implement skip paths for the exposed endpoints

config/config.go

@@ -9,6 +9,7 @@ type Config struct {
 	Layers      *LayersOpts            `json:"layers"`
 	Exporters   map[string]Exporter    `json:"exporters"`
 	Instance    *Instance              `json:"instance"`
+	SkipPaths   []string               `json:"skip_paths"`
 	Extra       map[string]interface{} `json:"extra"`
 }
 
@@ -47,10 +48,9 @@ type LayersOpts struct {
 // We can select if we want to disable the metrics,
 // the traces, and / or the trace propagation.
 type RouterOpts struct {
-	DisableMetrics     bool     `json:"disable_metrics"`
-	DisableTraces      bool     `json:"disable_traces"`
-	DisablePropagation bool     `json:"disable_propagation"`
-	SkipPaths          []string `json:"skip_paths"`
+	DisableMetrics     bool `json:"disable_metrics"`
+	DisableTraces      bool `json:"disable_traces"`
+	DisablePropagation bool `json:"disable_propagation"`
 }
 
 // PipeOpts has the options for the KrakenD pipe stage

config/lura.go

@@ -35,6 +35,9 @@ func FromLura(srvCfg config.ServiceConfig) (*Config, error) {
 		return nil, err
 	}
 
+	// TODO: we might want to move these defaults to the config.go
+	// file, as is not specific to reading the config from the Lura
+	// config.
 	if cfg.Layers == nil {
 		cfg.Layers = &LayersOpts{}
 	}
@@ -76,6 +79,17 @@ func FromLura(srvCfg config.ServiceConfig) (*Config, error) {
 		}
 	}
 
+	if len(cfg.SkipPaths) == 0 {
+		// if there are no defined skip paths, we use the default ones:
+		// to avoid using defaultSkipPaths, provide a list with an empty string
+		cfg.SkipPaths = []string{
+			"/healthz",
+			"/_ah/health",
+			"/__debug",
+			"/__echo",
+		}
+	}
+
 	if cfg.ServiceName == "" {
 		if srvCfg.Name != "" {
 			cfg.ServiceName = srvCfg.Name

example/make_requests.sh

@@ -1,10 +1,10 @@
 #!/bin/bash
 
 # for i in {1..10}
-for i in {1..2}
+for i in {1..1}
 do
-#    curl localhost:54444/fake/fsf
-#    curl localhost:54444/combination/2
+    curl localhost:54444/fake/fsf
+    curl localhost:54444/combination/2
     curl localhost:54444/combination/1
 done
 

example/server/main.go

@@ -91,20 +91,23 @@ func main() {
 
 	bf := func(backendConfig *config.Backend) proxy.Proxy {
 		reqExec := lura.HTTPRequestExecutorFromConfig(client.NewHTTPClient,
-			backendConfig, obsConfig.Layers.Backend)
+			backendConfig, obsConfig.Layers.Backend, obsConfig.SkipPaths)
 		return proxy.NewHTTPProxyWithHTTPExecutor(backendConfig, reqExec, backendConfig.Decoder)
 	}
+	bf = lura.BackendFactory(bf, state.GlobalState, obsConfig.Layers.Backend, obsConfig.SkipPaths)
 
-	defaultPF := proxy.NewDefaultFactory(lura.BackendFactory(bf, state.GlobalState, obsConfig.Layers.Backend), logger)
-	pf := lura.ProxyFactory(defaultPF, state.GlobalState, obsConfig.Layers.Pipe)
+	defaultPF := proxy.NewDefaultFactory(bf, logger)
+	pf := lura.ProxyFactory(defaultPF, state.GlobalState, obsConfig.Layers.Pipe, obsConfig.SkipPaths)
 
+	handlerF := otelgin.New(krakendgin.EndpointHandler, state.GlobalState,
+		obsConfig.Layers.Router, obsConfig.SkipPaths)
 	// setup the krakend router
 	routerFactory := krakendgin.NewFactory(krakendgin.Config{
 		Engine:         gin.Default(),
 		ProxyFactory:   pf,
 		Middlewares:    []gin.HandlerFunc{},
 		Logger:         logger,
-		HandlerFactory: otelgin.New(krakendgin.EndpointHandler, state.GlobalState, obsConfig.Layers.Router),
+		HandlerFactory: handlerF,
 		RunServer:      server.RunServer,
 	})
 

