Snapshot/Restore: add support for changing index settings during restore process

Closes #7887

Author: imotov

docs/reference/modules/snapshots.asciidoc

@@ -243,6 +243,24 @@ restore such indices by setting `partial` to `true`. Please note, that only succ
 restored in this case and all missing shards will be recreated empty.
 
 
+[float]
+=== Changing index settings during restore
+
+Most of index settings can be overridden during the restore process. For example, the following command will restore
+the index `index_1` without creating any replicas while switching back to default refresh interval:
+
+[source,js]
+-----------------------------------
+$ curl -XPOST "localhost:9200/_snapshot/my_backup/snapshot_1/_restore" -d '{
+    "indices": "index_1",
+    "index_settings" : {
+        "index.number_of_replicas": 0
+    },
+    "ignore_index_settings": ["index.refresh_interval"]
+}'
+-----------------------------------
+
+
 [float]
 === Snapshot status
 

src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequest.java

@@ -74,6 +74,10 @@ public class RestoreSnapshotRequest extends MasterNodeOperationRequest<RestoreSn
 
     private Settings settings = EMPTY_SETTINGS;
 
+    private Settings indexSettings = EMPTY_SETTINGS;
+
+    private String[] ignoreIndexSettings = Strings.EMPTY_ARRAY;
+
     RestoreSnapshotRequest() {
     }
 
@@ -106,7 +110,12 @@ public ActionRequestValidationException validate() {
         if (settings == null) {
             validationException = addValidationError("settings are missing", validationException);
         }
-
+        if (indexSettings == null) {
+            validationException = addValidationError("indexSettings are missing", validationException);
+        }
+        if (ignoreIndexSettings == null) {
+            validationException = addValidationError("ignoreIndexSettings are missing", validationException);
+        }
         return validationException;
     }
 
@@ -364,6 +373,29 @@ public Settings settings() {
         return this.settings;
     }
 
+    /**
+     * Sets the list of index settings and index settings groups that shouldn't be restored from snapshot
+     */
+    public RestoreSnapshotRequest ignoreIndexSettings(String... ignoreIndexSettings) {
+        this.ignoreIndexSettings = ignoreIndexSettings;
+        return this;
+    }
+
+    /**
+     * Sets the list of index settings and index settings groups that shouldn't be restored from snapshot
+     */
+    public RestoreSnapshotRequest ignoreIndexSettings(List<String> ignoreIndexSettings) {
+        this.ignoreIndexSettings = ignoreIndexSettings.toArray(new String[ignoreIndexSettings.size()]);
+        return this;
+    }
+
+    /**
+     * Returns the list of index settings and index settings groups that shouldn't be restored from snapshot
+     */
+    public String[] ignoreIndexSettings() {
+        return ignoreIndexSettings;
+    }
+
     /**
      * If set to true the restore procedure will restore global cluster state.
      * <p/>
@@ -406,6 +438,51 @@ public boolean includeAliases() {
         return includeAliases;
     }
 
+    /**
+     * Sets settings that should be added/changed in all restored indices
+     */
+    public RestoreSnapshotRequest indexSettings(Settings settings) {
+        this.indexSettings = settings;
+        return this;
+    }
+
+    /**
+     * Sets settings that should be added/changed in all restored indices
+     */
+    public RestoreSnapshotRequest indexSettings(Settings.Builder settings) {
+        this.indexSettings = settings.build();
+        return this;
+    }
+
+    /**
+     * Sets settings that should be added/changed in all restored indices
+     */
+    public RestoreSnapshotRequest indexSettings(String source) {
+        this.indexSettings = ImmutableSettings.settingsBuilder().loadFromSource(source).build();
+        return this;
+    }
+
+    /**
+     * Sets settings that should be added/changed in all restored indices
+     */
+    public RestoreSnapshotRequest indexSettings(Map<String, Object> source) {
+        try {
+            XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+            builder.map(source);
+            indexSettings(builder.string());
+        } catch (IOException e) {
+            throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
+        }
+        return this;
+    }
+
+    /**
+     * Returns settings that should be added/changed in all restored indices
+     */
+    public Settings indexSettings() {
+        return this.indexSettings;
+    }
+
     /**
      * Parses restore definition
      *
@@ -454,7 +531,7 @@ public RestoreSnapshotRequest source(Map source) {
                 partial(nodeBooleanValue(entry.getValue()));
             } else if (name.equals("settings")) {
                 if (!(entry.getValue() instanceof Map)) {
-                    throw new ElasticsearchIllegalArgumentException("malformed settings section, should indices an inner object");
+                    throw new ElasticsearchIllegalArgumentException("malformed settings section");
                 }
                 settings((Map<String, Object>) entry.getValue());
             } else if (name.equals("include_global_state")) {
@@ -473,6 +550,19 @@ public RestoreSnapshotRequest source(Map source) {
                 } else {
                     throw new ElasticsearchIllegalArgumentException("malformed rename_replacement");
                 }
+            } else if (name.equals("index_settings")) {
+                if (!(entry.getValue() instanceof Map)) {
+                    throw new ElasticsearchIllegalArgumentException("malformed index_settings section");
+                }
+                indexSettings((Map<String, Object>) entry.getValue());
+            } else if (name.equals("ignore_index_settings")) {
+                    if (entry.getValue() instanceof String) {
+                        ignoreIndexSettings(Strings.splitStringByCommaToArray((String) entry.getValue()));
+                    } else if (entry.getValue() instanceof List) {
+                        ignoreIndexSettings((List<String>) entry.getValue());
+                    } else {
+                        throw new ElasticsearchIllegalArgumentException("malformed ignore_index_settings section, should be an array of strings");
+                    }
             } else {
                 throw new ElasticsearchIllegalArgumentException("Unknown parameter " + name);
             }
@@ -563,6 +653,10 @@ public void readFrom(StreamInput in) throws IOException {
         partial = in.readBoolean();
         includeAliases = in.readBoolean();
         settings = readSettingsFromStream(in);
+        if (in.getVersion().onOrAfter(Version.V_1_5_0)) {
+            indexSettings = readSettingsFromStream(in);
+            ignoreIndexSettings = in.readStringArray();
+        }
     }
 
