### Application Startup Log

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-mvc

Observe the console logs upon starting the SOFABoot application to confirm successful initialization.

```log
2018-05-11 11:55:11.932  INFO 66490 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'SpringMvcOpenTracingFilter' to urls: [/*]
2018-05-11 11:55:13.961  INFO 66490 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2018-05-11 11:55:13.970  INFO 66490 --- [           main] c.a.s.t.e.springmvc.DemoApplication      : Started DemoApplication in 8.361 seconds (JVM running for 9.34)
```

--------------------------------

### OkHttp Summary Log Example (JSON)

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-okhttp

This is an example of the JSON output for OkHttp summary logs. It includes details like timestamp, application name, trace ID, span ID, request URL, HTTP method, result code, request/response sizes, and time cost.

```json
{"time":"2019-09-03 11:35:28.429","local.app":"OkHttpDemo","traceId":"0a0fe9271567481728265100112783","spanId":"0","span.kind":"client","result.code":"200","current.thread.name":"main","time.cost.milliseconds":"164ms","request.url":"http://localhost:8081/okhttp?name=sofa","method":"GET","result.code":"200","req.size.bytes":0,"resp.size.bytes":0,"remote.app":"","sys.baggage":"","biz.baggage":""}
```

--------------------------------

### OkHttp Statistical Log Example (JSON)

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-okhttp

This example shows the JSON format for OkHttp statistical logs. It aggregates statistics based on a 'stat.key' which includes local application name, request URL, and HTTP method. It also provides request count, total cost, success status, and load test marking.

```json
{"time":"2019-09-03 11:43:06.975","stat.key":{"method":"GET","local.app":"OkHttpDemo","request.url":"http://localhost:8081/okhttp?name=sofa"},"count":1,"total.cost.milliseconds":174,"success":"true","load.test":"F"}
```

--------------------------------

### Create a RESTful Controller

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-okhttp

Implement a simple RESTful controller to provide an endpoint for OkHttp calls. This example uses Spring Boot annotations.

```java
@RestController
public class SampleRestController {

    private final AtomicLong counter = new AtomicLong(0);

    /**
     * Request http://localhost:8081/okhttp?name=sofa
     * @param name name
     * @return Map of Result
     */
    @RequestMapping("/okhttp")
    public Map<String, Object> greeting(@RequestParam(value = "name", defaultValue = "okhttp") String name) {
        Map<String, Object> map = new HashMap<>();
        map.put("count", counter.incrementAndGet());
        map.put("name", name);
        return map;
    }
}
```

--------------------------------

### Construct OkHttp Client Instance and Make Call

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-okhttp

Instantiate an OkHttp client and execute a GET request to the previously defined RESTful service. This demonstrates making an outbound HTTP call.

```java
OkHttpClientInstance httpClient = new OkHttpClientInstance();
String httpGetUrl = "http://localhost:8081/okhttp?name=sofa";
String responseStr = httpClient.executeGet(httpGetUrl);
```

--------------------------------

### Datasource Client Stat Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-datasource

Review the datasource-client-stat.log file for aggregated statistics of SQL operations, such as execution count, total cost, and success rate.

```json
{"time":"2019-09-02 21:31:50.435","stat.key":{"local.app":"SOFATracerDataSource","database.name":"test","sql":"DROP TABLE IF EXISTS TEST;\nCREATE TABLE TEST(ID INT PRIMARY KEY%2C NAME VARCHAR(255));"},"count":1,"total.cost.milliseconds":15,"success":"true","load.test":"F"}
```

--------------------------------

### Dubbo Consumer Statistics Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-dubbo

Example of a JSON-formatted statistics log from a Dubbo service consumer. This log aggregates request counts and performance metrics.

```json
{"time":"2019-09-02 23:36:13.040","stat.key":{"method":"SayHello","local.app":"dubbo-consumer","service":"com.glmapper.bridge.boot.service.HelloService"},"count":1,"total.cost.milliseconds":205,"success":"true","load.test":"F"}
```

--------------------------------

### Example TraceId Format

Source: https://www.sofastack.tech/projects/sofa-tracer/traceid-generated-rule

A TraceId is composed of the server IP, timestamp, an incrementing sequence, and the process ID. The example shows the combined format.

```text
0ad1348f1403169275002100356696
```

--------------------------------

### Dubbo Provider Statistics Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-dubbo

Example of a JSON-formatted statistics log from a Dubbo service provider. This log aggregates request counts and performance metrics for incoming requests.

```json
{"time":"2019-09-02 23:36:13.208","stat.key":{"method":"SayHello","local.app":"dubbo-provider","service":"com.glmapper.bridge.boot.service.HelloService"},"count":1,"total.cost.milliseconds":9,"success":"true","load.test":"F"}
```

