refactor: separate the logic of distributed tracing (yomorun#736)

# Description

Omit the `WithTracerProvider()` options as manual injection of the
tracer provider in the code is unnecessary. The tracing functionality
will be activated upon setting the 'OTEL_EXPORTER_OTLP_ENDPOINT'
environment variable.

# Changes

Before:

```golang
// create trace provider manully
tp, shutdown, e := trace.NewTracerProvider("yomo-sfn")
if e == nil {
  log.Println("[sfn] 🛰 trace enabled")
}
defer shutdown(context.Background())

sfn := yomo.NewStreamFunction(
  name,
  addr,
  yomo.WithCredential(credential),
  yomo.WithTracerProvider(tp),  // add trace provider to opts
)
```

After:

```golang
sfn := yomo.NewStreamFunction(
  name,
  addr,
  yomo.WithCredential(credential),
)
```
run: 

```sh
OTEL_EXPORTER_OTLP_ENDPOINT=https://opentracing.acme.com:7234 yomo run sfn.go
```

# TODO

update related docs.

.github/workflows/go.yml

@@ -23,6 +23,6 @@ jobs:
         run: go build $(go list ./... | grep -v /example)
 
       - name: Upload coverage
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@v3
         with:
           file: coverage.txt

cli/serve.go

@@ -25,7 +25,6 @@ import (
 	"github.com/yomorun/yomo/core/router"
 	pkgconfig "github.com/yomorun/yomo/pkg/config"
 	"github.com/yomorun/yomo/pkg/log"
-	"github.com/yomorun/yomo/pkg/trace"
 
 	"github.com/yomorun/yomo/pkg/bridge/ai"
 	"github.com/yomorun/yomo/pkg/bridge/ai/provider/azopenai"
@@ -51,16 +50,10 @@ var serveCmd = &cobra.Command{
 			return
 		}
 		ctx := context.Background()
-		// trace
-		tp, shutdown, err := trace.NewTracerProvider("yomo-zipper")
-		if err == nil {
-			log.InfoStatusEvent(os.Stdout, "[zipper] 🛰 trace enabled")
-		}
-		defer shutdown(ctx)
 		// listening address.
 		listenAddr := fmt.Sprintf("%s:%d", conf.Host, conf.Port)
 
-		options := []yomo.ZipperOption{yomo.WithZipperTracerProvider(tp)}
+		options := []yomo.ZipperOption{}
 		tokenString := ""
 		if _, ok := conf.Auth["type"]; ok {
 			if tokenString, ok = conf.Auth["token"]; ok {

cli/serverless/deno/runtime.go

@@ -2,7 +2,6 @@
 package deno
 
 import (
-	"context"
 	"encoding/binary"
 	"errors"
 	"io"
@@ -15,7 +14,6 @@ import (
 	"github.com/yomorun/yomo"
 	"github.com/yomorun/yomo/core/frame"
 	"github.com/yomorun/yomo/pkg/file"
-	"github.com/yomorun/yomo/pkg/trace"
 	"github.com/yomorun/yomo/serverless"
 )
 
@@ -90,17 +88,10 @@ func runDeno(jsPath string, socketPath string, errCh chan<- error) {
 }
 
 func startSfn(name string, zipperAddr string, credential string, observed []frame.Tag, conn net.Conn, errCh chan<- error) (yomo.StreamFunction, error) {
-	// trace
-	tp, shutdown, err := trace.NewTracerProvider("yomo-sfn")
-	if err == nil {
-		log.Println("[sfn] 🛰 trace enabled")
-	}
-	defer shutdown(context.Background())
 	sfn := yomo.NewStreamFunction(
 		name,
 		zipperAddr,
 		yomo.WithSfnCredential(credential),
-		yomo.WithSfnTracerProvider(tp),
 	)
 
 	// init
@@ -168,7 +159,7 @@ func startSfn(name string, zipperAddr string, credential string, observed []fram
 		},
 	)
 
