feat(otel): add NewMetricsHook, use api interface instead of SDK type (…

…#530)

Signed-off-by: Igor Morozov <morozov.ig.s@gmail.com>

hooks/open-telemetry/README.md

@@ -15,14 +15,31 @@ This hook performs metric collection by tapping into various hook stages. Given
 - `feature_flag.evaluation_error_total`
 - `feature_flag.evaluation_active_count`
 
-Consider example below for usage,
+There are two ways to create hooks:
+
+### Using Global MeterProvider
+
+Global provider should be set somewhere using `otel.SetMeterProvider` before calling this constructor.
+
+```go
+// Derive metric hook from reader
+metricsHook, err := hooks.NewMetricsHook()
+if err != nil {
+    return err
+}
+
+// Register OpenFeature API level hooks
+openfeature.AddHooks(metricsHook)
+```
+
+### Passing MeterProvider to Constructor
 
 ```go
 // provider must be configured and provided to constructor based on application configurations
 var provider *metric.MeterProvider
-        
+
 // Derive metric hook from reader
-metricsHook, _ := hooks.NewMetricsHookForProvider(provider)
+metricsHook, err := hooks.NewMetricsHookForProvider(provider)
 if err != nil {
     return err
 }
@@ -44,15 +61,15 @@ NewMetricsHookForProvider(provider,
     WithMetricsAttributeSetter(
     func(metadata openfeature.FlagMetadata) []attribute.KeyValue {
 		// custom attribute extraction logic
-		
+
         return attributes
     }))
 ```
 
