SQOOP-629: Provide better exception handling during server-client communication

(Jarek Jarcec Cecho)

client/src/main/java/org/apache/sqoop/client/core/ClientError.java

@@ -39,7 +39,7 @@ public enum ClientError implements ErrorCode {
   /** We're not able to get user input */
   CLIENT_0005("Can't get user input"),
 
-  /** There occured exception on server side **/
+  /** There occurred exception on server side **/
   CLIENT_0006("Server has returned exception"),
 
   ;

client/src/main/java/org/apache/sqoop/client/request/Request.java

@@ -28,7 +28,7 @@
 import org.apache.sqoop.client.core.ClientError;
 import org.apache.sqoop.common.SqoopException;
 import org.apache.sqoop.common.SqoopProtocolConstants;
-import org.apache.sqoop.json.ExceptionInfo;
+import org.apache.sqoop.json.ThrowableBean;
 import org.json.simple.JSONObject;
 import org.json.simple.JSONValue;
 
@@ -91,13 +91,13 @@ public ClientResponse handle(ClientRequest cr) {
         if(resp.getHeaders().containsKey(
           SqoopProtocolConstants.HEADER_SQOOP_INTERNAL_ERROR_CODE)) {
 
-          ExceptionInfo ex = new ExceptionInfo();
+          ThrowableBean ex = new ThrowableBean();
 
           String responseText = resp.getEntity(String.class);
           JSONObject json = (JSONObject) JSONValue.parse(responseText);
           ex.restore(json);
 
-          throw new SqoopException(ClientError.CLIENT_0006, ex.toString());
+          throw new SqoopException(ClientError.CLIENT_0006, ex.getThrowable());
         }
       }
 

client/src/main/java/org/apache/sqoop/client/shell/DeleteCommand.java

@@ -37,6 +37,7 @@ public DeleteCommand(Shell shell) {
       "Delete", "info");
   }
 
+  @Override
   @SuppressWarnings("unchecked")
   public Object execute(List args) {
     if (args.size() == 0) {
@@ -59,5 +60,6 @@ public Object execute(List args) {
     } else {
       String msg = "Usage: delete " + getUsage();
       throw new SqoopException(ClientError.CLIENT_0002, msg);
-    }  }
+    }
+  }
 }

client/src/main/java/org/apache/sqoop/client/shell/SqoopCommand.java

@@ -137,4 +137,4 @@ protected void resolveVariables(List arg) {
     }
     Collections.copy(arg, temp);
   }
-}
+}

client/src/main/java/org/apache/sqoop/client/shell/SqoopShell.java

@@ -23,6 +23,8 @@
 import java.util.HashSet;
 import java.util.Iterator;
 
+import org.apache.sqoop.client.utils.ThrowableDisplayer;
+import org.codehaus.groovy.runtime.MethodClosure;
 import org.codehaus.groovy.tools.shell.Command;
 import org.codehaus.groovy.tools.shell.CommandRegistry;
 import org.codehaus.groovy.tools.shell.Groovysh;
@@ -45,6 +47,11 @@ public static void main (String[] args) throws Exception
     System.setProperty("groovysh.prompt", "sqoop");
     Groovysh shell = new Groovysh();
 
+    // Install our error hook (exception handling)
+    shell.setErrorHook(
+      new MethodClosure(ThrowableDisplayer.class, "errorHook"));
+    ThrowableDisplayer.setIo(shell.getIo());
+
     CommandRegistry registry = shell.getRegistry();
     @SuppressWarnings("unchecked")
     Iterator<Command> iterator = registry.iterator();

client/src/main/java/org/apache/sqoop/client/utils/ThrowableDisplayer.java

@@ -0,0 +1,97 @@
+/**
+ * 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.sqoop.client.utils;
+
+import org.apache.sqoop.client.core.ClientError;
+import org.apache.sqoop.common.SqoopException;
+import org.codehaus.groovy.tools.shell.IO;
+
+/**
+ * Pretty printing of Throwable objects
+ */
+public class ThrowableDisplayer {
+
+  /**
+   * Associated shell IO object.
+   *
+   * This objects needs to be set explicitly as some of the methods are called
+   * by Groovy shell without ability to pass additional arguments.
+   */
+  private static IO io;
+
+  public static void setIo(IO ioObject) {
+    io = ioObject;
+  }
+
+  /**
+   * Error hook installed to Groovy shell.
+   *
+   * Will display exception that appeared during executing command. In most
+   * cases we will simply delegate the call to printing throwable method,
+   * however in case that we've received ClientError.CLIENT_0006 (server
+   * exception), we will unwrap server issue and view only that as local
+   * context shouldn't make any difference.
+   *
+   * @param t Throwable to be displayed
+   */
+  public static void errorHook(Throwable t) {
+    io.out.println("@|red Exception has occurred during processing command |@");
+
+    // If this is server exception from server
+    if(t instanceof SqoopException
+      && ((SqoopException)t).getErrorCode() == ClientError.CLIENT_0006) {
+      io.out.print("@|red Server has returned exception: |@");
+      printThrowable(io, t.getCause());
+    } else {
+      printThrowable(io, t);
+    }
+  }
+
+  /**
+   * Pretty print Throwable instance including stack trace and causes.
+   *
+   * @param io IO object to use for generating output
+   * @param t Throwable to display
+   */
+  protected static void printThrowable(IO io, Throwable t) {
+    io.out.print("@|red Exception: |@");
+    io.out.print(t.getClass().getName());
+    io.out.print(" @|red Message: |@");
+    io.out.print(t.getMessage());
+    io.out.println();
+
+    io.out.println("Stack trace:");
+    for(StackTraceElement e : t.getStackTrace()) {
+      io.out.print("\t @|bold at |@ ");
+      io.out.print(e.getClassName());
+      io.out.print(" (@|bold " + e.getFileName() + ":"
+        + e.getLineNumber() + ") |@ ");
+      io.out.println();
+    }
+
+    Throwable cause = t.getCause();
+    if(cause != null) {
+      io.out.print("Caused by: ");
+      printThrowable(io, cause);
+    }
+  }
+
+  private ThrowableDisplayer() {
+    // Instantiation is prohibited
+  }
+}