-	err = sfn.Connect()
+	err := sfn.Connect()
 	if err != nil {
 		return nil, err
 	}

cli/serverless/golang/templates/main.tmpl

@@ -24,17 +24,10 @@ func main() {
 }
 
 func runSFN(name string, addr string, credential string) (closeFn func() error, err error) {
-	// trace
-	tp, shutdown, e := trace.NewTracerProvider("yomo-sfn")
-	if e == nil {
-		log.Println("[sfn] 🛰 trace enabled")
-	}
-	defer shutdown(context.Background())
 	sfn := yomo.NewStreamFunction(
     name,
 		addr,
 		yomo.WithCredential(credential),
-		yomo.WithTracerProvider(tp),
 	)
 	closeFn = sfn.Close
 

cli/serverless/golang/templates/main_rx.tmpl

@@ -24,17 +24,11 @@ func main() {
 }
 
 func runSFN(name string, addr string, credential string) (closeFn func() error, err error) {
-	// trace
-	tp, shutdown, e := trace.NewTracerProvider("yomo-sfn")
-	if e == nil {
-		log.Println("[sfn] 🛰 trace enabled")
-	}
 	defer shutdown(context.Background())
 	sfn := yomo.NewStreamFunction(
 		name,
 		addr,
 		yomo.WithCredential(credential),
-		yomo.WithTracerProvider(tp),
 	)
 	closeFn = sfn.Close
 

cli/serverless/wasm/serverless.go

@@ -2,15 +2,13 @@
 package wasm
 
 import (
-	"context"
 	"log"
 	"os"
 	"sync"
 
 	"github.com/yomorun/yomo"
 	cli "github.com/yomorun/yomo/cli/serverless"
 	pkglog "github.com/yomorun/yomo/pkg/log"
-	"github.com/yomorun/yomo/pkg/trace"
 	"github.com/yomorun/yomo/serverless"
 )
 
@@ -53,21 +51,13 @@ func (s *wasmServerless) Build(clean bool) error {
 
 // Run the wasm serverless function
 func (s *wasmServerless) Run(verbose bool) error {
-	// trace
-	tp, shutdown, err := trace.NewTracerProvider("yomo-sfn")
-	if err == nil {
-		pkglog.InfoStatusEvent(os.Stdout, "[sfn] 🛰 trace enabled")
-	}
-	defer shutdown(context.Background())
-
 	sfn := yomo.NewStreamFunction(
 		s.name,
 		s.zipperAddr,
 		yomo.WithSfnCredential(s.credential),
-		yomo.WithSfnTracerProvider(tp),
 	)
 	// init
-	err = sfn.Init(func() error {
+	err := sfn.Init(func() error {
 		return s.runtime.RunInit()
 	})
 	if err != nil {

core/client.go

@@ -6,7 +6,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"reflect"
 	"runtime"
 	"time"
 
@@ -16,24 +15,22 @@ import (
 	"github.com/yomorun/yomo/pkg/frame-codec/y3codec"
 	"github.com/yomorun/yomo/pkg/id"
 	yquic "github.com/yomorun/yomo/pkg/listener/quic"
-	oteltrace "go.opentelemetry.io/otel/trace"
 	"golang.org/x/exp/slog"
 )
 
 // Client is the abstraction of a YoMo-Client. a YoMo-Client can be
 // Source, Upstream Zipper or StreamFunction.
 type Client struct {
-	zipperAddr     string
-	name           string                 // name of the client
-	clientID       string                 // id of the client
-	reconnCounter  uint                   // counter for reconnection
-	clientType     ClientType             // type of the client
-	processor      func(*frame.DataFrame) // function to invoke when data arrived
-	errorfn        func(error)            // function to invoke when error occured
-	wantedTarget   string
-	opts           *clientOptions
-	Logger         *slog.Logger
-	tracerProvider oteltrace.TracerProvider
+	zipperAddr    string
+	name          string                 // name of the client
+	clientID      string                 // id of the client
+	reconnCounter uint                   // counter for reconnection
+	clientType    ClientType             // type of the client
+	processor     func(*frame.DataFrame) // function to invoke when data arrived
+	errorfn       func(error)            // function to invoke when error occured
+	wantedTarget  string
+	opts          *clientOptions
+	Logger        *slog.Logger
 