go.mod

@@ -4,13 +4,16 @@ go 1.20
 
 require (
 	github.com/gin-gonic/gin v1.9.1
-	github.com/luraproject/lura/v2 v2.4.0
+	github.com/luraproject/lura/v2 v2.4.3-0.20240111145738-b6784e5701d8
+	github.com/prometheus/client_golang v1.17.0
 	go.opentelemetry.io/otel v1.21.0
-	go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.21.0
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.21.0
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.21.0
+	go.opentelemetry.io/otel/exporters/prometheus v0.44.0
 	go.opentelemetry.io/otel/metric v1.21.0
+	go.opentelemetry.io/otel/sdk v1.21.0
 	go.opentelemetry.io/otel/sdk/metric v1.21.0
 	go.opentelemetry.io/otel/trace v1.21.0
-	google.golang.org/grpc v1.59.0
 )
 
 require (
@@ -31,36 +34,29 @@ require (
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.16.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.4 // indirect
-	github.com/kr/pretty v0.3.1 // indirect
 	github.com/krakendio/flatmap v1.1.1 // indirect
 	github.com/leodido/go-urn v1.2.4 // indirect
 	github.com/mattn/go-isatty v0.0.19 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/pelletier/go-toml/v2 v2.0.8 // indirect
-	github.com/prometheus/client_golang v1.17.0 // indirect
 	github.com/prometheus/client_model v0.5.0 // indirect
 	github.com/prometheus/common v0.44.0 // indirect
 	github.com/prometheus/procfs v0.11.1 // indirect
-	github.com/rogpeppe/go-internal v1.10.0 // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.2.11 // indirect
 	github.com/valyala/fastrand v1.1.0 // indirect
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.21.0 // indirect
-	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.21.0 // indirect
-	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.21.0 // indirect
-	go.opentelemetry.io/otel/exporters/prometheus v0.44.0 // indirect
-	go.opentelemetry.io/otel/sdk v1.21.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.0.0 // indirect
 	golang.org/x/arch v0.3.0 // indirect
-	golang.org/x/crypto v0.14.0 // indirect
+	golang.org/x/crypto v0.17.0 // indirect
 	golang.org/x/net v0.17.0 // indirect
 	golang.org/x/sys v0.15.0 // indirect
-	golang.org/x/text v0.13.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
 	google.golang.org/genproto/googleapis/api v0.0.0-20230822172742-b8732ec3820d // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20230822172742-b8732ec3820d // indirect
+	google.golang.org/grpc v1.59.0 // indirect
 	google.golang.org/protobuf v1.31.0 // indirect
-	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

lura/backend.go

@@ -34,8 +34,17 @@ var defaultOpts = otelconfig.BackendOpts{
 // HTTPRequestExecutorFromConfig creates an HTTPRequestExecutor to be used
 // for the backend requests.
 func HTTPRequestExecutorFromConfig(clientFactory transport.HTTPClientFactory,
-	cfg *config.Backend, opts *otelconfig.BackendOpts,
+	cfg *config.Backend, opts *otelconfig.BackendOpts, skipPaths []string,
 ) transport.HTTPRequestExecutor {
+
+	for _, sp := range skipPaths {
+		if cfg.ParentEndpoint == sp {
+			// TODO: check if there might be some othe executor that is
+			// not the default one ?
+			return transport.DefaultHTTPRequestExecutor(clientFactory)
+		}
+	}
+
 	if !opts.Enabled() {
 		// no configuration for the backend, then .. no metrics nor tracing:
 		return transport.DefaultHTTPRequestExecutor(clientFactory)

lura/proxy.go

@@ -121,7 +121,9 @@ func Middleware(name string, stage string, gsf state.GetterFn, metricsEnabled bo
 
 // ProxyFactory returns a pipe stage factory that wraps the provided proxy factory with the
 // instrumentation [Middleware] based on the configuration options.
-func ProxyFactory(pf proxy.Factory, gsfn state.GetterFn, opts *kotelconfig.PipeOpts) proxy.FactoryFunc {
+func ProxyFactory(pf proxy.Factory, gsfn state.GetterFn, opts *kotelconfig.PipeOpts,
+	skipPaths []string) proxy.FactoryFunc {
+
 	if opts == nil {
 		return pf.New
 	}
@@ -141,8 +143,13 @@ func ProxyFactory(pf proxy.Factory, gsfn state.GetterFn, opts *kotelconfig.PipeO
 		if err != nil {
 			return next, err
 		}
+		for _, sp := range skipPaths {
+			if cfg.Endpoint == sp {
+				return next, nil
+			}
+		}
 
-		// TODO: check the followint warning:
+		// TODO: check the following warning:
 		// WARNING: this changes how it was working before:
 		// in original opencensus, we prefixed the endpoint with a `pipe` prefix
 		// return Middleware("pipe-" + cfg.Endpoint)(next), nil
@@ -153,7 +160,9 @@ func ProxyFactory(pf proxy.Factory, gsfn state.GetterFn, opts *kotelconfig.PipeO
 
