目录
- 增加 logback 记录日志
- 使用 AOP 统一控制输入输出
- 使用 MDC 存储 trace id
项目完整代码见： https://gitee.com/zhoumengkang/wechat-demo/tree/master/strace01
为什么大家都习惯用使用
logback-spring.xml
而不是
logback.log
，因为使用前者名字，可以使用一些结合spring的特殊扩展功能。这里，暂时用不到，后面再用。
https://docs.spring.io/spring-boot/docs/2.6.1/reference/html/features.html#features.logging.logback-extensions
我们在资源目录下新建
logback-spring.xml
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<include resource="org/springframework/boot/logging/logback/defaults.xml"/>
<property name="FILE_LOG_PATTERN" value="%d{yyyy-MM-dd HH:mm:ss.SSS} ${LOG_LEVEL_PATTERN:-%5p} ${PID:- } --- [%t] [%X{TRACE_ID}] %-40.40logger{39} : %m%n${LOG_EXCEPTION_CONVERSION_WORD:-%wEx}"/>
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<pattern>${FILE_LOG_PATTERN}</pattern>
<charset>utf8</charset>
</encoder>
</appender>
<root level="INFO">
<appender-ref ref="STDOUT" />
</root>
</configuration> 最重要的是
FILE_LOG_PATTERN
日志模板里面设置了
[%X{TRACE_ID}]
就可以从
MDC
里面获取
TRACE_ID
的值了
@Component
@Slf4j
@Aspect
public class ControllerHandler {
private final static String TRACE_ID = "TRACE_ID";
@Pointcut("execution(public * com.example.demo.controller..*.*(..)) ")
public void recordLog() {
}
@Before("recordLog()")
public void before(JoinPoint point){
MDC.put(TRACE_ID, UUID.randomUUID().toString());
}
@AfterReturning(pointcut = "recordLog()", returning = "responseData")
public void after(JoinPoint point, ResponseData responseData){
responseData.setRequestId(MDC.get(TRACE_ID));
log.info(JSON.toJSONString(responseData));
}
} 最重要的就是
MDC.put(TRACE_ID, UUID.randomUUID().toString()); 这样就和上面日志模板里面的
[%X{TRACE_ID}]
对接上了。
增加一个控制器然后查看日志
@RestController
@RequestMapping("/user")
@Slf4j
public class UserController {
@GetMapping("/{id}")
public ResponseData<UserDTO> detail(@PathVariable Long id){
Preconditions.checkNotNull(id, "id is null");
log.info("user id:{}", id);
UserDTO userDTO = new UserDTO();
userDTO.setId(id);
userDTO.setAge(20);
userDTO.setUsername("加班写Bug");
return ResponseData.success(userDTO);
}
} 访问
http://localhost:8080/user/1001 查看日志
2021-12-04 21:57:34.723 INFO 48311 --- [http-nio-8080-exec-1] [aba37c62-5850-4da0-bfaf-89fa9c4282ea] c.e.demo.controller.UserController : user id:1001
2021-12-04 21:57:34.859 INFO 48311 --- [http-nio-8080-exec-1] [aba37c62-5850-4da0-bfaf-89fa9c4282ea] com.example.demo.aop.ControllerHandler : {"code":200,"data":{"age":20,"id":1001,"username":"加班写Bug"},"message":"OK","success":true,"traceId":"aba37c62-5850-4da0-bfaf-89fa9c4282ea"} 实际工作中，可能在访问这台 web 应用服务器之前已经有一些链路，比如有统一的网关层，或者被反向代理。trace id 的可能是需要从该应用的上游往下传递，这里以 nginx 反向代理过程中，在 header 里增加了
Trace-Id
字段为例
@Component
@Slf4j
@Aspect
public class ControllerHandler {
private final static String TRACE_ID = "TRACE_ID";
@Autowired
HttpServletRequest request;
@Pointcut("execution(public * com.example.demo.controller..*.*(..)) ")
public void recordLog() {
}
@Before("recordLog()")
public void before(JoinPoint point){
if (request != null && request.getHeader("Trace-Id") != null) {
MDC.put(TRACE_ID, request.getHeader("Trace-Id"));
}else{
MDC.put(TRACE_ID, UUID.randomUUID().toString());
}
}
@AfterReturning(pointcut = "recordLog()", returning = "responseData")
public void after(JoinPoint point, ResponseData responseData){
responseData.setTraceId(MDC.get(TRACE_ID));
log.info(JSON.toJSONString(responseData));
}
} 使用 curl 校验下是否生效
