Post类型过滤器
Post类型过滤器执行顺序为：Postfilter(10) -> RequestEventInfoCollectorFilter(99) -> sendResponse(1000) -> Stats(2000)
Postfilter
后置处理过滤器，主要负责对响应内容进行修饰（如添加响应头）。
// PostDecoration.groovy
boolean shouldFilter() {
// 判断请求是否是从zuul路由到自身的
if (true.equals(NFRequestContext.getCurrentContext().zuulToZuul))
return false; //request was routed to a zuul server, so don't send response headers
return true
}
Object run() {
// 为响应添加一些header
addStandardResponseHeaders(RequestContext.getCurrentContext().getRequest(), RequestContext.getCurrentContext().getResponse())
return null;
}
void addStandardResponseHeaders(HttpServletRequest req, HttpServletResponse res) {
println(originatingURL)
String origin = req.getHeader(ORIGIN) // 没用到
RequestContext context = RequestContext.getCurrentContext()
List<Pair<String, String>> headers = context.getZuulResponseHeaders()
headers.add(new Pair(X_ZUUL, "zuul")) // X-Zuul
headers.add(new Pair(X_ZUUL_INSTANCE, System.getenv("EC2_INSTANCE_ID") ?: "unknown")) // X-Zuul-instance
headers.add(new Pair(CONNECTION, KEEP_ALIVE)) // Connection
headers.add(new Pair(X_ZUUL_FILTER_EXECUTION_STATUS, context.getFilterExecutionSummary().toString())) // X-Zuul-Filter-Executions
headers.add(new Pair(X_ORIGINATING_URL, originatingURL)) // X-Originating-URL
if (context.get("ErrorHandled") == null && context.responseStatusCode >= 400) {
headers.add(new Pair(X_NETFLIX_ERROR_CAUSE, "Error from Origin")) // X-Netflix-Error-Cause
ErrorStatsManager.manager.putStats(RequestContext.getCurrentContext().route, "Error_from_Origin_Server")
}
}
RequestEventInfoCollectorFilter
这个过滤器负责收集要发送到ESI, EventBus, Turbine等的数据，例如此次请求的数据和当前应用实例的数据。
TODO:: 虽然zuul收集了这些数据，但是并没有找到在哪里使用… mark一下
// RequestEventInfoCollector.groovy
boolean shouldFilter() {
return true
}
Object run() {
NFRequestContext ctx = NFRequestContext.getCurrentContext();
final Map<String, Object> event = ctx.getEventProperties();
try {
// 往eventProperties中写入与此次请求有关的数据
captureRequestData(event, ctx.request);
// 往eventProperties中写入与当前实例有关的数据
captureInstanceData(event);
} catch (Exception e) {
event.put("exception", e.toString());
LOG.error(e.getMessage(), e);
}
}
capture data这两个方法比较啰嗦，不过逻辑并不复杂，就是收集各种数据并写入map中
// RequestEventInfoCollector.groovy
void captureRequestData(Map<String, Object> event, HttpServletRequest req) {
try {
// 写入请求基本信息
// basic request properties
event.put("path", req.getPathInfo());
event.put("host", req.getHeader("host"));
event.put("query", req.getQueryString());
event.put("method", req.getMethod());
event.put("currentTime", System.currentTimeMillis());
// 写入请求头
// request headers
for (final Enumeration names = req.getHeaderNames(); names.hasMoreElements();) {
final String name = names.nextElement();
final StringBuilder valBuilder = new StringBuilder();
boolean firstValue = true;
for (final Enumeration vals = req.getHeaders(name); vals.hasMoreElements();) {
// only prepends separator for non-first header values
if (firstValue) firstValue = false;
else {
valBuilder.append(VALUE_SEPARATOR);
}
valBuilder.append(vals.nextElement());
}
event.put("request.header." + name, valBuilder.toString());
}
// 写入请求参数
// request params
final Map params = req.getParameterMap();
for (final Object key : params.keySet()) {
final String keyString = key.toString();
final Object val = params.get(key);
String valString;
if (val instanceof String[]) {
final String[] valArray = (String[]) val;
if (valArray.length == 1)
valString = valArray[0];
else
valString = Arrays.asList((String[]) val).toString();
} else {
valString = val.toString();
}
event.put("param." + key, valString);
// some special params get promoted to top-level fields
if (keyString.equals("esn")) {
event.put("esn", valString);
}
}
// 写入响应头
// response headers
NFRequestContext.getCurrentContext().getZuulResponseHeaders()?.each { Pair<String, String> it ->
event.put("response.header." + it.first().toLowerCase(), it.second())
}
} finally {
}
}
private static final void captureInstanceData(Map<String, Object> event) {
try {
final String stack = ConfigurationManager.getDeploymentContext().getDeploymentStack();
if (stack != null) event.put("stack", stack);
// TODO: add CLUSTER, ASG, etc.
