added OTEL support. Major refactoring

README.md

@@ -14,6 +14,7 @@ Logging & tracing utilities for micro services.
 Based on:
 * `go.uber.org/zap`
 * `go.opencensus.io/trace`
+* `go.opentelemetry.io/otel`
 
 Tested to be compatible wih Datadog tracing.
 
@@ -30,6 +31,8 @@ TODOs:
 
 ### Usage
 
+With OpenCensus tracing.
+
 ```go
 import (
     "context"
@@ -53,19 +56,48 @@ func tracedFunc() {
 }
 ```
 
+With OpenTelemetry tracing.
+
+```go
+import (
+    "context"
+
+    "github.com/fredbi/go-trace/log"
+	"go.opentelemetry.io/otel"
+)
+
+
+func tracedFunc() {
+    tracer := otel.Tracer("") // returns the global default tracer
+    ctx := context.Background()
+    zlg, closer := log.MustGetLogger("root")
+    defer closer()
+
+    lgf := log.NewFactory(zlg) // builds a logger with trace propagation
+
+    ctx, span := tracer.Start(ctx, "span name")
+    defer span.End()
+    lg := lgf.For(ctx)
+
+    lg.Info("log propagated as a trace span")
+}
+```
+
 [Full example](https://github.com/fredbi/go-trace/blob/master/log/examples_test.go)
 
 ## Tracing
 
-Simple utilities to instrument tracing inside apps with minimal boiler-plate.
+A simple wrapper to instrument tracing in apps with minimal boiler-plate.
+
 
+With OpenCensus tracing.
 
 ```go
 import (
     "context"
 
     "github.com/fredbi/go-trace/log"
-    "github.com/fredbi/go-trace/trace"
+    "github.com/fredbi/go-trace/opencensus/tracer"
 )
 
 type loggable struct {
@@ -88,21 +120,62 @@ func tracedFunc() {
 }
 ```
 
-[Full example](https://github.com/fredbi/go-trace/blob/master/tracer/example_test.go)
+[Full example](https://github.com/fredbi/go-trace/blob/master/opencensus/tracer/example_test.go)
+
+With OpenTelemetry tracing.
+
+```go
+import (
+    "context"
+
+    "github.com/fredbi/go-trace/log"
+    "github.com/fredbi/go-trace/otel/tracer"
+)
+
+type loggable struct {
+    lgf log.Factory
+    tracer trace.Tracer
+}
+
+func (l *loggable) Logger() log.Factory {
+    return l.lgf
+}
+
+// Tracer returns the configured tracer. If this method, is not provided,
+// the default globally registered OTEL tracer is returned.
+func (l *loggable) Tracer() trace.Tracer {
+    return l.tracer 
+}
+
+func tracedFunc() {
+    zlg := log.MustGetLogger("root") // builds a named zap logger with sensible defaults
+    lgf := log.NewFactory(zlg, log.WithOTEL(true)) // builds a logger with trace propagation
+    component := loggable{lfg:  lgf}
+
+    ctx, span, lg := tracer.StartSpan(context.Background(), component) // the span is named automatically from the calling function
+    defer span.End()
+
+    lg.Info("log propagated as a trace span")
+}
+```
+
+[Full example](https://github.com/fredbi/go-trace/blob/master/otel/tracer/example_test.go)
 
 ## Middleware
 
 * `middleware.LogRequests` logs all requests from a http server, using the logger factory
-* `middleware.OCHTTP` wraps the `ochttp` opencensus plugin into a more convenient middleware function.
+
+* `opencensus/middleware.OCHTTP` wraps the `ochttp` opencensus plugin into a more convenient middleware function.
+* `otel/middleware.OTELHTTP` wraps the `otelhttp` OTEL contrib plugin.
 
 ## Exporters
 
-Various opencensus exporters (as a separate module).
-* influxdb: export opencensus metrics to an influxdb sink
-* amplitude (experimental): propagate trace event to the amplitude API
+Mock trace exporters for opencensus and OTEL.
 
