Application Real-Time Monitoring Service:Use custom extension to create OpenTelemetry span

Prerequisites

• Ensure the current application's Golang version is 1.18 or higher.

• Connect the Golang application to ARMS.

  Important

  Ensure the compile statement is modified to ./instgo go build xxx as per the access document.

Procedure

1. Create a hook folder outside the current project's folder. Initialize the folder using the go mod init hook command and then create a hook.go file in the hook folder with the following code:

   Below is the custom extension feature to be injected:

   package hook
   
   import (
   	"encoding/json"
   	"fmt"
     	"go.opentelemetry.io/otel"
   	"go.opentelemetry.io/otel/attribute"
   	"github.com/alibaba/opentelemetry-go-auto-instrumentation/pkg/api"
   	"net/http"
   )
   
   // Note: The first parameter of the injected code must be api.CallContext, subsequent parameters must match the target function's parameters
   func httpClientEnterHook(call api.CallContext, t *http.Transport, req *http.Request) {
   	header, _ := json.Marshal(req.Header)
   	fmt.Println("request header is ", string(header))
       tracer := otel.GetTracerProvider().Tracer("")
     	_, span := tracer.Start(context.Background(), "Client/User defined span")
     	span.SetAttributes(attribute.String("client", "client-with-ot"))
     	span.SetAttributes(attribute.Bool("user.defined", true))
     	span.End()
   }
   // Note: The first parameter of the injected code must be api.CallContext, subsequent parameters must match the target function's return values
   func httpClientExitHook(call api.CallContext, res *http.Response, err error) {
   	header, _ := json.Marshal(res.Header)
   	fmt.Println("response header is ", string(header))
   }
   

   The code segment responsible for creating the span is:

   tracer := otel.GetTracerProvider().Tracer("")
     	_, span := tracer.Start(context.Background(), "Client/User defined span")
     	span.SetAttributes(attribute.String("client", "client-with-ot"))
     	span.SetAttributes(attribute.Bool("user.defined", true))
     	span.End()

2. Write a test demo.

   Create a folder for the demo application in a separate directory from the hook folder. Initialize it with the go mod init demo command and then create a main.go file in the demo folder with the following code:

   Note

   If the project already depends on OpenTelemetry, you do not need to add _ "go.opentelemetry.io/otel" in main. If not, it is required.

   package main
   
   import (
   	"context"
   	"fmt"
   	"io/ioutil"
   	"log"
   	"net/http"
       _ "go.opentelemetry.io/otel"
   )
   
   func main() {
   	// Define the request URL
   	req, _ := http.NewRequestWithContext(context.Background(), "GET", "http://www.aliyun.com", nil)
   	req.Header.Set("otelbuild", "true")
   	client := &http.Client{}
   	resp, _ := client.Do(req)
   
   	// Ensure the response body is closed when the function ends
   	defer resp.Body.Close()
   }
   

3. Create a conf.json configuration file in the demo folder with the following code:

   The code below instructs the Golang probe to inject the custom hook code into the database/sql::(*DB).Query() function.

   [{
     "ImportPath":"net/http",
     "Function":"RoundTrip",
     "OnEnter":"httpClientEnterHook",
     "ReceiverType": "*Transport",
     "OnExit": "httpClientExitHook",
     "Path": "/path/to/hook" # Modify Path to the local path of the hook code
   }]

4. Navigate to the demo directory. Compile and execute the program using the instgo tool to verify SQL injection protection effectiveness.

   $ ./instgo set --rule=./conf.json
   $ ./instgo go build 

5. Launch the demo program.

   You can start it locally by directly declaring environment variables, or opt to deploy the demo program in a containerized environment.

   1. Declare the environment variables:

      export ARMS_ENABLE=true
      export ARMS_APP_NAME=xxx   # Application name.
      export ARMS_REGION_ID=xxx   # RegionID of the corresponding Alibaba Cloud account.
      export ARMS_LICENSE_KEY=xxx   # LicenseKey obtained in step one.

   2. Start the demo program:

      ./demo

6. Monitor the application's data on the or the ARMS console on the Application Monitoring > Application List page.

References

Use the custom extension capabilities of the Golang probe