common/src/main/java/org/apache/sqoop/json/ExceptionInfo.java

@@ -1,73 +0,0 @@
-/**
- * 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.sqoop.json;
-
-import java.io.PrintWriter;
-import java.io.StringWriter;
-
-import org.json.simple.JSONObject;
-
-public class ExceptionInfo implements JsonBean {
-
-  public static final String ERROR_CODE = "error-code";
-  public static final String ERROR_MESSAGE = "error-message";
-  public static final String STACK_TRACE = "stack-trace";
-
-  private String errorCode;
-  private String errorMessage;
-  private String stackTrace;
-
-  // For "extract"
-  public ExceptionInfo(String code, String message, Exception ex) {
-    errorCode = code;
-    errorMessage = message;
-
-    StringWriter writer = new StringWriter();
-    ex.printStackTrace(new PrintWriter(writer));
-    writer.flush();
-
-    stackTrace = writer.getBuffer().toString();
-  }
-
-  // For "restore"
-  public ExceptionInfo() {
-  }
-
-  @SuppressWarnings("unchecked")
-  @Override
-  public JSONObject extract() {
-    JSONObject result = new JSONObject();
-    result.put(ERROR_CODE, errorCode);
-    result.put(ERROR_MESSAGE, errorMessage);
-    result.put(STACK_TRACE, stackTrace);
-
-    return result;
-  }
-
-  @Override
-  public void restore(JSONObject jsonObject) {
-    errorCode = (String) jsonObject.get(ERROR_CODE);
-    errorMessage = (String) jsonObject.get(ERROR_MESSAGE);
-    stackTrace = (String) jsonObject.get(STACK_TRACE);
-  }
-
-  @Override
-  public String toString() {
-    return errorMessage;
-  }
-}

common/src/main/java/org/apache/sqoop/json/ThrowableBean.java

@@ -0,0 +1,116 @@
+/**
+ * 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.sqoop.json;
+
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * Transfer throwable.
+ *
+ * TODO(jarcec): After SQOOP-627 will get committed, change the throwable
+ * creation to same class as was on the server instead of Throwable.
+ */
+public class ThrowableBean implements JsonBean {
+
+  public static final String MESSAGE = "message";
+  public static final String STACK_TRACE = "stack-trace";
+  public static final String CLASS = "class";
+  public static final String METHOD = "method";
+  public static final String FILE = "file";
+  public static final String LINE = "line";
+  public static final String CAUSE = "cause";
+
+  private Throwable throwable;
+
+  // For "extract"
+  public ThrowableBean(Throwable ex) {
+    throwable = ex;
+  }
+
+  // For "restore"
+  public ThrowableBean() {
+  }
+
+  public Throwable getThrowable() {
+    return throwable;
+  }
+
+  @Override
+  @SuppressWarnings("unchecked")
+  public JSONObject extract() {
+    JSONObject result = new JSONObject();
+
+    result.put(MESSAGE, throwable.getMessage());
+    result.put(CLASS, throwable.getClass().getName());
+
+    JSONArray st = new JSONArray();
+    for(StackTraceElement element : throwable.getStackTrace()) {
+      JSONObject obj = new JSONObject();
+
+      obj.put(CLASS, element.getClassName());
+      obj.put(METHOD, element.getMethodName());
+      obj.put(FILE, element.getFileName());
+      obj.put(LINE, element.getLineNumber());
+
+      st.add(obj);
+    }
+
+    result.put(STACK_TRACE, st);
+
+    Throwable cause = throwable.getCause();
+    if(cause != null) {
+      ThrowableBean causeBean = new ThrowableBean(cause);
+      result.put(CAUSE, causeBean.extract());
+    }
+
+    return result;
+  }
+
+  @Override
+  public void restore(JSONObject jsonObject) {
+    throwable = new Throwable((String) jsonObject.get(MESSAGE));
+
+    List<StackTraceElement> st = new LinkedList<StackTraceElement>();
+    for(Object object : (JSONArray)jsonObject.get(STACK_TRACE)) {
+      JSONObject json = (JSONObject)object;
+      StackTraceElement element = new StackTraceElement(
+        (String)json.get(CLASS),
+        (String)json.get(METHOD),
+        (String)json.get(FILE),
+        ((Long)json.get(LINE)).intValue()
+      );
+      st.add(element);
+    }
+
+    throwable.setStackTrace(st.toArray(new StackTraceElement[]{}));
+
+    Object cause = jsonObject.get(CAUSE);
+    if(cause != null) {
+      JSONObject causeJson = (JSONObject)cause;
+
+      ThrowableBean causeBean = new ThrowableBean();
+      causeBean.restore(causeJson);
+
+      throwable.initCause(causeBean.getThrowable());
+    }
+  }
+}

