Deprecate Array attribute in favor of *Slice types (#2162)

* Deprecate Array attribute in favor of *Slice types

* Use new attr types in Jaeger exporter

* Use slice attr types in otlpmetric

* Use slice attr types in otlptrace

* Use slice attr types in zipkin exporter

* Remove array attr test from deprectated oteltest func

* Use StringSlice for cmd arg resource attr

* Add changes to the changelog

* Remove use of deprecated Array func

CHANGELOG.md

@@ -11,6 +11,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 ### Added
 
 - Added `ErrorHandlerFunc` to use a function as an `"go.opentelemetry.io/otel".ErrorHandler`. (#2149)
+- Added typed slice attribute types and functionality to the `go.opentelemetry.io/otel/attribute` package to replace the existing array type and functions. (#2162)
+  - `BoolSlice`, `IntSlice`, `Int64Slice`, `Float64Slice`, and `StringSlice` replace the use of the `Array` function in the package.
 
 ### Changed
 
@@ -21,6 +23,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - The `go.opentelemetry.io/otel/bridge/opencensus/utils` package is deprecated.
   All functionality from this package now exists in the `go.opentelemetry.io/otel/bridge/opencensus` package.
   The functions from that package should be used instead. (#2166)
+- The `"go.opentelemetry.io/otel/attribute".Array` function and the related `ARRAY` value type is deprecated.
+  Use the typed `*Slice` functions and types added to the package instead. (#2162)
 
 ### Removed
 

attribute/benchmark_test.go

@@ -27,9 +27,13 @@ var (
 	outKV attribute.KeyValue
 
 	outBool         bool
+	outBoolSlice    []bool
 	outInt64        int64
+	outInt64Slice   []int64
 	outFloat64      float64
+	outFloat64Slice []float64
 	outStr          string
+	outStrSlice     []string
 )
 
 func benchmarkAny(k string, v interface{}) func(*testing.B) {
@@ -91,6 +95,32 @@ func BenchmarkBool(b *testing.B) {
 	b.Run("Array", benchmarkArray(k, array))
 }
 
+func BenchmarkBoolSlice(b *testing.B) {
+	k, v := "bool slice", []bool{true, false, true}
+	kv := attribute.BoolSlice(k, v)
+
+	b.Run("Value", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outV = attribute.BoolSliceValue(v)
+		}
+	})
+	b.Run("KeyValue", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outKV = attribute.BoolSlice(k, v)
+		}
+	})
+	b.Run("AsBoolSlice", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outBoolSlice = kv.Value.AsBoolSlice()
+		}
+	})
+	b.Run("Any", benchmarkAny(k, v))
+	b.Run("Emit", benchmarkEmit(kv))
+}
+
 func BenchmarkInt(b *testing.B) {
 	k, v := "int", int(42)
 	kv := attribute.Int(k, v)
@@ -113,6 +143,26 @@ func BenchmarkInt(b *testing.B) {
 	b.Run("Array", benchmarkArray(k, array))
 }
 
+func BenchmarkIntSlice(b *testing.B) {
+	k, v := "int slice", []int{42, -3, 12}
+	kv := attribute.IntSlice(k, v)
+
+	b.Run("Value", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outV = attribute.IntSliceValue(v)
+		}
+	})
+	b.Run("KeyValue", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outKV = attribute.IntSlice(k, v)
+		}
+	})
+	b.Run("Any", benchmarkAny(k, v))
+	b.Run("Emit", benchmarkEmit(kv))
+}
+
 func BenchmarkInt8(b *testing.B) {
 	b.Run("Any", benchmarkAny("int8", int8(42)))
 }
@@ -153,6 +203,32 @@ func BenchmarkInt64(b *testing.B) {
 	b.Run("Array", benchmarkArray(k, array))
 }
 
+func BenchmarkInt64Slice(b *testing.B) {
+	k, v := "int64 slice", []int64{42, -3, 12}
+	kv := attribute.Int64Slice(k, v)
+
+	b.Run("Value", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outV = attribute.Int64SliceValue(v)
+		}
+	})
+	b.Run("KeyValue", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outKV = attribute.Int64Slice(k, v)
+		}
+	})
+	b.Run("AsInt64Slice", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outInt64Slice = kv.Value.AsInt64Slice()
+		}
+	})
+	b.Run("Any", benchmarkAny(k, v))
+	b.Run("Emit", benchmarkEmit(kv))
+}
+
 func BenchmarkFloat64(b *testing.B) {
 	k, v := "float64", float64(42)
 	kv := attribute.Float64(k, v)
@@ -181,6 +257,32 @@ func BenchmarkFloat64(b *testing.B) {
 	b.Run("Array", benchmarkArray(k, array))
 }
 
+func BenchmarkFloat64Slice(b *testing.B) {
+	k, v := "float64 slice", []float64{42, -3, 12}
+	kv := attribute.Float64Slice(k, v)
+
+	b.Run("Value", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outV = attribute.Float64SliceValue(v)
+		}
+	})
+	b.Run("KeyValue", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outKV = attribute.Float64Slice(k, v)
+		}
+	})
+	b.Run("AsFloat64Slice", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outFloat64Slice = kv.Value.AsFloat64Slice()
+		}
+	})
+	b.Run("Any", benchmarkAny(k, v))
+	b.Run("Emit", benchmarkEmit(kv))
+}
+
 func BenchmarkString(b *testing.B) {
 	k, v := "string", "42"
 	kv := attribute.String(k, v)
@@ -209,12 +311,32 @@ func BenchmarkString(b *testing.B) {
 	b.Run("Array", benchmarkArray(k, array))
 }
 
