bazel: test scoped logs not directly available

[RaduBerinde]

Many tests dump out their logs in separate files. When running under bazel, these logs are left in the sandbox which is removed (unless --debug_sandbox) is used.

I220117 05:35:34.291146 1 (gostd) rand.go:147  [-] 1  random seed: 6532117856687621002
test logs left over in: /home/radu/.cache/bazel/_bazel_radu/c5a4e7d36696d9cd970af2045211a7df/sandbox/linux-sandbox/1891/execroot/cockroach/_tmp/b287de7194e17a0386ee1775f0d198ba/logTestSchemaChangeReverseMutations4230933597
--- FAIL: TestSchemaChangeReverseMutations (0.91s)
    test_log_scope.go:79: test logs captured to: /home/radu/.cache/bazel/_bazel_radu/c5a4e7d36696d9cd970af2045211a7df/sandbox/linux-sandbox/1891/execroot/cockroach/_tmp/b287de7194e17a0386ee1775f0d198ba/logTestSchemaChangeReverseMutations4230933597
    test_log_scope.go:80: use -show-logs to present logs inline
    schema_changer_test.go:1788: pq: failed to construct index entries during backfill: unable to encode table key: <nil>
    panic.go:642: -- test log scope end --
FAIL

ls: cannot access '/home/radu/.cache/bazel/_bazel_radu/c5a4e7d36696d9cd970af2045211a7df/sandbox/linux-sandbox/1891/execroot/cockroach/_tmp/b287de7194e17a0386ee1775f0d198ba/logTestSchemaChangeReverseMutations4230933597': No such file or directory

Jira issue: CRDB-12316

[rickystewart]

You should set --test_tmpdir=SOME_PERSISTENT_DIRECTORY, then your logs will be in SOME_PERSISTENT_DIRECTORY after the test runs.

[RaduBerinde]

Good to knowm thanks. We need to find a way to convey this information.. even if we have to modify the message generated in test_log_scope.go.

Or, could we set this up by default in the repo's bazelrc? We could allow a gitignored testlogs directory.

[rickystewart]

Or, could we set this up by default in the repo's bazelrc?

I've only ever used this flag with an absolute path, not sure if it works with a relative path? You can give it a shot.

We already put the tmpdir in a special spot for --config ci, we would just have to make sure we don't break the existing stuff.

[github-actions]

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[rickystewart]

./dev doctor guides you to set up your tmpdir appropriately.