feat: add otel tracing

example/handler.go

@@ -10,43 +10,43 @@ import (
 )
 
 func handleSuccess() gin.HandlerFunc {
-	return server.Handler(http.StatusOK, func(ctx *gin.Context) (any, error) {
+	return server.Handler("handleSuccess", http.StatusOK, func(ctx *gin.Context) (any, error) {
 		return "success", nil
 	})
 }
 
 func handleError() gin.HandlerFunc {
-	return server.Handler(http.StatusOK, func(ctx *gin.Context) (any, error) {
+	return server.Handler("handleError", http.StatusOK, func(ctx *gin.Context) (any, error) {
 		return nil, ungerr.Unknown("this error should be handled as InternalServerError")
 	})
 }
 
 func handleWrappedError() gin.HandlerFunc {
-	return server.Handler(http.StatusOK, func(ctx *gin.Context) (any, error) {
+	return server.Handler("handleWrappedError", http.StatusOK, func(ctx *gin.Context) (any, error) {
 		return nil, ungerr.Wrap(http.ErrNoCookie, "no cookie")
 	})
 }
 
 func handleUnwrappedError() gin.HandlerFunc {
-	return server.Handler(http.StatusOK, func(ctx *gin.Context) (any, error) {
+	return server.Handler("handleUnwrappedError", http.StatusOK, func(ctx *gin.Context) (any, error) {
 		return nil, http.ErrNoCookie
 	})
 }
 
 func handleAppError() gin.HandlerFunc {
-	return server.Handler(http.StatusOK, func(ctx *gin.Context) (any, error) {
+	return server.Handler("handleAppError", http.StatusOK, func(ctx *gin.Context) (any, error) {
 		return nil, ungerr.BadRequestError("error should be returned")
 	})
 }
 
 func handleKnownError() gin.HandlerFunc {
-	return server.Handler(http.StatusOK, func(ctx *gin.Context) (any, error) {
+	return server.Handler("handleKnownError", http.StatusOK, func(ctx *gin.Context) (any, error) {
 		return nil, &json.SyntaxError{}
 	})
 }
 
 func handlePanic() gin.HandlerFunc {
-	return server.Handler(http.StatusOK, func(ctx *gin.Context) (any, error) {
+	return server.Handler("handlePanic", http.StatusOK, func(ctx *gin.Context) (any, error) {
 		panic("panicking")
 	})
 }

go.mod

@@ -9,6 +9,8 @@ require (
 	github.com/itsLeonB/ezutil/v2 v2.4.0
 	github.com/itsLeonB/ungerr v0.3.0
 	github.com/stretchr/testify v1.11.1
+	go.opentelemetry.io/otel v1.40.0
+	go.opentelemetry.io/otel/trace v1.40.0
 	golang.org/x/time v0.14.0
 )
 
@@ -20,13 +22,14 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/gabriel-vasile/mimetype v1.4.9 // indirect
 	github.com/gin-contrib/sse v1.1.0 // indirect
+	github.com/go-logr/logr v1.4.3 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-playground/locales v0.14.1 // indirect
 	github.com/go-playground/universal-translator v0.18.1 // indirect
 	github.com/goccy/go-json v0.10.5 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.10 // indirect
-	github.com/kr/pretty v0.3.1 // indirect
 	github.com/leodido/go-urn v1.4.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mfridman/interpolate v0.0.2 // indirect
@@ -39,7 +42,8 @@ require (
 	github.com/shopspring/decimal v1.4.0 // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.3.0 // indirect
-	go.opentelemetry.io/otel v1.40.0 // indirect
+	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
+	go.opentelemetry.io/otel/metric v1.40.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/arch v0.18.0 // indirect
 	golang.org/x/crypto v0.40.0 // indirect

