微服务全链路跟踪：jaeger集成istio，并兼容uber-trace-id与b3
公司有自己的一套基于k8s的paas系统，并且集成了istio，这里主要是想讲解下springcloud服务如何集成istio
在基于HTTP协议的分布式调用中，通常会使用HTTP Header来传递SpanContext的内容。常见的Wire Protocol包含Zipkin使用的b3 HTTP header，Jaeger使用的uber-trace-id HTTP Header,LightStep使用的"x-ot-span-context" HTTP Header等。Istio1.0支持b3 header和x-ot-span-context header,可以和Zipkin,Jaeger及LightStep对接；istio1.4以上支持uber-trace-id，请参考github官方说明： https://github.com/istio/istio/issues/12400现在我们我们接入非istio服务都是默认配置uber-trace-id
图中可以看到其中traceId、spanId等字段都拼接到一个key中了
istio的b3头详情可以参考： https://www.envoyproxy.io/docs/envoy/latest/configuration/http/http_conn_man/headers#x-request-idb3并没有将字段都拼接，而是单个传递，下面是案例：
X-B3-TraceId:427fde2dc7edb084
X-B3-ParentSpanId:427fde2dc7edb084
X-B3-SpanId:827e270489aafbd7
X-B3-Sampled:1 如果需要集成istio的jaeger，则需要将传输方式修改为b3 微服务全链路跟踪：springcloud集成jaeger该章中已经描述了如何集成jaeger，这里只需要修改一个配置enable-b3-propagation，如下
opentracing:
jaeger:
enable-b3-propagation: true// 默认为false
udp-sender:
host: localhost
port: 6831
remote-reporter:
flush-interval: 1000
max-queue-size: 5000
log-spans: true
probabilistic-sampler:
sampling-rate: 1 这样springboot服务就可以与istio中的jaeger信息串起来形成完整全链路。 
现在遇到了另外一个问题，公司已经很早就搭建了一套全链路jaeger，并且已经接入了大部分系统，采用的是默认的header传输，即：uber-trace-id 而下游有很多paas内部系统都是非java的不方便接入jaeger，只是注入了istio，并自动注入了jaeger-agent，这里使用的是b3头传输，这就导致了部分链路上下游无法串联起来。而如果需要统一传输方式暂不现实，首先如果都改成b3，则需要上游很多已接入的系统修改配置为b3，如果是都改成uber-trace-id，istio当前版本不支持，如果需要升级istio，则需要升级kubernetes，风险比较大，所以这里根据实际情况先采用集成两种头，即上游都是uber-trace-id，到中间层服务时手动注入b3相关头如下。
这里需要使用grpc的拦截器
import com.google.common.collect.ImmutableMap;
import io.grpc.*;
import io.opentracing.Span;
import io.opentracing.Tracer;
import io.opentracing.propagation.Format;
import io.opentracing.propagation.TextMap;
import lombok.extern.slf4j.Slf4j;
import javax.annotation.Nullable;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.TimeUnit;
/**
* An intercepter that applies tracing via OpenTracing to all client requests.
*/
@Slf4j
public class ClientTracingInterceptor implements ClientInterceptor {
private final Tracer tracer;
private final OperationNameConstructor operationNameConstructor;
private final boolean streaming;
private final boolean verbose;
private final Set<clientrequestattribute> tracedAttributes;
private final ActiveSpanSource activeSpanSource;
private final Metadata.Key<string> b3TraceIdKey = Metadata.Key.of("X-B3-TraceId", Metadata.ASCII_STRING_MARSHALLER);
private final Metadata.Key<string> b3SpanIdKey = Metadata.Key.of("X-B3-SpanId", Metadata.ASCII_STRING_MARSHALLER);
private final Metadata.Key<string> b3ParentSpanIdKey = Metadata.Key.of("X-B3-ParentSpanId", Metadata.ASCII_STRING_MARSHALLER);
private final Metadata.Key<string> b3SampledKey = Metadata.Key.of("X-B3-Sampled", Metadata.ASCII_STRING_MARSHALLER);
/**
* @param
*/
public ClientTracingInterceptor(Tracer tracer) {
this.tracer=tracer;
this.operationNameConstructor = OperationNameConstructor.DEFAULT;
this.streaming = false;
this.verbose = false;
this.tracedAttributes = new HashSet<clientrequestattribute>();
this.activeSpanSource = ActiveSpanSource.GRPC_CONTEXT;
}
private ClientTracingInterceptor(Tracer tracer, OperationNameConstructor operationNameConstructor, boolean streaming,
boolean verbose, Set<clientrequestattribute> tracedAttributes, ActiveSpanSource activeSpanSource) {
this.tracer = tracer;
this.operationNameConstructor = operationNameConstructor;
this.streaming = streaming;
this.verbose = verbose;
this.tracedAttributes = tracedAttributes;
this.activeSpanSource = activeSpanSource;
}
/**
* Use this intercepter to trace all requests made by this client channel.