+func BenchmarkStringSlice(b *testing.B) {
+	k, v := "float64 slice", []string{"forty-two", "negative three", "twelve"}
+	kv := attribute.StringSlice(k, v)
+
+	b.Run("Value", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outV = attribute.StringSliceValue(v)
+		}
+	})
+	b.Run("KeyValue", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outKV = attribute.StringSlice(k, v)
+		}
+	})
+	b.Run("AsStringSlice", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			outStrSlice = kv.Value.AsStringSlice()
+		}
+	})
+	b.Run("Any", benchmarkAny(k, v))
+	b.Run("Emit", benchmarkEmit(kv))
+}
+
 func BenchmarkBytes(b *testing.B) {
 	b.Run("Any", benchmarkAny("bytes", []byte("bytes")))
 }
-
-type test struct{}
-
-func BenchmarkStruct(b *testing.B) {
-	b.Run("Any", benchmarkAny("struct", test{}))
-}

attribute/key.go

@@ -29,6 +29,17 @@ func (k Key) Bool(v bool) KeyValue {
 	}
 }
 
+// BoolSlice creates a KeyValue instance with a BOOLSLICE Value.
+//
+// If creating both a key and value at the same time, use the provided
+// convenience function instead -- BoolSlice(name, value).
+func (k Key) BoolSlice(v []bool) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: BoolSliceValue(v),
+	}
+}
+
 // Int creates a KeyValue instance with an INT64 Value.
 //
 // If creating both a key and value at the same time, use the provided
@@ -40,6 +51,17 @@ func (k Key) Int(v int) KeyValue {
 	}
 }
 
+// IntSlice creates a KeyValue instance with an INT64SLICE Value.
+//
+// If creating both a key and value at the same time, use the provided
+// convenience function instead -- IntSlice(name, value).
+func (k Key) IntSlice(v []int) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: IntSliceValue(v),
+	}
+}
+
 // Int64 creates a KeyValue instance with an INT64 Value.
 //
 // If creating both a key and value at the same time, use the provided
@@ -51,6 +73,17 @@ func (k Key) Int64(v int64) KeyValue {
 	}
 }
 
+// Int64Slice creates a KeyValue instance with an INT64SLICE Value.
+//
+// If creating both a key and value at the same time, use the provided
+// convenience function instead -- Int64Slice(name, value).
+func (k Key) Int64Slice(v []int64) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: Int64SliceValue(v),
+	}
+}
+
 // Float64 creates a KeyValue instance with a FLOAT64 Value.
 //
 // If creating both a key and value at the same time, use the provided
@@ -62,6 +95,17 @@ func (k Key) Float64(v float64) KeyValue {
 	}
 }
 
+// Float64Slice creates a KeyValue instance with a FLOAT64SLICE Value.
+//
+// If creating both a key and value at the same time, use the provided
+// convenience function instead -- Float64(name, value).
+func (k Key) Float64Slice(v []float64) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: Float64SliceValue(v),
+	}
+}
+
 // String creates a KeyValue instance with a STRING Value.
 //
 // If creating both a key and value at the same time, use the provided
@@ -73,10 +117,23 @@ func (k Key) String(v string) KeyValue {
 	}
 }
 
+// StringSlice creates a KeyValue instance with a STRINGSLICE Value.
+//
+// If creating both a key and value at the same time, use the provided
+// convenience function instead -- StringSlice(name, value).
+func (k Key) StringSlice(v []string) KeyValue {
+	return KeyValue{
+		Key:   k,
+		Value: StringSliceValue(v),
+	}
+}
+
 // Array creates a KeyValue instance with an ARRAY Value.
 //
 // If creating both a key and value at the same time, use the provided
 // convenience function instead -- Array(name, value).
+//
+// Deprecated: Use the typed *Slice methods instead.
 func (k Key) Array(v interface{}) KeyValue {
 	return KeyValue{
 		Key:   k,

attribute/kv.go

@@ -36,26 +36,51 @@ func Bool(k string, v bool) KeyValue {
 	return Key(k).Bool(v)
 }
 
+// BoolSlice creates a KeyValue with a BOOLSLICE Value type.
+func BoolSlice(k string, v []bool) KeyValue {
+	return Key(k).BoolSlice(v)
+}
+
 // Int creates a KeyValue with an INT64 Value type.
 func Int(k string, v int) KeyValue {
 	return Key(k).Int(v)
 }
 
-// Int64 creates a KeyValue with a INT64 Value type.
+// IntSlice creates a KeyValue with an INT64SLICE Value type.
+func IntSlice(k string, v []int) KeyValue {
+	return Key(k).IntSlice(v)
+}
+
+// Int64 creates a KeyValue with an INT64 Value type.
 func Int64(k string, v int64) KeyValue {
 	return Key(k).Int64(v)
 }
 
+// Int64Slice creates a KeyValue with an INT64SLICE Value type.
+func Int64Slice(k string, v []int64) KeyValue {
+	return Key(k).Int64Slice(v)
+}
+
 // Float64 creates a KeyValue with a FLOAT64 Value type.
 func Float64(k string, v float64) KeyValue {
 	return Key(k).Float64(v)
 }
 
+// Float64Slice creates a KeyValue with a FLOAT64SLICE Value type.
+func Float64Slice(k string, v []float64) KeyValue {
+	return Key(k).Float64Slice(v)
+}
+
 // String creates a KeyValue with a STRING Value type.
 func String(k, v string) KeyValue {
 	return Key(k).String(v)
 }
 
+// StringSlice creates a KeyValue with a STRINGSLICE Value type.
+func StringSlice(k string, v []string) KeyValue {
+	return Key(k).StringSlice(v)
+}
+
 // Stringer creates a new key-value pair with a passed name and a string
 // value generated by the passed Stringer interface.
 func Stringer(k string, v fmt.Stringer) KeyValue {
@@ -64,6 +89,8 @@ func Stringer(k string, v fmt.Stringer) KeyValue {
 
