| // Copyright (C) 2017 The Android Open Source Project |
| // |
| // 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.ericsson.gerrit.plugins.highavailability.forwarder.rest; |
| |
| import static java.nio.charset.StandardCharsets.UTF_8; |
| import static javax.servlet.http.HttpServletResponse.SC_CONFLICT; |
| import static javax.servlet.http.HttpServletResponse.SC_METHOD_NOT_ALLOWED; |
| import static javax.servlet.http.HttpServletResponse.SC_NOT_FOUND; |
| import static javax.servlet.http.HttpServletResponse.SC_NO_CONTENT; |
| |
| import com.ericsson.gerrit.plugins.highavailability.forwarder.Context; |
| import com.google.gwtorm.server.OrmException; |
| import java.io.IOException; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.concurrent.atomic.AtomicInteger; |
| import javax.servlet.ServletException; |
| import javax.servlet.http.HttpServlet; |
| import javax.servlet.http.HttpServletRequest; |
| import javax.servlet.http.HttpServletResponse; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| public abstract class AbstractIndexRestApiServlet<T> extends HttpServlet { |
| private static final long serialVersionUID = -1L; |
| private static final Logger logger = LoggerFactory.getLogger(AbstractIndexRestApiServlet.class); |
| private final Map<T, AtomicInteger> idLocks = new HashMap<>(); |
| private final String type; |
| private final boolean allowDelete; |
| |
| enum Operation { |
| INDEX, |
| DELETE |
| } |
| |
| abstract T parse(String id); |
| |
| abstract void index(T id, Operation operation) throws IOException, OrmException; |
| |
| AbstractIndexRestApiServlet(String type, boolean allowDelete) { |
| this.type = type; |
| this.allowDelete = allowDelete; |
| } |
| |
| AbstractIndexRestApiServlet(String type) { |
| this(type, false); |
| } |
| |
| @Override |
| protected void doPost(HttpServletRequest req, HttpServletResponse rsp) |
| throws IOException, ServletException { |
| process(req, rsp, Operation.INDEX); |
| } |
| |
| @Override |
| protected void doDelete(HttpServletRequest req, HttpServletResponse rsp) |
| throws IOException, ServletException { |
| if (!allowDelete) { |
| sendError(rsp, SC_METHOD_NOT_ALLOWED, String.format("cannot delete %s from index", type)); |
| } else { |
| process(req, rsp, Operation.DELETE); |
| } |
| } |
| |
| private void process(HttpServletRequest req, HttpServletResponse rsp, Operation operation) { |
| rsp.setContentType("text/plain"); |
| rsp.setCharacterEncoding(UTF_8.name()); |
| String path = req.getPathInfo(); |
| T id = parse(path.substring(path.lastIndexOf('/') + 1)); |
| logger.debug("{} {} {}", operation.name(), type, id); |
| try { |
| Context.setForwardedEvent(true); |
| AtomicInteger idLock = getAndIncrementIdLock(id); |
| synchronized (idLock) { |
| index(id, operation); |
| } |
| if (idLock.decrementAndGet() == 0) { |
| removeIdLock(id); |
| } |
| rsp.setStatus(SC_NO_CONTENT); |
| } catch (IOException e) { |
| sendError(rsp, SC_CONFLICT, e.getMessage()); |
| logger.error(String.format("Unable to update %s index", type), e); |
| } catch (OrmException e) { |
| String msg = String.format("Error trying to find %s \n", type); |
| sendError(rsp, SC_NOT_FOUND, msg); |
| logger.debug(msg, e); |
| } finally { |
| Context.unsetForwardedEvent(); |
| } |
| } |
| |
| private AtomicInteger getAndIncrementIdLock(T id) { |
| synchronized (idLocks) { |
| AtomicInteger lock = idLocks.get(id); |
| if (lock == null) { |
| lock = new AtomicInteger(1); |
| idLocks.put(id, lock); |
| } else { |
| lock.incrementAndGet(); |
| } |
| return lock; |
| } |
| } |
| |
| private void removeIdLock(T id) { |
| synchronized (idLocks) { |
| idLocks.remove(id); |
| } |
| } |
| |
| private void sendError(HttpServletResponse rsp, int statusCode, String message) { |
| try { |
| rsp.sendError(statusCode, message); |
| } catch (IOException e) { |
| logger.error("Failed to send error messsage: " + e.getMessage(), e); |
| } |
| } |
| } |