Initial naive impl for user-agent parsing

pkg/ottl/ottlfuncs/func_useragent.go

@@ -0,0 +1,20 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package ottlfuncs // import "github.com/open-telemetry/opentelemetry-collector-contrib/pkg/ottl/ottlfuncs"
+import (
+	"context"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/ottl"
+)
+
+func userAgent[K any](userAgentSource ottl.StringGetter[K]) ottl.ExprFunc[K] { //revive:disable-line:var-naming
+	return func(ctx context.Context, tCtx K) (any, error) {
+		userAgentString, err := userAgentSource.Get(ctx, tCtx)
+		if err != nil {
+			return nil, err
+		}
+
+		return map[string]any{}, nil
+	}
+}

pkg/ottl/ottlfuncs/func_useragent_test.go

@@ -0,0 +1,54 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package ottlfuncs // import "github.com/open-telemetry/opentelemetry-collector-contrib/pkg/ottl/ottlfuncs"
+import (
+	"context"
+	"testing"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/ottl"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	semconv "go.opentelemetry.io/collector/semconv/v1.25.0"
+)
+
+func TestUserAgentParser(t *testing.T) {
+	testCases := []struct {
+		Name        string
+		Original    string
+		ExpectedMap map[string]any
+	}{
+		{
+			Name:     "Firefox on Linux",
+			Original: "Mozilla/5.0 (X11; Linux x86_64; rv:126.0) Gecko/20100101 Firefox/126.0",
+			ExpectedMap: map[string]any{
+				semconv.AttributeUserAgentOriginal: "Mozilla/5.0 (X11; Linux x86_64; rv:126.0) Gecko/20100101 Firefox/126.0",
+				semconv.AttributeUserAgentName:     "Firefox",
+				semconv.AttributeUserAgentVersion:  "",
+			},
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.Name, func(t *testing.T) {
+			source := &ottl.StandardStringGetter[any]{
+				Getter: func(_ context.Context, _ any) (any, error) {
+					return tt.Original, nil
+				},
+			}
+
+			exprFunc := userAgent[any](source) //revive:disable-line:var-naming
+			res, err := exprFunc(context.Background(), nil)
+			require.NoError(t, err)
+			require.IsType(t, map[string]any{}, res)
+			resMap := res.(map[string]any)
+			assert.Equal(t, tt.ExpectedMap, resMap)
+			assert.Len(t, resMap, len(tt.ExpectedMap))
+			for k, v := range tt.ExpectedMap {
+				if assert.Containsf(t, resMap, k, "key not found %q", k) {
+					assert.Equal(t, v, resMap[k])
+				}
+			}
+		})
+	}
+}