 // Array creates a new key-value pair with a passed name and a array.
 // Only arrays of primitive type are supported.
+//
+// Deprecated: Use the typed *Slice functions instead.
 func Array(k string, v interface{}) KeyValue {
 	return Key(k).Array(v)
 }
@@ -82,8 +109,24 @@ func Any(k string, value interface{}) KeyValue {
 	rv := reflect.ValueOf(value)
 
 	switch rv.Kind() {
-	case reflect.Array, reflect.Slice:
+	case reflect.Array:
-		return Array(k, value)
+		rv = rv.Slice(0, rv.Len())
+		fallthrough
+	case reflect.Slice:
+		switch reflect.TypeOf(value).Elem().Kind() {
+		case reflect.Bool:
+			return BoolSlice(k, rv.Interface().([]bool))
+		case reflect.Int:
+			return IntSlice(k, rv.Interface().([]int))
+		case reflect.Int64:
+			return Int64Slice(k, rv.Interface().([]int64))
+		case reflect.Float64:
+			return Float64Slice(k, rv.Interface().([]float64))
+		case reflect.String:
+			return StringSlice(k, rv.Interface().([]string))
+		default:
+			return KeyValue{Key: Key(k), Value: Value{vtype: INVALID}}
+		}
 	case reflect.Bool:
 		return Bool(k, rv.Bool())
 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:

attribute/type_string.go

@@ -13,12 +13,16 @@ func _() {
 	_ = x[INT64-2]
 	_ = x[FLOAT64-3]
 	_ = x[STRING-4]
-	_ = x[ARRAY-5]
+	_ = x[BOOLSLICE-5]
+	_ = x[INT64SLICE-6]
+	_ = x[FLOAT64SLICE-7]
+	_ = x[STRINGSLICE-8]
+	_ = x[ARRAY-9]
 }
 
-const _Type_name = "INVALIDBOOLINT64FLOAT64STRINGARRAY"
+const _Type_name = "INVALIDBOOLINT64FLOAT64STRINGBOOLSLICEINT64SLICEFLOAT64SLICESTRINGSLICEARRAY"
 
-var _Type_index = [...]uint8{0, 7, 11, 16, 23, 29, 34}
+var _Type_index = [...]uint8{0, 7, 11, 16, 23, 29, 38, 48, 60, 71, 76}
 
 func (i Type) String() string {
 	if i < 0 || i >= Type(len(_Type_index)-1) {

attribute/value.go

@@ -33,9 +33,7 @@ type Value struct {
 	vtype    Type
 	numeric  uint64
 	stringly string
-	// TODO Lazy value type?
+	slice    interface{}
-
-	array interface{}
 }
 
 const (
@@ -49,9 +47,19 @@ const (
 	FLOAT64
 	// STRING is a string Type Value.
 	STRING
+	// BOOLSLICE is a slice of booleans Type Value.
+	BOOLSLICE
+	// INT64SLICE is a slice of 64-bit signed integral numbers Type Value.
+	INT64SLICE
+	// FLOAT64SLICE is a slice of 64-bit floating point numbers Type Value.
+	FLOAT64SLICE
+	// STRINGSLICE is a slice of strings Type Value.
+	STRINGSLICE
 	// ARRAY is an array Type Value used to store 1-dimensional slices or
 	// arrays of bool, int, int32, int64, uint, uint32, uint64, float,
 	// float32, float64, or string types.
+	//
+	// Deprecated: Use slice types instead.
 	ARRAY
 )
 
@@ -63,11 +71,33 @@ func BoolValue(v bool) Value {
 	}
 }
 
+// BoolSliceValue creates a BOOLSLICE Value.
+func BoolSliceValue(v []bool) Value {
+	cp := make([]bool, len(v))
+	copy(cp, v)
+	return Value{
+		vtype: BOOLSLICE,
+		slice: cp,
+	}
+}
+
 // IntValue creates an INT64 Value.
 func IntValue(v int) Value {
 	return Int64Value(int64(v))
 }
 
+// IntSliceValue creates an INTSLICE Value.
+func IntSliceValue(v []int) Value {
+	cp := make([]int64, 0, len(v))
+	for _, i := range v {
+		cp = append(cp, int64(i))
+	}
+	return Value{
+		vtype: INT64SLICE,
+		slice: cp,
+	}
+}
+
 // Int64Value creates an INT64 Value.
 func Int64Value(v int64) Value {
 	return Value{
@@ -76,6 +106,16 @@ func Int64Value(v int64) Value {
 	}
 }
 
+// Int64SliceValue creates an INT64SLICE Value.
+func Int64SliceValue(v []int64) Value {
+	cp := make([]int64, len(v))
+	copy(cp, v)
+	return Value{
+		vtype: INT64SLICE,
+		slice: cp,
+	}
+}
+
 // Float64Value creates a FLOAT64 Value.
 func Float64Value(v float64) Value {
 	return Value{
@@ -84,6 +124,16 @@ func Float64Value(v float64) Value {
 	}
 }
 
+// Float64SliceValue creates a FLOAT64SLICE Value.
+func Float64SliceValue(v []float64) Value {
+	cp := make([]float64, len(v))
+	copy(cp, v)
+	return Value{
+		vtype: FLOAT64SLICE,
+		slice: cp,
+	}
+}
+
 // StringValue creates a STRING Value.
 func StringValue(v string) Value {
 	return Value{
@@ -92,11 +142,23 @@ func StringValue(v string) Value {
 	}
 }
 
