*:first-child {
margin-top: 0 !important; }
body > *:last-child {
margin-bottom: 0 !important; }
a {
color: #4183C4; }
a.absent {
color: #cc0000; }
a.anchor {
display: block;
padding-left: 30px;
margin-left: -30px;
cursor: pointer;
position: absolute;
top: 0;
left: 0;
bottom: 0; }
h1, h2, h3, h4, h5, h6 {
margin: 20px 0 10px;
padding: 0;
font-weight: bold;
-webkit-font-smoothing: antialiased;
cursor: text;
position: relative; }
h1:hover a.anchor, h2:hover a.anchor, h3:hover a.anchor, h4:hover a.anchor, h5:hover a.anchor, h6:hover a.anchor {
background: url(data:image/png;base64,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) no-repeat 10px center;
text-decoration: none; }
h1 tt, h1 code {
font-size: inherit; }
h2 tt, h2 code {
font-size: inherit; }
h3 tt, h3 code {
font-size: inherit; }
h4 tt, h4 code {
font-size: inherit; }
h5 tt, h5 code {
font-size: inherit; }
h6 tt, h6 code {
font-size: inherit; }
h1 {
font-size: 28px;
color: black; }
h2 {
font-size: 24px;
border-bottom: 1px solid #cccccc;
color: black; }
h3 {
font-size: 18px; }
h4 {
font-size: 16px; }
h5 {
font-size: 14px; }
h6 {
color: #777777;
font-size: 14px; }
p, blockquote, ul, ol, dl, li, table, pre {
margin: 15px 0; }
hr {
background: transparent url(data:image/png;base64,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) repeat-x 0 0;
border: 0 none;
color: #cccccc;
height: 4px;
padding: 0;
}
body > h2:first-child {
margin-top: 0;
padding-top: 0; }
body > h1:first-child {
margin-top: 0;
padding-top: 0; }
body > h1:first-child + h2 {
margin-top: 0;
padding-top: 0; }
body > h3:first-child, body > h4:first-child, body > h5:first-child, body > h6:first-child {
margin-top: 0;
padding-top: 0; }
a:first-child h1, a:first-child h2, a:first-child h3, a:first-child h4, a:first-child h5, a:first-child h6 {
margin-top: 0;
padding-top: 0; }
h1 p, h2 p, h3 p, h4 p, h5 p, h6 p {
margin-top: 0; }
li p.first {
display: inline-block; }
li {
margin: 0; }
ul, ol {
padding-left: 30px; }
ul :first-child, ol :first-child {
margin-top: 0; }
dl {
padding: 0; }
dl dt {
font-size: 14px;
font-weight: bold;
font-style: italic;
padding: 0;
margin: 15px 0 5px; }
dl dt:first-child {
padding: 0; }
dl dt > :first-child {
margin-top: 0; }
dl dt > :last-child {
margin-bottom: 0; }
dl dd {
margin: 0 0 15px;
padding: 0 15px; }
dl dd > :first-child {
margin-top: 0; }
dl dd > :last-child {
margin-bottom: 0; }
blockquote {
border-left: 4px solid #dddddd;
padding: 0 15px;
color: #777777; }
blockquote > :first-child {
margin-top: 0; }
blockquote > :last-child {
margin-bottom: 0; }
img {
max-width: 100%; }
span.frame {
display: block;
overflow: hidden; }
span.frame > span {
border: 1px solid #dddddd;
display: block;
float: left;
overflow: hidden;
margin: 13px 0 0;
padding: 7px;
width: auto; }
span.frame span img {
display: block;
float: left; }
span.frame span span {
clear: both;
color: #333333;
display: block;
padding: 5px 0 0; }
span.align-center {
display: block;
overflow: hidden;
clear: both; }
span.align-center > span {
display: block;
overflow: hidden;
margin: 13px auto 0;
text-align: center; }
span.align-center span img {
margin: 0 auto;
text-align: center; }
span.align-right {
display: block;
overflow: hidden;
clear: both; }
span.align-right > span {
display: block;
overflow: hidden;
margin: 13px 0 0;
text-align: right; }
span.align-right span img {
margin: 0;
