Allow date math for naming newly-created snapshots (elastic#7939) (elastic#30479)

(cherry picked from commit fe3e025)

Author: Vladimir Dolzhenko

docs/reference/modules/snapshots.asciidoc

@@ -289,6 +289,20 @@ By setting `include_global_state` to false it's possible to prevent the cluster
 the snapshot. By default, the entire snapshot will fail if one or more indices participating in the snapshot don't have
 all primary shards available. This behaviour can be changed by setting `partial` to `true`.
 
+Snapshot names can be automatically derived using <<date-math-index-names,date math expressions>>, similarly as when creating
+new indices. Note that special characters need to be URI encoded.
+
+For example, creating a snapshot with the current day in the name, like `snapshot-2018.05.11`, can be achieved with
+the following command:
+[source,js]
+-----------------------------------
+# PUT /_snapshot/my_backup/<snapshot-{now/d}>
+PUT /_snapshot/my_backup/%3Csnapshot-%7Bnow%2Fd%7D%3E
+-----------------------------------
+// CONSOLE
+// TEST[continued]
+
+
 The index snapshot process is incremental. In the process of making the index snapshot Elasticsearch analyses
 the list of the index files that are already stored in the repository and copies only files that were created or
 changed since the last snapshot. That allows multiple snapshots to be preserved in the repository in a compact form.

server/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/create/TransportCreateSnapshotAction.java

@@ -71,8 +71,9 @@ protected ClusterBlockException checkBlock(CreateSnapshotRequest request, Cluste
 
     @Override
     protected void masterOperation(final CreateSnapshotRequest request, ClusterState state, final ActionListener<CreateSnapshotResponse> listener) {
+        final String snapshotName = indexNameExpressionResolver.resolveDateMathExpression(request.snapshot());
         SnapshotsService.SnapshotRequest snapshotRequest =
-                new SnapshotsService.SnapshotRequest(request.repository(), request.snapshot(), "create_snapshot [" + request.snapshot() + "]")
+                new SnapshotsService.SnapshotRequest(request.repository(), snapshotName, "create_snapshot [" + snapshotName + "]")
                         .indices(request.indices())
                         .indicesOptions(request.indicesOptions())
                         .partial(request.partial())
@@ -87,7 +88,7 @@ public void onResponse() {
                         @Override
                         public void onSnapshotCompletion(Snapshot snapshot, SnapshotInfo snapshotInfo) {
                             if (snapshot.getRepository().equals(request.repository()) &&
-                                    snapshot.getSnapshotId().getName().equals(request.snapshot())) {
+                                    snapshot.getSnapshotId().getName().equals(snapshotName)) {
                                 listener.onResponse(new CreateSnapshotResponse(snapshotInfo));
                                 snapshotsService.removeListener(this);
                             }
@@ -96,7 +97,7 @@ public void onSnapshotCompletion(Snapshot snapshot, SnapshotInfo snapshotInfo) {
                         @Override
                         public void onSnapshotFailure(Snapshot snapshot, Exception e) {
                             if (snapshot.getRepository().equals(request.repository()) &&
-                                    snapshot.getSnapshotId().getName().equals(request.snapshot())) {
+                                    snapshot.getSnapshotId().getName().equals(snapshotName)) {
                                 listener.onFailure(e);
                                 snapshotsService.removeListener(this);
                             }

server/src/test/java/org/elasticsearch/snapshots/DedicatedClusterSnapshotRestoreIT.java

@@ -32,6 +32,7 @@
 import org.elasticsearch.action.admin.cluster.state.ClusterStateResponse;
 import org.elasticsearch.action.index.IndexRequestBuilder;
 import org.elasticsearch.action.support.ActiveShardCount;
+import org.elasticsearch.client.AdminClient;
 import org.elasticsearch.client.Client;
 import org.elasticsearch.client.node.NodeClient;
 import org.elasticsearch.cluster.ClusterState;
@@ -41,6 +42,7 @@
 import org.elasticsearch.cluster.SnapshotDeletionsInProgress;
 import org.elasticsearch.cluster.SnapshotsInProgress;
 import org.elasticsearch.cluster.health.ClusterHealthStatus;
+import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.cluster.metadata.MetaDataIndexStateService;
 import org.elasticsearch.cluster.routing.allocation.decider.EnableAllocationDecider;
@@ -49,13 +51,15 @@
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.Priority;
+import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.Writeable;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.settings.SettingsFilter;
 import org.elasticsearch.common.unit.ByteSizeUnit;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.common.util.set.Sets;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.discovery.zen.ElectMasterService;
@@ -68,6 +72,7 @@
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.rest.RestResponse;
+import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.rest.action.admin.cluster.RestClusterStateAction;
 import org.elasticsearch.rest.action.admin.cluster.RestGetRepositoriesAction;
 import org.elasticsearch.snapshots.mockstore.MockRepository;
@@ -96,6 +101,7 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.lessThan;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.notNullValue;
@@ -981,6 +987,38 @@ public void testRestoreShrinkIndex() throws Exception {
         ensureYellow();
     }
 
+    public void testSnapshotWithDateMath() {
+        final String repo = "repo";
+        final AdminClient admin = client().admin();
+
+        final IndexNameExpressionResolver nameExpressionResolver = new IndexNameExpressionResolver(Settings.EMPTY);
+        final String snapshotName = "<snapshot-{now/d}>";
+
+        logger.info("-->  creating repository");
+        assertAcked(admin.cluster().preparePutRepository(repo).setType("fs")
+            .setSettings(Settings.builder().put("location", randomRepoPath())
+                .put("compress", randomBoolean())));
+
+        final String expression1 = nameExpressionResolver.resolveDateMathExpression(snapshotName);
+        logger.info("-->  creating date math snapshot");
+        CreateSnapshotResponse snapshotResponse =
+            admin.cluster().prepareCreateSnapshot(repo, snapshotName)
+                .setIncludeGlobalState(true)
+                .setWaitForCompletion(true)
+                .get();
+        assertThat(snapshotResponse.status(), equalTo(RestStatus.OK));
+        // snapshot could be taken before or after a day rollover
+        final String expression2 = nameExpressionResolver.resolveDateMathExpression(snapshotName);
+
+        SnapshotsStatusResponse response = admin.cluster().prepareSnapshotStatus(repo)
+            .setSnapshots(Sets.newHashSet(expression1, expression2).toArray(Strings.EMPTY_ARRAY))
+            .setIgnoreUnavailable(true)
+            .get();
+        List<SnapshotStatus> snapshots = response.getSnapshots();
+        assertThat(snapshots, hasSize(1));
+        assertThat(snapshots.get(0).getState().completed(), equalTo(true));
+    }
+
     public static class SnapshottableMetadata extends TestCustomMetaData {
         public static final String TYPE = "test_snapshottable";