+// StringSliceValue creates a STRINGSLICE Value.
+func StringSliceValue(v []string) Value {
+	cp := make([]string, len(v))
+	copy(cp, v)
+	return Value{
+		vtype: STRINGSLICE,
+		slice: cp,
+	}
+}
+
 // ArrayValue creates an ARRAY value from an array or slice.
 // Only arrays or slices of bool, int, int64, float, float64, or string types are allowed.
 // Specifically, arrays  and slices can not contain other arrays, slices, structs, or non-standard
 // types. If the passed value is not an array or slice of these types an
 // INVALID value is returned.
+//
+// Deprecated: Use the typed *SliceValue functions instead.
 func ArrayValue(v interface{}) Value {
 	switch reflect.TypeOf(v).Kind() {
 	case reflect.Array, reflect.Slice:
@@ -112,7 +174,7 @@ func ArrayValue(v interface{}) Value {
 			reflect.Copy(frozen, val)
 			return Value{
 				vtype: ARRAY,
-				array: frozen.Interface(),
+				slice: frozen.Interface(),
 			}
 		default:
 			return Value{vtype: INVALID}
@@ -132,27 +194,65 @@ func (v Value) AsBool() bool {
 	return internal.RawToBool(v.numeric)
 }
 
+// AsBoolSlice returns the []bool value. Make sure that the Value's type is
+// BOOLSLICE.
+func (v Value) AsBoolSlice() []bool {
+	if s, ok := v.slice.([]bool); ok {
+		return s
+	}
+	return nil
+}
+
 // AsInt64 returns the int64 value. Make sure that the Value's type is
 // INT64.
 func (v Value) AsInt64() int64 {
 	return internal.RawToInt64(v.numeric)
 }
 
+// AsInt64Slice returns the []int64 value. Make sure that the Value's type is
+// INT64SLICE.
+func (v Value) AsInt64Slice() []int64 {
+	if s, ok := v.slice.([]int64); ok {
+		return s
+	}
+	return nil
+}
+
 // AsFloat64 returns the float64 value. Make sure that the Value's
 // type is FLOAT64.
 func (v Value) AsFloat64() float64 {
 	return internal.RawToFloat64(v.numeric)
 }
 
+// AsFloat64Slice returns the []float64 value. Make sure that the Value's type is
+// INT64SLICE.
+func (v Value) AsFloat64Slice() []float64 {
+	if s, ok := v.slice.([]float64); ok {
+		return s
+	}
+	return nil
+}
+
 // AsString returns the string value. Make sure that the Value's type
 // is STRING.
 func (v Value) AsString() string {
 	return v.stringly
 }
 
+// AsStringSlice returns the []string value. Make sure that the Value's type is
+// INT64SLICE.
+func (v Value) AsStringSlice() []string {
+	if s, ok := v.slice.([]string); ok {
+		return s
+	}
+	return nil
+}
+
 // AsArray returns the array Value as an interface{}.
+//
+// Deprecated: Use the typed As*Slice functions instead.
 func (v Value) AsArray() interface{} {
-	return v.array
+	return v.slice
 }
 
 type unknownValueType struct{}
@@ -164,12 +264,20 @@ func (v Value) AsInterface() interface{} {
 		return v.AsArray()
 	case BOOL:
 		return v.AsBool()
+	case BOOLSLICE:
+		return v.AsBoolSlice()
 	case INT64:
 		return v.AsInt64()
+	case INT64SLICE:
+		return v.AsInt64Slice()
 	case FLOAT64:
 		return v.AsFloat64()
+	case FLOAT64SLICE:
+		return v.AsFloat64Slice()
 	case STRING:
 		return v.stringly
+	case STRINGSLICE:
+		return v.AsStringSlice()
 	}
 	return unknownValueType{}
 }
@@ -177,8 +285,8 @@ func (v Value) AsInterface() interface{} {
 // Emit returns a string representation of Value's data.
 func (v Value) Emit() string {
 	switch v.Type() {
-	case ARRAY:
+	case ARRAY, BOOLSLICE, INT64SLICE, FLOAT64SLICE, STRINGSLICE:
-		return fmt.Sprint(v.array)
+		return fmt.Sprint(v.slice)
 	case BOOL:
 		return strconv.FormatBool(v.AsBool())
 	case INT64:

attribute/value_test.go

@@ -25,7 +25,6 @@ import (
 
 func TestValue(t *testing.T) {
 	k := attribute.Key("test")
-	bli := getBitlessInfo(42)
 	for _, testcase := range []struct {
 		name      string
 		value     attribute.Value
@@ -38,6 +37,12 @@ func TestValue(t *testing.T) {
 			wantType:  attribute.BOOL,
 			wantValue: true,
 		},
+		{
+			name:      "Key.BoolSlice() correctly returns keys's internal []bool value",
+			value:     k.BoolSlice([]bool{true, false, true}).Value,
+			wantType:  attribute.BOOLSLICE,
+			wantValue: []bool{true, false, true},
+		},
 		{
 			name:      "Key.Array([]bool) correctly return key's internal bool values",
 			value:     k.Array([]bool{true, false}).Value,
@@ -51,22 +56,10 @@ func TestValue(t *testing.T) {
 			wantValue: int64(42),
 		},
 		{
-			name:      "Key.Float64() correctly returns keys's internal float64 value",
+			name:      "Key.Int64Slice() correctly returns keys's internal []int64 value",
-			value:     k.Float64(42.1).Value,
+			value:     k.Int64Slice([]int64{42, -3, 12}).Value,
-			wantType:  attribute.FLOAT64,
+			wantType:  attribute.INT64SLICE,
-			wantValue: 42.1,
+			wantValue: []int64{42, -3, 12},
-		},
-		{
-			name:      "Key.String() correctly returns keys's internal string value",
-			value:     k.String("foo").Value,
-			wantType:  attribute.STRING,
-			wantValue: "foo",
-		},
-		{
-			name:      "Key.Int() correctly returns keys's internal signed integral value",
-			value:     k.Int(bli.intValue).Value,
-			wantType:  bli.signedType,
-			wantValue: bli.signedValue,
 		},
 		{
 			name:      "Key.Array([]int64) correctly returns keys's internal int64 values",
@@ -75,16 +68,16 @@ func TestValue(t *testing.T) {
 			wantValue: [2]int64{42, 43},
 		},
 		{
-			name:      "Key.Array([]float64) correctly returns keys's internal float64 values",
+			name:      "Key.Int() correctly returns keys's internal signed integral value",
-			value:     k.Array([]float64{42, 43}).Value,
+			value:     k.Int(42).Value,
-			wantType:  attribute.ARRAY,
+			wantType:  attribute.INT64,
-			wantValue: [2]float64{42, 43},
+			wantValue: int64(42),
 		},
 		{
-			name:      "Key.Array([]string) correctly return key's internal string values",
+			name:      "Key.IntSlice() correctly returns keys's internal []int64 value",
-			value:     k.Array([]string{"foo", "bar"}).Value,
+			value:     k.IntSlice([]int{42, -3, 12}).Value,
-			wantType:  attribute.ARRAY,
+			wantType:  attribute.INT64SLICE,
-			wantValue: [2]string{"foo", "bar"},
+			wantValue: []int64{42, -3, 12},
 		},
 		{
 			name:      "Key.Array([]int) correctly returns keys's internal signed integral values",
@@ -92,6 +85,42 @@ func TestValue(t *testing.T) {
 			wantType:  attribute.ARRAY,
 			wantValue: [2]int{42, 43},
 		},
+		{
+			name:      "Key.Float64() correctly returns keys's internal float64 value",
+			value:     k.Float64(42.1).Value,
+			wantType:  attribute.FLOAT64,
+			wantValue: 42.1,
+		},
+		{
+			name:      "Key.Float64Slice() correctly returns keys's internal []float64 value",
+			value:     k.Float64Slice([]float64{42, -3, 12}).Value,
+			wantType:  attribute.FLOAT64SLICE,
+			wantValue: []float64{42, -3, 12},
+		},
+		{
+			name:      "Key.Array([]float64) correctly returns keys's internal float64 values",
+			value:     k.Array([]float64{42, 43}).Value,
+			wantType:  attribute.ARRAY,
+			wantValue: [2]float64{42, 43},
+		},
+		{
+			name:      "Key.String() correctly returns keys's internal string value",
+			value:     k.String("foo").Value,
+			wantType:  attribute.STRING,
+			wantValue: "foo",
+		},
+		{
+			name:      "Key.StringSlice() correctly returns keys's internal []string value",
+			value:     k.StringSlice([]string{"forty-two", "negative three", "twelve"}).Value,
+			wantType:  attribute.STRINGSLICE,
+			wantValue: []string{"forty-two", "negative three", "twelve"},
+		},
+		{
+			name:      "Key.Array([]string) correctly return key's internal string values",
+			value:     k.Array([]string{"foo", "bar"}).Value,
+			wantType:  attribute.ARRAY,
+			wantValue: [2]string{"foo", "bar"},
+		},
 		{
 			name:      "Key.Array([][]int) refuses to create multi-dimensional array",
 			value:     k.Array([][]int{{1, 2}, {3, 4}}).Value,
@@ -113,22 +142,6 @@ func TestValue(t *testing.T) {
 	}
 }
 
-type bitlessInfo struct {
-	intValue    int
-	uintValue   uint
-	signedType  attribute.Type
-	signedValue interface{}
-}
-
-func getBitlessInfo(i int) bitlessInfo {
-	return bitlessInfo{
-		intValue:    i,
-		uintValue:   uint(i),
-		signedType:  attribute.INT64,
-		signedValue: int64(i),
-	}
-}
-
 func TestAsArrayValue(t *testing.T) {
 	v := attribute.ArrayValue([]int{1, 2, 3}).AsArray()
 	// Ensure the returned dynamic type is stable.

exporters/jaeger/jaeger.go

@@ -248,8 +248,11 @@ func keyValueToTag(keyValue attribute.KeyValue) *gen.Tag {
 			VDouble: &f,
 			VType:   gen.TagType_DOUBLE,
 		}
-	case attribute.ARRAY:
+	case attribute.BOOLSLICE,
-		json, _ := json.Marshal(keyValue.Value.AsArray())
+		attribute.INT64SLICE,
+		attribute.FLOAT64SLICE,
+		attribute.STRINGSLICE:
+		json, _ := json.Marshal(keyValue.Value.AsInterface())
 		a := (string)(json)
 		tag = &gen.Tag{
 			Key:   string(keyValue.Key),

exporters/jaeger/jaeger_test.go

@@ -323,7 +323,7 @@ func Test_spanSnapshotToThrift(t *testing.T) {
 				StartTime: now,
 				EndTime:   now,
 				Attributes: []attribute.KeyValue{
-					attribute.Array("arr", []int{0, 1, 2, 3}),
+					attribute.IntSlice("arr", []int{0, 1, 2, 3}),
 				},
 				Status: sdktrace.Status{
 					Code:        codes.Unset,

exporters/otlp/otlpmetric/internal/metrictransform/attribute.go

@@ -15,8 +15,6 @@
 package metrictransform
 
 import (
-	"reflect"
-
 	"go.opentelemetry.io/otel/attribute"
 	commonpb "go.opentelemetry.io/proto/otlp/common/v1"
 
