1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17

   +-------------+  +---------+  +----------+  +------------+
   | Application |  | Library |  |   OSS    |  |  RPC/IPC   |
   |    Code     |  |  Code   |  | Services |  | Frameworks |
   +-------------+  +---------+  +----------+  +------------+
          |              |             |             |
          |              |             |             |
          v              v             v             v
     +-----------------------------------------------------+
     | · · · · · · · · · · OpenTracing · · · · · · · · · · |
     +-----------------------------------------------------+
       |               |                |               |
       |               |                |               |
       v               v                v               v
 +-----------+  +-------------+  +-------------+  +-----------+
 |  Tracing  |  |   Logging   |  |   Metrics   |  |  Tracing  |
 | System A  |  | Framework B |  | Framework C |  | System D  |
 +-----------+  +-------------+  +-------------+  +-----------+

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16

Causal relationships between Spans in a single Trace


        [Span A]  ←←←(the root span)
            |
     +------+------+
     |             |
 [Span B]      [Span C] ←←←(Span C is a `ChildOf` Span A)
     |             |
 [Span D]      +---+-------+
               |           |
           [Span E]    [Span F] >>> [Span G] >>> [Span H]
                                       ↑
                                       ↑
                                       ↑
                         (Span G `FollowsFrom` Span F)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10

Temporal relationships between Spans in a single Trace


––|–––––––|–––––––|–––––––|–––––––|–––––––|–––––––|–––––––|–> time

 [Span A···················································]
   [Span B··············································]
      [Span D··········································]
    [Span C········································]
         [Span E·······]        [Span F··] [Span G··] [Span H··]

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

import (
    "net/http"

    opentracing "github.com/opentracing/opentracing-go"
    "github.com/opentracing/opentracing-go/ext"
)

...

tracer := opentracing.GlobalTracer()

clientSpan := tracer.StartSpan("client")
defer clientSpan.Finish()

url := "http://localhost:8082/publish"
req, _ := http.NewRequest("GET", url, nil)

// Set some tags on the clientSpan to annotate that it's the client span. The additional HTTP tags are useful for debugging purposes.
ext.SpanKindRPCClient.Set(clientSpan)
ext.HTTPUrl.Set(clientSpan, url)
ext.HTTPMethod.Set(clientSpan, "GET")

// Inject the client span context into the headers
tracer.Inject(clientSpan.Context(), opentracing.HTTPHeaders, opentracing.HTTPHeadersCarrier(req.Header))
resp, _ := http.DefaultClient.Do(req)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

import (
    "log"
    "net/http"

    opentracing "github.com/opentracing/opentracing-go"
    "github.com/opentracing/opentracing-go/ext"
)

func main() {

    // Tracer initialization, etc.

    ...

    http.HandleFunc("/publish", func(w http.ResponseWriter, r *http.Request) {
        // Extract the context from the headers
        spanCtx, _ := tracer.Extract(opentracing.HTTPHeaders, opentracing.HTTPHeadersCarrier(r.Header))
        serverSpan := tracer.StartSpan("server", ext.RPCServerOption(spanCtx))
        defer serverSpan.Finish()
    })

    log.Fatal(http.ListenAndServe(":8082", nil))
}

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16

// java -javaagent:xxx.jar -jar yy.jar

/**
 * The main entrance of sky-walking agent, based on javaagent mechanism.
 */
public class SkyWalkingAgent {
    /**
     * Main entrance. Use byte-buddy transform to enhance all classes, which define in plugins.
     */
    public static void premain(String agentArgs, Instrumentation instrumentation) throws PluginException {
       // instrument
       ...
       
    }
    
}