[Language] Tracer: Open Telemetry, Golang, and Jagger Simple Implementation

Tracer

Tracer is part of Observability which plays an important role in the implementation of Microservices Architecture and provides a 'Trace' overview of the processes running in an application logic.

Simply put, in Webservice, Tracer will provide an idea of ​​how long the execution time of a logic is by emitting a Trace signal. Later, this Tracer will be visualized and seen in the form of a nested span after transmitting a signal through the Exporter to the Collector. [OpenTelemetry: Traces]

OpenTelemetry

To be able to transmit Traces signals which can later be collected by the Collector, Webservice requires OpenTelemetry as a library which has become a standard Observability protocol which is usually called OpenTelemetry Protocol (OTLP). [OpenTelemetry: Language - Go]

Jaeger

Visualization of Traces signals is really needed to provide an overview of what processes occur in the Webservice. Jaeger is an Open-Source platform that supports OTLP by utilizing the HTTP or gRPC communication protocol. [Jaeger]

Implementation in Golang

The implementation of Tracer in the Golang programming language will implement a simple case where the Webservice will only return data with different response durations. The library that will be used is:

• Chi: HTTP Framework
• OpenTelemetry: Telemetry Signaling

Setup OpenTelemetry as a Telemetry module

Implement the Telemetry module in the pkg/telemetry/telemetry.go directory:

package telemetry

import (
    "context"
    "errors"
    "time"

    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/exporters/otlp/otlptrace"
    "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
    "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
    "go.opentelemetry.io/otel/sdk/resource"
    "go.opentelemetry.io/otel/sdk/trace"
)

// enumeration constant for which protocol used
const (
    HTTP uint8 = iota
    GRPC
)

// setup client to connect web-service with Jaeger
func SetupTraceClient(ctx context.Context, protocol uint8, endpoint string) otlptrace.Client {
    switch protocol {
    case GRPC:
        return otlptracegrpc.NewClient(otlptracegrpc.WithEndpoint(endpoint), otlptracegrpc.WithInsecure(), otlptracegrpc.WithCompressor("gzip"))
    default:
        return otlptracehttp.NewClient(otlptracehttp.WithEndpoint(endpoint), otlptracehttp.WithInsecure(), otlptracehttp.WithCompression(otlptracehttp.NoCompression))
    }
}

func setupTraceProvider(ctx context.Context, traceClient otlptrace.Client) (*trace.TracerProvider, error) {
    // set resource
    res, err := resource.New(
        ctx,
        resource.WithFromEnv(),
    )
    if err != nil {
        return nil, err
    }

    // init trace exporter
    traceExporter, err := otlptrace.New(ctx, traceClient)
    if err != nil {
        return nil, err
    }

    // init trace exporter
    traceProvider := trace.NewTracerProvider(
        trace.WithBatcher(
            traceExporter,
            trace.WithBatchTimeout(time.Duration(time.Second*3)),
        ),
        trace.WithResource(res), // Discover and provide attributes from OTEL_RESOURCE_ATTRIBUTES and OTEL_SERVICE_NAME environment variables.
    )

    return traceProvider, nil
}

func SetupTelemetrySDK(ctx context.Context, traceClient otlptrace.Client) (func(context.Context) error, error) {
    var err error
    var shutdownFuncs []func(context.Context) error

    shutdown := func(ctx context.Context) error {
        var err error
        for _, fn := range shutdownFuncs {
            err = errors.Join(err, fn(ctx))
        }
        shutdownFuncs = nil
        return err
    }

    handleErr := func(inErr error) {
        err = errors.Join(inErr, shutdown(ctx))
    }

    traceProvider, err := setupTraceProvider(ctx, traceClient)
    if err != nil {
        handleErr(err)
        return shutdown, err
    }

    shutdownFuncs = append(shutdownFuncs, traceProvider.Shutdown)
    otel.SetTracerProvider(traceProvider)

    return shutdown, nil
}

Then, setup the Telemetry configuration in the main function main.go:

package main

import (
    "context"
    "fmt"
    "net/http"
    "os"
    "os/signal"
    "syscall"
    "time"