@@ -68,22 +66,40 @@ func Value(v attribute.Value) *commonpb.AnyValue {
 		av.Value = &commonpb.AnyValue_BoolValue{
 			BoolValue: v.AsBool(),
 		}
+	case attribute.BOOLSLICE:
+		av.Value = &commonpb.AnyValue_ArrayValue{
+			ArrayValue: &commonpb.ArrayValue{
+				Values: boolSliceValues(v.AsBoolSlice()),
+			},
+		}
 	case attribute.INT64:
 		av.Value = &commonpb.AnyValue_IntValue{
 			IntValue: v.AsInt64(),
 		}
+	case attribute.INT64SLICE:
+		av.Value = &commonpb.AnyValue_ArrayValue{
+			ArrayValue: &commonpb.ArrayValue{
+				Values: int64SliceValues(v.AsInt64Slice()),
+			},
+		}
 	case attribute.FLOAT64:
 		av.Value = &commonpb.AnyValue_DoubleValue{
 			DoubleValue: v.AsFloat64(),
 		}
+	case attribute.FLOAT64SLICE:
+		av.Value = &commonpb.AnyValue_ArrayValue{
+			ArrayValue: &commonpb.ArrayValue{
+				Values: float64SliceValues(v.AsFloat64Slice()),
+			},
+		}
 	case attribute.STRING:
 		av.Value = &commonpb.AnyValue_StringValue{
 			StringValue: v.AsString(),
 		}
-	case attribute.ARRAY:
+	case attribute.STRINGSLICE:
 		av.Value = &commonpb.AnyValue_ArrayValue{
 			ArrayValue: &commonpb.ArrayValue{
-				Values: arrayValues(v),
+				Values: stringSliceValues(v.AsStringSlice()),
 			},
 		}
 	default:
@@ -94,56 +110,50 @@ func Value(v attribute.Value) *commonpb.AnyValue {
 	return av
 }
 
-func arrayValues(v attribute.Value) []*commonpb.AnyValue {
+func boolSliceValues(vals []bool) []*commonpb.AnyValue {
-	a := v.AsArray()
+	converted := make([]*commonpb.AnyValue, len(vals))
-	aType := reflect.TypeOf(a)
+	for i, v := range vals {
-	var valueFunc func(reflect.Value) *commonpb.AnyValue
+		converted[i] = &commonpb.AnyValue{
-	switch aType.Elem().Kind() {
-	case reflect.Bool:
-		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
-			return &commonpb.AnyValue{
 			Value: &commonpb.AnyValue_BoolValue{
-					BoolValue: v.Bool(),
+				BoolValue: v,
-				},
-			}
-		}
-	case reflect.Int, reflect.Int64:
-		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
-			return &commonpb.AnyValue{
-				Value: &commonpb.AnyValue_IntValue{
-					IntValue: v.Int(),
-				},
-			}
-		}
-	case reflect.Uintptr:
-		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
-			return &commonpb.AnyValue{
-				Value: &commonpb.AnyValue_IntValue{
-					IntValue: int64(v.Uint()),
-				},
-			}
-		}
-	case reflect.Float64:
-		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
-			return &commonpb.AnyValue{
-				Value: &commonpb.AnyValue_DoubleValue{
-					DoubleValue: v.Float(),
-				},
-			}
-		}
-	case reflect.String:
-		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
-			return &commonpb.AnyValue{
-				Value: &commonpb.AnyValue_StringValue{
-					StringValue: v.String(),
 			},
 		}
 	}
+	return converted
 }
 
-	results := make([]*commonpb.AnyValue, aType.Len())
+func int64SliceValues(vals []int64) []*commonpb.AnyValue {
-	for i, aValue := 0, reflect.ValueOf(a); i < aValue.Len(); i++ {
+	converted := make([]*commonpb.AnyValue, len(vals))
-		results[i] = valueFunc(aValue.Index(i))
+	for i, v := range vals {
+		converted[i] = &commonpb.AnyValue{
+			Value: &commonpb.AnyValue_IntValue{
+				IntValue: v,
+			},
 		}
-	return results
+	}
+	return converted
+}
+
+func float64SliceValues(vals []float64) []*commonpb.AnyValue {
+	converted := make([]*commonpb.AnyValue, len(vals))
+	for i, v := range vals {
+		converted[i] = &commonpb.AnyValue{
+			Value: &commonpb.AnyValue_DoubleValue{
+				DoubleValue: v,
+			},
+		}
+	}
+	return converted
+}
+
+func stringSliceValues(vals []string) []*commonpb.AnyValue {
+	converted := make([]*commonpb.AnyValue, len(vals))
+	for i, v := range vals {
+		converted[i] = &commonpb.AnyValue{
+			Value: &commonpb.AnyValue_StringValue{
+				StringValue: v,
+			},
+		}
+	}
+	return converted
 }

exporters/otlp/otlpmetric/internal/metrictransform/attribute_test.go

@@ -112,7 +112,10 @@ func TestArrayAttributes(t *testing.T) {
 		{nil, nil},
 		{
 			[]attribute.KeyValue{
-				attribute.Array("invalid", [][]string{{"1", "2"}, {"a"}}),
+				{
+					Key:   attribute.Key("invalid"),
+					Value: attribute.Value{},
+				},
 			},
 			[]*commonpb.KeyValue{
 				{
@@ -127,18 +130,18 @@ func TestArrayAttributes(t *testing.T) {
 		},
 		{
 			[]attribute.KeyValue{
-				attribute.Array("bool array to bool array", []bool{true, false}),
+				attribute.BoolSlice("bool slice to bool array", []bool{true, false}),
-				attribute.Array("int array to int64 array", []int{1, 2, 3}),
+				attribute.IntSlice("int slice to int64 array", []int{1, 2, 3}),
-				attribute.Array("int64 array to int64 array", []int64{1, 2, 3}),
+				attribute.Int64Slice("int64 slice to int64 array", []int64{1, 2, 3}),
-				attribute.Array("float64 array to double array", []float64{1.11, 2.22, 3.33}),
+				attribute.Float64Slice("float64 slice to double array", []float64{1.11, 2.22, 3.33}),
-				attribute.Array("string array to string array", []string{"foo", "bar", "baz"}),
+				attribute.StringSlice("string slice to string array", []string{"foo", "bar", "baz"}),
 			},
 			[]*commonpb.KeyValue{
-				newOTelBoolArray("bool array to bool array", []bool{true, false}),
+				newOTelBoolArray("bool slice to bool array", []bool{true, false}),
-				newOTelIntArray("int array to int64 array", []int64{1, 2, 3}),
+				newOTelIntArray("int slice to int64 array", []int64{1, 2, 3}),
-				newOTelIntArray("int64 array to int64 array", []int64{1, 2, 3}),
+				newOTelIntArray("int64 slice to int64 array", []int64{1, 2, 3}),
-				newOTelDoubleArray("float64 array to double array", []float64{1.11, 2.22, 3.33}),
+				newOTelDoubleArray("float64 slice to double array", []float64{1.11, 2.22, 3.33}),
-				newOTelStringArray("string array to string array", []string{"foo", "bar", "baz"}),
+				newOTelStringArray("string slice to string array", []string{"foo", "bar", "baz"}),
 			},
 		},
 	} {

