Bug: Snapshot status "partial" misreported

[redbearsam]

Related to issue #5792 .

Bug: Snapshot status "partial" misreported

When hitting the _snapshot/{repoName}/{snapshotName}/_status endpoint, the partial state is never returned (as it is for example when hitting the _snapshot/{repoName}/{snapshotName} endpoint.

The following code and TODO are to be found inside the relevant file (elasticsearch/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/status/TransportSnapshotStatusAction):

final SnapshotsInProgress.State state;
switch (snapshotInfo.state()) {
    case FAILED:
        state = SnapshotsInProgress.State.FAILED;
        break;
    case SUCCESS:
    case PARTIAL:
        // Translating both PARTIAL and SUCCESS to SUCCESS for now
        // TODO: add the differentiation on the metadata level in the next major release
        state = SnapshotsInProgress.State.SUCCESS;
        break;
    default:
        throw new IllegalArgumentException("Unknown snapshot state " + snapshotInfo.state());

Suggest implementing the suggested TODO. Can't see any obvious issues therein. I expect to make a pull request to this effect quite soon, given the go-ahead.

Elasticsearch version (bin/elasticsearch --version): v1.7 through v6.2

[bleskes]

@tlrx can you voice an opinion please?

[tlrx]

Thanks @redbearsam. Indeed, I think we can now correctly report the PARTIAL status. Do you still want to submit a pull request?

[redbearsam]

Cool yes, thy will be done. Submission will be tomorrow. Thanks tlrx.

[tlrx]

Pull request has been submitted: #28801

[original-brownbear]

There is another issue here, SUCCESS from the status API doesn't necessarily mean that the snapshot has actually completed. It will also be returned after all shard snapshots have finished but before snapshot finalization has happened, see #49533

[elasticsearchmachine]

Pinging @elastic/es-distributed (Team:Distributed)