 	// ctx and ctxCancel manage the lifecycle of client.
 	ctx       context.Context
@@ -68,16 +65,15 @@ func NewClient(appName, zipperAddr string, clientType ClientType, opts ...Client
 	ctx, ctxCancel := context.WithCancelCause(context.Background())
 
 	return &Client{
-		zipperAddr:     zipperAddr,
-		name:           appName,
-		clientID:       clientID,
-		processor:      func(df *frame.DataFrame) { logger.Warn("the processor has not been set") },
-		clientType:     clientType,
-		opts:           option,
-		Logger:         logger,
-		tracerProvider: option.tracerProvider,
-		ctx:            ctx,
-		ctxCancel:      ctxCancel,
+		zipperAddr: zipperAddr,
+		name:       appName,
+		clientID:   clientID,
+		processor:  func(df *frame.DataFrame) { logger.Warn("the processor has not been set") },
+		clientType: clientType,
+		opts:       option,
+		Logger:     logger,
+		ctx:        ctx,
+		ctxCancel:  ctxCancel,
 
 		done: make(chan struct{}),
 		wrCh: make(chan frame.Frame),
@@ -429,14 +425,3 @@ type Downstream interface {
 	Close() error
 	Connect(context.Context) error
 }
-
-// TracerProvider returns the tracer provider of client.
-func (c *Client) TracerProvider() oteltrace.TracerProvider {
-	if c.tracerProvider == nil {
-		return nil
-	}
-	if reflect.ValueOf(c.tracerProvider).IsNil() {
-		return nil
-	}
-	return c.tracerProvider
-}

core/client_options.go

@@ -16,7 +16,6 @@ import (
 	"github.com/yomorun/yomo/core/frame"
 	"github.com/yomorun/yomo/core/ylog"
 	pkgtls "github.com/yomorun/yomo/pkg/tls"
-	"go.opentelemetry.io/otel/trace"
 	"golang.org/x/exp/slog"
 )
 
@@ -32,7 +31,6 @@ type clientOptions struct {
 	reconnect       bool
 	nonBlockWrite   bool
 	logger          *slog.Logger
-	tracerProvider  trace.TracerProvider
 	// ai function
 	aiFunctionInputModel  any
 	aiFunctionDescription string
@@ -107,13 +105,6 @@ func WithLogger(logger *slog.Logger) ClientOption {
 	}
 }
 
-// WithTracerProvider sets tracer provider for the client.
-func WithTracerProvider(tp trace.TracerProvider) ClientOption {
-	return func(o *clientOptions) {
-		o.tracerProvider = tp
-	}
-}
-
 // WithAIFunctionDefinition sets AI function definition for the client.
 func WithAIFunctionDefinition(description string, inputModel any) ClientOption {
 	return func(o *clientOptions) {

core/client_test.go

@@ -163,7 +163,7 @@ func TestFrameRoundTrip(t *testing.T) {
 	exited = checkClientExited(sfn2, time.Second)
 	assert.False(t, exited, "sfn stream should not exited")
 
-	sfnMd := NewMetadata(source.clientID, "tid", "trace-id", "span-id", false)
+	sfnMd := NewMetadata(source.clientID, "tid")
 
 	sfnMetaBytes, _ := sfnMd.Encode()
 
@@ -186,7 +186,7 @@ func TestFrameRoundTrip(t *testing.T) {
 	assert.ElementsMatch(t, nameList, []string{"source", "sfn-1", "sfn-2"})
 
 	md := metadata.New(
-		NewMetadata(source.clientID, "tid", "trace-id", "span-id", false),
+		NewMetadata(source.clientID, "tid"),
 		metadata.M{
 			"foo": "bar",
 		},