exporters/otlp/otlptrace/internal/tracetransform/attribute.go

@@ -15,8 +15,6 @@
 package tracetransform
 
 import (
-	"reflect"
-
 	"go.opentelemetry.io/otel/attribute"
 	commonpb "go.opentelemetry.io/proto/otlp/common/v1"
 
@@ -68,22 +66,40 @@ func Value(v attribute.Value) *commonpb.AnyValue {
 		av.Value = &commonpb.AnyValue_BoolValue{
 			BoolValue: v.AsBool(),
 		}
+	case attribute.BOOLSLICE:
+		av.Value = &commonpb.AnyValue_ArrayValue{
+			ArrayValue: &commonpb.ArrayValue{
+				Values: boolSliceValues(v.AsBoolSlice()),
+			},
+		}
 	case attribute.INT64:
 		av.Value = &commonpb.AnyValue_IntValue{
 			IntValue: v.AsInt64(),
 		}
+	case attribute.INT64SLICE:
+		av.Value = &commonpb.AnyValue_ArrayValue{
+			ArrayValue: &commonpb.ArrayValue{
+				Values: int64SliceValues(v.AsInt64Slice()),
+			},
+		}
 	case attribute.FLOAT64:
 		av.Value = &commonpb.AnyValue_DoubleValue{
 			DoubleValue: v.AsFloat64(),
 		}
+	case attribute.FLOAT64SLICE:
+		av.Value = &commonpb.AnyValue_ArrayValue{
+			ArrayValue: &commonpb.ArrayValue{
+				Values: float64SliceValues(v.AsFloat64Slice()),
+			},
+		}
 	case attribute.STRING:
 		av.Value = &commonpb.AnyValue_StringValue{
 			StringValue: v.AsString(),
 		}
-	case attribute.ARRAY:
+	case attribute.STRINGSLICE:
 		av.Value = &commonpb.AnyValue_ArrayValue{
 			ArrayValue: &commonpb.ArrayValue{
-				Values: arrayValues(v),
+				Values: stringSliceValues(v.AsStringSlice()),
 			},
 		}
 	default:
@@ -94,56 +110,50 @@ func Value(v attribute.Value) *commonpb.AnyValue {
 	return av
 }
 
-func arrayValues(v attribute.Value) []*commonpb.AnyValue {
+func boolSliceValues(vals []bool) []*commonpb.AnyValue {
-	a := v.AsArray()
+	converted := make([]*commonpb.AnyValue, len(vals))
-	aType := reflect.TypeOf(a)
+	for i, v := range vals {
-	var valueFunc func(reflect.Value) *commonpb.AnyValue
+		converted[i] = &commonpb.AnyValue{
-	switch aType.Elem().Kind() {
-	case reflect.Bool:
-		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
-			return &commonpb.AnyValue{
 			Value: &commonpb.AnyValue_BoolValue{
-					BoolValue: v.Bool(),
+				BoolValue: v,
-				},
-			}
-		}
-	case reflect.Int, reflect.Int64:
-		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
-			return &commonpb.AnyValue{
-				Value: &commonpb.AnyValue_IntValue{
-					IntValue: v.Int(),
-				},
-			}
-		}
-	case reflect.Uintptr:
-		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
-			return &commonpb.AnyValue{
-				Value: &commonpb.AnyValue_IntValue{
-					IntValue: int64(v.Uint()),
-				},
-			}
-		}
-	case reflect.Float64:
-		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
-			return &commonpb.AnyValue{
-				Value: &commonpb.AnyValue_DoubleValue{
-					DoubleValue: v.Float(),
-				},
-			}
-		}
-	case reflect.String:
-		valueFunc = func(v reflect.Value) *commonpb.AnyValue {
-			return &commonpb.AnyValue{
-				Value: &commonpb.AnyValue_StringValue{
-					StringValue: v.String(),
 			},
 		}
 	}
+	return converted
 }
 
-	results := make([]*commonpb.AnyValue, aType.Len())
+func int64SliceValues(vals []int64) []*commonpb.AnyValue {
-	for i, aValue := 0, reflect.ValueOf(a); i < aValue.Len(); i++ {
+	converted := make([]*commonpb.AnyValue, len(vals))
-		results[i] = valueFunc(aValue.Index(i))
+	for i, v := range vals {
+		converted[i] = &commonpb.AnyValue{
+			Value: &commonpb.AnyValue_IntValue{
+				IntValue: v,
+			},
 		}
-	return results
+	}
+	return converted
+}
+
+func float64SliceValues(vals []float64) []*commonpb.AnyValue {
+	converted := make([]*commonpb.AnyValue, len(vals))
+	for i, v := range vals {
+		converted[i] = &commonpb.AnyValue{
+			Value: &commonpb.AnyValue_DoubleValue{
+				DoubleValue: v,
+			},
+		}
+	}
+	return converted
+}
+
+func stringSliceValues(vals []string) []*commonpb.AnyValue {
+	converted := make([]*commonpb.AnyValue, len(vals))
+	for i, v := range vals {
+		converted[i] = &commonpb.AnyValue{
+			Value: &commonpb.AnyValue_StringValue{
+				StringValue: v,
+			},
+		}
+	}
+	return converted
 }

