1 files changed, 61 insertions, 0 deletions
diff --git a/java/com/google/gerrit/elasticsearch/ElasticIndexVersionDiscovery.java b/java/com/google/gerrit/elasticsearch/ElasticIndexVersionDiscovery.java
new file mode 100644
index 0000000000..100022a181
--- /dev/null
+++ b/java/com/google/gerrit/elasticsearch/ElasticIndexVersionDiscovery.java
@@ -0,0 +1,61 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.elasticsearch;
+
+import static java.util.stream.Collectors.toList;
+
+import com.google.common.flogger.FluentLogger;
+import com.google.gson.JsonParser;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+import java.io.IOException;
+import java.util.List;
+import org.apache.http.HttpStatus;
+import org.apache.http.StatusLine;
+import org.elasticsearch.client.Request;
+import org.elasticsearch.client.Response;
+
+@Singleton
+class ElasticIndexVersionDiscovery {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  private final ElasticRestClientProvider client;
+
+  @Inject
+  ElasticIndexVersionDiscovery(ElasticRestClientProvider client) {
+    this.client = client;
+  }
+
+  List<String> discover(String prefix, String indexName) throws IOException {
+    String name = prefix + indexName + "_";
+    Request request = new Request("GET", client.adapter().getVersionDiscoveryUrl(name));
+    Response response = client.get().performRequest(request);
+
+    StatusLine statusLine = response.getStatusLine();
+    if (statusLine.getStatusCode() != HttpStatus.SC_OK) {
+      String message =
+          String.format(
+              "Failed to discover index versions for %s: %d: %s",
+              name, statusLine.getStatusCode(), statusLine.getReasonPhrase());
+      logger.atSevere().log(message);
+      throw new IOException(message);
+    }
+
+    return new JsonParser()
+        .parse(AbstractElasticIndex.getContent(response)).getAsJsonObject().entrySet().stream()
+            .map(e -> e.getKey().replace(name, ""))
+            .collect(toList());
+  }
+}