Fix celery docker env var parsing

[mattfaltyn]

Summary & Motivation

Fixes #34006.

dagster-celery-docker manually split list-form container_kwargs.environment entries on every =, so valid values like TOKEN=a=b crashed with ValueError: too many values to unpack. This reuses Dagster's existing parse_env_var() helper so only the first = separates the key from the value.

Test Plan

• UV_CACHE_DIR=/tmp/uv-cache uv run --frozen --project python_modules/libraries/dagster-celery-docker --group test pytest python_modules/libraries/dagster-celery-docker/dagster_celery_docker_tests/test_executor.py -q — passed, 1 passed in 0.06s
• UV_CACHE_DIR=/tmp/uv-cache UV_TOOL_DIR=/tmp/uv-tools uvx ruff==0.15.15 check python_modules/libraries/dagster-celery-docker/dagster_celery_docker/executor.py python_modules/libraries/dagster-celery-docker/dagster_celery_docker_tests/test_executor.py — passed
• UV_CACHE_DIR=/tmp/uv-cache UV_TOOL_DIR=/tmp/uv-tools uvx ruff==0.15.15 format --check python_modules/libraries/dagster-celery-docker/dagster_celery_docker/executor.py python_modules/libraries/dagster-celery-docker/dagster_celery_docker_tests/test_executor.py — passed, 2 files already formatted
• UV_CACHE_DIR=/tmp/uv-cache uv run --frozen --project python_modules/libraries/dagster-celery-docker --group test pytest python_modules/libraries/dagster-celery-docker/dagster_celery_docker_tests -q — attempted; local run reached 3 passed, 2 errors, with both errors in Docker Compose fixture setup because the docker executable is unavailable locally (FileNotFoundError: [Errno 2] No such file or directory: 'docker')

Changelog

Fixed dagster-celery-docker handling of list-form Docker environment values that contain additional equals signs.

[greptile-apps]

Greptile Summary

This PR fixes a ValueError: too many values to unpack crash in dagster-celery-docker when Docker container environment entries in list form (e.g., TOKEN=a=b) contain extra = characters. The fix replaces a bare v.split("=") with the existing parse_env_var() helper that uses split("=", maxsplit=1).

• executor.py: Imports and uses parse_env_var() instead of v.split("=") in the list-form environment variable processing path.
• test_executor.py: Adds a focused unit test that stubs out all Docker and Dagster I/O and asserts that TOKEN=a=b is correctly parsed to key TOKEN and value a=b.

Confidence Score: 5/5

The change is minimal, targeted, and replaces a proven-broken code path with a well-tested utility already used elsewhere in the codebase.

The one-line change in executor.py is straightforwardly correct: parse_env_var uses maxsplit=1 to isolate only the first =, fixing the crash without touching any other logic. The new test exercises the exact failure scenario end-to-end, monkeypatching cleanly without leaving real side-effects. No other code paths are affected.

No files require special attention; both changed files are clean.

Important Files Changed

Filename	Overview
python_modules/libraries/dagster-celery-docker/dagster_celery_docker/executor.py	Single-line fix replacing v.split('=') with parse_env_var(v) to correctly handle env values containing =; import added correctly.
python_modules/libraries/dagster-celery-docker/dagster_celery_docker_tests/test_executor.py	New regression test that monkeypatches Docker and Dagster dependencies to verify the env var parsing fix end-to-end without requiring a Docker daemon.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["container_kwargs.environment provided"] --> B{isinstance dict?}
    B -- Yes --> C["docker_env.update(e_vars)"]
    B -- No --> D["for v in e_vars (list)"]
    D --> E["parse_env_var(v)"]
    E --> F{Contains '='?}
    F -- Yes --> G["split on first '=' only\ne.g. TOKEN=a=b → ('TOKEN','a=b')"]
    F -- No --> H["os.getenv(v)\n(inherit from worker env)"]
    G --> I["docker_env[key] = val"]
    H --> I
    I --> J["del container_kwargs['environment']"]
    J --> K["client.containers.run(..., environment=docker_env)"]

    style E fill:#90EE90
    style G fill:#90EE90

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%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
flowchart TD
    A["container_kwargs.environment provided"] --> B{isinstance dict?}
    B -- Yes --> C["docker_env.update(e_vars)"]
    B -- No --> D["for v in e_vars (list)"]
    D --> E["parse_env_var(v)"]
    E --> F{Contains '='?}
    F -- Yes --> G["split on first '=' only\ne.g. TOKEN=a=b → ('TOKEN','a=b')"]
    F -- No --> H["os.getenv(v)\n(inherit from worker env)"]
    G --> I["docker_env[key] = val"]
    H --> I
    I --> J["del container_kwargs['environment']"]
    J --> K["client.containers.run(..., environment=docker_env)"]

    style E fill:#90EE90
    style G fill:#90EE90

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_{Reviews (1): Last reviewed commit: "Fix celery docker env var parsing" | Re-trigger Greptile}

[mattfaltyn]

Buildkite unit-tests is currently blocked before jobs start. The Buildkite build reports creator_verified: false, started_at: null, jobs_started_count: 0, and jobs_failed_count: 0, so there are no unit-test failure logs available yet.

Local scoped validation passed as listed in the Test Plan: focused regression test, Ruff check, and Ruff format check. The broader dagster-celery-docker package test command was attempted locally, but the two Docker Compose integration tests could not run because the local docker executable is unavailable.