exporters/otlp/otlptrace/internal/tracetransform/attribute_test.go

@@ -112,7 +112,10 @@ func TestArrayAttributes(t *testing.T) {
 		{nil, nil},
 		{
 			[]attribute.KeyValue{
-				attribute.Array("invalid", [][]string{{"1", "2"}, {"a"}}),
+				{
+					Key:   attribute.Key("invalid"),
+					Value: attribute.Value{},
+				},
 			},
 			[]*commonpb.KeyValue{
 				{
@@ -127,18 +130,18 @@ func TestArrayAttributes(t *testing.T) {
 		},
 		{
 			[]attribute.KeyValue{
-				attribute.Array("bool array to bool array", []bool{true, false}),
+				attribute.BoolSlice("bool slice to bool array", []bool{true, false}),
-				attribute.Array("int array to int64 array", []int{1, 2, 3}),
+				attribute.IntSlice("int slice to int64 array", []int{1, 2, 3}),
-				attribute.Array("int64 array to int64 array", []int64{1, 2, 3}),
+				attribute.Int64Slice("int64 slice to int64 array", []int64{1, 2, 3}),
-				attribute.Array("float64 array to double array", []float64{1.11, 2.22, 3.33}),
+				attribute.Float64Slice("float64 slice to double array", []float64{1.11, 2.22, 3.33}),
-				attribute.Array("string array to string array", []string{"foo", "bar", "baz"}),
+				attribute.StringSlice("string slice to string array", []string{"foo", "bar", "baz"}),
 			},
 			[]*commonpb.KeyValue{
-				newOTelBoolArray("bool array to bool array", []bool{true, false}),
+				newOTelBoolArray("bool slice to bool array", []bool{true, false}),
-				newOTelIntArray("int array to int64 array", []int64{1, 2, 3}),
+				newOTelIntArray("int slice to int64 array", []int64{1, 2, 3}),
-				newOTelIntArray("int64 array to int64 array", []int64{1, 2, 3}),
+				newOTelIntArray("int64 slice to int64 array", []int64{1, 2, 3}),
-				newOTelDoubleArray("float64 array to double array", []float64{1.11, 2.22, 3.33}),
+				newOTelDoubleArray("float64 slice to double array", []float64{1.11, 2.22, 3.33}),
-				newOTelStringArray("string array to string array", []string{"foo", "bar", "baz"}),
+				newOTelStringArray("string slice to string array", []string{"foo", "bar", "baz"}),
 			},
 		},
 	} {

exporters/zipkin/model.go

@@ -181,9 +181,18 @@ func toZipkinTags(data tracesdk.ReadOnlySpan) map[string]string {
 	m := make(map[string]string, len(attr)+len(extraZipkinTags))
 	for _, kv := range attr {
 		switch kv.Value.Type() {
-		// For array attributes, serialize as JSON list string.
+		// For slice attributes, serialize as JSON list string.
-		case attribute.ARRAY:
+		case attribute.BOOLSLICE:
-			json, _ := json.Marshal(kv.Value.AsArray())
+			json, _ := json.Marshal(kv.Value.AsBoolSlice())
+			m[(string)(kv.Key)] = (string)(json)
+		case attribute.INT64SLICE:
+			json, _ := json.Marshal(kv.Value.AsInt64Slice())
+			m[(string)(kv.Key)] = (string)(json)
+		case attribute.FLOAT64SLICE:
+			json, _ := json.Marshal(kv.Value.AsFloat64Slice())
+			m[(string)(kv.Key)] = (string)(json)
+		case attribute.STRINGSLICE:
+			json, _ := json.Marshal(kv.Value.AsStringSlice())
 			m[(string)(kv.Key)] = (string)(json)
 		default:
 			m[(string)(kv.Key)] = kv.Value.Emit()

exporters/zipkin/model_test.go

@@ -59,7 +59,7 @@ func TestModelConversion(t *testing.T) {
 			Attributes: []attribute.KeyValue{
 				attribute.Int64("attr1", 42),
 				attribute.String("attr2", "bar"),
-				attribute.Array("attr3", []int{0, 1, 2}),
+				attribute.IntSlice("attr3", []int{0, 1, 2}),
 			},
 			Events: []tracesdk.Event{
 				{

oteltest/tracestate_test.go

@@ -33,9 +33,8 @@ func TestTraceStateFromKeyValues(t *testing.T) {
 		attribute.Bool("key1", true),
 		attribute.Int64("key2", 1),
 		attribute.Float64("key3", 1.1),
-		attribute.Array("key4", []int{1, 1}),
 	)
 	require.NoError(t, err)
-	expected := "key0=string,key1=true,key2=1,key3=1.1,key4=[1 1]"
+	expected := "key0=string,key1=true,key2=1,key3=1.1"
 	assert.Equal(t, expected, ts.String())
 }

sdk/resource/process.go

@@ -138,7 +138,7 @@ func (processExecutablePathDetector) Detect(ctx context.Context) (*Resource, err
 // Detect returns a *Resource that describes all the command arguments as received
 // by the process.
 func (processCommandArgsDetector) Detect(ctx context.Context) (*Resource, error) {
-	return NewWithAttributes(semconv.SchemaURL, semconv.ProcessCommandArgsKey.Array(commandArgs())), nil
+	return NewWithAttributes(semconv.SchemaURL, semconv.ProcessCommandArgsKey.StringSlice(commandArgs())), nil
 }
 
 // Detect returns a *Resource that describes the username of the user that owns the