text-align: right; }
span.float-left {
display: block;
margin-right: 13px;
overflow: hidden;
float: left; }
span.float-left span {
margin: 13px 0 0; }
span.float-right {
display: block;
margin-left: 13px;
overflow: hidden;
float: right; }
span.float-right > span {
display: block;
overflow: hidden;
margin: 13px auto 0;
text-align: right; }
code, tt {
margin: 0 2px;
padding: 0 5px;
white-space: nowrap;
border: 1px solid #eaeaea;
background-color: #f8f8f8;
border-radius: 3px; }
pre code {
margin: 0;
padding: 0;
white-space: pre;
border: none;
background: transparent; }
.highlight pre {
background-color: #f8f8f8;
border: 1px solid #cccccc;
font-size: 13px;
line-height: 19px;
overflow: auto;
padding: 6px 10px;
border-radius: 3px; }
pre {
background-color: #f8f8f8;
border: 1px solid #cccccc;
font-size: 13px;
line-height: 19px;
overflow: auto;
padding: 6px 10px;
border-radius: 3px; }
pre code, pre tt {
background-color: transparent;
border: none; }
sup {
font-size: 0.83em;
vertical-align: super;
line-height: 0;
}
kbd {
display: inline-block;
padding: 3px 5px;
font-size: 11px;
line-height: 10px;
color: #555;
vertical-align: middle;
background-color: #fcfcfc;
border: solid 1px #ccc;
border-bottom-color: #bbb;
border-radius: 3px;
box-shadow: inset 0 -1px 0 #bbb
}
* {
-webkit-print-color-adjust: exact;
}
@media screen and (min-width: 914px) {
body {
margin:0 auto;
}
}
@media print {
table, pre {
page-break-inside: avoid;
}
pre {
word-wrap: break-word;
}
}
-->
code[class*="language-"],
pre[class*="language-"] {
background: #f5f2f0;
}
/* Inline code */
:not(pre) > code[class*="language-"] {
padding: .1em;
border-radius: .3em;
white-space: normal;
}
.token.comment,
.token.prolog,
.token.doctype,
.token.cdata {
color: slategray;
}
.token.punctuation {
color: #999;
}
.namespace {
opacity: .7;
}
.token.property,
.token.tag,
.token.boolean,
.token.number,
.token.constant,
.token.symbol,
.token.deleted {
color: #905;
}
.token.selector,
.token.attr-name,
.token.string,
.token.char,
.token.builtin,
.token.inserted {
color: #690;
}
.token.operator,
.token.entity,
.token.url,
.language-css .token.string,
.style .token.string {
color: #a67f59;
background: hsla(0, 0%, 100%, .5);
}
.token.atrule,
.token.attr-value,
.token.keyword {
color: #07a;
}
.token.function {
color: #DD4A68;
}
.token.regex,
.token.important,
.token.variable {
color: #e90;
}
.token.important,
.token.bold {
font-weight: bold;
}
.token.italic {
font-style: italic;
}
.token.entity {
cursor: help;
}
-->
去年的时候写过dubbo+zipkin调用链监控,最近看到zipkin2配合brave实现起来会比我之前的实现要简单很多，因为brave将很多交互的内容都封装起来了，不需要自己去写具体的实现，比如如何去构建span，如何去上报数据。
收集器抽象
由于zipkin支持http以及kafka两种方式上报数据，所以在配置上需要做下抽象。
AbstractZipkinCollectorConfiguration
主要是针对下面两种收集方式的一些配置上的定义，最核心的是Sender接口的定义，http与kafka是两类完全不同的实现。
public abstract Sender getSender();其次是协助性的构造函数，主要是配合构建收集器所需要的一些参数。
- zipkinUrl
如果是http收集，那么对应的是zipkin api域名，如果是kafka，对应的是kafka集群的地址
- topic
仅在收集方式为kafka是有效，http时传空值即可。
public AbstractZipkinCollectorConfiguration(String serviceName,String zipkinUrl,String topic){
this.zipkinUrl=zipkinUrl;
this.serviceName=serviceName;
this.topic=topic;
this.tracing=this.tracing();
}配置上报方式,这里统一采用异常上传，并且配置上报的超时时间。
protected AsyncReporter<Span> spanReporter() {
return AsyncReporter
.builder(getSender())
.closeTimeout(500, TimeUnit.MILLISECONDS)
.build(SpanBytesEncoder.JSON_V2);
}下面这两方法，是配合应用构建span使用的。