 // BackendFactory returns a backend factory that wraps the provided backend factory with the
 // instrumentation [Middleware] based on the configuration options.
-func BackendFactory(bf proxy.BackendFactory, gsfn state.GetterFn, opts *kotelconfig.BackendOpts) proxy.BackendFactory {
+func BackendFactory(bf proxy.BackendFactory, gsfn state.GetterFn, opts *kotelconfig.BackendOpts,
+	skipPaths []string) proxy.BackendFactory {
+
 	if opts == nil || (opts.Metrics.DisableStage && opts.Traces.DisableStage) {
 		return bf
 	}
@@ -162,6 +171,11 @@ func BackendFactory(bf proxy.BackendFactory, gsfn state.GetterFn, opts *kotelcon
 
 	return func(cfg *config.Backend) proxy.Proxy {
 		next := bf(cfg)
+		for _, sp := range skipPaths {
+			if cfg.ParentEndpoint == sp {
+				return next
+			}
+		}
 		urlPattern := kotelconfig.NormalizeURLPattern(cfg.URLPattern)
 		return Middleware(urlPattern, "backend", gsfn, metricsEnabled, tracesEnabled)(next)
 	}

router/gin/endpoint.go

@@ -17,57 +17,38 @@ import (
 	"github.com/krakend/krakend-otel/state"
 )
 
-var defaultSkipPaths = []string{
-	"/healthz",
-	"/_ah/health",
-	"/__debug",
-	"/__echo",
-}
-
-// defaultRouterOpts return the default options when no options
-// are provided
-func defaultRouterOpts() *kconfig.RouterOpts {
-	return &kconfig.RouterOpts{
-		DisableMetrics:     false,
-		DisableTraces:      false,
-		DisablePropagation: false,
-	}
-}
-
 // New wraps a handler factory adding some simple instrumentation to the generated handlers
-func New(hf krakendgin.HandlerFactory, gsfn state.GetterFn, opts *kconfig.RouterOpts) krakendgin.HandlerFactory {
-	if opts == nil {
-		opts = defaultRouterOpts()
-	}
+func New(hf krakendgin.HandlerFactory, gsfn state.GetterFn,
+	opts *kconfig.RouterOpts, skipPaths []string) krakendgin.HandlerFactory {
+
 	if gsfn == nil {
 		gsfn = state.GlobalState
 	}
 	return func(cfg *config.EndpointConfig, p proxy.Proxy) gin.HandlerFunc {
-		return HandlerFunc(cfg, opts, gsfn, hf(cfg, p))
+		return HandlerFunc(cfg, opts, gsfn, skipPaths, hf(cfg, p))
 	}
 }
 
 // HandlerFunc creates and instrumented gin.Handler wrapper with traces and / or metrics enabled
 // according to the [config.RouterOpts].
-func HandlerFunc(cfg *config.EndpointConfig, opts *kconfig.RouterOpts, gsfn state.GetterFn, next gin.HandlerFunc) gin.HandlerFunc {
-	s := gsfn()
+func HandlerFunc(cfg *config.EndpointConfig, opts *kconfig.RouterOpts, gsfn state.GetterFn,
+	skipPaths []string, next gin.HandlerFunc) gin.HandlerFunc {
 
-	if opts == nil || (opts.DisableMetrics && opts.DisableTraces) {
-		if opts != nil && opts.DisablePropagation {
+	// skip paths will not try to read the propagation header, because nothing
+	// in the downstream pipeline will be instruemented. The header can be passed
+	// using the regular `headers` feature.
+	for _, sp := range skipPaths {
+		if cfg.Endpoint == sp {
 			return next
 		}
-		return PropagationMiddleware(next, s.Propagator())
 	}
 
-	if len(opts.SkipPaths) == 0 {
-		// if there are no defined skip paths, we use the default ones:
-		// to avoid using defaultSkipPaths, provide a list with an empty string
-		opts.SkipPaths = defaultSkipPaths
-	}
-	for _, sp := range opts.SkipPaths {
-		if cfg.Endpoint == sp {
+	s := gsfn()
+	if opts == nil || (opts.DisableMetrics && opts.DisableTraces) {
+		if opts != nil && opts.DisablePropagation {
 			return next
 		}
+		return PropagationMiddleware(next, s.Propagator())
 	}
 
 	// TODO: check that the endpoint path parameters are all standarized;

router/gin/propagation.go

@@ -1,8 +1,6 @@
 package gin
 
 import (
-	"fmt"
-
 	"github.com/gin-gonic/gin"
 	"go.opentelemetry.io/otel/propagation"
 	"go.opentelemetry.io/otel/trace"