Persist credentials depending on conf setting

zeppelin-interpreter/src/main/java/org/apache/zeppelin/user/Credentials.java

@@ -18,6 +18,8 @@
 package org.apache.zeppelin.user;
 
 
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -33,15 +35,30 @@ public class Credentials {
 
   private static Credentials credentials = null;
   private Map<String, UserCredentials> credentialsMap;
+  private Gson gson;
+  private Boolean credentialsPersist = true;
+  File credentialsFile;
 
-  private Credentials() {
+  private Credentials(Boolean credentialsPersist, String credentialsPath) {
+    this.credentialsPersist = credentialsPersist;
+    credentialsFile = new File(credentialsPath);
     credentialsMap = new HashMap<>();
+    if (credentialsPersist) {
+      GsonBuilder builder = new GsonBuilder();
+      builder.setPrettyPrinting();
+      gson = builder.create();
+      loadFromFile();
+    }
   }
 
-  public static synchronized Credentials getCredentials() {
+  public static synchronized void initCredentials(Boolean credentialsPersist,
+                                                        String credentialsPath) {
     if (credentials == null) {
-      credentials = new Credentials();
+      credentials = new Credentials(credentialsPersist, credentialsPath);
     }
+  }
+
+  public static Credentials getCredentials() {
     return credentials;
   }
 
@@ -55,6 +72,62 @@ public class Credentials {
 
   public void putUserCredentials(String username, UserCredentials uc) throws IOException {
     credentialsMap.put(username, uc);
+    if (credentialsPersist) {
+      saveToFile();
+    }
+  }
+
+  private void loadFromFile() {
+    LOG.info(credentialsFile.getAbsolutePath());
+    if (!credentialsFile.exists()) {
+      // nothing to read
+      return;
+    }
+
+    try {
+      FileInputStream fis = new FileInputStream(credentialsFile);
+      InputStreamReader isr = new InputStreamReader(fis);
+      BufferedReader bufferedReader = new BufferedReader(isr);
+      StringBuilder sb = new StringBuilder();
+      String line;
+      while ((line = bufferedReader.readLine()) != null) {
+        sb.append(line);
+      }
+      isr.close();
+      fis.close();
+
+      String json = sb.toString();
+      CredentialsInfoSaving info = gson.fromJson(json, CredentialsInfoSaving.class);
+      this.credentialsMap = info.credentialsMap;
+    } catch (IOException e) {
+      LOG.error("Error loading credentials file");
+      e.printStackTrace();
+    }
+  }
+
+  private void saveToFile() throws IOException {
+    String jsonString;
+
+    synchronized (credentials) {
+      CredentialsInfoSaving info = new CredentialsInfoSaving();
+      info.credentialsMap = credentialsMap;
+      jsonString = gson.toJson(info);
+    }
+
+    try {
+      if (!credentialsFile.exists()) {
+        credentialsFile.createNewFile();
+      }
+
+      FileOutputStream fos = new FileOutputStream(credentialsFile, false);
+      OutputStreamWriter out = new OutputStreamWriter(fos);
+      out.append(jsonString);
+      out.close();
+      fos.close();
+    } catch  (IOException e) {
+      LOG.error("Error saving credentials file");
+      e.printStackTrace();
+    }
   }
 
 }

zeppelin-interpreter/src/main/java/org/apache/zeppelin/user/CredentialsInfoSaving.java

@@ -0,0 +1,27 @@
+/*
+ * 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.zeppelin.user;
+
+import java.util.Map;
+
+/**
+ * Helper class to save credentials
+ */
+public class CredentialsInfoSaving {
+  public Map<String, UserCredentials> credentialsMap;
+}

zeppelin-server/src/main/java/org/apache/zeppelin/server/ZeppelinServer.java

@@ -31,6 +31,7 @@ import org.apache.zeppelin.scheduler.SchedulerFactory;
 import org.apache.zeppelin.search.LuceneSearch;
 import org.apache.zeppelin.search.SearchService;
 import org.apache.zeppelin.socket.NotebookServer;
+import org.apache.zeppelin.user.Credentials;
 import org.eclipse.jetty.http.HttpVersion;
 import org.eclipse.jetty.server.*;
 import org.eclipse.jetty.server.handler.ContextHandlerCollection;
@@ -90,6 +91,9 @@ public class ZeppelinServer extends Application {
     ZeppelinConfiguration conf = ZeppelinConfiguration.create();
     conf.setProperty("args", args);
 
+    Credentials.initCredentials(conf.credentialsPersist(),
+            conf.getCredentialsPath());
+
     jettyWebServer = setupJettyServer(conf);
 
     ContextHandlerCollection contexts = new ContextHandlerCollection();

zeppelin-zengine/src/main/java/org/apache/zeppelin/conf/ZeppelinConfiguration.java

@@ -362,6 +362,14 @@ public class ZeppelinConfiguration extends XMLConfiguration {
     return getRelativeDir(String.format("%s/notebook-authorization.json", getConfDir()));
   }
 
+  public Boolean credentialsPersist() {
+    return getBoolean(ConfVars.ZEPPELIN_CREDENTIALS_PERSIST);
+  }
+
+  public String getCredentialsPath() {
+    return getRelativeDir(String.format("%s/credentials.json", getConfDir()));
+  }
+
   public String getShiroPath() {
     return getRelativeDir(String.format("%s/shiro.ini", getConfDir()));
   }
@@ -528,8 +536,10 @@ public class ZeppelinConfiguration extends XMLConfiguration {
     // i.e. http://localhost:8080
     ZEPPELIN_ALLOWED_ORIGINS("zeppelin.server.allowed.origins", "*"),
     ZEPPELIN_ANONYMOUS_ALLOWED("zeppelin.anonymous.allowed", true),
+    ZEPPELIN_CREDENTIALS_PERSIST("zeppelin.credentials.persist", true),
     ZEPPELIN_WEBSOCKET_MAX_TEXT_MESSAGE_SIZE("zeppelin.websocket.max.text.message.size", "1024000");
 
+
     private String varName;
     @SuppressWarnings("rawtypes")
     private Class varClass;