    "github.com/go-chi/chi/v5"
    "github.com/wahyurudiyan/medium/otel-jaeger/config"
    "github.com/wahyurudiyan/medium/otel-jaeger/pkg/telemetry"
    "github.com/wahyurudiyan/medium/otel-jaeger/router"
)

func SetupTelemetry(ctx context.Context, config *config.Config) (func(context.Context) error, error) {
    otlpCli := telemetry.SetupTraceClient(ctx, telemetry.GRPC, config.JaegerGRPCEndpoint)
    shutdownFn, err := telemetry.SetupTelemetrySDK(ctx, otlpCli)
    return shutdownFn, err
}

func main() {
    ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
    defer cancel()

    cfg := config.Get()

    shutdownFn, err := SetupTelemetry(ctx, cfg)
    if err != nil {
        shutdownFn(ctx)
        panic(err)
    }

    r := chi.NewRouter()
    r.Route("/api", func(r chi.Router) {
        router.Router(r)
    })

    srv := http.Server{
        Addr:    "0.0.0.0:8080",
        Handler: r,
    }
    go func() {
        fmt.Println("Server running at port:", srv.Addr)
        if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
            fmt.Printf("listen: %s\n", err)
        }
    }()

    quit := make(chan os.Signal, 1)
    signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
    



<p>Use Tracer in the handler in the router/router.go file to transmit Traces signals:<br>
</p>

<pre class="brush:php;toolbar:false">package router

import (
    "encoding/json"
    "net/http"
    "time"

    "github.com/go-chi/chi/v5"
    "github.com/wahyurudiyan/medium/otel-jaeger/pkg/random"
    "go.opentelemetry.io/otel"
)

var (
    tracer = otel.Tracer("WebServer-Otel-Jaeger")
)

func getUserHandler(w http.ResponseWriter, r *http.Request) {
    _, span := tracer.Start(r.Context(), "GetUser")
    defer span.End()

    user := struct {
        Name     string
        Email    string
        Password string
    }{
        Name:     "John Doe",
        Email:    "john@email.com",
        Password: "Super5ecr3t!",
    }
    blob, _ := json.Marshal(&user)

    sleepDuration := time.Duration(time.Millisecond * time.Duration(random.GenerateRandNum()))
    time.Sleep(sleepDuration)

    w.Header().Add("Content-Type", "application/json")
    w.WriteHeader(http.StatusOK)
    w.Write(blob)
}

func Router(router chi.Router) {
    router.Get("/user", getUserHandler)
}

Deployments

Docker configuration for this Build Webservice, utilizing the Multi-Stage Build Image mechanism in the Dockerfile:

FROM golang:1.23.4 AS build
WORKDIR /src
COPY . .
RUN go get -v
RUN CGO_ENABLED=0 go build -o /bin/service .

FROM alpine:latest
WORKDIR /app
COPY --from=build /bin/service /bin/service
CMD ["/bin/service"]

Next, the image build will be carried out via the docker-compose.yaml file with the following configuration:

services:
  web-service:
    container_name: service
    build:
      context: .
      dockerfile: Dockerfile
    environment:
      OTEL_SERVICE_NAME: service-otel-jaeger
      JAEGER_GRPC_ENDPOINT: jaeger:4317
    entrypoint: ["service"]
    ports:
      - 8080:8080

  jaeger:
    container_name: jaeger
    image: jaegertracing/all-in-one:latest
    environment:
      COLLECTOR_ZIPKIN_HOST_PORT: :9411
    ports:
      - 16686:16686 
      - 4317:4317 
      - 4318:4318 
      - 9411:9411

In service.jaeger.ports, the port exposed is the port for:

• 16686: Jaeger Dashboard
• 4317: Jaeger OTLP Protobuf with gRPC protocol
• 4318: Jaeger OTLP Protobuf/JSON with HTTP protocol
• 9411: Zipkin Collector

Run the application that has been defined in docker-compose.yaml, you can use the command:

docker compose up --build

After the application is running, you can try hitting the application on the endpoint http://127.0.0.1:8080/api/user, if the Webservice and application are connected, the service name will appear as in the picture.

a span will appear to define how long it takes to run a process.

