agent/src/main/java/com/cloud/agent/properties/AgentPropertiesFileHandler.java

/*
 *
 * 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.cloud.agent.properties;

import com.cloud.utils.PropertiesUtil;
import java.io.File;
import java.io.IOException;
import org.apache.cloudstack.utils.security.KeyStoreUtils;
import org.apache.commons.beanutils.ConvertUtils;
import org.apache.commons.beanutils.converters.IntegerConverter;
import org.apache.commons.beanutils.converters.LongConverter;
import org.apache.commons.lang3.StringUtils;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;

/**
 * This class provides a facility to read the agent's properties file and get
 * its properties, according to the {@link AgentProperties} properties constants.
 *
 */
public class AgentPropertiesFileHandler {

    protected static Logger LOGGER = LogManager.getLogger(AgentPropertiesFileHandler.class);

    /**
     * This method reads the property in the agent.properties file.
     *
     * @param property the property to retrieve.
     * @return The value of the property. If the property is not available, the
     * default defined value will be used.
     */
    public static <T> T getPropertyValue(AgentProperties.Property<T> property) {
        T defaultValue = property.getDefaultValue();
        String name = property.getName();

        File agentPropertiesFile = PropertiesUtil.findConfigFile(KeyStoreUtils.AGENT_PROPSFILE);

        if (agentPropertiesFile == null) {
            LOGGER.debug("File [{}] was not found, we will use default defined values. Property [{}]: [{}].", KeyStoreUtils.AGENT_PROPSFILE, name, defaultValue);

            return defaultValue;
        }

        try {
            String configValue = PropertiesUtil.loadFromFile(agentPropertiesFile).getProperty(name);
            if (StringUtils.isBlank(configValue)) {
                LOGGER.debug("Property [{}] has empty or null value. Using default value [{}].", name, defaultValue);
                return defaultValue;
            }

            if (defaultValue instanceof Integer) {
                ConvertUtils.register(new IntegerConverter(defaultValue), Integer.class);
            }

            if (defaultValue instanceof Long) {
                ConvertUtils.register(new LongConverter(defaultValue), Long.class);
            }

            LOGGER.debug("Property [{}] was altered. Now using the value [{}].", name, configValue);
            return (T)ConvertUtils.convert(configValue, property.getTypeClass());

        } catch (IOException ex) {
            LOGGER.debug("Failed to get property [{}]. Using default value [{}].", name, defaultValue, ex);
        }

        return defaultValue;
    }

}