--------------------------------

### Dubbo Consumer Digest Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-dubbo

Example of a JSON-formatted digest log from a Dubbo service consumer. This log captures details about outgoing requests.

```json
{"time":"2019-09-02 23:36:08.250","local.app":"dubbo-consumer","traceId":"1e27a79c156743856804410019644","spanId":"0","span.kind":"client","result.code":"00","current.thread.name":"http-nio-8080-exec-2","time.cost.milliseconds":"205ms","protocol":"dubbo","service":"com.glmapper.bridge.boot.service.HelloService","method":"SayHello","invoke.type":"sync","remote.host":"192.168.2.103","remote.port":"20880","local.host":"192.168.2.103","client.serialize.time":35,"client.deserialize.time":5,"req.size.bytes":336,"resp.size.bytes":48,"error":"","sys.baggage":"","biz.baggage":""}
```

--------------------------------

### Dubbo Provider Digest Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-dubbo

Example of a JSON-formatted digest log from a Dubbo service provider. This log captures details about incoming requests.

```json
{"time":"2019-09-02 23:36:08.219","local.app":"dubbo-provider","traceId":"1e27a79c156743856804410019644","spanId":"0","span.kind":"server","result.code":"00","current.thread.name":"DubboServerHandler-192.168.2.103:20880-thread-2","time.cost.milliseconds":"9ms","protocol":"dubbo","service":"com.glmapper.bridge.boot.service.HelloService","method":"SayHello","local.host":"192.168.2.103","local.port":"62443","server.serialize.time":0,"server.deserialize.time":27,"req.size.bytes":336,"resp.size.bytes":0,"error":"","sys.baggage":"","biz.baggage":""}
```

--------------------------------

### REST Service Response Example

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-mvc

Example of the JSON response received when accessing the REST service at http://localhost:8080/springmvc.

```json
{
    "content": "Hello, SOFATracer SpringMVC DEMO!",
    "id": 1,
    "success": true
}
```

--------------------------------

### OpenFeign Statistics Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-openfeign

This is an example of a statistics log entry generated by SOFATracer for Spring Cloud OpenFeign. It aggregates request data over a period, including count, total cost, and success rate.

```json
{"time":"2019-09-03 10:29:34.528","stat.key":{"method":"GET","local.app":"tracer-consumer","request.url":"http://10.15.233.39:8800/feign"},"count":2,"total.cost.milliseconds":378,"success":"true","load.test":"F"}
```

--------------------------------

### OpenFeign Digest Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-openfeign

This is an example of a digest log entry generated by SOFATracer for Spring Cloud OpenFeign. It captures detailed information about a single request.

```json
{"time":"2019-09-03 10:28:52.363","local.app":"tracer-consumer","traceId":"0a0fe9271567477731347100110969","spanId":"0.1","span.kind":"client","result.code":"200","current.thread.name":"http-nio-8082-exec-1","time.cost.milliseconds":"219ms","request.url":"http://10.15.233.39:8800/feign","method":"GET","error":"","req.size.bytes":0,"resp.size.bytes":18,"remote.host":"10.15.233.39","remote.port":"8800","sys.baggage":"","biz.baggage":""}
```

--------------------------------

### Verify SOFATracer with Sampled Requests

Source: https://www.sofastack.tech/projects/sofa-tracer/sampler

This example shows the expected log output when SOFATracer is configured with a 20% sampling rate. The output includes details of requests made to the '/springmvc' endpoint.

```json
json {"time":"2018-11-09 12:14:29.466","local.app":"SOFATracerSpringMVC","traceId":"0a0fe8ec154173686946410159846","spanId":"0.1","request.url":"http://localhost:8080/springmvc","method":"GET","result.code":"200","req.size.bytes":-1,"resp.size.bytes":0,"time.cost.milliseconds":2,"current.thread.name":"http-nio-8080-exec-5","baggage":""} {"time":"2018-11-09 12:15:21.776","local.app":"SOFATracerSpringMVC","traceId":"0a0fe8ec154173692177410319846","spanId":"0.1","request.url":"http://localhost:8080/springmvc","method":"GET","result.code":"200","req.size.bytes":-1,"resp.size.bytes":0,"time.cost.milliseconds":2,"current.thread.name":"http-nio-8080-exec-2","baggage":""} {"time":"2018-11-09 12:15:22.439","local.app":"SOFATracerSpringMVC","traceId":"0a0fe8ec154173692243810359846","spanId":"0.1","request.url":"http://localhost:8080/springmvc","method":"GET","result.code":"200","req.size.bytes":-1,"resp.size.bytes":0,"time.cost.milliseconds":1,"current.thread.name":"http-nio-8080-exec-6","baggage":""} {"time":"2018-11-09 12:15:22.817","local.app":"SOFATracerSpringMVC","traceId":"0a0fe8ec154173692281510379846","spanId":"0.1","request.url":"http://localhost:8080/springmvc","method":"GET","result.code":"200","req.size.bytes":-1,"resp.size.bytes":0,"time.cost.milliseconds":2,"current.thread.name":"http-nio-8080-exec-8","baggage":""} 
```