// 获取此实例（zuul）的信息
final InstanceInfo instanceInfo = ApplicationInfoManager.getInstance().getInfo();
// 写入实例信息，id和metadata等
if (instanceInfo != null) {
event.put("instance.id", instanceInfo.getId());
for (final Map.Entry<String, String> e : instanceInfo.getMetadata().entrySet()) {
event.put("instance." + e.getKey(), e.getValue());
}
}
// AWS相关，跳过
// caches value after first call. multiple threads could get here simultaneously, but I think that is fine
final AmazonInfo amazonInfo = AmazonInfoHolder.getInfo();
for (final Map.Entry<String, String> e : amazonInfo.getMetadata().entrySet()) {
event.put("amazon." + e.getKey(), e.getValue());
}
} finally {
}
}
sendResponse
sendResponse是比较重要的一个过滤器，负责将响应写回请求来源。
// sendResponse.groovy
boolean shouldFilter() {
return !RequestContext.currentContext.getZuulResponseHeaders().isEmpty() ||
RequestContext.currentContext.getResponseDataStream() != null ||
RequestContext.currentContext.responseBody != null
}
Object run() {
// 添加一些响应头并收集响应debug信息到上下文
addResponseHeaders()
// 写响应流
writeResponse()
}
void writeResponse() {
RequestContext context = RequestContext.currentContext
// there is no body to send
if (context.getResponseBody() == null && context.getResponseDataStream() == null) return;
HttpServletResponse servletResponse = context.getResponse()
servletResponse.setCharacterEncoding("UTF-8")
OutputStream outStream = servletResponse.getOutputStream();
InputStream is = null
try {
// 如果上下文中设置了responseBody，则覆盖掉原来的输出
if (RequestContext.currentContext.responseBody != null) {
String body = RequestContext.currentContext.responseBody
writeResponse(new ByteArrayInputStream(body.getBytes(Charset.forName("UTF-8"))), outStream)
return;
}
// 判断请求是否能接收gzip压缩
boolean isGzipRequested = false
final String requestEncoding = context.getRequest().getHeader(ZuulHeaders.ACCEPT_ENCODING)
if (requestEncoding != null && requestEncoding.equals("gzip"))
isGzipRequested = true;
is = context.getResponseDataStream();
InputStream inputStream = is
if (is != null) {
if (context.sendZuulResponse()) {
// if origin response is gzipped, and client has not requested gzip, decompress stream
// before sending to client
// else, stream gzip directly to client
// 如果原始响应是gzip压缩的，但请求来源并不接受gzip，就解压后再返回，否则直接返回gzip响应
if (context.getResponseGZipped() && !isGzipRequested)
try {
inputStream = new GZIPInputStream(is);
} catch (java.util.zip.ZipException e) {
println("gzip expected but not received assuming unencoded response" + RequestContext.currentContext.getRequest().getRequestURL().toString())
inputStream = is
}
else if (context.getResponseGZipped() && isGzipRequested)
servletResponse.setHeader(ZuulHeaders.CONTENT_ENCODING, "gzip")
writeResponse(inputStream, outStream)
}
}
} finally {
try {
is?.close();
outStream.flush()
outStream.close()
} catch (IOException e) {
}
}
}
// 其它方法比较简单，省略了...
Stats
负责收集统计数据，以及将filter执行过程中收集到的debug信息输出到控制台。
@Override
boolean shouldFilter() {
return true
}
@Override
Object run() {
int status = RequestContext.getCurrentContext().getResponseStatusCode();
StatsManager sm = StatsManager.manager
// 收集统计数据
sm.collectRequestStats(RequestContext.getCurrentContext().getRequest());
sm.collectRouteStats(RequestContext.getCurrentContext().route, status);
// 打印debug信息
dumpRoutingDebug()
dumpRequestDebug()
}