-#### WithFlagMetadataDimensions 
+#### WithFlagMetadataDimensions
 
-This constructor option allows to configure dimension descriptions to be extracted from `openfeature.FlagMetadata`. 
-If present, these dimension will be added to the `feature_flag.evaluation_success_total` metric. 
+This constructor option allows to configure dimension descriptions to be extracted from `openfeature.FlagMetadata`.
+If present, these dimension will be added to the `feature_flag.evaluation_success_total` metric.
 Missing metadata keys will be ignored by the implementation.
 
 ```go
@@ -100,7 +117,7 @@ These attributes are added at the `After` stage of the hook.
 NewTracesHook(WithMetricsAttributeSetter(
     func(metadata openfeature.FlagMetadata) []attribute.KeyValue {
 		// custom attribute extraction logic
-		
+
         return attributes
     }))
-```
+```

hooks/open-telemetry/go.sum

@@ -9,42 +9,24 @@ github.com/golang/mock v1.6.0 h1:ErTB+efbowRARo13NNdxyJji2egdxLGQhRaY+DUumQc=
 github.com/golang/mock v1.6.0/go.mod h1:p6yTPP+5HYm5mzsMV8JkE6ZKdX+/wYM6Hr+LicevLPs=
 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/open-feature/go-sdk v1.9.0 h1:1Nyj+XNHfL0rRGZgGCbZ29CHDD57PQJL7Q/2ZbW/E8c=
-github.com/open-feature/go-sdk v1.9.0/go.mod h1:n5BM4DfvIiKaWWquZnL/yVihcGM5aLsz7rNYE3BkXAM=
-github.com/open-feature/go-sdk v1.10.0 h1:druQtYOrN+gyz3rMsXp0F2jW1oBXJb0V26PVQnUGLbM=
-github.com/open-feature/go-sdk v1.10.0/go.mod h1:+rkJhLBtYsJ5PZNddAgFILhRAAxwrJ32aU7UEUm4zQI=
 github.com/open-feature/go-sdk v1.11.0 h1:4cp9rXl16ZvlMCef7O+I3vQSXae8DzAF0SfV9mvYInw=
 github.com/open-feature/go-sdk v1.11.0/go.mod h1:+rkJhLBtYsJ5PZNddAgFILhRAAxwrJ32aU7UEUm4zQI=
 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/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
-github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
-go.opentelemetry.io/otel v1.22.0 h1:xS7Ku+7yTFvDfDraDIJVpw7XPyuHlB9MCiqqX5mcJ6Y=
-go.opentelemetry.io/otel v1.22.0/go.mod h1:eoV4iAi3Ea8LkAEI9+GFT44O6T/D0GWAVFyZVCC6pMI=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 go.opentelemetry.io/otel v1.25.0 h1:gldB5FfhRl7OJQbUHt/8s0a7cE8fbsPAtdpRaApKy4k=
 go.opentelemetry.io/otel v1.25.0/go.mod h1:Wa2ds5NOXEMkCmUou1WA7ZBfLTHWIsp034OVD7AO+Vg=
-go.opentelemetry.io/otel/metric v1.22.0 h1:lypMQnGyJYeuYPhOM/bgjbFM6WE44W1/T45er4d8Hhg=
-go.opentelemetry.io/otel/metric v1.22.0/go.mod h1:evJGjVpZv0mQ5QBRJoBF64yMuOf4xCWdXjK8pzFvliY=
 go.opentelemetry.io/otel/metric v1.25.0 h1:LUKbS7ArpFL/I2jJHdJcqMGxkRdxpPHE0VU/D4NuEwA=
 go.opentelemetry.io/otel/metric v1.25.0/go.mod h1:rkDLUSd2lC5lq2dFNrX9LGAbINP5B7WBkC78RXCpH5s=
-go.opentelemetry.io/otel/sdk v1.22.0 h1:6coWHw9xw7EfClIC/+O31R8IY3/+EiRFHevmHafB2Gw=
-go.opentelemetry.io/otel/sdk v1.22.0/go.mod h1:iu7luyVGYovrRpe2fmj3CVKouQNdTOkxtLzPvPz1DOc=
 go.opentelemetry.io/otel/sdk v1.25.0 h1:PDryEJPC8YJZQSyLY5eqLeafHtG+X7FWnf3aXMtxbqo=
 go.opentelemetry.io/otel/sdk v1.25.0/go.mod h1:oFgzCM2zdsxKzz6zwpTZYLLQsFwc+K0daArPdIhuxkw=
-go.opentelemetry.io/otel/sdk/metric v1.22.0 h1:ARrRetm1HCVxq0cbnaZQlfwODYJHo3gFL8Z3tSmHBcI=
-go.opentelemetry.io/otel/sdk/metric v1.22.0/go.mod h1:KjQGeMIDlBNEOo6HvjhxIec1p/69/kULDcp4gr0oLQQ=
 go.opentelemetry.io/otel/sdk/metric v1.25.0 h1:7CiHOy08LbrxMAp4vWpbiPcklunUshVpAvGBrdDRlGw=
 go.opentelemetry.io/otel/sdk/metric v1.25.0/go.mod h1:LzwoKptdbBBdYfvtGCzGwk6GWMA3aUzBOwtQpR6Nz7o=
-go.opentelemetry.io/otel/trace v1.22.0 h1:Hg6pPujv0XG9QaVbGOBVHunyuLcCC3jN7WEhPx83XD0=
-go.opentelemetry.io/otel/trace v1.22.0/go.mod h1:RbbHXVqKES9QhzZq/fE5UnOSILqRt40a21sPw2He1xo=
 go.opentelemetry.io/otel/trace v1.25.0 h1:tqukZGLwQYRIFtSQM2u2+yfMVTgGVeqRLPUYx1Dq6RM=
 go.opentelemetry.io/otel/trace v1.25.0/go.mod h1:hCCs70XM/ljO+BeQkyFnbK28SBIJ/Emuha+ccrCRT7I=
-golang.org/x/exp v0.0.0-20230811145659-89c5cff77bcb h1:mIKbk8weKhSeLH2GmUTrvx8CjkyJmnU1wFmg59CUjFA=
-golang.org/x/exp v0.0.0-20230811145659-89c5cff77bcb/go.mod h1:FXUEEKJgO7OQYeo8N01OfiKP8RXMtf6e8aTskBGqWdc=
 golang.org/x/exp v0.0.0-20240205201215-2c58cdc269a3 h1:/RIbNt/Zr7rVhIkQhooTxCxFcdWLGIKnZA4IXNFSrvo=
 golang.org/x/exp v0.0.0-20240205201215-2c58cdc269a3/go.mod h1:idGWGoKP1toJGkd5/ig9ZLuPcZBC3ewk7SzmH0uou08=
-golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
-golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.18.0 h1:DBdB3niSjOA/O0blCZBqDefyWNYveAYMNF1Wum0DYQ4=
 golang.org/x/sys v0.18.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=

hooks/open-telemetry/pkg/metrics.go

@@ -2,10 +2,11 @@ package otel
 
 import (
 	"context"
+
 	"github.com/open-feature/go-sdk/openfeature"
+	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	api "go.opentelemetry.io/otel/metric"
-	"go.opentelemetry.io/otel/sdk/metric"
 	semconv "go.opentelemetry.io/otel/semconv/v1.18.0"
 )
 
@@ -30,8 +31,14 @@ type MetricsHook struct {
 
 var _ openfeature.Hook = &MetricsHook{}
 
+// NewMetricsHook builds a metric hook backed by a globally set metric.MeterProvider.
+// Use otel.SetMeterProvider to set the global provider or use NewMetricsHookForProvider.
+func NewMetricsHook(opts ...MetricOptions) (*MetricsHook, error) {
+	return NewMetricsHookForProvider(otel.GetMeterProvider(), opts...)
+}
+
 // NewMetricsHookForProvider builds a metric hook backed by metric.MeterProvider.
-func NewMetricsHookForProvider(provider *metric.MeterProvider, opts ...MetricOptions) (*MetricsHook, error) {
+func NewMetricsHookForProvider(provider api.MeterProvider, opts ...MetricOptions) (*MetricsHook, error) {
 	meter := provider.Meter(meterName)
 
 	activeCounter, err := meter.Int64UpDownCounter(evaluationActive, api.WithDescription("active flag evaluations counter"))