--------------------------------

### Datasource Client Digest Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-datasource

Examine the datasource-client-digest.log file to view detailed tracing information for SQL operations, including trace ID, execution time, and SQL statement.

```json
{"time":"2019-09-02 21:31:31.566","local.app":"SOFATracerDataSource","traceId":"0a0fe91d156743109138810017302","spanId":"0.1","span.kind":"client","result.code":"00","current.thread.name":"http-nio-8080-exec-1","time.cost.milliseconds":"15ms","database.name":"test","sql":"DROP TABLE IF EXISTS TEST;\nCREATE TABLE TEST(ID INT PRIMARY KEY%2C NAME VARCHAR(255));","connection.establish.span":"128ms","db.execute.cost":"15ms","database.type":"h2","database.endpoint":"jdbc:h2:~/test:-1","sys.baggage":"","biz.baggage":""}
```

--------------------------------

### Implement Custom Sampler Rule

Source: https://www.sofastack.tech/projects/sofa-tracer/sampler

Implement the Sampler interface to define custom sampling logic. This example samples based on whether the span is from a server.

```java
public class CustomOpenRulesSamplerRuler implements Sampler {

    private static final String TYPE = "CustomOpenRulesSamplerRuler";

    @Override
    public SamplingStatus sample(SofaTracerSpan sofaTracerSpan) {
        SamplingStatus samplingStatus = new SamplingStatus();
        Map<String, Object> tags = new HashMap<String, Object>();
        tags.put(SofaTracerConstant.SAMPLER_TYPE_TAG_KEY, TYPE);
        tags = Collections.unmodifiableMap(tags);
        samplingStatus.setTags(tags);

        if (sofaTracerSpan.isServer()) {
            samplingStatus.setSampled(false);
        } else {
            samplingStatus.setSampled(true);
        }
        return samplingStatus;
    }

    @Override
    public String getType() {
        return TYPE;
    }

    @Override
    public void close() {
        // do nothing 
    }
}
```

--------------------------------

### DataSource Statistics Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-datasource

This JSON log entry summarizes SQL execution statistics over a period. It includes aggregated data such as execution count, total cost, success rate, and load test markers, keyed by application, database, and SQL statement.

```json
{"time":"2019-09-02 21:31:50.435","stat.key":{"local.app":"SOFATracerDataSource","database.name":"test","sql":"DROP TABLE IF EXISTS TEST;
CREATE TABLE TEST(ID INT PRIMARY KEY%2C NAME VARCHAR(255));"},"count":1,"total.cost.milliseconds":15,"success":"true","load.test":"F"}
```

--------------------------------

### Get RestTemplate via Autowiring

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-resttemplate

Obtain a RestTemplate instance through Spring's dependency injection mechanism.

```java
@Autowired
RestTemplate             restTemplate;
```

--------------------------------

### DataSource Digest Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-datasource

This JSON log entry represents a single SQL statement execution trace. It includes details like timestamp, application name, trace IDs, span information, SQL statement, and execution times.

```json
{"time":"2019-09-02 21:31:31.566","local.app":"SOFATracerDataSource","traceId":"0a0fe91d156743109138810017302","spanId":"0.1","span.kind":"client","result.code":"00","current.thread.name":"http-nio-8080-exec-1","time.cost.milliseconds":"15ms","database.name":"test","sql":"DROP TABLE IF EXISTS TEST;
CREATE TABLE TEST(ID INT PRIMARY KEY%2C NAME VARCHAR(255));","connection.establish.span":"128ms","db.execute.cost":"15ms","database.type":"h2","database.endpoint":"jdbc:h2:~/test:-1","sys.baggage":"","biz.baggage":""}
```

--------------------------------

### HttpClient Digest Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-httpclient

This JSON log provides detailed information about an individual HttpClient request, including timestamps, trace IDs, request details, and response sizes. The application name can be configured when building the HttpClient instance.

```json
{"time":"2019-09-02 23:43:13.191","local.app":"HttpClientDemo","traceId":"1e27a79c1567438993170100210107","spanId":"0","span.kind":"client","result.code":"200","current.thread.name":"I/O dispatcher 1","time.cost.milliseconds":"21ms","request.url":"http://localhost:8080/httpclient","method":"GET","req.size.bytes":0,"resp.size.bytes":-1,"remote.app":"","sys.baggage":"","biz.baggage":""}
```

--------------------------------

### SOFARPC Client Statistics Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-sofarpc

This JSON log entry provides aggregated statistics for RPC client calls. It includes the time, a unique stat key (method, app, service), call count, total duration, and success status.

```json
{"time":"2018-05-18 07:02:19.717","stat.key":{"method":"method","local.app":"client","service":"app.service:1.0"},"count":10,"total.cost.milliseconds":17,"success":"Y"}
```

