[WIP] Add github.com/go-chi/chi instrumentation (#227)

* Initial instrumentation layout

* Add changes to changelog

* Add initial config and instrumentation

The config is mostly copied from
#226

* Implement instrumentation

Remove unneeded Config methods.

* Add integration tests

* Shutdown TracerProvider in tests

* Update Middleware docs

* Fix example test

.github/dependabot.yml

@@ -30,6 +30,14 @@ updates:
     directory: "/instrumentation/github.com/confluentinc/confluent-kafka-go/kafka/splunkkafka/test"
     schedule:
       interval: "daily"
+  - package-ecosystem: "gomod"
+    directory: "/instrumentation/github.com/go-chi/chi/splunkchi"
+    schedule:
+      interval: "daily"
+  - package-ecosystem: "gomod"
+    directory: "/instrumentation/github.com/go-chi/chi/splunkchi/test"
+    schedule:
+      interval: "daily"
   - package-ecosystem: "gomod"
     directory: "/instrumentation/github.com/go-sql-driver/mysql/splunkmysql"
     schedule:

CHANGELOG.md

@@ -43,6 +43,9 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Add the
   `github.com/signalfx/splunk-otel-go/instrumentation/k8s.io/client-go/splunkclient-go`
   instrumentation for the `k8s.io/client-go` package. (#224)
+- Add the
+  `github.com/signalfx/splunk-otel-go/instrumentation/github.com/go-chi/chi/splunkchi`
+  instrumentation for the `github.com/go-chi/chi` package. (#227)
 
 ### Changed
 

README.md

@@ -100,6 +100,7 @@ Supported libraries are listed
 
 Additional recommended Splunk specific instrumentations:
 
+- [`splunkchi`](./instrumentation/github.com/go-chi/chi/splunkchi)
 - [`splunkclient-go`](./instrumentation/k8s.io/client-go/splunkclient-go)
 - [`splunkdns`](./instrumentation/github.com/miekg/dns/splunkdns)
 - [`splunkgorm`](./instrumentation/github.com/jinzhu/gorm/splunkgorm)

instrumentation/github.com/go-chi/chi/splunkchi/README.md

@@ -0,0 +1,10 @@
+# Splunk instrumentation for `github.com/go-chi/chi`
+
+This package provides OpenTelemetry instrumentation for the
+[github.com/go-chi/chi](https://github.com/go-chi/chi) package.
+
+## Getting Started
+
+This package is designed to be used as middleware for the
+`github.com/go-chi/chi` package. See [example_test.go](./example_test.go) for
+more information.

instrumentation/github.com/go-chi/chi/splunkchi/chi.go

@@ -0,0 +1,77 @@
+// Copyright Splunk Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package splunkchi provides OpenTelemetry instrumentation for the
+// github.com/go-chi/chi package.
+package splunkchi
+
+import (
+	"net/http"
+
+	"github.com/go-chi/chi"
+	"github.com/go-chi/chi/middleware"
+	"go.opentelemetry.io/otel/propagation"
+	semconv "go.opentelemetry.io/otel/semconv/v1.7.0"
+	"go.opentelemetry.io/otel/trace"
+
+	"github.com/signalfx/splunk-otel-go/instrumentation/internal"
+)
+
+// instrumentationName is the instrumentation library identifier for a Tracer.
+const instrumentationName = "github.com/signalfx/splunk-otel-go/instrumentation/github.com/go-chi/chi/splunkchi"
+
+// Middleware returns github.com/go-chi/chi middleware that traces served
+// requests.
+func Middleware(options ...Option) func(http.Handler) http.Handler {
+	o := append([]internal.Option{
+		internal.OptionFunc(func(c *internal.Config) {
+			c.DefaultStartOpts = append(c.DefaultStartOpts, trace.WithSpanKind(trace.SpanKindServer))
+		}),
+	}, localToInternal(options)...)
+	cfg := internal.NewConfig(instrumentationName, o...)
+
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			// Allows us to track the ultimate status.
+			ww := middleware.NewWrapResponseWriter(w, r.ProtoMajor)
+
+			tracer := cfg.ResolveTracer(r.Context())
+			carrier := propagation.HeaderCarrier(r.Header)
+			ctx := cfg.Propagator.Extract(r.Context(), carrier)
+			// The full handler chain needs to be complete before we are sure
+			// what path is being requested. Delay full naming and annotation
+			// until then.
+			name := "HTTP " + r.Method
+			ctx, span := tracer.Start(ctx, name, cfg.DefaultStartOpts...)
+			defer span.End()
+			r = r.WithContext(ctx)
+
+			next.ServeHTTP(ww, r)
+
+			path := chi.RouteContext(r.Context()).RoutePattern()
+			attrs := semconv.HTTPServerAttributesFromHTTPRequest("", path, r)
+			attrs = append(attrs, semconv.HTTPAttributesFromHTTPStatusCode(ww.Status())...)
+			attrs = append(attrs, semconv.NetAttributesFromHTTPRequest("tcp", r)...)
+			attrs = append(attrs, semconv.EndUserAttributesFromHTTPRequest(r)...)
+			span.SetAttributes(attrs...)
+
+			if path != "" {
+				span.SetName(name + " " + path)
+			}
+
+			code, desc := semconv.SpanStatusFromHTTPStatusCode(ww.Status())
+			span.SetStatus(code, desc)
+		})
+	}
+}

