Emit attributes slices as their json representation (#5159)

* emit slices as their json representation

* add changelog

* fix resource tests

* indicate invalid slice if we couldn't turn them into json

* move changelog entry to the unreleased section

---------

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

CHANGELOG.md

@@ -51,6 +51,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Improve performance of baggage member character validation in `go.opentelemetry.io/otel/baggage`. (#5214)
 - The `otel-collector` example now uses docker compose to bring up services instead of kubernetes. (#5244)
 
+### Fixed
+
+- Slice attribute values in `go.opentelemetry.io/otel/attribute` are now emitted as their JSON representation. (#5159)
+
 ## [1.25.0/0.47.0/0.0.8/0.1.0-alpha] 2024-04-05
 
 ### Added

attribute/key_test.go

@@ -63,11 +63,21 @@ func TestEmit(t *testing.T) {
 			v:    attribute.BoolValue(true),
 			want: "true",
 		},
+		{
+			name: `test Key.Emit() can emit a string representing self.INT64SLICE`,
+			v:    attribute.Int64SliceValue([]int64{1, 42}),
+			want: `[1,42]`,
+		},
 		{
 			name: `test Key.Emit() can emit a string representing self.INT64`,
 			v:    attribute.Int64Value(42),
 			want: "42",
 		},
+		{
+			name: `test Key.Emit() can emit a string representing self.FLOAT64SLICE`,
+			v:    attribute.Float64SliceValue([]float64{1.0, 42.5}),
+			want: `[1,42.5]`,
+		},
 		{
 			name: `test Key.Emit() can emit a string representing self.FLOAT64`,
 			v:    attribute.Float64Value(42.1),
@@ -78,6 +88,11 @@ func TestEmit(t *testing.T) {
 			v:    attribute.StringValue("foo"),
 			want: "foo",
 		},
+		{
+			name: `test Key.Emit() can emit a string representing self.STRINGSLICE`,
+			v:    attribute.StringSliceValue([]string{"foo", "bar"}),
+			want: `["foo","bar"]`,
+		},
 	} {
 		t.Run(testcase.name, func(t *testing.T) {
 			// proto: func (v attribute.Value) Emit() string {

attribute/value.go

@@ -231,15 +231,27 @@ func (v Value) Emit() string {
 	case BOOL:
 		return strconv.FormatBool(v.AsBool())
 	case INT64SLICE:
-		return fmt.Sprint(v.asInt64Slice())
+		j, err := json.Marshal(v.asInt64Slice())
+		if err != nil {
+			return fmt.Sprintf("invalid: %v", v.asInt64Slice())
+		}
+		return string(j)
 	case INT64:
 		return strconv.FormatInt(v.AsInt64(), 10)
 	case FLOAT64SLICE:
-		return fmt.Sprint(v.asFloat64Slice())
+		j, err := json.Marshal(v.asFloat64Slice())
+		if err != nil {
+			return fmt.Sprintf("invalid: %v", v.asFloat64Slice())
+		}
+		return string(j)
 	case FLOAT64:
 		return fmt.Sprint(v.AsFloat64())
 	case STRINGSLICE:
-		return fmt.Sprint(v.asStringSlice())
+		j, err := json.Marshal(v.asStringSlice())
+		if err != nil {
+			return fmt.Sprintf("invalid: %v", v.asStringSlice())
+		}
+		return string(j)
 	case STRING:
 		return v.stringly
 	default:

sdk/resource/resource_test.go

@@ -601,8 +601,9 @@ func TestWithProcessCommandArgs(t *testing.T) {
 	)
 
 	require.NoError(t, err)
+	jsonCommandArgs, _ := json.Marshal(fakeCommandArgs)
 	require.EqualValues(t, map[string]string{
-		"process.command_args": fmt.Sprint(fakeCommandArgs),
+		"process.command_args": string(jsonCommandArgs),
 	}, toMap(res))
 }
 
@@ -671,11 +672,12 @@ func TestWithProcess(t *testing.T) {
 	)
 
 	require.NoError(t, err)
+	jsonCommandArgs, _ := json.Marshal(fakeCommandArgs)
 	require.EqualValues(t, map[string]string{
 		"process.pid":                 fmt.Sprint(fakePID),
 		"process.executable.name":     fakeExecutableName,
 		"process.executable.path":     fakeExecutablePath,
-		"process.command_args":        fmt.Sprint(fakeCommandArgs),
+		"process.command_args":        string(jsonCommandArgs),
 		"process.owner":               fakeOwner,
 		"process.runtime.name":        fakeRuntimeName,
 		"process.runtime.version":     fakeRuntimeVersion,