--------------------------------

### HttpClient Statistics Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-httpclient

This JSON log aggregates statistics for HttpClient requests over a specific time period. It includes the total count, total cost, success status, and load test flag, identified by a unique stat.key.

```json
{"time":"2019-09-02 23:44:11.785","stat.key":{"method":"GET","local.app":"HttpClientDemo","request.url":"http://localhost:8080/httpclient"},"count":2,"total.cost.milliseconds":229,"success":"true","load.test":"F"}
```

--------------------------------

### RestTemplate Statistical Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-resttemplate

This JSON log provides aggregated statistical data for RestTemplate requests over a period. It summarizes request counts, total cost, success rates, and load test indicators.

```json
{"time":"2019-09-03 10:34:04.130","stat.key":{"method":"GET","local.app":"RestTemplateDemo","request.url":"http://localhost:8801/asyncrest"},"count":1,"total.cost.milliseconds":5009,"success":"true","load.test":"F"}
```

--------------------------------

### Propagate SOFATracer Context with Callable

Source: https://www.sofastack.tech/projects/sofa-tracer/async

For asynchronous tasks using `java.util.concurrent.Callable`, wrap your Callable with `SofaTracerCallable` to propagate SOFATracer context. This example demonstrates submitting a task to an `ExecutorService` and retrieving the result.

```java
ExecutorService executor = Executors.newCachedThreadPool();
 SofaTracerCallable<Object> sofaTracerSpanSofaTracerCallable = new SofaTracerCallable<Object>(new Callable<Object>() {
     @Override
     public Object call() throws Exception {
         return new Object();
     }
 });
 Future<Object> futureResult = executor.submit(sofaTracerSpanSofaTracerCallable);
 //do something in current thread
 Thread.sleep(1000);
 //another thread execute success and get result
 Object objectReturn = futureResult.get();

```

--------------------------------

### RestTemplate Digest Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-resttemplate

This JSON log captures detailed request and response information for a RestTemplate call. It includes timing, trace IDs, request details, and baggage data.

```json
{"time":"2019-09-03 10:33:10.336","local.app":"RestTemplateDemo","traceId":"0a0fe9271567477985327100211176","spanId":"0","span.kind":"client","result.code":"200","current.thread.name":"SimpleAsyncTaskExecutor-1","time.cost.milliseconds":"5009ms","request.url":"http://localhost:8801/asyncrest","method":"GET","req.size.bytes":0,"resp.size.bytes":0,"sys.baggage":"","biz.baggage":""}
```

--------------------------------

### SOFARPC Client Digest Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-sofarpc

This JSON log entry represents a client-side RPC call's trace data. It includes details like timestamp, trace ID, span ID, protocol, service, method, and performance metrics.

```json
{"timestamp":"2018-05-20 17:03:20.708","tracerId":"1e27326d1526807000498100185597","spanId":"0","span.kind":"client","local.app":"SOFATracerRPC","protocol":"bolt","service":"com.alipay.sofa.tracer.examples.sofarpc.direct.DirectService:1.0","method":"sayDirect","current.thread.name":"main","invoke.type":"sync","router.record":"DIRECT","remote.app":"samples","remote.ip":"127.0.0.1:12200","local.client.ip":"127.0.0.1","result.code":"00","req.serialize.time":"33","resp.deserialize.time":"39","resp.size":"170","req.size":"582","client.conn.time":"0","client.elapse.time":"155","local.client.port":"59774","baggage":""}
```

--------------------------------

### SOFARPC Server Digest Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-sofarpc

This JSON log entry represents a server-side RPC request's trace data. It contains information such as timestamp, trace ID, span ID, service details, method, and server-specific performance metrics.

```json
{"timestamp":"2018-05-20 17:00:53.312","tracerId":"1e27326d1526806853032100185011","spanId":"0","span.kind":"server","service":"com.alipay.sofa.tracer.examples.sofarpc.direct.DirectService:1.0","method":"sayDirect","remote.ip":"127.0.0.1","remote.app":"SOFATracerRPC","protocol":"bolt","local.app":"SOFATracerRPC","current.thread.name":"SOFA-BOLT-BIZ-12200-5-T1","result.code":"00","server.pool.wait.time":"3","biz.impl.time":"0","resp.serialize.time":"4","req.deserialize.time":"38","resp.size":"170","req.size":"582","baggage":""}
```

--------------------------------

### Spring MVC Statistics Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-springmvc

This JSON log entry provides aggregated statistics for a set of Spring MVC requests. It includes the time, a statistical key (combining app, URL, and method), request count, total cost, success status, and load test flag.

```json
{"time":"2019-09-03 10:34:04.129","stat.key":{"method":"GET","local.app":"RestTemplateDemo","request.url":"http://localhost:8801/asyncrest"},"count":1,"total.cost.milliseconds":5006,"success":"true","load.test":"F"}
```