-TODOs:
-* [] opentelemetry/opentracing
+## Misc
+Various opencensus exporters (as a separate module).
+* misc/influxdb: export opencensus metrics to an influxdb sink
+* misc/amplitude (experimental): propagate trace event to the amplitude API
 
 ## Credits
 

go.mod

@@ -6,17 +6,26 @@ require (
 	github.com/felixge/httpsnoop v1.0.4
 	github.com/stretchr/testify v1.8.4
 	go.opencensus.io v0.24.0
+	go.opentelemetry.io/otel v1.21.0
+	go.opentelemetry.io/otel/trace v1.21.0
 	go.uber.org/zap v1.26.0
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
+	github.com/go-logr/logr v1.3.0 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
-	github.com/google/go-cmp v0.5.9 // indirect
-	github.com/kr/pretty v0.3.0 // indirect
+	github.com/kr/pretty v0.3.1 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+	github.com/rogpeppe/go-internal v1.10.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.46.1 // indirect
+	go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.21.0 // indirect
+	go.opentelemetry.io/otel/metric v1.21.0 // indirect
+	go.opentelemetry.io/otel/sdk v1.21.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/net v0.17.0 // indirect
-	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
+	golang.org/x/sys v0.14.0 // indirect
+	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -14,6 +14,11 @@ github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1m
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
 github.com/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
 github.com/felixge/httpsnoop v1.0.4/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
+github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
+github.com/go-logr/logr v1.3.0 h1:2y3SDp0ZXuc6/cjLSZ+Q3ir+QB9T/iG5yYRXqsagWSY=
+github.com/go-logr/logr v1.3.0/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/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
 github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da h1:oI5xCqsCo564l8iNU+DwB5epxmsaqB+rhGL0m5jtYqE=
@@ -34,22 +39,24 @@ github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMyw
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.3/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
-github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
-github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
-github.com/kr/pretty v0.3.0 h1:WgNl7dwNpEZ6jJ9k1snq4pZsg7DOEN8hP9Xw0Tsjwk0=
-github.com/kr/pretty v0.3.0/go.mod h1:640gp4NfQd8pI5XOwp5fnNeVWj67G7CFk/SaSQn7NBk=
+github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
+github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
+github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
-github.com/rogpeppe/go-internal v1.6.1 h1:/FiVV8dS/e+YqF2JvO3yXRFbBLTIuSDkuC7aBOAvL+k=
-github.com/rogpeppe/go-internal v1.6.1/go.mod h1:xXDCJY+GAPziupqXw64V24skbSoqbTEfhy4qGm1nDQc=
+github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
+github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
+github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
@@ -60,6 +67,18 @@ github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcU
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 go.opencensus.io v0.24.0 h1:y73uSU6J157QMP2kn2r30vwW1A2W2WFwSCGnAVxeaD0=
 go.opencensus.io v0.24.0/go.mod h1:vNK8G9p7aAivkbmorf4v+7Hgx+Zs0yY+0fOtgBfjQKo=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.46.1 h1:aFJWCqJMNjENlcleuuOkGAPH82y0yULBScfXcIEdS24=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.46.1/go.mod h1:sEGXWArGqc3tVa+ekntsN65DmVbVeW+7lTKTjZF3/Fo=
+go.opentelemetry.io/otel v1.21.0 h1:hzLeKBZEL7Okw2mGzZ0cc4k/A7Fta0uoPgaJCr8fsFc=
+go.opentelemetry.io/otel v1.21.0/go.mod h1:QZzNPQPm1zLX4gZK4cMi+71eaorMSGT3A4znnUvNNEo=
+go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.21.0 h1:VhlEQAPp9R1ktYfrPk5SOryw1e9LDDTZCbIPFrho0ec=
+go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.21.0/go.mod h1:kB3ufRbfU+CQ4MlUcqtW8Z7YEOBeK2DJ6CmR5rYYF3E=
+go.opentelemetry.io/otel/metric v1.21.0 h1:tlYWfeo+Bocx5kLEloTjbcDwBuELRrIFxwdQ36PlJu4=
+go.opentelemetry.io/otel/metric v1.21.0/go.mod h1:o1p3CA8nNHW8j5yuQLdc1eeqEaPfzug24uvsyIEJRWM=
+go.opentelemetry.io/otel/sdk v1.21.0 h1:FTt8qirL1EysG6sTQRZ5TokkU8d0ugCj8htOgThZXQ8=
+go.opentelemetry.io/otel/sdk v1.21.0/go.mod h1:Nna6Yv7PWTdgJHVRD9hIYywQBRx7pbox6nwBnZIxl/E=
+go.opentelemetry.io/otel/trace v1.21.0 h1:WD9i5gzvoUPuXIXH24ZNBudiarZDKuekPqi/E8fpfLc=
+go.opentelemetry.io/otel/trace v1.21.0/go.mod h1:LGbsEB0f9LGjN+OZaQQ26sohbOmiMR+BaslueVtS/qQ=
 go.uber.org/goleak v1.2.0 h1:xqgm/S+aQvhWFTtR0XK3Jvg7z8kGV8P4X14IzwN3Eqk=
 go.uber.org/goleak v1.2.0/go.mod h1:XJYK+MuIchqpmGmUSAzotztawfKvYLUIgg7guXrwVUo=
 go.uber.org/multierr v1.11.0 h1:blXXJkSxSSfBVBlC76pxqeO+LN3aDfLQo+309xJstO0=
@@ -88,6 +107,8 @@ golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.14.0 h1:Vz7Qs629MkJkGyHxUlRHizWJRG2j8fbQKjELVSNhy7Q=
+golang.org/x/sys v0.14.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.13.0 h1:ablQoSUd0tRdKxZewP80B+BaqeKJuVhuRxj/dkrun3k=
@@ -118,10 +139,8 @@ google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2
 google.golang.org/protobuf v1.23.1-0.20200526195155-81db48ad09cc/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
 google.golang.org/protobuf v1.25.0/go.mod h1:9JNX74DMeImyA3h4bdi1ymwjUzf21/xIlbajtzgsN7c=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
-gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/itracer/globals.go

