Add a key benchmark, use reflection in key.Infer() (#679)

* Add a key benchmark, optimize SDK SetAttribute

* Use reflect in key.Infer

* Move to separate benchmark file; remove pointer test; remove dead comment

* Run go mod tidy

* Add license header

* Use the reflect scalar accessors

Co-authored-by: Liz Fong-Jones <lizf@honeycomb.io>

api/key/benchmark_test.go

@@ -0,0 +1,75 @@
+// Copyright The OpenTelemetry Authors
+//
+// 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 key_test
+
+import (
+	"context"
+	"testing"
+
+	"go.opentelemetry.io/otel/api/global"
+	"go.opentelemetry.io/otel/api/key"
+	"go.opentelemetry.io/otel/api/trace"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+)
+
+// Note: The tests below load a real SDK to ensure the compiler isn't optimizing
+// the test based on global analysis limited to the NoopSpan implementation.
+func getSpan() trace.Span {
+	_, sp := global.Tracer("Test").Start(context.Background(), "Span")
+	tr, _ := sdktrace.NewProvider()
+	global.SetTraceProvider(tr)
+	return sp
+}
+
+func BenchmarkKeyInfer(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		key.Infer("Attr", int(256))
+	}
+}
+
+func BenchmarkMultiNoKeyInference(b *testing.B) {
+	sp := getSpan()
+
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		sp.SetAttributes(key.Int("Attr", 1))
+	}
+}
+
+func BenchmarkMultiWithKeyInference(b *testing.B) {
+	sp := getSpan()
+
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		sp.SetAttributes(key.Infer("Attr", 1))
+	}
+}
+
+func BenchmarkSingleWithKeyInferenceValue(b *testing.B) {
+	sp := getSpan()
+
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		sp.SetAttribute("Attr", 1)
+	}
+
+	b.StopTimer()
+}

api/key/key.go

@@ -16,6 +16,7 @@ package key
 
 import (
 	"fmt"
+	"reflect"
 
 	"go.opentelemetry.io/otel/api/core"
 )
@@ -96,30 +97,37 @@ func Uint(k string, v uint) core.KeyValue {
 // Infer creates a new key-value pair instance with a passed name and
 // automatic type inference. This is slower, and not type-safe.
 func Infer(k string, value interface{}) core.KeyValue {
-	switch v := value.(type) {
-	case bool:
-		return Bool(k, v)
-	case int:
-		return Int(k, v)
-	case uint:
-		return Uint(k, v)
-	case int32:
-		return Int32(k, v)
-	case int64:
-		return Int64(k, v)
-	case uint32:
-		return Uint32(k, v)
-	case uint64:
-		return Uint64(k, v)
-	case float32:
-		return Float32(k, v)
-	case float64:
-		return Float64(k, v)
-	case string:
-		return String(k, v)
-	case fmt.Stringer:
-		return Stringer(k, v)
-	default:
-		return String(k, fmt.Sprint(v))
+	if value == nil {
+		return String(k, "<nil>")
 	}
+
+	if stringer, ok := value.(fmt.Stringer); ok {
+		return String(k, stringer.String())
+	}
+
+	rv := reflect.ValueOf(value)
+
+	switch rv.Kind() {
+	case reflect.Bool:
+		return Bool(k, rv.Bool())
+	case reflect.Int, reflect.Int8, reflect.Int16:
+		return Int(k, int(rv.Int()))
+	case reflect.Int32:
+		return Int32(k, int32(rv.Int()))
+	case reflect.Int64:
+		return Int64(k, int64(rv.Int()))
+	case reflect.Uint, reflect.Uint8, reflect.Uint16:
+		return Uint(k, uint(rv.Uint()))
+	case reflect.Uint32:
+		return Uint32(k, uint32(rv.Uint()))
+	case reflect.Uint64, reflect.Uintptr:
+		return Uint64(k, rv.Uint())
+	case reflect.Float32:
+		return Float32(k, float32(rv.Float()))
+	case reflect.Float64:
+		return Float64(k, rv.Float())
+	case reflect.String:
+		return String(k, rv.Interface().(string))
+	}
+	return String(k, fmt.Sprint(rv.Interface()))
 }

exporters/trace/zipkin/go.sum

@@ -1,8 +1,10 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/DataDog/sketches-go v0.0.0-20190923095040-43f19ad77ff7 h1:qELHH0AWCvf98Yf+CNIJx9vOZOfHFDDzgDRYsnNk/vs=
 github.com/DataDog/sketches-go v0.0.0-20190923095040-43f19ad77ff7/go.mod h1:Q5DbzQ+3AkgGwymQO7aZFNP7ns2lZKGtvRBzRXfdi60=
 github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
 github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
+github.com/benbjohnson/clock v1.0.0 h1:78Jk/r6m4wCi6sndMpty7A//t4dw/RW5fV4ZgDVfX1w=
 github.com/benbjohnson/clock v1.0.0/go.mod h1:bGMdMPoPVvcYyt1gHDf4J2KE153Yf9BuiUKYMaxlTDM=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
@@ -27,6 +29,7 @@ github.com/golang/snappy v0.0.0-20180518054509-2e65f85255db/go.mod h1:/XxbfmMg8l
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
 github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/gofuzz v1.0.0 h1:A8PeW59pxE9IoFRqBp37U+mSNaQoZ46F1f0f863XSXw=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/gorilla/context v1.1.1/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51q0aT7Yg=
 github.com/gorilla/mux v1.6.2/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=