--------------------------------

### Add SOFATracer Dependency

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-mvc

Include the tracer-sofa-boot-starter dependency in your project's pom.xml to enable SOFATracer.

```xml
<dependency>
    <groupId>com.alipay.sofa</groupId>
    <artifactId>tracer-sofa-boot-starter</artifactId>
</dependency>
```

--------------------------------

### Create Rest Service for Demo

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-datasource

Implement a RestController to trigger SQL execution, allowing you to observe the generated tracer logs for SQL operations.

```java
@RestController
public class SimpleRestController {

    @Autowired
    private DataSource simpleDataSource;

    @RequestMapping("/create")
    public Map<String, Object> create() {
        Map<String, Object> resultMap = new HashMap<String, Object>();
        try {
            Connection cn = simpleDataSource.getConnection();
            Statement st = cn.createStatement();
            st.execute("DROP TABLE IF EXISTS TEST;
                    CREATE TABLE TEST(ID INT PRIMARY KEY, NAME VARCHAR(255));");
            resultMap.put("success", true);
            resultMap.put("result", "CREATE TABLE TEST(ID INT PRIMARY KEY, NAME VARCHAR(255))");
        } catch (Throwable throwable) {
            resultMap.put("success", false);
            resultMap.put("error", throwable.getMessage());
        }
        return resultMap;
    }

}
```

--------------------------------

### Configure Provider Application Properties

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-openfeign

Set the application name, server port, and Zookeeper connection details for the provider. Enable Zookeeper discovery and set an instance ID.

```properties
spring.application.name=tracer-provider
server.port=8800
spring.cloud.zookeeper.connect-string=localhost:2181
spring.cloud.zookeeper.discovery.enabled=true
spring.cloud.zookeeper.discovery.instance-id=tracer-provider
```

--------------------------------

### Configure Consumer Application Properties

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-openfeign

Set the application name, server port, and Zookeeper connection details for the consumer. Enable Zookeeper discovery and set an instance ID.

```properties
spring.application.name=tracer-consumer
server.port=8082
spring.cloud.zookeeper.connect-string=localhost:2181
spring.cloud.zookeeper.discovery.enabled=true
spring.cloud.zookeeper.discovery.instance-id=tracer-consumer
```

--------------------------------

### Reference Dubbo Service and Run

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-dubbo

Reference the HelloService using the @Reference annotation and use ApplicationRunner to invoke the service. This demonstrates how the consumer interacts with the provider.

```java
@Reference(async = false)
public HelloService helloService;
    
@Bean
public ApplicationRunner runner() {
    return args -> {
        logger.info(helloService.SayHello("sofa"));
    };
}
```

--------------------------------

### Introduce h2database and mysql-connector-java Dependencies

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-datasource

Include h2database for in-memory testing and mysql-connector-java for database connectivity.

```xml
<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <scope>runtime</scope>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>
```

--------------------------------

### Add SOFATracer and OpenFeign Dependencies to Provider

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-openfeign

Include SOFATracer, Zookeeper discovery, and OpenFeign starters in the provider's pom.xml. SOFATracer version is managed by SOFABoot; manual specification might be needed for versions below 3.0.4.

```xml
<dependency>
    <groupId>com.alipay.sofa</groupId>
    <artifactId>tracer-sofa-boot-starter</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-zookeeper-discovery</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
```

--------------------------------

### Get Baggage Data from SpanContext

Source: https://www.sofastack.tech/projects/sofa-tracer/utils

Retrieve business (bizBaggage) and system (sysBaggage) data from the SpanContext. These are stored as maps.

```java
SofaTracerSpanContext sofaTracerSpanContext = sofaTracerSpan.getSofaTracerSpanContext();
//获取 bizBaggage
Map<String, String> bizBaggages = sofaTracerSpanContext.getBizBaggage();
//获取 sysBaggage
Map<String, String> sysBaggages = sofaTracerSpanContext.getSysBaggage();
```

--------------------------------

### Get Logs from Span

Source: https://www.sofastack.tech/projects/sofa-tracer/utils

Retrieve log data associated with a Span. The logs are returned as a list of LogData objects.

```java
List<LogData> logDataList = sofaTracerSpan.getLogs();
```

--------------------------------

### Manual Datasource Configuration with SmartDataSource

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-datasource

In non-Spring Boot environments or when using connection pools not automatically supported, manually configure SOFATracer by wrapping your data source with `com.alipay.sofa.tracer.plugins.datasource.SmartDataSource`.

```xml
...
  <bean id="smartDataSource" class="com.alipay.sofa.tracer.plugins.datasource.SmartDataSource">
    <property name="targetDataSource" ref="yourDataSource"/>
  </bean>
...
```