@@ -0,0 +1,26 @@
+package itracer
+
+import (
+	"sync"
+)
+
+var (
+	prefixLock sync.Mutex
+	prefix     = "function"
+)
+
+// RegisterPrefix sets a package level tracer prefix at initialization time.
+//
+// This is used as the key in structured logs to hold the signature of the trace.
+//
+// The default value is "function", so a log entry looks like:
+//
+//	2023-11-01T17:19:58.615+0100	INFO	tracer/example_test.go:33	test	{
+//		"function": "tracer_test.ExampleStartSpan",
+//		"field": "fred"
+//		}
+func RegisterPrefix(custom string) {
+	prefixLock.Lock()
+	prefix = custom
+	prefixLock.Unlock()
+}

internal/itracer/globals_test.go

@@ -0,0 +1,35 @@
+package itracer
+
+import (
+	"sync"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestRegisterPrefix(t *testing.T) {
+	const before = "function"
+	t.Cleanup(func() {
+		RegisterPrefix(before)
+	})
+
+	// ... but still want to demonstrate that the registration is goroutine-safe
+	require.NotPanics(t, func() {
+		var wg sync.WaitGroup
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			RegisterPrefix("x")
+		}()
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			RegisterPrefix("y")
+		}()
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			RegisterPrefix("z")
+		}()
+	})
+}

internal/itracer/signature.go

@@ -0,0 +1,27 @@
+package itracer
+
+import (
+	"path"
+	"runtime"
+
+	"go.uber.org/zap"
+)
+
+// SignedFields prepends a slice of zap.Fields with a signature string
+func SignedFields(signature string, fields []zap.Field) []zap.Field {
+	signedFields := make([]zap.Field, 0, len(fields)+1)
+	signedFields = append(signedFields, zap.String(prefix, signature))
+	signedFields = append(signedFields, fields...)
+
+	return signedFields
+}
+
+// Signature returns the function name of the caller.
+func Signature() string {
+	pc, _, _, ok := runtime.Caller(2)
+	if ok {
+		return path.Base(runtime.FuncForPC(pc).Name())
+	}
+
+	return ""
+}

log/doc.go

@@ -1,2 +1,6 @@
 // Package log exposes logging utilities based on go.uber.org/zap.
+//
+// Opencensus tracing:
+//
+// Open Telemetry tracing:
 package log