/**
* Copyright 2013 Netflix, Inc.
*
* Licensed 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 com.netflix.servo.publish;
import com.google.common.base.Preconditions;
import com.google.common.io.Closer;
import com.netflix.servo.Metric;
import com.netflix.servo.util.Clock;
import com.netflix.servo.util.ClockWithOffset;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.TimeZone;
import java.util.zip.GZIPOutputStream;
/**
* Writes observations to a file. The format is a basic text file with tabs
* separating the fields.
*/
public final class FileMetricObserver extends BaseMetricObserver {
private static final Logger LOGGER =
LoggerFactory.getLogger(FileMetricObserver.class);
private static final String FILE_DATE_FORMAT = "yyyy_dd_MM_HH_mm_ss_SSS";
private final File dir;
private final boolean compress;
private final Clock clock;
private final SimpleDateFormat fileFormat;
/**
* Creates a new instance that stores files in {@code dir} with a prefix of
* {@code name} and a suffix of a timestamp in the format
* {@code yyyy_dd_MM_HH_mm_ss_SSS}.
*
* @param name name to use as a prefix on files
* @param dir directory where observations will be stored
*/
public FileMetricObserver(String name, File dir) {
this(name, dir, false);
}
/**
* Creates a new instance that stores files in {@code dir} with a prefix of
* {@code name} and a suffix of a timestamp in the format
* {@code yyyy_dd_MM_HH_mm_ss_SSS}.
*
* @param name name to use as a prefix on files
* @param dir directory where observations will be stored
* @param compress whether to compress our output
*/
public FileMetricObserver(String name, File dir, boolean compress) {
this(name,
String.format("'%s'_%s", name, FILE_DATE_FORMAT) + (compress ? "'.log.gz'" : "'.log'"),
dir,
compress);
}
/**
* Creates a new instance that stores files in {@code dir} with a name that
* is created using {@code namePattern}.
*
* @param name name of the observer
* @param namePattern date format pattern used to create the file names
* @param dir directory where observations will be stored
* @param compress whether to compress our output
*/
public FileMetricObserver(String name, String namePattern, File dir, boolean compress) {
this(name, namePattern, dir, compress, ClockWithOffset.INSTANCE);
}
/**
* Creates a new instance that stores files in {@code dir} with a name that
* is created using {@code namePattern}.
*
* @param name name of the observer
* @param namePattern date format pattern used to create the file names
* @param dir directory where observations will be stored
* @param compress whether to compress our output
* @param clock clock instance to use for getting the time used in the filename
*/
public FileMetricObserver(String name, String namePattern, File dir,
boolean compress, Clock clock) {
super(name);
this.dir = dir;
this.compress = compress;
this.clock = clock;
fileFormat = new SimpleDateFormat(namePattern);
fileFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
}
/** {@inheritDoc} */
public void updateImpl(List<Metric> metrics) {
Preconditions.checkNotNull(metrics);
File file = new File(dir, fileFormat.format(new Date(clock.now())));
Closer closer = Closer.create();
Writer out = null;
try {
try {
LOGGER.debug("writing {} metrics to file {}", metrics.size(), file);
OutputStream fileOut = new FileOutputStream(file, true);
if (compress) {
fileOut = new GZIPOutputStream(fileOut);
}
out = closer.register(new OutputStreamWriter(fileOut, "UTF-8"));
for (Metric m : metrics) {
out.append(m.getConfig().getName()).append('\t')
.append(m.getConfig().getTags().toString()).append('\t')
.append(m.getValue().toString()).append('\n');
}
} catch (Throwable t) {
throw closer.rethrow(t);
} finally {
closer.close();
}
} catch (IOException e) {
incrementFailedCount();
LOGGER.error("failed to write update to file " + file, e);
}
}
}