--------------------------------

### Get BaggageItem from Span

Source: https://www.sofastack.tech/projects/sofa-tracer/utils

Retrieve the value of a specific BaggageItem from the Span using its key. This operation accesses bizBaggage.

```java
String baggageKey = "key";
String baggageValue = sofaTracerSpan.getBaggageItem(baggageKey);
```

--------------------------------

### Enable Discovery Client and Feign Clients

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-openfeign

Annotate the main application class with @SpringBootApplication, @RestController, @EnableDiscoveryClient, and @EnableFeignClients. Autowire the FeignService to make calls.

```java
@SpringBootApplication
@RestController
@EnableDiscoveryClient
@EnableFeignClients
public class FeignClientApplication {
    
    public static void main(String[] args) {
        SpringApplication.run(FeignClientApplication.class,args);
    }
    
    @Autowired
    private FeignService feignService;
    
    @RequestMapping
    public String test(){
        return feignService.testFeign();
    }
}
```

--------------------------------

### Implement and Publish Dubbo Service

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-dubbo

Implement the HelloService interface and use the @Service annotation to publish it as a Dubbo service. This makes the service available for consumers.

```java
@Service
public class HelloServiceImpl implements HelloService {
    @Override
    public String SayHello(String name) {
        return "Hello , "+name;
    }
}
```

--------------------------------

### Get Tags from Span

Source: https://www.sofastack.tech/projects/sofa-tracer/utils

Retrieve tags associated with a Span. SOFATracer categorizes tags into string, boolean, and number types.

```java
Map<String, String>    tagsStr = sofaTracerSpan.getTagsWithStr();
Map<String, Boolean>  tagsBool = sofaTracerSpan.getTagsWithBool();
Map<String, Number> tagsNumber = sofaTracerSpan.getTagsWithNumber();
```

--------------------------------

### Add SOFATracer and OkHttp Dependencies

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-okhttp

Include SOFATracer and OkHttp dependencies in your project's pom.xml. Ensure you are using compatible versions.

```xml
<!-- SOFATracer 依赖 -->
<dependency>
    <groupId>com.alipay.sofa</groupId>
    <artifactId>tracer-sofa-boot-starter</artifactId>
</dependency>
<!-- okhttp 依赖 -->
<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>3.12.1</version>
</dependency>
```

--------------------------------

### Get SOFATracer Context

Source: https://www.sofastack.tech/projects/sofa-tracer/utils

Retrieve the current SOFATracer context, which is cached in ThreadLocal. This context allows for operations on cached Spans.

```java
SofaTraceContext sofaTraceContext = SofaTraceContextHolder.getSofaTraceContext();
```

--------------------------------

### Get TraceId and SpanId from Span

Source: https://www.sofastack.tech/projects/sofa-tracer/utils

Extract the TraceId and SpanId from a Span's context. Ensure the Span is not null before attempting to retrieve its context.

```java
SofaTracerSpanContext sofaTracerSpanContext = currentSpan.getSofaTracerSpanContext();
String traceId = sofaTracerSpanContext.getTraceId();
String spanId = sofaTracerSpanContext.getSpanId();
```

--------------------------------

### Get Current Span from Context

Source: https://www.sofastack.tech/projects/sofa-tracer/utils

Obtain the current Span from the SOFATracer context. This is useful for application developers who need to access Span information.

```java
SofaTracerSpan sofaTracerSpan = sofaTraceContext.getCurrentSpan();
```

--------------------------------

### Configure SOFATracer Properties

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-resttemplate

Set the application name and logging path in application.properties for SOFATracer.

```properties
# Application Name
spring.application.name=TestTemplateDemo
# logging path
logging.path=./logs
```

--------------------------------

### Logback Implementation Dependency for Spring Boot

Source: https://www.sofastack.tech/projects/sofa-tracer/print-traceid-spanid

Add the Spring Boot starter for logging if you are using Logback as your logging implementation within a Spring Boot application.

```xml
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-logging</artifactId>
</dependency>
```

--------------------------------

### Log4j2 Implementation Dependency for Spring Boot

Source: https://www.sofastack.tech/projects/sofa-tracer/print-traceid-spanid

Include the Spring Boot starter for Log4j2 if you choose Log4j2 as your logging implementation. Note that SOFABoot does not manage the Log4j2 version.

```xml
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-log4j2</artifactId>
    <version>1.4.2.RELEASE</version>
</dependency>
```

--------------------------------

### Configure Custom Sampler in application.properties

Source: https://www.sofastack.tech/projects/sofa-tracer/sampler

Configure your custom sampler by specifying its class name in the application.properties file. This tells SOFATracer which custom rule to use.

```properties
com.alipay.sofa.tracer.samplerName.samplerCustomRuleClassName=com.alipay.sofa.tracer.examples.springmvc.sampler.CustomOpenRulesSamplerRuler
```

