| /* |
| * 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.impala.util; |
| |
| import org.apache.log4j.Logger; |
| import org.codehaus.jackson.JsonFactory; |
| import org.codehaus.jackson.JsonGenerator; |
| |
| import javax.management.AttributeNotFoundException; |
| import javax.management.InstanceNotFoundException; |
| import javax.management.IntrospectionException; |
| import javax.management.MBeanAttributeInfo; |
| import javax.management.MBeanException; |
| import javax.management.MBeanInfo; |
| import javax.management.MBeanServer; |
| import javax.management.ObjectName; |
| import javax.management.ReflectionException; |
| import javax.management.RuntimeErrorException; |
| import javax.management.RuntimeMBeanException; |
| import javax.management.openmbean.CompositeData; |
| import javax.management.openmbean.CompositeType; |
| import javax.management.openmbean.TabularData; |
| import java.io.IOException; |
| import java.io.StringWriter; |
| import java.lang.management.ManagementFactory; |
| import java.lang.reflect.Array; |
| import java.util.Iterator; |
| import java.util.Set; |
| |
| /** |
| * Utility class that returns a JSON representation of the JMX beans. |
| * This is based on hadoop-common's implementation of JMXJsonServlet. |
| * |
| * Output format: |
| * { |
| * "beans" : [ |
| * { |
| * "name":"bean-name" |
| * ... |
| * } |
| * ] |
| * } |
| * Each bean's attributes will be converted to a JSON object member. |
| * If the attribute is a boolean, a number, a string, or an array |
| * it will be converted to the JSON equivalent. |
| * |
| * If the value is a {@link CompositeData} then it will be converted |
| * to a JSON object with the keys as the name of the JSON member and |
| * the value is converted following these same rules. |
| * If the value is a {@link TabularData} then it will be converted |
| * to an array of the {@link CompositeData} elements that it contains. |
| * All other objects will be converted to a string and output as such. |
| * The bean's name and modelerType will be returned for all beans. |
| * |
| */ |
| public class JMXJsonUtil { |
| // MBean server instance |
| protected static transient MBeanServer mBeanServer = |
| ManagementFactory.getPlatformMBeanServer(); |
| |
| private static final Logger LOG = Logger.getLogger(JMXJsonUtil.class); |
| |
| // Returns the JMX beans as a JSON string. |
| public static String getJMXJson() { |
| StringWriter writer = new StringWriter(); |
| try { |
| JsonGenerator jg = null; |
| try { |
| JsonFactory jsonFactory = new JsonFactory(); |
| jg = jsonFactory.createJsonGenerator(writer); |
| jg.disable(JsonGenerator.Feature.AUTO_CLOSE_TARGET); |
| jg.writeStartObject(); |
| if (mBeanServer == null) { |
| jg.writeStringField("result", "ERROR"); |
| jg.writeStringField("message", "No MBeanServer could be found"); |
| jg.close(); |
| LOG.error("No MBeanServer could be found."); |
| return writer.toString(); |
| } |
| listBeans(jg); |
| } finally { |
| if (jg != null) { |
| jg.close(); |
| } |
| if (writer != null) { |
| writer.close(); |
| } |
| } |
| } catch ( IOException e ) { |
| LOG.error("Caught an exception while processing JMX request", e); |
| } |
| return writer.toString(); |
| } |
| |
| // Utility method that lists all the mbeans and write them using the supplied |
| // JsonGenerator. |
| private static void listBeans(JsonGenerator jg) throws IOException { |
| Set<ObjectName> names; |
| names = mBeanServer.queryNames(null, null); |
| jg.writeArrayFieldStart("beans"); |
| Iterator<ObjectName> it = names.iterator(); |
| while (it.hasNext()) { |
| ObjectName oname = it.next(); |
| MBeanInfo minfo; |
| String code = ""; |
| Object attributeinfo = null; |
| try { |
| minfo = mBeanServer.getMBeanInfo(oname); |
| code = minfo.getClassName(); |
| String prs = ""; |
| try { |
| if ("org.apache.commons.modeler.BaseModelMBean".equals(code)) { |
| prs = "modelerType"; |
| code = (String) mBeanServer.getAttribute(oname, prs); |
| } |
| } catch (AttributeNotFoundException e) { |
| // If the modelerType attribute was not found, the class name is used |
| // instead. |
| LOG.error("getting attribute " + prs + " of " + oname |
| + " threw an exception", e); |
| } catch (MBeanException e) { |
| // The code inside the attribute getter threw an exception so log it, |
| // and fall back on the class name |
| LOG.error("getting attribute " + prs + " of " + oname |
| + " threw an exception", e); |
| } catch (RuntimeException e) { |
| // For some reason even with an MBeanException available to them |
| // Runtime exceptionscan still find their way through, so treat them |
| // the same as MBeanException |
| LOG.error("getting attribute " + prs + " of " + oname |
| + " threw an exception", e); |
| } catch ( ReflectionException e ) { |
| // This happens when the code inside the JMX bean (setter?? from the |
| // java docs) threw an exception, so log it and fall back on the |
