GetSnapshotsResponse should re-wrap failed exceptions so callsites are visible in the stacktrace

[dakrone]

From the following code:

elasticsearch/server/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/get/GetSnapshotsResponse.java

Lines 156 to 166 in f879e84

	public List<SnapshotInfo> getSnapshots(String repo) {
	List<SnapshotInfo> snapshots = successfulResponses.get(repo);
	if (snapshots != null) {
	return snapshots;
	}
	ElasticsearchException error = failedResponses.get(repo);
	if (error == null) {
	throw new IllegalArgumentException("No such repository");
	}
	throw error;
	}

It's possible for snapshot exceptions to be generated on a different line than where they are actually thrown, for example, code that prior to #42090 worked like this:

GetSnapshotsRequest getSnapshotsRequest = new GetSnapshotsRequest(new String[]{repo}, new String[]{snapshotName});
final GetSnapshotsResponse snaps;
try {
    snaps = client.snapshot().get(getSnapshotsRequest, RequestOptions.DEFAULT);
} catch (Exception e) {
    if (e.getMessage().contains("snapshot_missing_exception")) {
        fail("snapshot does not exist: " + snapshotName);
    }
    throw e;
}

Optional<SnapshotInfo> info = snaps.getSnapshots(repo).stream().findFirst();
if (info.isPresent()) {
    info.ifPresent(si -> {
        assertThat(si.snapshotId().getName(), equalTo(snapshotName));
        assertThat(si.state(), equalTo(SnapshotState.SUCCESS));
    });
} else {
    fail("unable to find snapshot; " + snapshotName);
}

Now fails.

The exception is generated from the snaps.getSnapshots(repo) call above, however, the stacktrace for the exception actually traces back to the line

    snaps = client.snapshot().get(getSnapshotsRequest, RequestOptions.DEFAULT);

which is very confusing, because that line itself is wrapped in a try/catch.

GetSnapshotsResponse should change this line:

elasticsearch/server/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/get/GetSnapshotsResponse.java

Line 165 in f879e84

throw error;

Into something like

throw new ElasticsearchException(error);

So that the stacktrace correctly identifies the caller.

[elasticmachine]

Pinging @elastic/es-distributed

[ywelsch]

@dakrone Thanks for your analysis. Would you like to contribute a PR?

[0xamogh]

I am willing to take this up

[dakrone]

@amogh-jrules if you'd like to submit a PR for this that would be great, check out our contributing document if you need assistance getting an environment set up.