--------------------------------

### Configure Optional Application Settings

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-datasource

Configure logging path and h2database console properties for easier debugging and log viewing. These are optional for SOFATracer integration but useful for the demo.

```properties
# logging path
logging.path=./logs

# h2 web consloe 路径
spring.h2.console.path=/h2-console
# 开启 h2 web consloe，默认为 false
spring.h2.console.enabled=true
#允许远程访问 h2 web consloe
spring.h2.console.settings.web-allow-others=true

spring.datasource.username=sofa
spring.datasource.password=123456
spring.datasource.url=jdbc:h2:~/test
spring.datasource.driver-class-name=org.h2.Driver
```

--------------------------------

### Logback Pattern Configuration for TraceId and SpanId

Source: https://www.sofastack.tech/projects/sofa-tracer/print-traceid-spanid

Configure the Logback pattern layout to include SOFATracer's TraceId and SpanId by referencing them from the MDC using %X{SOFA-TraceId} and %X{SOFA-SpanId}. If these values are not present, they will appear as empty strings.

```xml
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} %5p  [%X{SOFA-TraceId},
%X{SOFA-SpanId}]
---- %m%n</pattern>
```

--------------------------------

### Configure SOFATracer Application Properties

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-okhttp

Set the application name and logging path in application.properties for SOFATracer. The application name is used for tracing identification.

```properties
# Application Name
spring.application.name=OkHttpClientDemo
# logging path
logging.path=./logs
# port
server.port=8081
```

--------------------------------

### Introduce Connection Pool Dependencies

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-datasource

Add dependencies for your chosen database connection pool, such as Druid, c3p0, Tomcat JDBC, DBCP, or HikariCP.

```xml
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.0.12</version>
</dependency>
<dependency>
    <groupId>c3p0</groupId>
    <artifactId>c3p0</artifactId>
    <version>0.9.1.1</version>
</dependency>
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat-jdbc</artifactId>
    <version>8.5.31</version>
</dependency>
<dependency>
    <groupId>commons-dbcp</groupId>
    <artifactId>commons-dbcp</artifactId>
    <version>1.4</version>
</dependency>
<dependency>
    <groupId>com.zaxxer</groupId>
    <artifactId>HikariCP-java6</artifactId>
    <version>2.3.8</version>
</dependency>
```

--------------------------------

### Spring MVC Digest Log Example

Source: https://www.sofastack.tech/projects/sofa-tracer/log-format-springmvc

This JSON log entry represents a single traced request in Spring MVC. It includes details like timestamp, application name, trace ID, span ID, request URL, method, and response status.

```json
{"time":"2019-09-03 10:33:10.336","local.app":"RestTemplateDemo","traceId":"0a0fe9271567477985327100211176","spanId":"0.1","span.kind":"server","result.code":"200","current.thread.name":"http-nio-8801-exec-2","time.cost.milliseconds":"5006ms","request.url":"http://localhost:8801/asyncrest","method":"GET","req.size.bytes":-1,"resp.size.bytes":0,"sys.baggage":"","biz.baggage":""}
```

--------------------------------

### Build Asynchronous RestTemplate

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-resttemplate

Construct an AsyncRestTemplate instance using SofaTracerRestTemplateBuilder for asynchronous calls.

```java
AsyncRestTemplate asyncRestTemplate = SofaTracerRestTemplateBuilder
    .buildAsyncRestTemplate();
ListenableFuture<ResponseEntity<String>> forEntity = asyncRestTemplate.getForEntity(
            "http://sac.alipay.net:8080/asyncrest", String.class);
```

--------------------------------

### Define HelloService Interface

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-dubbo

Define the service interface that will be used for communication between Dubbo provider and consumer. This interface specifies the methods available for remote invocation.

```java
public interface HelloService {
    String SayHello(String name);
}
```

--------------------------------

### Configure SOFATracer Properties

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-mvc

Set the spring.application.name and logging.path in application.properties for SOFATracer configuration.

```properties
# Application Name
spring.application.name=SOFATracerSpringMVC
# logging path
logging.path=./logs
```

--------------------------------

### SOFATracer Sampling: Probabilistic Rate (20%)

Source: https://www.sofastack.tech/projects/sofa-tracer/sampler

When the sampling rate is set between 0 and 100 (e.g., 20%), logs are printed probabilistically. This allows for capturing a subset of traces for performance monitoring.

```json
{"time":"2018-11-09 12:14:29.466","local.app":"SOFATracerSpringMVC","traceId":"0a0fe8ec154173686946410159846","spanId":"0.1","request.url":"http://localhost:8080/springmvc","method":"GET","result.code":"200","req.size.bytes":-1,"resp.size.bytes":0,"time.cost.milliseconds":2,"current.thread.name":"http-nio-8080-exec-5","baggage":""}
{"time":"2018-11-09 12:15:21.776","local.app":"SOFATracerSpringMVC","traceId":"0a0fe8ec154173692177410319846","spanId":"0.1","request.url":"http://localhost:8080/springmvc","method":"GET","result.code":"200","req.size.bytes":-1,"resp.size.bytes":0,"time.cost.milliseconds":2,"current.thread.name":"http-nio-8080-exec-2","baggage":""}
```

