feat: make shared memory directory configurable

[pypingou]

Make the shared memory file location configurable via SCORE_LOG_SHM_DIR environment variable while maintaining backward compatibility (defaults to /tmp/).

This enables containerized deployments where both the datarouter and applications run in separate containers and communicate via shared memory files. By configuring a specific subdirectory (e.g., /tmp/score-logging or /dev/shm/logging), containers can share only that directory via volume mounts without exposing the entire /tmp or /dev/shm filesystem, which may be used for other purposes by other applications.

Changes:

• Add path_utils module for shared directory path resolution
• Update writer_factory.cpp to use configurable path
• Update socketserver.cpp to use configurable path
• Auto-create directory if it doesn't exist (0755 permissions)
• Add unit tests for path utilities (6 tests, all passing)
• Update BUILD files to integrate path_utils library

Environment variable:

• SCORE_LOG_SHM_DIR: Directory for shared memory files (default: "/tmp/")

Example usage for containerized datarouter + application:

Both containers set:

export SCORE_LOG_SHM_DIR=/tmp/score-logging

And mount the same volume at /tmp/score-logging

The environment variable also allows flexible deployment for better performance (e.g., /dev/shm on Linux) while ensuring both application and datarouter sides use identical paths.

Notes for Reviewer

Pre-Review Checklist for the PR Author

• PR title is short, expressive and meaningful
• Commits are properly organized
• Relevant issues are linked in the References section
• Tests are conducted
• Unit tests are added

Checklist for the PR Reviewer

• Commits are properly organized and messages are according to the guideline
• Unit tests have been written for new behavior
• Public API is documented
• PR title describes the changes

Post-review Checklist for the PR Author

• All open points are addressed and tracked via issues

References

Closes #

[github-actions]

License Check Results

🚀 The license check job ran with the Bazel command:

bazel run --lockfile_mode=error //:license-check

Status: ⚠️ Needs Review

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[License Check Output]
Extracting Bazel installation...
Starting local Bazel server (8.6.0) and connecting to it...
INFO: Invocation ID: 2e1fe4aa-6892-49af-badb-786deb0eac6d
Computing main repo mapping: 
Computing main repo mapping: 
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Computing main repo mapping: 
Loading: 
Loading: 4 packages loaded
Loading: 4 packages loaded
    currently loading: 
WARNING: Target pattern parsing failed.
ERROR: Skipping '//:license-check': no such target '//:license-check': target 'license-check' not declared in package '' defined by /home/runner/work/logging/logging/BUILD
ERROR: no such target '//:license-check': target 'license-check' not declared in package '' defined by /home/runner/work/logging/logging/BUILD
INFO: Elapsed time: 10.546s
INFO: 0 processes.
ERROR: Build did NOT complete successfully
ERROR: Build failed. Not running target

[github-actions]

The created documentation from the pull request is available at: docu-html

[github-actions]

Thanks for the pull request. This thread has been quiet for 30 days, so we are marking it as stale for now. Please take a quick look and let us know whether it is still up to date, still relevant, needs review, or is ready to merge. Any new activity will remove the stale label automatically. If nothing changes in the next 10 days, we will close it to keep the backlog current.

[pypingou]

I still think this could be an interesting addition and am looking for feedback

[github-actions]

Thanks for the pull request. This thread has been quiet for 30 days, so we are marking it as stale for now. Please take a quick look and let us know whether it is still up to date, still relevant, needs review, or is ready to merge. Any new activity will remove the stale label automatically. If nothing changes in the next 10 days, we will close it to keep the backlog current.