com.netflix.config.sources.URLConfigurationSource Maven / Gradle / Ivy
/**
* Copyright 2014 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.config.sources;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.netflix.config.PollResult;
import com.netflix.config.PolledConfigurationSource;
/**
* A polled configuration source based on a set of URLs. For each poll,
* it always returns the complete union of properties defined in all files. If one property
* is defined in more than one URL, the value in file later on the list will override
* the value in the previous one. The content of the URL should conform to the properties file format.
*
* @author awang
*
*/
public class URLConfigurationSource implements PolledConfigurationSource {
private final URL[] configUrls;
/**
* System property name to define a set of URLs to be used by the
* default constructor.
*/
public static final String CONFIG_URL = "archaius.configurationSource.additionalUrls";
/**
* Default configuration file name to be used by default constructor. This file should
* be on the classpath. The file name can be overridden by the value of system property
* configurationSource.defaultFileName
*/
public static final String DEFAULT_CONFIG_FILE_NAME = "config.properties";
public static final String DEFAULT_CONFIG_FILE_FROM_CLASSPATH =
System.getProperty("archaius.configurationSource.defaultFileName") == null ? DEFAULT_CONFIG_FILE_NAME : System.getProperty("archaius.configurationSource.defaultFileName");
private static final Logger logger = LoggerFactory.getLogger(URLConfigurationSource.class);
/**
* Create an instance with a list URLs to be used.
*
* @param urls list of URLs to be used
*/
public URLConfigurationSource(String... urls) {
configUrls = createUrls(urls);
}
private static URL[] createUrls(String... urlStrings) {
if (urlStrings == null || urlStrings.length == 0) {
throw new IllegalArgumentException("urlStrings is null or empty");
}
URL[] urls = new URL[urlStrings.length];
try {
for (int i = 0; i < urls.length; i++) {
urls[i] = new URL(urlStrings[i]);
}
} catch (Throwable e) {
throw new RuntimeException(e);
}
return urls;
}
/**
* Create an instance with a list URLs to be used.
*
* @param urls list of URLs to be used
*/
public URLConfigurationSource(URL... urls) {
configUrls = urls;
}
/**
* Create the instance for the default list of URLs, which is composed by the following order
*
*
* - A configuration file (default name to be
config.properties, see {@link #DEFAULT_CONFIG_FILE_NAME}) on the classpath
* - A list of URLs defined by system property {@value #CONFIG_URL} with values separated by comma
",".
*
*/
public URLConfigurationSource() {
List urlList = new ArrayList();
URL configFromClasspath = getConfigFileFromClasspath();
if (configFromClasspath != null) {
urlList.add(configFromClasspath);
}
String[] fileNames = getDefaultFileSources();
if (fileNames.length != 0) {
urlList.addAll(Arrays.asList(createUrls(fileNames)));
}
if (urlList.size() == 0) {
configUrls = new URL[0];
logger.warn("No URLs will be polled as dynamic configuration sources.");
logger.info("To enable URLs as dynamic configuration sources, define System property "
+ CONFIG_URL + " or make " + DEFAULT_CONFIG_FILE_FROM_CLASSPATH + " available on classpath.");
} else {
configUrls = urlList.toArray(new URL[urlList.size()]);
logger.info("URLs to be used as dynamic configuration source: " + urlList);
}
}
private URL getConfigFileFromClasspath() {
URL url = null;
// attempt to load from the context classpath
ClassLoader loader = Thread.currentThread().getContextClassLoader();
if (loader != null) {
url = loader.getResource(DEFAULT_CONFIG_FILE_FROM_CLASSPATH);
}
if (url == null) {
// attempt to load from the system classpath
url = ClassLoader.getSystemResource(DEFAULT_CONFIG_FILE_FROM_CLASSPATH);
}
if (url == null) {
// attempt to load from the system classpath
url = URLConfigurationSource.class.getResource(DEFAULT_CONFIG_FILE_FROM_CLASSPATH);
}
return url;
}
public List getConfigUrls() {
return Collections.unmodifiableList(Arrays.asList(configUrls));
}
private static final String[] getDefaultFileSources() {
String name = System.getProperty(CONFIG_URL);
String[] fileNames;
if (name != null) {
fileNames = name.split(",");
} else {
fileNames = new String[0];
}
return fileNames;
}
/**
* Retrieve the content of the property files. For each poll, it always
* returns the complete union of properties defined in all URLs. If one
* property is defined in content of more than one URL, the value in file later on the
* list will override the value in the previous one.
*
* @param initial this parameter is ignored by the implementation
* @param checkPoint this parameter is ignored by the implementation
* @throws IOException IOException occurred in file operation
*/
@Override
public PollResult poll(boolean initial, Object checkPoint)
throws IOException {
if (configUrls == null || configUrls.length == 0) {
return PollResult.createFull(null);
}
Map map = new HashMap();
for (URL url: configUrls) {
Properties props = new Properties();
InputStream fin = url.openStream();
props.load(fin);
fin.close();
for (Entry entry: props.entrySet()) {
map.put((String) entry.getKey(), entry.getValue());
}
}
return PollResult.createFull(map);
}
@Override
public String toString() {
return "FileConfigurationSource [fileUrls=" + Arrays.toString(configUrls)
+ "]";
}
}