--------------------------------

### Configure Dubbo Consumer for SOFATracer

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-dubbo

Configure the Dubbo consumer's application.properties to enable SOFATracer integration. This includes setting the application name, registry address, and consumer filter.

```properties
spring.application.name=dubbo-consumer
dubbo.registry.address=zookeeper://localhost:2181
dubbo.consumer.filter=dubboSofaTracerFilter
logging.path=./logs
```

--------------------------------

### Build Synchronous RestTemplate

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-resttemplate

Construct a RestTemplate instance using SofaTracerRestTemplateBuilder for synchronous calls.

```java
RestTemplate restTemplate = SofaTracerRestTemplateBuilder.buildRestTemplate();
ResponseEntity<String> responseEntity = restTemplate.getForEntity(
            "http://sac.alipay.net:8080/rest", String.class);
```

--------------------------------

### SLF4J Logger Initialization

Source: https://www.sofastack.tech/projects/sofa-tracer/print-traceid-spanid

Initialize an SLF4J logger instance in your application code. This is necessary for logging messages and utilizing MDC features.

```java
//引入接口
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

//构造日志打印实例
private static final Logger logger = LoggerFactory.getLogger(XXX.class);
```

--------------------------------

### Create a RESTful Controller

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-resttemplate

Define a Spring RestController with endpoints for RESTful services.

```java
@RestController
public class SampleController {
    private final AtomicLong counter = new AtomicLong(0);
    @RequestMapping("/rest")
    public Map<String, Object> rest() {
        Map<String, Object> map = new HashMap<String, Object>();
        map.put("count", counter.incrementAndGet());
        return map;
    }

    @RequestMapping("/asyncrest")
    public Map<String, Object> asyncrest() throws InterruptedException {
        Map<String, Object> map = new HashMap<String, Object>();
        map.put("count", counter.incrementAndGet());
        Thread.sleep(5000);
        return map;
    }
}
```

--------------------------------

### Create a RESTful Controller

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-mvc

Implement a simple REST controller in your Spring MVC application to handle requests.

```java
@RestController
public class SampleRestController {

    private static final String TEMPLATE = "Hello, %s!";
    private final AtomicLong    counter  = new AtomicLong();
    /**
     * http://localhost:8080/springmvc
     * @param name name
     * @return map
     */
    @RequestMapping("/springmvc")
    public Map<String, Object> springmvc(@RequestParam(value = "name", defaultValue = "SOFATracer SpringMVC DEMO") String name) {
        Map<String, Object> resultMap = new HashMap<String, Object>();
        resultMap.put("success", true);
        resultMap.put("id", counter.incrementAndGet());
        resultMap.put("content", String.format(TEMPLATE, name));
        return resultMap;
    }
}
```

--------------------------------

### Configure Application Name

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-datasource

Set the spring.application.name property in your application configuration. SOFATracer requires this to be set, similar to SOFABoot's requirements.

```properties
spring.application.name=SOFATracerDataSource
```

--------------------------------

### SOFATracer Sampling: Rate 0%

Source: https://www.sofastack.tech/projects/sofa-tracer/sampler

When the sampling rate is set to 0, no summary logs will be printed. This is useful for disabling tracing entirely.

```text
No spring-mvc-digest.log file is generated in the ./logs/tracerlog/ directory.
```

--------------------------------

### Configure Dubbo Provider for SOFATracer

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-dubbo

Configure the Dubbo provider's application.properties to enable SOFATracer integration. This includes setting the application name, Dubbo scan packages, provider filter, protocol, and registry address.

```properties
spring.application.name=dubbo-provider
dubbo.scan.base-packages=com.alipay.sofa.tracer.examples.dubbo.impl
dubbo.provider.filter=dubboSofaTracerFilter
dubbo.protocol.name=dubbo
dubbo.registry.address=zookeeper://localhost:2181
logging.path=./logs
```

--------------------------------

### SOFATracer Log File Structure

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-mvc

Overview of the log file structure generated by SOFATracer in the configured log directory.

```file-structure
./logs
    ├── spring.log
    └── tracelog
        ├── spring-mvc-digest.log
        ├── spring-mvc-stat.log
        ├── static-info.log
        └── tracer-self.log
```

--------------------------------

### Provider REST Controller

Source: https://www.sofastack.tech/projects/sofa-tracer/usage-of-openfeign

A simple REST controller for the provider that returns a string response. This endpoint will be called by the OpenFeign consumer.

```java
@RestController
public class UserController {
    @RequestMapping("/feign")
    public String testFeign(HttpServletRequest request) {
        return "hello tracer feign";
    }
}
```