[33/50] incubator-slider git commit: SLIDER-724 Implement OfflineFilter to return 503 "unavailable", for AM bootstrap

[st...@apache.org]

SLIDER-724 Implement OfflineFilter to return 503 "unavailable", for AM bootstrap


Project: http://git-wip-us.apache.org/repos/asf/incubator-slider/repo
Commit: http://git-wip-us.apache.org/repos/asf/incubator-slider/commit/fe3ffc9a
Tree: http://git-wip-us.apache.org/repos/asf/incubator-slider/tree/fe3ffc9a
Diff: http://git-wip-us.apache.org/repos/asf/incubator-slider/diff/fe3ffc9a

Branch: refs/heads/feature/SLIDER-151_REST_API
Commit: fe3ffc9a591d569cc0ba79e029fa9b27a6aaece8
Parents: b42e250
Author: Steve Loughran <st...@apache.org>
Authored: Mon Dec 15 14:24:44 2014 +0000
Committer: Steve Loughran <st...@apache.org>
Committed: Tue Dec 16 20:25:39 2014 +0000

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 .../appmaster/web/utils/OfflineFilter.java      | 104 +++++++++++++++++++
 1 file changed, 104 insertions(+)
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http://git-wip-us.apache.org/repos/asf/incubator-slider/blob/fe3ffc9a/slider-core/src/main/java/org/apache/slider/server/appmaster/web/utils/OfflineFilter.java
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diff --git a/slider-core/src/main/java/org/apache/slider/server/appmaster/web/utils/OfflineFilter.java b/slider-core/src/main/java/org/apache/slider/server/appmaster/web/utils/OfflineFilter.java
new file mode 100644
index 0000000..ad16f4e
--- /dev/null
+++ b/slider-core/src/main/java/org/apache/slider/server/appmaster/web/utils/OfflineFilter.java
@@ -0,0 +1,104 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.slider.server.appmaster.web.utils;
+
+import com.google.common.base.Preconditions;
+import org.apache.hadoop.http.FilterContainer;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Offline filter. 
+ * All filter instances share the static offline flag.
+ * <p>
+ *   Callers must use the method {@link #bindFilter(FilterContainer)}
+ *   to bind to the web container.
+ */
+public class OfflineFilter implements Filter {
+
+  private static final AtomicBoolean offline = new AtomicBoolean(true);
+
+  private static String offlineMessage = "offline";
+  private static final AtomicInteger retry = new AtomicInteger(10);
+
+  public OfflineFilter() {
+  }
+
+  public static synchronized void goOffline(String message) {
+    Preconditions.checkArgument(message != null, "null message");
+      offline.set(true);
+      offlineMessage = message;
+  }
+
+  public static synchronized String getOfflineMessage() {
+    return offlineMessage;
+  }
+
+  public static int getRetry() {
+    return retry.intValue();
+  }
+
+  public static void setRetry(int retryCount) {
+    retry.set(retryCount);
+  }
+
+  @Override
+  public void init(FilterConfig filterConfig) throws ServletException {
+
+  }
+
+  @Override
+  public void doFilter(ServletRequest request,
+      ServletResponse response,
+      FilterChain chain) throws IOException, ServletException {
+
+    if (!offline.get()) {
+      chain.doFilter(request, response);
+    } else {
+      // service is offline
+      HttpServletResponse httpResponse = (HttpServletResponse) response;
+      httpResponse.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
+          getOfflineMessage());
+    }
+  }
+
+  @Override
+  public void destroy() {
+
+  }
+
+  /**
+   * Add the filter to a container
+   * @param container container
+   */
+  public static void bindFilter(FilterContainer container) {
+    container.addFilter("OfflineFilter",
+        "org.apache.slider.server.appmaster.web.utils.OfflineFilter",
+        null);
+  }
+}