/*
* 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.tomcat.util.digester;
import org.apache.tomcat.util.IntrospectionUtils;
/**
* A {@link org.apache.tomcat.util.IntrospectionUtils.PropertySource} that uses environment variables to resolve
* expressions.
* <p>
* <strong>Usage example:</strong>
* </p>
* Configure the certificate with environment variables.
*
* <pre>
* {@code
* <SSLHostConfig>
* <Certificate certificateKeyFile="${CERTIFICATE_KEY_FILE}"
* certificateFile="${CERTIFICATE_FILE}"
* certificateChainFile="${CERTIFICATE_CHAIN_FILE}"
* type="RSA" />
* </SSLHostConfig> }
* </pre>
*
* How to configure:
*
* <pre>
* {@code
* echo "org.apache.tomcat.util.digester.PROPERTY_SOURCE=org.apache.tomcat.util.digester.EnvironmentPropertySource" >> conf/catalina.properties}
* </pre>
*
* or add this to {@code CATALINA_OPTS}
*
* <pre>
* {@code
* -Dorg.apache.tomcat.util.digester.PROPERTY_SOURCE=org.apache.tomcat.util.digester.EnvironmentPropertySource}
* </pre>
*
* <b>NOTE</b>: When configured the PropertySource for resolving expressions from system properties is still active.
*
* @see Digester
* @see <a href="https://tomcat.apache.org/tomcat-9.0-doc/config/systemprops.html#Property_replacements">Tomcat
* Configuration Reference System Properties</a>
*/
public class EnvironmentPropertySource implements IntrospectionUtils.PropertySource {
@Override
public String getProperty(String key) {
return System.getenv(key);
}
}