| // class name |
| LOG.error("getting attribute " + prs + " of " + oname |
| + " threw an exception", e); |
| } |
| } catch (InstanceNotFoundException e) { |
| //Ignored for some reason the bean was not found so don't output it |
| continue; |
| } catch ( IntrospectionException | ReflectionException e ) { |
| // This is an internal error, something odd happened with reflection so |
| // log it and don't output the bean. |
| LOG.error("Problem while trying to process JMX query with MBean " + oname, e); |
| continue; |
| } |
| jg.writeStartObject(); |
| jg.writeStringField("name", oname.toString()); |
| jg.writeStringField("modelerType", code); |
| MBeanAttributeInfo attrs[] = minfo.getAttributes(); |
| for (int i = 0; i < attrs.length; i++) { |
| writeAttribute(jg, oname, attrs[i]); |
| } |
| jg.writeEndObject(); |
| } |
| jg.writeEndArray(); |
| } |
| |
| // Utility method to write mBean attributes. |
| private static void writeAttribute(JsonGenerator jg, ObjectName oname, |
| MBeanAttributeInfo attr) throws IOException { |
| if (!attr.isReadable()) { |
| return; |
| } |
| String attName = attr.getName(); |
| if ("modelerType".equals(attName)) { |
| return; |
| } |
| if (attName.indexOf("=") >= 0 || attName.indexOf(":") >= 0 |
| || attName.indexOf(" ") >= 0) { |
| return; |
| } |
| Object value = null; |
| try { |
| value = mBeanServer.getAttribute(oname, attName); |
| } catch (RuntimeMBeanException e) { |
| // UnsupportedOperationExceptions happen in the normal course of business, |
| // so no need to log them as errors all the time. |
| if (e.getCause() instanceof UnsupportedOperationException) { |
| LOG.trace("getting attribute "+attName+" of "+oname+" threw an exception", e); |
| } else { |
| LOG.error("getting attribute "+attName+" of "+oname+" threw an exception", e); |
| } |
| return; |
| } catch (RuntimeErrorException e) { |
| // RuntimeErrorException happens when an unexpected failure occurs in getAttribute |
| // for example https://issues.apache.org/jira/browse/DAEMON-120 |
| LOG.debug("getting attribute "+attName+" of "+oname+" threw an exception", e); |
| return; |
| } catch (AttributeNotFoundException e) { |
| //Ignored the attribute was not found, which should never happen because the bean |
| //just told us that it has this attribute, but if this happens just don't output |
| //the attribute. |
| return; |
| } catch (MBeanException e) { |
| //The code inside the attribute getter threw an exception so log it, and |
| // skip outputting the attribute |
| LOG.error("getting attribute "+attName+" of "+oname+" threw an exception", e); |
| return; |
| } catch (RuntimeException e) { |
| //For some reason even with an MBeanException available to them Runtime exceptions |
| //can still find their way through, so treat them the same as MBeanException |
| LOG.error("getting attribute "+attName+" of "+oname+" threw an exception", e); |
| return; |
| } catch (ReflectionException e) { |
| //This happens when the code inside the JMX bean (setter?? from the java docs) |
| //threw an exception, so log it and skip outputting the attribute |
| LOG.error("getting attribute "+attName+" of "+oname+" threw an exception", e); |
| return; |
| } catch (InstanceNotFoundException e) { |
| //Ignored the mbean itself was not found, which should never happen because we |
| //just accessed it (perhaps something unregistered in-between) but if this |
| //happens just don't output the attribute. |
| return; |
| } |
| writeAttribute(jg, attName, value); |
| } |
| |
| private static void writeAttribute(JsonGenerator jg, String attName, Object value) |
| throws IOException { |
| jg.writeFieldName(attName); |
| writeObject(jg, value); |
| } |
| |
| private static void writeObject(JsonGenerator jg, Object value) throws IOException { |
| if(value == null) { |
| jg.writeNull(); |
| } else { |
| Class<?> c = value.getClass(); |
| if (c.isArray()) { |
| jg.writeStartArray(); |
| int len = Array.getLength(value); |
| for (int j = 0; j < len; j++) { |
| Object item = Array.get(value, j); |
| writeObject(jg, item); |
| } |
| jg.writeEndArray(); |
| } else if(value instanceof Number) { |
| Number n = (Number)value; |
| jg.writeNumber(n.toString()); |
| } else if(value instanceof Boolean) { |
| Boolean b = (Boolean)value; |
| jg.writeBoolean(b); |
| } else if(value instanceof CompositeData) { |
| CompositeData cds = (CompositeData)value; |
| CompositeType comp = cds.getCompositeType(); |
| Set<String> keys = comp.keySet(); |
| jg.writeStartObject(); |
| for(String key: keys) { |
| writeAttribute(jg, key, cds.get(key)); |
| } |
| jg.writeEndObject(); |
| } else if(value instanceof TabularData) { |
| TabularData tds = (TabularData)value; |
| jg.writeStartArray(); |
| for(Object entry : tds.values()) { |
| writeObject(jg, entry); |
| } |
| jg.writeEndArray(); |
| } else { |
| jg.writeString(value.toString()); |
| } |
| } |
| } |
| } |