Fix execution timeout enforcement in task supervisor (#57174)

[qwe-kev]

closes: #53337
related: #57174

This PR implements proper execution timeout handling for Airflow 3.0 by moving timeout enforcement from the task process to the supervisor process.

Previously, execution_timeout was handled inside the task process using a timeout decorator. This approach failed when:

• Task process encountered SIGSEGV or other signals (DagBag Processing SIGSEGV causes runaway tasks with LocalExecutor #57174)
• Native code ran in tight loops without handling Python signals
• Process was killed before timeout could be enforced

Changes

• Added TaskExecutionTimeout message for worker-to-supervisor communication
• Supervisor monitors execution time and enforces timeout with SIGTERM/SIGKILL
• Removed in-process timeout decorator from task execution
• Timeout measurement starts after DAG parsing (excludes startup overhead)

Implementation

1. Worker sends timeout_seconds to supervisor after DAG parsing
2. Supervisor tracks elapsed time using monotonic clock
3. On timeout: sends SIGTERM, then SIGKILL after 5-second grace period

This ensures reliable timeout enforcement at the supervisor level, preventing runaway tasks even when the task process encounters errors.

[boring-cyborg]

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[potiuk]

This looks really good - can you please add test cases covering the timeout handling in supervisor ?

[qwe-kev]

Added a comprehensive test suite for timeout handling as requested. All tests are passing.

Test Coverage:

• 9 unit tests for timeout logic (SIGTERM/SIGKILL escalation, grace periods, etc.)
• 4 integration tests with real subprocesses
• All 13 tests passing locally
• No existing tests broken

[qwe-kev]

Hi, I wanted to follow up on this contribution. Is there anything I can do to help move this forward or any additional information needed?

[potiuk]

Hi, I wanted to follow up on this contribution. Is there anything I can do to help move this forward or any additional information needed?

Turning that PR green might be a good start.

[qwe-kev]

Hi, I wanted to follow up on this contribution.

[amoghrajesh]

@qwe-kev can you help fixing the CI and resolving merge conflicts on this one? We could take a look once that's done.

[potiuk]

@qwe-kev This PR has been converted to draft because it does not yet meet our Pull Request quality criteria.

Issues found:

• ❌ Merge conflicts: This PR has merge conflicts with the main branch. Your branch is 747 commits behind main. Please rebase your branch (git fetch origin && git rebase origin/main), resolve the conflicts, and push again. See contributing quick start.
• ❌ Pre-commit / static checks: Failing: CI image checks / Static checks. Run prek run --from-ref main locally to find and fix issues. See Pre-commit / static checks docs.
• ❌ Build docs: Failing: CI image checks / Build documentation (--docs-only). Run breeze build-docs locally to reproduce. See Build docs docs.
• ❌ Provider tests: Failing: Postgres tests: providers / DB-prov:Postgres:14:3.10:-amazon,celer...standard, MySQL tests: providers / DB-prov:MySQL:8.0:3.10:-amazon,celer...standard, Sqlite tests: providers / DB-prov:Sqlite:3.10:-amazon,celer...standard, Special tests / Min SQLAlchemy test: providers / DB-prov:MinSQLAlchemy-Postgres:14:3.10:-amazon,celer...standard, Special tests / Latest SQLAlchemy test: providers / DB-prov:LatestSQLAlchemy-Postgres:14:3.10:-amazon,celer...standard (+2 more). Run provider tests with breeze run pytest <provider-test-path> -xvs. See Provider tests docs.
• ❌ Other failing CI checks: Failing: CI image checks / Build documentation (--spellcheck-only), Postgres tests: core / DB-core:Postgres:14:3.10:API...Serialization, MySQL tests: core / DB-core:MySQL:8.0:3.10:API...Serialization, Sqlite tests: core / DB-core:Sqlite:3.10:API...Serialization, Non-DB tests: core / Non-DB-core::3.10:API...Serialization (+5 more). Run prek run --from-ref main locally to reproduce. See static checks docs.
• ⚠️ Unresolved review comments: This PR has 1 unresolved review thread from maintainers: @uranusjr (MEMBER): 1 unresolved thread. Please review and resolve all inline review comments before requesting another review. You can resolve a conversation by clicking 'Resolve conversation' on each thread after addressing the feedback. See pull request guidelines.

Note: Your branch is 747 commits behind main. Some check failures may be caused by changes in the base branch rather than by your PR. Please rebase your branch and push again to get up-to-date CI results.

What to do next:

• The comment informs you what you need to do.
• Fix each issue, then mark the PR as "Ready for review" in the GitHub UI - but only after making sure that all the issues are fixed.
• There is no rush — take your time and work at your own pace. We appreciate your contribution and are happy to wait for updates.
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Converting a PR to draft is not a rejection — it is an invitation to bring the PR up to the project's standards so that maintainer review time is spent productively. There is no rush — take your time and work at your own pace. We appreciate your contribution and are happy to wait for updates. If you have questions, feel free to ask on the Airflow Slack.