Perf: skip license scanner injection (#3796)

* (perf): allow library users to skip default scanner injection

Signed-off-by: Adam McClenaghan <adam@mcclenaghan.co.uk>

* (perf): remove prints

Signed-off-by: Adam McClenaghan <adam@mcclenaghan.co.uk>

* perf: move to cataloging licenses.go

Signed-off-by: adammcclenaghan <adam.mcclenaghan@upwind.io>

* perf: Simplify to expose a SetContextLicenseScanner func

Signed-off-by: adammcclenaghan <adam.mcclenaghan@upwind.io>

---------

Signed-off-by: Adam McClenaghan <adam@mcclenaghan.co.uk>
Signed-off-by: adammcclenaghan <adam.mcclenaghan@upwind.io>

internal/licenses/context.go

@@ -6,12 +6,19 @@ import (
 
 type licenseScannerKey struct{}
 
+var ctxKey = licenseScannerKey{}
+
 func SetContextLicenseScanner(ctx context.Context, s Scanner) context.Context {
-	return context.WithValue(ctx, licenseScannerKey{}, s)
+	return context.WithValue(ctx, ctxKey, s)
+}
+
+func IsContextLicenseScannerSet(ctx context.Context) bool {
+	_, ok := ctx.Value(ctxKey).(Scanner)
+	return ok
 }
 
 func ContextLicenseScanner(ctx context.Context) (Scanner, error) {
-	if s, ok := ctx.Value(licenseScannerKey{}).(Scanner); ok {
+	if s, ok := ctx.Value(ctxKey).(Scanner); ok {
 		return s, nil
 	}
 	return NewDefaultScanner()

internal/licenses/context_test.go

@@ -0,0 +1,47 @@
+package licenses
+
+import (
+	"context"
+	"github.com/stretchr/testify/require"
+	"testing"
+)
+
+func TestSetContextLicenseScanner(t *testing.T) {
+	scanner := testScanner(true)
+	ctx := context.Background()
+	ctx = SetContextLicenseScanner(ctx, scanner)
+
+	val := ctx.Value(ctxKey)
+	require.NotNil(t, val)
+	s, ok := val.(Scanner)
+	require.True(t, ok)
+	require.Equal(t, scanner, s)
+}
+
+func TestIsContextLicenseScannerSet(t *testing.T) {
+	scanner := testScanner(true)
+	ctx := context.Background()
+	require.False(t, IsContextLicenseScannerSet(ctx))
+
+	ctx = SetContextLicenseScanner(ctx, scanner)
+	require.True(t, IsContextLicenseScannerSet(ctx))
+}
+
+func TestContextLicenseScanner(t *testing.T) {
+	t.Run("with scanner", func(t *testing.T) {
+		scanner := testScanner(true)
+		ctx := SetContextLicenseScanner(context.Background(), scanner)
+		s, err := ContextLicenseScanner(ctx)
+		if err != nil || s != scanner {
+			t.Fatal("expected scanner from context")
+		}
+	})
+
+	t.Run("without scanner", func(t *testing.T) {
+		ctx := context.Background()
+		s, err := ContextLicenseScanner(ctx)
+		if err != nil || s == nil {
+			t.Fatal("expected default scanner")
+		}
+	})
+}