* @param channel to be traced
* @return intercepted channel
*/
public Channel intercept(Channel channel) {
return ClientInterceptors.intercept(channel, this);
}
@Override
public <reqt, respt> ClientCall<reqt, respt> interceptCall(
MethodDescriptor<reqt, respt> method,
CallOptions callOptions,
Channel next
) {
final String operationName = operationNameConstructor.constructOperationName(method);
Span activeSpan = this.activeSpanSource.getActiveSpan();
final Span span = createSpanFromParent(activeSpan, operationName);
for (ClientRequestAttribute attr : this.tracedAttributes) {
switch (attr) {
case ALL_CALL_OPTIONS:
span.setTag("grpc.call_options", callOptions.toString());
break;
case AUTHORITY:
if (callOptions.getAuthority() == null) {
span.setTag("grpc.authority", "null");
} else {
span.setTag("grpc.authority", callOptions.getAuthority());
}
break;
case COMPRESSOR:
if (callOptions.getCompressor() == null) {
span.setTag("grpc.compressor", "null");
} else {
span.setTag("grpc.compressor", callOptions.getCompressor());
}
break;
case DEADLINE:
if (callOptions.getDeadline() == null) {
span.setTag("grpc.deadline_millis", "null");
} else {
span.setTag("grpc.deadline_millis", callOptions.getDeadline().timeRemaining(TimeUnit.MILLISECONDS));
}
break;
case METHOD_NAME:
span.setTag("grpc.method_name", method.getFullMethodName());
break;
case METHOD_TYPE:
if (method.getType() == null) {
span.setTag("grpc.method_type", "null");
} else {
span.setTag("grpc.method_type", method.getType().toString());
}
break;
case HEADERS:
break;
}
}
return new ForwardingClientCall.SimpleForwardingClientCall<reqt, respt>(next.newCall(method, callOptions)) {
@Override
public void start(Listener<respt> responseListener, Metadata headers) {
if (verbose) {
span.log("Started call");
}
if (tracedAttributes.contains(ClientRequestAttribute.HEADERS)) {
span.setTag("grpc.headers", headers.toString());
}
tracer.inject(span.context(), Format.Builtin.HTTP_HEADERS, new TextMap() {
@Override
public void put(String key, String value) {
log.info("jaeger key:{},value:{}",key,value);
Metadata.Key<string> headerKey = Metadata.Key.of(key, Metadata.ASCII_STRING_MARSHALLER);
headers.put(headerKey, value);
String[] mm=value.split("%3A");
if("uber-trace-id".equals(key)&&mm.length==4){
headers.put(b3TraceIdKey,mm[0]);
log.info("jaeger traceId:{}",mm[0]);
headers.put(b3SpanIdKey,mm[1]);
headers.put(b3ParentSpanIdKey,mm[2]);
headers.put(b3SampledKey,mm[3]);
}
}
@Override
public Iterator<entry<string, string>> iterator() {
throw new UnsupportedOperationException(
"TextMapInjectAdapter should only be used with Tracer.inject()");
}
});
Listener<respt> tracingResponseListener = new ForwardingClientCallListener
.SimpleForwardingClientCallListener<respt>(responseListener) {
@Override
public void onHeaders(Metadata headers) {
if (verbose) { span.log(ImmutableMap.of("Response headers received", headers.toString())); }
delegate().onHeaders(headers);
}
@Override
public void onMessage(RespT message) {
if (streaming || verbose) { span.log("Response received"); }
delegate().onMessage(message);
}
@Override
public void onClose(Status status, Metadata trailers) {
if (verbose) {
if (status.getCode().value() == 0) { span.log("Call closed"); }
else { span.log(ImmutableMap.of("Call failed", status.getDescription())); }
}
span.finish();
delegate().onClose(status, trailers);
}
};
delegate().start(tracingResponseListener, headers);
}
@Override
public void cancel(@Nullable String message, @Nullable Throwable cause) {
String errorMessage;
if (message == null) {
errorMessage = "Error";
} else {
errorMessage = message;
}
if (cause == null) {
span.log(errorMessage);
} else {
span.log(ImmutableMap.of(errorMessage, cause.getMessage()));
}
delegate().cancel(message, cause);
}
@Override
public void halfClose() {
if (streaming) { span.log("Finished sending messages"); }
delegate().halfClose();
}
@Override
public void sendMessage(ReqT message) {
if (streaming || verbose) { span.log("Message sent"); }
delegate().sendMessage(message);
}
};
}
private Span createSpanFromParent(Span parentSpan, String operationName) {
if (parentSpan == null) {
return tracer.buildSpan(operationName).startManual();
} else {
return tracer.buildSpan(operationName).asChildOf(parentSpan).startManual();
}
}
/**
* Builds the configuration of a ClientTracingInterceptor.