注意那个sampler()方法，默认是什么也不做的意思，我们要想看到数据就需要配置成Sampler.ALWAYS_SAMPLE，这样才能真正将数据上报到zipkin服务器。
protected Tracing tracing() {
this.tracing= Tracing
.newBuilder()
.localServiceName(this.serviceName)
.sampler(Sampler.ALWAYS_SAMPLE)
.spanReporter(spanReporter())
.build();
return this.tracing;
}
protected Tracing getTracing(){
return this.tracing;
}HttpZipkinCollectorConfiguration
主要是实现getSender方法，可以借用OkHttpSender这个对象来快速构建，api版本采用v2。
public class HttpZipkinCollectorConfiguration extends AbstractZipkinCollectorConfiguration {
public HttpZipkinCollectorConfiguration(String serviceName,String zipkinUrl) {
super(serviceName,zipkinUrl,null);
}
@Override
public Sender getSender() {
return OkHttpSender.create(super.getZipkinUrl()+"/api/v2/spans");
}
}OkHttpSender这个类需要引用这个包
<dependency>
<groupId>io.zipkin.reporter2</groupId>
<artifactId>zipkin-sender-okhttp3</artifactId>
<version>${zipkin-reporter2.version}</version>
</dependency>KafkaZipkinCollectorConfiguration
同样也是实现getSender方法
public class KafkaZipkinCollectorConfiguration extends AbstractZipkinCollectorConfiguration {
public KafkaZipkinCollectorConfiguration(String serviceName,String zipkinUrl,String topic) {
super(serviceName,zipkinUrl,topic);
}
@Override
public Sender getSender() {
return KafkaSender
.newBuilder()
.bootstrapServers(super.getZipkinUrl())
.topic(super.getTopic())
.encoding(Encoding.JSON)
.build();
}
}KafkaSender这个类需要引用这个包：
<dependency>
<groupId>io.zipkin.reporter2</groupId>
<artifactId>zipkin-sender-kafka11</artifactId>
<version>${zipkin-reporter2.version}</version>
</dependency>收集器工厂
由于上面创建了两个收集器配置类，使用时只能是其中之一，所以实际运行的实例需要根据配置来动态生成。ZipkinCollectorConfigurationFactory就是负责生成收集器实例的。
private final AbstractZipkinCollectorConfiguration zipkinCollectorConfiguration;
@Autowired
public ZipkinCollectorConfigurationFactory(TraceConfig traceConfig){
if(Objects.equal("kafka", traceConfig.getZipkinSendType())){
zipkinCollectorConfiguration=new KafkaZipkinCollectorConfiguration(
traceConfig.getApplicationName(),
traceConfig.getZipkinUrl(),
traceConfig.getZipkinKafkaTopic());
}
else {
zipkinCollectorConfiguration = new HttpZipkinCollectorConfiguration(
traceConfig.getApplicationName(),
traceConfig.getZipkinUrl());
}
}通过构建函数将我们的配置类TraceConfig注入进来，然后根据发送方式来构建实例。另外提供一个辅助函数：
public Tracing getTracing(){
return this.zipkinCollectorConfiguration.getTracing();
}过滤器
在dubbo的过滤器中实现数据上传的功能逻辑相对简单，一般都在invoke方法执行前记录数据，然后方法执行完成后再次记录数据。这个逻辑不变，有变化的是数据上报的实现，上一个版本是通过发http请求实现需要编码，现在可以直接借用brave所提供的span来帮助我们完成，有两重要的方法:
- finish
方法源码如下，在完成的时候会填写上完成的时间并上报数据，这一般应用于同步调用场景。
public void finish(TraceContext context, long finishTimestamp) {
MutableSpan span = this.spanMap.remove(context);
if(span != null && !this.noop.get()) {
synchronized(span) {
span.finish(Long.valueOf(finishTimestamp));
this.reporter.report(span.toSpan());
}
}
}- flush 与上面finish方法的不同点在于，在报数据时没有完成时间，这应该是适用于一些异步调用但不关心结果的场景，比如dubbo所提供的oneway方式调用。
public void flush(TraceContext context) {
MutableSpan span = this.spanMap.remove(context);
if(span != null && !this.noop.get()) {
synchronized(span) {
span.finish((Long)null);
this.reporter.report(span.toSpan());
}
}
}消费者
做为消费方，有一个核心功能就是将traceId以及spanId传递到服务提供方，这里还是通过dubbo提供的附加参数方式实现。
@Override
public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
if(!RpcTraceContext.getTraceConfig().isEnabled()){
return invoker.invoke(invocation);
}
ZipkinCollectorConfigurationFactory zipkinCollectorConfigurationFactory=