common/src/test/java/org/apache/sqoop/json/TestThrowableBean.java

@@ -0,0 +1,49 @@
+/**
+ * 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.sqoop.json;
+
+import junit.framework.TestCase;
+import org.json.simple.JSONObject;
+import org.json.simple.JSONValue;
+
+/**
+ *
+ */
+public class TestThrowableBean extends TestCase {
+  public void testSerialization() {
+    Throwable ex = new RuntimeException("A");
+    ex.initCause(new Exception("B"));
+
+    // Serialize it to JSON object
+    ThrowableBean bean = new ThrowableBean(ex);
+    JSONObject json = bean.extract();
+
+    // "Move" it across network in text form
+    String string = json.toJSONString();
+
+    // Retrieved transferred object
+    JSONObject retrievedJson = (JSONObject) JSONValue.parse(string);
+    ThrowableBean retrievedBean = new ThrowableBean();
+    retrievedBean.restore(retrievedJson);
+    Throwable retrieved = retrievedBean.getThrowable();
+
+    assertEquals("A", retrieved.getMessage());
+    assertEquals("B", retrieved.getCause().getMessage());
+    assertNull(retrieved.getCause().getCause());
+  }
+}

core/src/main/java/org/apache/sqoop/connector/ConnectorManager.java

@@ -77,6 +77,10 @@ public static ResourceBundle getResourceBundle(long connectorId,
 
   public static MConnector getConnectorMetadata(long connectorId) {
     ConnectorHandler handler = handlerMap.get(nameMap.get(connectorId));
+    if(handler == null) {
+      return null;
+    }
+
     return handler.getMetadata();
   }
 

server/src/main/java/org/apache/sqoop/handler/ConnectorRequestHandler.java

@@ -25,6 +25,7 @@
 import org.apache.sqoop.model.MConnector;
 import org.apache.sqoop.server.RequestContext;
 import org.apache.sqoop.server.RequestHandler;
+import org.apache.sqoop.server.common.ServerError;
 
 import java.util.LinkedList;
 import java.util.List;
@@ -58,6 +59,11 @@ public JsonBean handleEvent(RequestContext ctx) {
     } else {
       Long id = Long.parseLong(cid);
 
+      // Check that user is not asking for non existing connector id
+      if(!ConnectorManager.getConnectoIds().contains(id)) {
+        throw new SqoopException(ServerError.SERVER_0004, "Invalid id " + id);
+      }
+
       connectors = new LinkedList<MConnector>();
       bundles = new LinkedList<ResourceBundle>();
 

server/src/main/java/org/apache/sqoop/server/SqoopProtocolServlet.java

@@ -26,7 +26,7 @@
 
 import org.apache.log4j.Logger;
 import org.apache.sqoop.common.ErrorCode;
-import org.apache.sqoop.json.ExceptionInfo;
+import org.apache.sqoop.json.ThrowableBean;
 import org.apache.sqoop.common.SqoopException;
 import org.apache.sqoop.common.SqoopProtocolConstants;
 import org.apache.sqoop.common.SqoopResponseCode;
@@ -136,11 +136,10 @@ private void sendErrorResponse(RequestContext ctx, Exception ex)
           SqoopProtocolConstants.HEADER_SQOOP_INTERNAL_ERROR_MESSAGE,
           ex.getMessage());
 
-      ExceptionInfo exceptionInfo = new ExceptionInfo(ec.getCode(),
-        ex.getMessage(), ex);
+      ThrowableBean throwableBean = new ThrowableBean(ex);
 
       response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
-      response.getWriter().write(exceptionInfo.extract().toJSONString());
+      response.getWriter().write(throwableBean.extract().toJSONString());
     } else {
       response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
     }

server/src/main/java/org/apache/sqoop/server/common/ServerError.java

@@ -33,6 +33,9 @@ public enum ServerError implements ErrorCode {
   /** We've received invalid HTTP request */
   SERVER_0003("Invalid HTTP request"),
 
+  /** Invalid argument in HTTP request */
+  SERVER_0004("Invalid argument in HTTP request"),
+
   ;
 
   private final String message;