     @Override
@@ -579,5 +673,9 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeBoolean(partial);
         out.writeBoolean(includeAliases);
         writeSettingsToStream(settings, out);
+        if (out.getVersion().onOrAfter(Version.V_1_5_0)) {
+            writeSettingsToStream(indexSettings, out);
+            out.writeStringArray(ignoreIndexSettings);
+        }
     }
 }

src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestBuilder.java

@@ -25,6 +25,7 @@
 import org.elasticsearch.client.ClusterAdminClient;
 import org.elasticsearch.common.settings.Settings;
 
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -230,6 +231,68 @@ public RestoreSnapshotRequestBuilder setIncludeAliases(boolean restoreAliases) {
         return this;
     }
 
+    /**
+     * Sets index settings that should be added or replaced during restore
+
+     * @param settings index settings
+     * @return this builder
+     */
+    public RestoreSnapshotRequestBuilder setIndexSettings(Settings settings) {
+        request.indexSettings(settings);
+        return this;
+    }
+
+    /**
+     * Sets index settings that should be added or replaced during restore
+
+     * @param settings index settings
+     * @return this builder
+     */
+    public RestoreSnapshotRequestBuilder setIndexSettings(Settings.Builder settings) {
+        request.indexSettings(settings);
+        return this;
+    }
+
+    /**
+     * Sets index settings that should be added or replaced during restore
+
+     * @param source index settings
+     * @return this builder
+     */
+    public RestoreSnapshotRequestBuilder setIndexSettings(String source) {
+        request.indexSettings(source);
+        return this;
+    }
+
+    /**
+     * Sets index settings that should be added or replaced during restore
+
+     * @param source index settings
+     * @return this builder
+     */
+    public RestoreSnapshotRequestBuilder setIndexSettings(Map<String, Object> source) {
+        request.indexSettings(source);
+        return this;
+    }
+
+
+    /**
+     * Sets the list of index settings and index settings groups that shouldn't be restored from snapshot
+     */
+    public RestoreSnapshotRequestBuilder setIgnoreIndexSettings(String... ignoreIndexSettings) {
+        request.ignoreIndexSettings(ignoreIndexSettings);
+        return this;
+    }
+
+    /**
+     * Sets the list of index settings and index settings groups that shouldn't be restored from snapshot
+     */
+    public RestoreSnapshotRequestBuilder setIgnoreIndexSettings(List<String> ignoreIndexSettings) {
+        request.ignoreIndexSettings(ignoreIndexSettings);
+        return this;
+    }
+
+
     @Override
     protected void doExecute(ActionListener<RestoreSnapshotResponse> listener) {
         client.restoreSnapshot(request, listener);

src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/TransportRestoreSnapshotAction.java

@@ -73,7 +73,8 @@ protected void masterOperation(final RestoreSnapshotRequest request, ClusterStat
         RestoreService.RestoreRequest restoreRequest = new RestoreService.RestoreRequest(
                 "restore_snapshot[" + request.snapshot() + "]", request.repository(), request.snapshot(),
                 request.indices(), request.indicesOptions(), request.renamePattern(), request.renameReplacement(),
-                request.settings(), request.masterNodeTimeout(), request.includeGlobalState(), request.partial(), request.includeAliases());
+                request.settings(), request.masterNodeTimeout(), request.includeGlobalState(), request.partial(), request.includeAliases(),
+                request.indexSettings(), request.ignoreIndexSettings());
 
         restoreService.restoreSnapshot(restoreRequest, new ActionListener<RestoreInfo>() {
             @Override