gorm-opentelemetry【ORM层可观测性插件】

gorm-opentelemetry

• https://github.com/go-gorm/opentelemetry

介绍

一个gorm插件：实现了orm层的可观测性

Demo（Jaeger、MySQL）:

注：可优先关注 main 函数

package main

import (
	"context"
	"fmt"
	"os"
	"time"

	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/exporters/jaeger"
	"go.opentelemetry.io/otel/exporters/stdout/stdouttrace"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"
	"go.opentelemetry.io/otel/trace"
	"gorm.io/driver/mysql"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"

	"gorm.io/plugin/opentelemetry/logging/logrus"
	"gorm.io/plugin/opentelemetry/tracing"
)

func ConfigureOpentelemetry(ctx context.Context) func() {
	switch {
	case os.Getenv("OTEL_EXPORTER_JAEGER_ENDPOINT") != "":
		return configureJaeger(ctx)
	default:
		return configureStdout(ctx)
	}
}

func configureJaeger(ctx context.Context) func() {
	provider := sdktrace.NewTracerProvider()
	otel.SetTracerProvider(provider)

	exp, err := jaeger.New(jaeger.WithCollectorEndpoint())
	if err != nil {
		panic(err)
	}

	bsp := sdktrace.NewBatchSpanProcessor(exp)
	provider.RegisterSpanProcessor(bsp)

	return func() {
		if err := provider.Shutdown(ctx); err != nil {
			panic(err)
		}
	}
}

func configureStdout(ctx context.Context) func() {
	provider := sdktrace.NewTracerProvider()
	otel.SetTracerProvider(provider)

	exp, err := stdouttrace.New(stdouttrace.WithPrettyPrint())
	if err != nil {
		panic(err)
	}

	bsp := sdktrace.NewBatchSpanProcessor(exp)
	provider.RegisterSpanProcessor(bsp)

	return func() {
		if err := provider.Shutdown(ctx); err != nil {
			panic(err)
		}
	}
}

func PrintTraceID(ctx context.Context) {
	fmt.Println("trace:", TraceURL(trace.SpanFromContext(ctx)))
}

func TraceURL(span trace.Span) string {
	switch {
	case os.Getenv("OTEL_EXPORTER_JAEGER_ENDPOINT") != "":
		return fmt.Sprintf("http://localhost:16686/trace/%s", span.SpanContext().TraceID())
	default:
		return fmt.Sprintf("http://localhost:16686/trace/%s", span.SpanContext().TraceID())
	}
}

func main() {
	ctx := context.Background()

	shutdown := ConfigureOpentelemetry(ctx)
	defer shutdown()

	logger := logger.New(
		logrus.NewWriter(),// <--<--
		logger.Config{
			SlowThreshold: time.Millisecond,
			LogLevel:      logger.Warn,
			Colorful:      false,
		},
	)

	db, err := gorm.Open(mysql.Open("root:rootpassword@tcp(127.0.0.1:3306)/test?charset=utf8mb4&parseTime=True&loc=Local"), &gorm.Config{Logger: logger})
	if err != nil {
		panic(err)
	}
	tx := db.Begin()
	defer tx.Rollback()
	if err := db.Use(tracing.NewPlugin()); err != nil {// <--<-- tracing.NewPlugin()
		panic(err)
	}

	tracer := otel.Tracer("gorm.io/plugin/opentelemetry")

	ctx, span := tracer.Start(ctx, "root")
	defer span.End()
	
	if os.Getenv("OTEL_EXPORTER_JAEGER_ENDPOINT") != "" {
		PrintTraceID(ctx)
	}

	ids := []int64{1, 2, 3}
	var users []int64
	
	_ = tx.Debug().WithContext(ctx).Table("users").Where("id IN ?", ids).Find(&users)
	fmt.Println(users)
	err = tx.Commit().Error
	if err != nil {
		fmt.Println("commit err:", err)
	}
}

正常查询：

报Error:

tracing.NewPlugin内部实现

tracing.NewPlugin是实现orm层链路监控的一个gorm插件，具体实现是利用了gorm的callback。

// gorm-opentelemetry/tracing/tracing.go
func (p otelPlugin) Initialize(db *gorm.DB) (err error) {
	if !p.excludeMetrics {
		if db, ok := db.ConnPool.(*sql.DB); ok {
			metrics.ReportDBStatsMetrics(db)
		}
	}

	cb := db.Callback()
	hooks := []struct {
		callback gormRegister
		hook     gormHookFunc // type gormHookFunc func(tx *gorm.DB)
		name     string
	}{
		{cb.Create().Before("gorm:create"), p.before("gorm.Create"), "before:create"},
		{cb.Create().After("gorm:create"), p.after(), "after:create"},

		{cb.Query().Before("gorm:query"), p.before("gorm.Query"), "before:select"},
		{cb.Query().After("gorm:query"), p.after(), "after:select"},

		{cb.Delete().Before("gorm:delete"), p.before("gorm.Delete"), "before:delete"},
		{cb.Delete().After("gorm:delete"), p.after(), "after:delete"},

		{cb.Update().Before("gorm:update"), p.before("gorm.Update"), "before:update"},
		{cb.Update().After("gorm:update"), p.after(), "after:update"},

		{cb.Row().Before("gorm:row"), p.before("gorm.Row"), "before:row"},
		{cb.Row().After("gorm:row"), p.after(), "after:row"},

		{cb.Raw().Before("gorm:raw"), p.before("gorm.Raw"), "before:raw"},
		{cb.Raw().After("gorm:raw"), p.after(), "after:raw"},
	}

	var firstErr error

	for _, h := range hooks {
		if err := h.callback.Register("otel:"+h.name, h.hook); err != nil && firstErr == nil {
			firstErr = fmt.Errorf("callback register %s failed: %w", h.name, err)
		}
	}

	return firstErr
}