com.google.apphosting.utils.config.BackendsXmlReader Maven / Gradle / Ivy
/*
* Copyright 2021 Google LLC
*
* 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
*
* https://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.google.apphosting.utils.config;
import java.io.InputStream;
import java.util.EnumSet;
import org.w3c.dom.Element;
/**
* Creates a {@link BackendsXml} instance from
* WEB-INF/backends.xml. If you want to read the
* configuration from a different file, subclass and override
* {@link #getFilename()}. If you want to read the configuration from
* something that isn't a file, subclass and override
* {@link #getInputStream()}.
*
*/
public class BackendsXmlReader extends AbstractConfigXmlReader {
// Relative location of the config file
private static final String FILENAME = "WEB-INF/backends.xml";
/**
* Constructs the reader for {@code backends.xml} in a given application directory.
* @param appDir the application directory
*/
public BackendsXmlReader(String appDir) {
super(appDir, false);
}
/**
* Parses the config file.
* @return A {@link BackendsXml} object representing the parsed configuration.
*/
public BackendsXml readBackendsXml() {
return readConfigXml();
}
@Override
protected BackendsXml processXml(InputStream is) {
BackendsXml backendsXml = new BackendsXml();
Element root = XmlUtils.parseXml(is).getDocumentElement();
for (Element backendElement : XmlUtils.getChildren(root, "backend")) {
backendsXml.addBackend(convertBackendNode(backendElement));
}
return backendsXml;
}
@Override
protected String getRelativeFilename() {
return FILENAME;
}
private BackendsXml.Entry convertBackendNode(Element backendElement) {
String name = trim(backendElement.getAttribute("name"));
Integer instances = null;
String instanceClass = XmlUtils.getOptionalChildElementBody(backendElement, "class");
Integer maxConcurrentRequests = null;
EnumSet options = EnumSet.noneOf(BackendsXml.Option.class);
String instancesText = XmlUtils.getOptionalChildElementBody(backendElement, "instances");
if (instancesText != null) {
instances = Integer.valueOf(instancesText);
}
String maxConcurrentRequestsText =
XmlUtils.getOptionalChildElementBody(backendElement, "max-concurrent-requests");
if (maxConcurrentRequestsText != null) {
maxConcurrentRequests = Integer.valueOf(maxConcurrentRequestsText);
}
Element optionsElement = XmlUtils.getOptionalChildElement(backendElement, "options");
if (optionsElement != null) {
if (getBooleanOption(optionsElement, "fail-fast")) {
options.add(BackendsXml.Option.FAIL_FAST);
}
if (getBooleanOption(optionsElement, "dynamic")) {
options.add(BackendsXml.Option.DYNAMIC);
}
if (getBooleanOption(optionsElement, "public")) {
options.add(BackendsXml.Option.PUBLIC);
}
}
return new BackendsXml.Entry(
name, instances, instanceClass, maxConcurrentRequests, options, null);
}
private boolean getBooleanOption(Element optionsElement, String optionName) {
Element optionElement = XmlUtils.getOptionalChildElement(optionsElement, optionName);
if (optionElement == null) {
return false;
}
String value = XmlUtils.getText(optionElement);
return (value.equalsIgnoreCase("true") || value.equals("1"));
}
private String trim(String attribute) {
return attribute == null ? null : attribute.trim();
}
}