curl -H 'Trace-Id:123456' http://localhost:8080/user/1001
{"success":true,"code":200,"message":"OK","traceId":"123456","data":{"id":1001,"username":"加班写Bug","age":20}} 这里是举例说明，trace id 可以有更多的算法来校验其是否合法。
打印更完整的链路日志
打印 trace id 不是目标，能够通过 trace id 精准的定位问题、排查问题才是目的，所以最好是 input 和 output 都打印下。这里使用
Around
代替了刚刚的 before 和 after ，并且对控制器的异常直接在这里做了处理。
@Component
@Slf4j
@Aspect
public class ControllerHandler {
private final static String TRACE_ID = "TRACE_ID";
@Autowired
HttpServletRequest request;
@Pointcut("execution(public * com.example.demo.controller..*.*(..)) ")
public void recordLog() {
}
public void setTraceId(){
if (request != null && request.getHeader("Trace-Id") != null) {
MDC.put(TRACE_ID, request.getHeader("Trace-Id"));
}else{
MDC.put(TRACE_ID, UUID.randomUUID().toString());
}
}
@Around("recordLog()")
public Object record(ProceedingJoinPoint joinPoint) throws Throwable {
setTraceId();
String classType = joinPoint.getTarget().getClass().getName();
Class<?> clazz = Class.forName(classType);
String clazzSimpleName = clazz.getSimpleName();
String methodName = joinPoint.getSignature().getName();
Signature signature = joinPoint.getSignature();
MethodSignature methodSignature = (MethodSignature) signature;
String[] parameterNames = methodSignature.getParameterNames();
Object[] parameters = joinPoint.getArgs();
Map<String, Object> parameterMap = new LinkedHashMap<>();
for (int i = 0; i < parameters.length; i++) {
String parameterName = parameterNames[i];
Object parameter = parameters[i];
parameterMap.put(parameterName, parameter);
}
String parametersJsonString = JSON.toJSONString(parameterMap, SerializerFeature.WriteMapNullValue);
log.info("{}#{} args:{}", clazzSimpleName, methodName, parametersJsonString);
Object response;
try {
response = joinPoint.proceed(joinPoint.getArgs());
} catch (Exception e) {
log.error("{}#{}, exception:{}:", clazzSimpleName, methodName, e.getClass().getSimpleName(), e);
ResponseData<Object> res = ResponseData.failure(ResponseCode.INTERNAL_ERROR);
if (e instanceof IllegalArgumentException || e instanceof NullPointerException) {
res.setCode(ResponseCode.BAD_REQUEST.getCode());
res.setMessage(e.getMessage());
}else if (e instanceof DemoRuntimeException) {
res.setMessage(e.getMessage());
}
response = res;
}
if (response instanceof ResponseData) {
((ResponseData) response).setTraceId(MDC.get(TRACE_ID));
}
String resultJsonString = JSON.toJSONString(response, SerializerFeature.WriteMapNullValue,
SerializerFeature.DisableCircularReferenceDetect);
log.info("{}#{} response:{}", clazzSimpleName, methodName, resultJsonString);
return response;
}
} 99% 的应用都不用考虑这点 I/O 性能的影响，真建议打上。再次访问
2021-12-04 23:24:38.122 INFO 90186 --- [http-nio-8080-exec-1] [e334594c-5ae2-48fa-91dc-10528004f6d2] com.example.demo.aop.ControllerHandler : UserController#detail args:{"id":1001}
2021-12-04 23:24:38.141 INFO 90186 --- [http-nio-8080-exec-1] [e334594c-5ae2-48fa-91dc-10528004f6d2] c.e.demo.controller.UserController : user id:1001
2021-12-04 23:24:38.209 INFO 90186 --- [http-nio-8080-exec-1] [e334594c-5ae2-48fa-91dc-10528004f6d2] com.example.demo.aop.ControllerHandler : UserController#detail response:{"code":200,"data":{"age":20,"id":1001,"username":"加班写Bug"},"message":"OK","success":true,"traceId":"e334594c-5ae2-48fa-91dc-10528004f6d2"} 这样控制器里的
log.info("user id:{}", id)
就可以删掉了。
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