JMXJsonUtil.java
// 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.
// This file is copied from
// https://github.com/apache/impala/blob/branch-4.0.0/fe/src/main/java/org/apache/impala/util/JMXJsonUtil.java
// and modified by Doris
package org.apache.doris.common.jni.utils;
import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import org.apache.log4j.Logger;
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;
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;
/**
* Utility class that returns a JSON representation of the JMX beans.
* This is based on hadoop-common's implementation of JMXJsonServlet.
* <p>
* 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.
* <p>
* 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 = "";
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
if (LOG.isDebugEnabled()) {
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());
}
}
}
}