[CI] Upload logs as artifacts to BuildKite

[MortalHappiness]

Previously, tests were run in GitHub Actions, and we uploaded logs as artifacts. Now that we've moved tests to BuildKite, the CI team has recently added support for uploading artifacts in BuildKite. Therefore, we need to upload artifacts there as well. (Prefer a zip file containing all the logs)

Details:

• Artifacts should only be uploaded when tests fail.
• The logs folder is located at ${{ env.KUBERAY_TEST_OUTPUT_DIR }}/**/*.log.
  • Reference (The config before migrating to BuildKite):

    kuberay/.github/workflows/e2e-tests-reusable-workflow.yaml

    Lines 100 to 107 in 4bd2dab

    	- name: Upload logs
    	uses: actions/upload-artifact@v4
    	if: (!inputs.plugin-test) && always() && steps.deploy.outcome == 'success'
    	with:
    	name: logs
    	retention-days: 10
    	path: |
    	${{ env.KUBERAY_TEST_OUTPUT_DIR }}/**/*.log

• To upload artifacts, write them to the /artifact-mount folder. All files in that folder will be automatically uploaded as artifacts.
  • Reference (Example of uploading artifacts): https://github.com/ray-project/kuberay/pull/3107/files
  • https://buildkite.com/ray-project/ray-ecosystem-ci-kuberay-ci/builds/7146#01953fb2-eb32-450d-ab50-f98ee2f9b4d4
    

[400Ping]

May I try this?