com.netflix.client.SimpleVipAddressResolver Maven / Gradle / Ivy
/*
*
* 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.client;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import com.netflix.client.config.IClientConfig;
import com.netflix.config.ConfigurationManager;
/**
* A "VipAddress" in Ribbon terminology is a logical name used for a target
* server farm. This class helps interpret and resolve a "macro" and obtain a
* finalized vipAddress.
*
* Ribbon supports a comma separated set of logcial addresses for a Ribbon
* Client. Typical/default implementation uses the list of servers obtained from
* the first of the comma separated list and progresses down the list only when
* the priorr vipAddress contains no servers.
*
* This class assumes that the vip address string may contain marcos in the format
* of ${foo}, where foo is a property in Archaius configuration, and tries to replace
* these macros with actual values.
*
*
* e.g. vipAddress settings
*
*
* ${foo}.bar:${port},${foobar}:80,localhost:8080
*
* The above list will be resolved by this class as
*
* apple.bar:80,limebar:80,localhost:8080
*
* provided that the Configuration library resolves the property foo=apple,port=80 and foobar=limebar
*
*
*
* @author stonse
*
*/
public class SimpleVipAddressResolver implements VipAddressResolver {
private static final Pattern VAR_PATTERN = Pattern.compile("\\$\\{(.*?)\\}");
/**
* Resolve the vip address by replacing macros with actual values in configuration.
* If there is no macro, the passed in string will be returned. If a macro is found but
* there is no property defined in configuration, the same macro is returned as part of the
* result.
*/
@Override
public String resolve(String vipAddressMacro, IClientConfig niwsClientConfig) {
if (vipAddressMacro == null || vipAddressMacro.length() == 0) {
return vipAddressMacro;
}
return replaceMacrosFromConfig(vipAddressMacro);
}
private static String replaceMacrosFromConfig(String macro) {
String result = macro;
Matcher matcher = VAR_PATTERN.matcher(result);
while (matcher.find()) {
String key = matcher.group(1);
String value = ConfigurationManager.getConfigInstance().getString(key);
if (value != null) {
result = result.replaceAll("\\$\\{" + key + "\\}", value);
matcher = VAR_PATTERN.matcher(result);
}
}
return result.trim();
}
}