/*
* Copyright (c) 2014 Spotify AB.
*
* 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 com.spotify.helios.master.http;
import com.spotify.helios.common.PomVersion;
import com.spotify.helios.common.VersionCompatibility.Status;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import static com.spotify.helios.common.Version.POM_VERSION;
import static com.spotify.helios.common.VersionCompatibility.HELIOS_SERVER_VERSION_HEADER;
import static com.spotify.helios.common.VersionCompatibility.HELIOS_VERSION_HEADER;
import static com.spotify.helios.common.VersionCompatibility.HELIOS_VERSION_STATUS_HEADER;
import static com.spotify.helios.common.VersionCompatibility.getStatus;
import static com.spotify.helios.common.VersionCompatibility.Status.INVALID;
import static com.spotify.helios.common.VersionCompatibility.Status.MISSING;
/**
* Checks if the client passed a Helios-Version: header, and does a version compatibility check
* against the server version, and sets a Helios-Version-Status: header with the status. Also
* sets a Helios-Server-Version: header with the server version (what else really?).
*/
public class VersionResponseFilter implements Filter {
private static final Logger log = LoggerFactory.getLogger(VersionResponseFilter.class);
private static final PomVersion SERVER_VERSION = PomVersion.parse(POM_VERSION);
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
// If ever there was a valid use of goto, this would be it... if Java had it.
if (!(request instanceof HttpServletRequest)) {
log.debug("request is not HTTP");
chain.doFilter(request, response);
return;
}
final HttpServletRequest httpReq = (HttpServletRequest) request;
final HttpServletResponse httpResponse = (HttpServletResponse) response;
httpResponse.addHeader(HELIOS_SERVER_VERSION_HEADER, SERVER_VERSION.toString());
final String header = httpReq.getHeader(HELIOS_VERSION_HEADER);
if (header == null) {
log.debug("No header " + HELIOS_VERSION_HEADER);
httpResponse.addHeader(HELIOS_VERSION_STATUS_HEADER, MISSING.toString());
chain.doFilter(request, response);
return;
}
final PomVersion clientVersion;
try {
clientVersion = PomVersion.parse(header);
} catch (RuntimeException e) {
log.debug("failure to parse version header " + header);
httpResponse.addHeader(HELIOS_VERSION_STATUS_HEADER, INVALID.toString());
httpResponse.sendError(400, "Helios client version format is bogus - expect n.n.n");
return;
}
final Status status = getStatus(SERVER_VERSION, clientVersion);
httpResponse.addHeader(HELIOS_VERSION_STATUS_HEADER, status.toString());
if (status == Status.INCOMPATIBLE) {
log.debug("version " + clientVersion + " is incompatible");
httpResponse.sendError(426, "Your client version is incompatible with the server version "
+ POM_VERSION);
} else {
log.debug("version " + clientVersion + " state " + status);
chain.doFilter(request, response);
}
}
@Override
public void init(FilterConfig arg0) throws ServletException {}
@Override
public void destroy() {}
}