*/
public static class Builder {
private Tracer tracer;
private OperationNameConstructor operationNameConstructor;
private boolean streaming;
private boolean verbose;
private Set<clientrequestattribute> tracedAttributes;
private ActiveSpanSource activeSpanSource;
/**
* @param tracer to use for this intercepter
* Creates a Builder with default configuration
*/
public Builder(Tracer tracer) {
this.tracer = tracer;
this.operationNameConstructor = OperationNameConstructor.DEFAULT;
this.streaming = false;
this.verbose = false;
this.tracedAttributes = new HashSet<clientrequestattribute>();
this.activeSpanSource = ActiveSpanSource.GRPC_CONTEXT;
}
/**
* @param operationNameConstructor to name all spans created by this intercepter
* @return this Builder with configured operation name
*/
public Builder withOperationName(OperationNameConstructor operationNameConstructor) {
this.operationNameConstructor = operationNameConstructor;
return this;
}
/**
* Logs streaming events to client spans.
* @return this Builder configured to log streaming events
*/
public Builder withStreaming() {
this.streaming = true;
return this;
}
/**
* @param tracedAttributes to set as tags on client spans
* created by this intercepter
* @return this Builder configured to trace attributes
*/
public Builder withTracedAttributes(ClientRequestAttribute... tracedAttributes) {
this.tracedAttributes = new HashSet<clientrequestattribute>(
Arrays.asList(tracedAttributes));
return this;
}
/**
* Logs all request life-cycle events to client spans.
* @return this Builder configured to be verbose
*/
public Builder withVerbosity() {
this.verbose = true;
return this;
}
/**
* @param activeSpanSource that provides a method of getting the
* active span before the client call
* @return this Builder configured to start client span as children
* of the span returned by activeSpanSource.getActiveSpan()
*/
public Builder withActiveSpanSource(ActiveSpanSource activeSpanSource) {
this.activeSpanSource = activeSpanSource;
return this;
}
/**
* @return a ClientTracingInterceptor with this Builder's configuration
*/
public ClientTracingInterceptor build() {
return new ClientTracingInterceptor(this.tracer, this.operationNameConstructor,
this.streaming, this.verbose, this.tracedAttributes, this.activeSpanSource);
}
}
public enum ClientRequestAttribute {
METHOD_TYPE,
METHOD_NAME,
DEADLINE,
COMPRESSOR,
AUTHORITY,
ALL_CALL_OPTIONS,
HEADERS
}
} 主要改动点在header那一块 
@Configuration
public class FeignConfig implements RequestInterceptor {
@Autowired
private final Tracer tracer;
@Override
public void apply(RequestTemplate requestTemplate) {
ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
if(attributes!=null&&attributes.getRequest()!=null){
HttpServletRequest request = attributes.getRequest();
JaegerSpanContext context=(JaegerSpanContext) tracer.activeSpan().context();
requestTemplate.header("X-B3-TraceId",String.valueOf(context.getTraceId()));
requestTemplate.header("X-B3-SpanId", String.valueOf(context.getSpanId()));
requestTemplate.header("X-B3-ParentSpanId", String.valueOf(context.getParentId()));
requestTemplate.header("X-B3-Sampled", context.isSampled()?"1":"0");
}
}
@Bean
Logger.Level feignLoggerLevel() {
return Logger.Level.FULL;
}
} 经过手动注入后，就可以实现上下游串起来，暂时达到目标，后面的方案是统一传输方式，慢慢升级。