go.sum

@@ -8,7 +8,6 @@ github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XL
 github.com/cloudwego/base64x v0.1.5 h1:XPciSp1xaq2VCSt6lF0phncD4koWyULpl5bUxbfCyP4=
 github.com/cloudwego/base64x v0.1.5/go.mod h1:0zlkT4Wn5C6NdauXdJRhSKRlJvmclQ1hhJgA0rcu/8w=
 github.com/cloudwego/iasm v0.2.0/go.mod h1:8rXZaNYT2n95jn+zTI1sDr+IgcD2GVs0nlbbQPiEFhY=
-github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -22,6 +21,11 @@ github.com/gin-contrib/sse v1.1.0 h1:n0w2GMuUpWDVp7qSpvze6fAu9iRxJY4Hmj6AmBOU05w
 github.com/gin-contrib/sse v1.1.0/go.mod h1:hxRZ5gVpWMT7Z0B0gSNYqqsSCNIJMjzvm6fqCz9vjwM=
 github.com/gin-gonic/gin v1.10.1 h1:T0ujvqyCSqRopADpgPgiTT63DUQVSfojyME59Ei63pQ=
 github.com/gin-gonic/gin v1.10.1/go.mod h1:4PMNQiOhvDRa013RKVbsiNwoyezlm2rm0uX/T7kzp5Y=
+github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
+github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
+github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
+github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
+github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
 github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
 github.com/go-playground/assert/v2 v2.2.0/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
 github.com/go-playground/locales v0.14.1 h1:EWaQ/wswjilfKLTECiXz7Rh+3BjFhfDFKv/oXslEjJA=
@@ -66,14 +70,12 @@ github.com/ncruces/go-strftime v0.1.9 h1:bY0MQC28UADQmHmaF5dgpLmImcShSi2kHU9XLdh
 github.com/ncruces/go-strftime v0.1.9/go.mod h1:Fwc5htZGVVkseilnfgOVb9mKy6w1naJmn9CehxcKcls=
 github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
 github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
-github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pressly/goose/v3 v3.26.0 h1:KJakav68jdH0WDvoAcj8+n61WqOIaPGgH0bJWS6jpmM=
 github.com/pressly/goose/v3 v3.26.0/go.mod h1:4hC1KrritdCxtuFsqgs1R4AU5bWtTAf+cnWvfhf2DNY=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
-github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
 github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
 github.com/sethvargo/go-retry v0.3.0 h1:EEt31A35QhrcRZtrYFDTBg91cqZVnFL2navjDrah2SE=
@@ -94,8 +96,14 @@ github.com/twitchyliquid64/golang-asm v0.15.1 h1:SU5vSMR7hnwNxj24w34ZyCi/FmDZTkS
 github.com/twitchyliquid64/golang-asm v0.15.1/go.mod h1:a1lVb/DtPvCB8fslRZhAngC2+aY1QWCk3Cedj/Gdt08=
 github.com/ugorji/go/codec v1.3.0 h1:Qd2W2sQawAfG8XSvzwhBeoGq71zXOC/Q1E9y/wUcsUA=
 github.com/ugorji/go/codec v1.3.0/go.mod h1:pRBVtBSKl77K30Bv8R2P+cLSGaTtex6fsA2Wjqmfxj4=
+go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
+go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
 go.opentelemetry.io/otel v1.40.0 h1:oA5YeOcpRTXq6NN7frwmwFR0Cn3RhTVZvXsP4duvCms=
 go.opentelemetry.io/otel v1.40.0/go.mod h1:IMb+uXZUKkMXdPddhwAHm6UfOwJyh4ct1ybIlV14J0g=
+go.opentelemetry.io/otel/metric v1.40.0 h1:rcZe317KPftE2rstWIBitCdVp89A2HqjkxR3c11+p9g=
+go.opentelemetry.io/otel/metric v1.40.0/go.mod h1:ib/crwQH7N3r5kfiBZQbwrTge743UDc7DTFVZrrXnqc=
+go.opentelemetry.io/otel/trace v1.40.0 h1:WA4etStDttCSYuhwvEa8OP8I5EWu24lkOzp+ZYblVjw=
+go.opentelemetry.io/otel/trace v1.40.0/go.mod h1:zeAhriXecNGP/s2SEG3+Y8X9ujcJOTqQ5RgdEJcawiA=
 go.uber.org/multierr v1.11.0 h1:blXXJkSxSSfBVBlC76pxqeO+LN3aDfLQo+309xJstO0=
 go.uber.org/multierr v1.11.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
 golang.org/x/arch v0.18.0 h1:WN9poc33zL4AzGxqf8VtpKUnGvMi8O9lhNyBMF/85qc=

pkg/middleware/const.go

@@ -0,0 +1,3 @@
+package middleware
+
+const packageName = "github.com/itsLeonB/ginkgo/pkg/middleware"

pkg/middleware/error-handling-convention.md

@@ -85,7 +85,7 @@ if err != nil {
 
 The middleware will catch this, but it logs at `ERROR` with a message explicitly telling developers the error was not wrapped:
 
