feat(config): support docker.socket.override in properties file

[Rajkaran-122]

Add support for reading TESTCONTAINERS_DOCKER_SOCKET_OVERRIDE from ~/.testcontainers.properties via the docker.socket.override property.

This enhancement addresses issue #8537, allowing users to configure the Docker socket override path in their properties file instead of requiring the environment variable. This is particularly useful for environments like Colima and Podman where the socket path needs to be configured for IDE test runs.

The implementation follows the existing pattern used for docker.client.strategy, checking TESTCONTAINERS_DOCKER_SOCKET_OVERRIDE environment variable first, then falling back to docker.socket.override property from user properties.

Closes #8537

[coderabbitai]

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Reviewing files that changed from the base of the PR and between ac44b34 and cbf6d8c.

📒 Files selected for processing (2)

• core/src/main/java/org/testcontainers/utility/TestcontainersConfiguration.java
• core/src/test/java/org/testcontainers/utility/TestcontainersConfigurationTest.java

🚧 Files skipped from review as they are similar to previous changes (2)

• core/src/test/java/org/testcontainers/utility/TestcontainersConfigurationTest.java
• core/src/main/java/org/testcontainers/utility/TestcontainersConfiguration.java

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Summary by CodeRabbit

• New Features

  • Added support for configuring the Docker socket override through environment variables or user properties.
  • Environment-based settings take precedence, with fallback to user properties when values are blank or unavailable.

• Bug Fixes

  • Improved Docker socket override handling so configured values are consistently recognized.

• Tests

  • Added coverage for default behavior, supported configuration sources, precedence rules, blank values, and excluded property sources.

Walkthrough

The change centralizes Docker socket override resolution. It prioritizes TESTCONTAINERS_DOCKER_SOCKET_OVERRIDE, then uses the unprefixed environment variable or docker.socket.override user property. Docker client setup uses this accessor, with tests covering sources and precedence.

Changes

Docker socket override

Layer / File(s)	Summary
Configuration resolution and validation core/src/main/java/org/testcontainers/utility/TestcontainersConfiguration.java, core/src/test/java/org/testcontainers/utility/TestcontainersConfigurationTest.java	Adds getDockerSocketOverride() with environment-variable precedence. Blank values are ignored. Tests cover defaults, user properties, classpath exclusion, sources, and precedence.
Docker client integration core/src/main/java/org/testcontainers/DockerClientFactory.java	Docker socket resolution now uses TestcontainersConfiguration.getInstance().getDockerSocketOverride().

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to cbf6d

The PR adds a localized properties-file fallback for the Docker socket override without any identified merge-blocking risk; it is merge-ready after normal checks and review.

Poem

A rabbit checks the socket path,
From environment or properties’ path.
Empty values hop aside,
Tests confirm each source and guide.
Docker reads the shared result.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: support for docker.socket.override in a properties file.
Description check	✅ Passed	The description explains the enhancement, motivation, precedence behavior, affected environments, and linked issue.
Linked Issues check	✅ Passed	The implementation and tests satisfy issue #8537 by supporting the properties fallback while preserving environment-variable precedence.
Out of Scope Changes check	✅ Passed	All changes are limited to Docker socket override configuration and its tests, with no unrelated scope identified.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

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Inline comments:
In
`@core/src/main/java/org/testcontainers/utility/TestcontainersConfiguration.java`:
- Around line 231-237: Update the prefixed override lookup in
TestcontainersConfiguration to treat empty or whitespace-only
TESTCONTAINERS_DOCKER_SOCKET_OVERRIDE values as unset, reusing the same
blank-value predicate or policy as getEnvVarOrUserProperty so fallback
resolution continues to DOCKER_SOCKET_OVERRIDE or docker.socket.override. Add a
regression test covering a blank prefixed environment variable and a configured
user property, verifying the property value is returned.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 87958589-3dcb-4ec4-9d87-d35a16730a2f

📥 Commits

Reviewing files that changed from the base of the PR and between 3a621f5 and c16df5b.

📒 Files selected for processing (3)

• core/src/main/java/org/testcontainers/DockerClientFactory.java
• core/src/main/java/org/testcontainers/utility/TestcontainersConfiguration.java
• core/src/test/java/org/testcontainers/utility/TestcontainersConfigurationTest.java

Included review availability: Your plan includes up to 8 reviews per rolling hour; 7 remain after this review.