instrumentation/github.com/go-chi/chi/splunkchi/example_test.go

@@ -0,0 +1,37 @@
+// Copyright Splunk Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package splunkchi_test
+
+import (
+	"net/http"
+
+	"github.com/go-chi/chi"
+
+	"github.com/signalfx/splunk-otel-go/instrumentation/github.com/go-chi/chi/splunkchi"
+)
+
+func Example() {
+	router := chi.NewRouter()
+	router.Use(splunkchi.Middleware())
+	router.Get("/hello", func(w http.ResponseWriter, r *http.Request) {
+		_, err := w.Write([]byte("Hello World!\n"))
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+		}
+	})
+	if err := http.ListenAndServe(":8080", router); err != nil {
+		panic(err)
+	}
+}

instrumentation/github.com/go-chi/chi/splunkchi/go.mod

@@ -0,0 +1,12 @@
+module github.com/signalfx/splunk-otel-go/instrumentation/github.com/go-chi/chi/splunkchi
+
+go 1.16
+
+require (
+	github.com/go-chi/chi v1.5.4
+	github.com/signalfx/splunk-otel-go v0.0.0-00010101000000-000000000000
+	go.opentelemetry.io/otel v1.2.0
+	go.opentelemetry.io/otel/trace v1.2.0
+)
+
+replace github.com/signalfx/splunk-otel-go => ../../../../../

instrumentation/github.com/go-chi/chi/splunkchi/go.sum

@@ -0,0 +1,23 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/go-chi/chi v1.5.4 h1:QHdzF2szwjqVV4wmByUnTcsbIg7UGaQ0tPF2t5GcAIs=
+github.com/go-chi/chi v1.5.4/go.mod h1:uaf8YgoFazUOkPBG7fxPftUylNumIev9awIWOENIuEg=
+github.com/google/go-cmp v0.5.6 h1:BKbKCqvP6I+rmFHt06ZmyQtvB8xAkWdhFyr0ZUNZcxQ=
+github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+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/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+go.opentelemetry.io/contrib/propagators/b3 v1.2.0/go.mod h1:kO8hNKCfa1YmQJ0lM7pzfJGvbXEipn/S7afbOfaw2Kc=
+go.opentelemetry.io/otel v1.2.0 h1:YOQDvxO1FayUcT9MIhJhgMyNO1WqoduiyvQHzGN0kUQ=
+go.opentelemetry.io/otel v1.2.0/go.mod h1:aT17Fk0Z1Nor9e0uisf98LrntPGMnk4frBO9+dkf69I=
+go.opentelemetry.io/otel/exporters/jaeger v1.2.0/go.mod h1:KJLFbEMKTNPIfOxcg/WikIozEoKcPgJRz3Ce1vLlM8E=
+go.opentelemetry.io/otel/sdk v1.2.0/go.mod h1:jNN8QtpvbsKhgaC6V5lHiejMoKD+V8uadoSafgHPx1U=
+go.opentelemetry.io/otel/trace v1.2.0 h1:Ys3iqbqZhcf28hHzrm5WAquMkDHNZTUkw7KHbuNjej0=
+go.opentelemetry.io/otel/trace v1.2.0/go.mod h1:N5FLswTubnxKxOJHM7XZC074qpeEdLy3CgAVsdMucK0=
+golang.org/x/sys v0.0.0-20210423185535-09eb48e85fd7/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

instrumentation/github.com/go-chi/chi/splunkchi/option.go

@@ -0,0 +1,62 @@
+// Copyright Splunk Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package splunkchi
+
+import (
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/trace"
+
+	"github.com/signalfx/splunk-otel-go/instrumentation/internal"
+)
+
+func localToInternal(opts []Option) []internal.Option {
+	out := make([]internal.Option, len(opts))
+	for i, o := range opts {
+		out[i] = internal.OptionFunc(func(c *internal.Config) { o.apply(c) })
+	}
+	return out
+}
+
+// Option applies options to a configuration.
+type Option interface {
+	apply(*internal.Config)
+}
+
+type optionConv struct {
+	iOpt internal.Option
+}
+
+func (o optionConv) apply(c *internal.Config) {
+	o.iOpt.Apply(c)
+}
+
+// WithTracerProvider returns an Option that sets the TracerProvider used for
+// a configuration.
+func WithTracerProvider(tp trace.TracerProvider) Option {
+	return optionConv{iOpt: internal.WithTracerProvider(tp)}
+}
+
+// WithAttributes returns an Option that appends attr to the attributes set
+// for every span created.
+func WithAttributes(attr []attribute.KeyValue) Option {
+	return optionConv{iOpt: internal.WithAttributes(attr)}
+}
+
+// WithPropagator returns an Option that sets p as the TextMapPropagator used
+// when propagating a span context.
+func WithPropagator(p propagation.TextMapPropagator) Option {
+	return optionConv{iOpt: internal.WithPropagator(p)}
+}