-```
+```text
 unwrapped error detected — wrap with ungerr.Wrap()
 ```
 
@@ -97,7 +97,7 @@ It will still return `500` to the client, but this is treated as a developer mis
 
 Use this to decide which tool to reach for:
 
-```
+```text
 Did something go wrong?
 │
 ├── Is it an expected client-side failure? (4xx)

pkg/middleware/error.go

@@ -12,10 +12,14 @@ import (
 	"github.com/itsLeonB/ezutil/v2"
 	"github.com/itsLeonB/ginkgo/pkg/response"
 	"github.com/itsLeonB/ungerr"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/codes"
+	"go.opentelemetry.io/otel/trace"
 )
 
 type errorMiddleware struct {
 	logger ezutil.Logger
+	tracer trace.Tracer
 }
 
 type errorObject struct {
@@ -33,7 +37,7 @@ func (eo errorObject) Error() string {
 // This converts them into AppError or validation errors, and sends a structured JSON response
 // with the appropriate HTTP status code. Returns a Gin HandlerFunc.
 func newErrorMiddleware(logger ezutil.Logger) gin.HandlerFunc {
-	m := &errorMiddleware{logger: logger}
+	m := &errorMiddleware{logger: logger, tracer: otel.GetTracerProvider().Tracer(packageName)}
 	return m.handle
 }
 
@@ -45,9 +49,13 @@ func appErrorToErrorObject(appError ungerr.AppError) any {
 }
 
 func (em *errorMiddleware) handle(ctx *gin.Context) {
+	c, span := em.tracer.Start(ctx.Request.Context(), "ErrorMiddleware.handle")
+	defer span.End()
+	ctx.Request = ctx.Request.WithContext(c)
+
 	defer func() {
 		if r := recover(); r != nil {
-			em.handlePanic(r, ctx)
+			em.handlePanic(r, ctx, span)
 		}
 	}()
 
@@ -63,6 +71,8 @@ func (em *errorMiddleware) handle(ctx *gin.Context) {
 
 	// Already a well-typed AppError — warn and respond.
 	if appError, ok := err.(ungerr.AppError); ok {
+		span.RecordError(appError)
+		span.SetStatus(codes.Error, "application error")
 		logCtx.WithError(appError).Warn("application error")
 		ctx.AbortWithStatusJSON(appError.HttpStatus(), appErrorToErrorObject(appError))
 		return
@@ -72,13 +82,18 @@ func (em *errorMiddleware) handle(ctx *gin.Context) {
 	if unknownErr, ok := err.(*ungerr.UnknownError); ok {
 		logCtx = logCtx.WithError(unknownErr)
 		if cause := ungerr.Unwrap(err); cause != nil {
+			span.RecordError(cause)
+			span.SetStatus(codes.Error, "wrapped error")
 			if appError := em.identifyKnownError(cause); appError != nil {
+				span.SetStatus(codes.Error, "identified error")
 				logCtx.WithError(appError).Warn("identified wrapped error")
 				ctx.AbortWithStatusJSON(appError.HttpStatus(), appErrorToErrorObject(appError))
 				return
 			}
 			logCtx.Error("unhandled error") // only if truly unidentifiable
 		} else {
+			span.RecordError(err)
+			span.SetStatus(codes.Error, "unexpected error")
 			logCtx.Error("unexpected error")
 		}
 		appError := ungerr.InternalServerError()
@@ -99,6 +114,8 @@ func (em *errorMiddleware) handle(ctx *gin.Context) {
 		appError = ungerr.InternalServerError()
 	}
 
+	span.RecordError(appError)
+	span.SetStatus(codes.Error, "application error")
 	ctx.AbortWithStatusJSON(appError.HttpStatus(), appErrorToErrorObject(appError))
 }
 
@@ -130,7 +147,7 @@ func (em *errorMiddleware) identifyKnownError(err error) ungerr.AppError {
 	}
 }
 
-func (em *errorMiddleware) handlePanic(r any, ctx *gin.Context) {
+func (em *errorMiddleware) handlePanic(r any, ctx *gin.Context, span trace.Span) {
 	em.logger.
 		WithContext(ctx.Request.Context()).
 		WithFields(map[string]any{
@@ -141,14 +158,16 @@ func (em *errorMiddleware) handlePanic(r any, ctx *gin.Context) {
 		}).
 		Error("panic recovered")
 
+	appError := ungerr.InternalServerError()
+	span.RecordError(appError)
+	span.SetStatus(codes.Error, "panic recovered")
+
 	if ctx.Writer.Written() {
 		em.logger.
 			WithContext(ctx.Request.Context()).
 			WithField("http.status_code", ctx.Writer.Status()).
 			Error("response already written after panic, could not send error JSON")
 		return
 	}
-
-	appError := ungerr.InternalServerError()
 	ctx.AbortWithStatusJSON(appError.HttpStatus(), appErrorToErrorObject(appError))
 }

pkg/server/const.go

@@ -0,0 +1,3 @@
+package server
+
+const packageName = "github.com/itsLeonB/ginkgo/pkg/server"

pkg/server/utils.go

@@ -6,6 +6,7 @@ import (
 	"github.com/itsLeonB/ezutil/v2"
 	"github.com/itsLeonB/ginkgo/pkg/response"
 	"github.com/itsLeonB/ungerr"
+	"go.opentelemetry.io/otel"
 )
 
 // GetPathParam extracts and parses a path parameter from the Gin context.
@@ -96,8 +97,13 @@ func GetAndParseFromContext[T any](ctx *gin.Context, key string) (T, error) {
 	return ezutil.Parse[T](asserted)
 }
 
-func Handler(successCode int, handler func(ctx *gin.Context) (any, error)) gin.HandlerFunc {
+func Handler(handlerName string, successCode int, handler func(ctx *gin.Context) (any, error)) gin.HandlerFunc {
+	tracer := otel.GetTracerProvider().Tracer(packageName)
 	return func(ctx *gin.Context) {
+		c, span := tracer.Start(ctx.Request.Context(), handlerName)
+		ctx.Request = ctx.Request.WithContext(c)
+		defer span.End()
+
 		if resp, err := handler(ctx); err == nil {
 			ctx.JSON(successCode, response.JSONResponse{Data: resp})
 		} else {