Load Test

Now let's try using the CLI tool hey [https://github.com/rakyll/hey] to run a load-test. The following command can be used to perform a simple load-test:

package telemetry

import (
    "context"
    "errors"
    "time"

    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/exporters/otlp/otlptrace"
    "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
    "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
    "go.opentelemetry.io/otel/sdk/resource"
    "go.opentelemetry.io/otel/sdk/trace"
)

// enumeration constant for which protocol used
const (
    HTTP uint8 = iota
    GRPC
)

// setup client to connect web-service with Jaeger
func SetupTraceClient(ctx context.Context, protocol uint8, endpoint string) otlptrace.Client {
    switch protocol {
    case GRPC:
        return otlptracegrpc.NewClient(otlptracegrpc.WithEndpoint(endpoint), otlptracegrpc.WithInsecure(), otlptracegrpc.WithCompressor("gzip"))
    default:
        return otlptracehttp.NewClient(otlptracehttp.WithEndpoint(endpoint), otlptracehttp.WithInsecure(), otlptracehttp.WithCompression(otlptracehttp.NoCompression))
    }
}

func setupTraceProvider(ctx context.Context, traceClient otlptrace.Client) (*trace.TracerProvider, error) {
    // set resource
    res, err := resource.New(
        ctx,
        resource.WithFromEnv(),
    )
    if err != nil {
        return nil, err
    }

    // init trace exporter
    traceExporter, err := otlptrace.New(ctx, traceClient)
    if err != nil {
        return nil, err
    }

    // init trace exporter
    traceProvider := trace.NewTracerProvider(
        trace.WithBatcher(
            traceExporter,
            trace.WithBatchTimeout(time.Duration(time.Second*3)),
        ),
        trace.WithResource(res), // Discover and provide attributes from OTEL_RESOURCE_ATTRIBUTES and OTEL_SERVICE_NAME environment variables.
    )

    return traceProvider, nil
}

func SetupTelemetrySDK(ctx context.Context, traceClient otlptrace.Client) (func(context.Context) error, error) {
    var err error
    var shutdownFuncs []func(context.Context) error

    shutdown := func(ctx context.Context) error {
        var err error
        for _, fn := range shutdownFuncs {
            err = errors.Join(err, fn(ctx))
        }
        shutdownFuncs = nil
        return err
    }

    handleErr := func(inErr error) {
        err = errors.Join(inErr, shutdown(ctx))
    }

    traceProvider, err := setupTraceProvider(ctx, traceClient)
    if err != nil {
        handleErr(err)
        return shutdown, err
    }

    shutdownFuncs = append(shutdownFuncs, traceProvider.Shutdown)
    otel.SetTracerProvider(traceProvider)

    return shutdown, nil
}

The command will run a load-test for 100 requests per second (RPS) for 10 minutes. The results that will appear on the Jaeger UI page will look like the following.

If the load test has finished running, there will be a report of the load test results.

package main

import (
    "context"
    "fmt"
    "net/http"
    "os"
    "os/signal"
    "syscall"
    "time"

    "github.com/go-chi/chi/v5"
    "github.com/wahyurudiyan/medium/otel-jaeger/config"
    "github.com/wahyurudiyan/medium/otel-jaeger/pkg/telemetry"
    "github.com/wahyurudiyan/medium/otel-jaeger/router"
)

func SetupTelemetry(ctx context.Context, config *config.Config) (func(context.Context) error, error) {
    otlpCli := telemetry.SetupTraceClient(ctx, telemetry.GRPC, config.JaegerGRPCEndpoint)
    shutdownFn, err := telemetry.SetupTelemetrySDK(ctx, otlpCli)
    return shutdownFn, err
}

func main() {
    ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
    defer cancel()

    cfg := config.Get()

    shutdownFn, err := SetupTelemetry(ctx, cfg)
    if err != nil {
        shutdownFn(ctx)
        panic(err)
    }

    r := chi.NewRouter()
    r.Route("/api", func(r chi.Router) {
        router.Router(r)
    })

    srv := http.Server{
        Addr:    "0.0.0.0:8080",
        Handler: r,
    }
    go func() {
        fmt.Println("Server running at port:", srv.Addr)
        if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
            fmt.Printf("listen: %s\n", err)
        }
    }()

    quit := make(chan os.Signal, 1)
    signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
    



<h2>
  
  
  Github Project
</h2>

<p>For those who want to try or see the full code, you can clone the following repository: https://github.com/wahyurudiyan/otel-jaeger.</p>


          

            
        

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