| /* |
| * FileContext.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. |
| */ |
| |
| package org.apache.hadoop.metrics.file; |
| |
| import java.io.BufferedOutputStream; |
| import java.io.File; |
| import java.io.FileWriter; |
| import java.io.IOException; |
| import java.io.PrintWriter; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.metrics.ContextFactory; |
| import org.apache.hadoop.metrics.spi.AbstractMetricsContext; |
| import org.apache.hadoop.metrics.spi.OutputRecord; |
| |
| /** |
| * Metrics context for writing metrics to a file.<p/> |
| * |
| * This class is configured by setting ContextFactory attributes which in turn |
| * are usually configured through a properties file. All the attributes are |
| * prefixed by the contextName. For example, the properties file might contain: |
| * <pre> |
| * myContextName.fileName=/tmp/metrics.log |
| * myContextName.period=5 |
| * </pre> |
| * @see org.apache.hadoop.metrics2.sink.FileSink for metrics 2.0. |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Evolving |
| @Deprecated |
| public class FileContext extends AbstractMetricsContext { |
| |
| /* Configuration attribute names */ |
| @InterfaceAudience.Private |
| protected static final String FILE_NAME_PROPERTY = "fileName"; |
| @InterfaceAudience.Private |
| protected static final String PERIOD_PROPERTY = "period"; |
| |
| private File file = null; // file for metrics to be written to |
| private PrintWriter writer = null; |
| |
| /** Creates a new instance of FileContext */ |
| @InterfaceAudience.Private |
| public FileContext() {} |
| |
| @InterfaceAudience.Private |
| public void init(String contextName, ContextFactory factory) { |
| super.init(contextName, factory); |
| |
| String fileName = getAttribute(FILE_NAME_PROPERTY); |
| if (fileName != null) { |
| file = new File(fileName); |
| } |
| |
| parseAndSetPeriod(PERIOD_PROPERTY); |
| } |
| |
| /** |
| * Returns the configured file name, or null. |
| */ |
| @InterfaceAudience.Private |
| public String getFileName() { |
| if (file == null) { |
| return null; |
| } else { |
| return file.getName(); |
| } |
| } |
| |
| /** |
| * Starts or restarts monitoring, by opening in append-mode, the |
| * file specified by the <code>fileName</code> attribute, |
| * if specified. Otherwise the data will be written to standard |
| * output. |
| */ |
| @InterfaceAudience.Private |
| public void startMonitoring() |
| throws IOException |
| { |
| if (file == null) { |
| writer = new PrintWriter(new BufferedOutputStream(System.out)); |
| } else { |
| writer = new PrintWriter(new FileWriter(file, true)); |
| } |
| super.startMonitoring(); |
| } |
| |
| /** |
| * Stops monitoring, closing the file. |
| * @see #close() |
| */ |
| @InterfaceAudience.Private |
| public void stopMonitoring() { |
| super.stopMonitoring(); |
| |
| if (writer != null) { |
| writer.close(); |
| writer = null; |
| } |
| } |
| |
| /** |
| * Emits a metrics record to a file. |
| */ |
| @InterfaceAudience.Private |
| public void emitRecord(String contextName, String recordName, OutputRecord outRec) { |
| writer.print(contextName); |
| writer.print("."); |
| writer.print(recordName); |
| String separator = ": "; |
| for (String tagName : outRec.getTagNames()) { |
| writer.print(separator); |
| separator = ", "; |
| writer.print(tagName); |
| writer.print("="); |
| writer.print(outRec.getTag(tagName)); |
| } |
| for (String metricName : outRec.getMetricNames()) { |
| writer.print(separator); |
| separator = ", "; |
| writer.print(metricName); |
| writer.print("="); |
| writer.print(outRec.getMetric(metricName)); |
| } |
| writer.println(); |
| } |
| |
| /** |
| * Flushes the output writer, forcing updates to disk. |
| */ |
| @InterfaceAudience.Private |
| public void flush() { |
| writer.flush(); |
| } |
| } |