SpringContextUtils.getApplicationContext().getBean(ZipkinCollectorConfigurationFactory.class);
Tracer tracer= zipkinCollectorConfigurationFactory.getTracing().tracer();
if(null==RpcTraceContext.getTraceId()){
RpcTraceContext.start();
RpcTraceContext.setTraceId(IdUtils.get());
RpcTraceContext.setParentId(null);
RpcTraceContext.setSpanId(IdUtils.get());
}
else {
RpcTraceContext.setParentId(RpcTraceContext.getSpanId());
RpcTraceContext.setSpanId(IdUtils.get());
}
TraceContext traceContext= TraceContext.newBuilder()
.traceId(RpcTraceContext.getTraceId())
.parentId(RpcTraceContext.getParentId())
.spanId(RpcTraceContext.getSpanId())
.sampled(true)
.build();
Span span=tracer.toSpan(traceContext).start();
invocation.getAttachments().put(RpcTraceContext.TRACE_ID_KEY, String.valueOf(span.context().traceId()));
invocation.getAttachments().put(RpcTraceContext.SPAN_ID_KEY, String.valueOf(span.context().spanId()));
Result result = invoker.invoke(invocation);
span.finish();
return result;
}提供者
@Override
public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
if(!RpcTraceContext.getTraceConfig().isEnabled()){
return invoker.invoke(invocation);
}
Map<String, String> attaches = invocation.getAttachments();
if (!attaches.containsKey(RpcTraceContext.TRACE_ID_KEY)){
return invoker.invoke(invocation);
}
Long traceId = Long.valueOf(attaches.get(RpcTraceContext.TRACE_ID_KEY));
Long spanId = Long.valueOf(attaches.get(RpcTraceContext.SPAN_ID_KEY));
attaches.remove(RpcTraceContext.TRACE_ID_KEY);
attaches.remove(RpcTraceContext.SPAN_ID_KEY);
RpcTraceContext.start();
RpcTraceContext.setTraceId(traceId);
RpcTraceContext.setParentId(spanId);
RpcTraceContext.setSpanId(IdUtils.get());
ZipkinCollectorConfigurationFactory zipkinCollectorConfigurationFactory=
SpringContextUtils.getApplicationContext().getBean(ZipkinCollectorConfigurationFactory.class);
Tracer tracer= zipkinCollectorConfigurationFactory.getTracing().tracer();
TraceContext traceContext= TraceContext.newBuilder()
.traceId(RpcTraceContext.getTraceId())
.parentId(RpcTraceContext.getParentId())
.spanId(RpcTraceContext.getSpanId())
.sampled(true)
.build();
Span span = tracer.toSpan(traceContext).start();
Result result = invoker.invoke(invocation);
span.finish();
return result;
}异常流程
上面无论是消费者的过滤器还是服务提供者的过滤器，均未考虑服务在调用invoker.invoke时出错的场景，如果出错，后面的span.finish方法将不会按预期执行，也就记录不了信息。所以需要针对此问题做优化：可以在finally块中执行finish方法。
try {
result = invoker.invoke(invocation);
}
finally {
span.finish();
}
消费者在调用服务时，异步调用问题
上面过滤器中调用span.finish都是基于同步模式，而由于dubbo除了同步调用外还提供了两种调用方式
异步调用 通过callback机制的异步
oneway
只发起请求并不等待结果的异步调用，无callback一说
针对上面两类异步再加上同步调用，我们要想准确记录服务真正的时间，需要在消费方的过滤器中做如下处理：
创建一个用于回调的处理类，它的主要目的是为了在回调成功时记录时间，这里无论是成功还是失败。
private class AsyncSpanCallback implements ResponseCallback{
private Span span;
public AsyncSpanCallback(Span span){
this.span=span;
}
@Override
public void done(Object o) {
span.finish();
}
@Override
public void caught(Throwable throwable) {
span.finish();
}
}
再在调用invoke方法时,如果是oneway方式，则调用flush方法结果，如果是同步则直接调用finish方法，如果是异步则在回调时调用finish方法。
Result result = null;
boolean isOneway = RpcUtils.isOneway(invoker.getUrl(), invocation);
try {
result = invoker.invoke(invocation);
}
finally {
if(isOneway) {
span.flush();
}
else if(!isAsync) {
span.finish();
}
}待完善问题
过滤器中生成span的方式应该有更好的方法，还没有对brave做过多研究，后续想办法再优化下。另外我测试的场景是consumer调用provider，provider内部再调用provider2，我测试时发现第三步调用传递的parentId好像有点小问题，后续需要再确认下。