so all requests are properly identified as JSON. Closes: apache#63209

amoghrajesh

The fix is redundant. The request() method override added by #57377 and #59676 already handles this exact scenario

amoghrajesh · 2026-04-14T13:45:11Z

Closing the PR with above comment.

YoannAbriel requested review from amoghrajesh, ashb and kaxil as code owners March 9, 2026 20:03

boring-cyborgBot added the area:task-sdk label Mar 9, 2026

YoannAbriel force-pushed the fix/issue-63209 branch 5 times, most recently from 9261699 to adb01e2Compare March 14, 2026 13:07

eladkal added this to the Airflow 3.1.9 milestone Mar 15, 2026

eladkal added type:bug-fix Changelog: Bug Fixes backport-to-v3-1-test labels Mar 15, 2026

YoannAbriel force-pushed the fix/issue-63209 branch 2 times, most recently from e5f4abd to 04352bfCompare March 23, 2026 13:09

YoannAbriel force-pushed the fix/issue-63209 branch from 04352bf to 6f70d36Compare March 23, 2026 19:07

YoannAbriel force-pushed the fix/issue-63209 branch from 6f70d36 to 1c59403Compare April 5, 2026 09:01

eladkal added backport-to-v3-2-test and removed backport-to-v3-1-test labels Apr 6, 2026

eladkal modified the milestones: Airflow 3.1.9, Airflow 3.2.1 Apr 6, 2026

YoannAbriel force-pushed the fix/issue-63209 branch 9 times, most recently from 995578e to d980ecaCompare April 10, 2026 09:04

kaxil requested a review from Copilot April 10, 2026 19:55

CopilotAI reviewed Apr 10, 2026

YoannAbriel force-pushed the fix/issue-63209 branch 3 times, most recently from c1b3043 to 2a1da0eCompare April 13, 2026 06:06

YoannAbriel force-pushed the fix/issue-63209 branch from 2a1da0e to 904604dCompare April 13, 2026 15:05

amoghrajesh requested changes Apr 14, 2026
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amoghrajesh closed this Apr 14, 2026