test: x-caddy extension parsing

pkg/client/compose/caddy.go

@@ -1,6 +1,10 @@
 package compose
 
-import "fmt"
+import (
+	"fmt"
+
+	"github.com/mitchellh/mapstructure"
+)
 
 const CaddyExtensionKey = "x-caddy"
 
@@ -17,16 +21,20 @@ func (c *Caddy) DecodeMapstructure(value any) error {
 		*c = *v
 		return nil
 	case string:
-		// Handle x-caddy: "caddyfile config"
+		// Handle x-caddy: "Caddyfile config"
 		*c = Caddy{Config: v}
 	case map[string]any:
-		// Handle the long syntax with a config key.
-		if config, ok := v["config"]; ok {
-			configStr, ok := config.(string)
-			if !ok {
-				return fmt.Errorf("x-caddy.config must be a string, got %T", config)
+		// Use mapstructure to decode the map directly to the struct.
+		decoder, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
+			Result:           c,
+			ErrorUnused:      true,  // Error if there are extra keys not in the struct.
+			WeaklyTypedInput: false, // Enforce strict type matching.
+		})
+		if err != nil {
+			return fmt.Errorf("create decoder for x-caddy extension: %w", err)
 		}
-			*c = Caddy{Config: configStr}
+		if err := decoder.Decode(v); err != nil {
+			return fmt.Errorf("decode x-caddy extension: %w", err)
 		}
 	default:
 		return fmt.Errorf("invalid type %T for x-caddy extension: expected string or object", value)

pkg/client/compose/caddy_test.go

@@ -0,0 +1,123 @@
+package compose
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCaddyExtension(t *testing.T) {
+	tests := []struct {
+		name           string
+		composeYAML    string
+		expectedConfig string
+		wantErr        bool
+	}{
+		{
+			name: "x-caddy as string",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+    x-caddy: |
+      example.com {
+        reverse_proxy web:80
+      }
+`,
+			expectedConfig: `example.com {
+  reverse_proxy web:80
+}
+`,
+		},
+		{
+			name: "x-caddy as object with config field",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+    x-caddy:
+      config: |
+        example.com {
+          reverse_proxy web:80
+        }
+`,
+			expectedConfig: `example.com {
+  reverse_proxy web:80
+}
+`,
+		},
+
+		{
+			name: "x-caddy with empty object",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+    x-caddy: {}
+`,
+			expectedConfig: "",
+		},
+		{
+			name: "x-caddy with empty string",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+    x-caddy: ""
+`,
+			expectedConfig: "",
+		},
+		{
+			name: "x-caddy with extra unknown field should fail",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+    x-caddy:
+      config: |
+        example.com {
+          reverse_proxy web:80
+        }
+      unknown_field: "should cause error"
+`,
+			wantErr: true,
+		},
+		{
+			name: "x-caddy with non-string config field should fail",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+    x-caddy:
+      config: 123
+`,
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			project, err := loadProjectFromContent(t, tt.composeYAML)
+
+			if tt.wantErr {
+				require.Error(t, err, "expected error for test case with invalid extension")
+				return
+			}
+
+			require.NoError(t, err)
+
+			service, err := project.GetService("web")
+			require.NoError(t, err)
+
+			// Verify the x-caddy extension was parsed correctly.
+			caddyExt, ok := service.Extensions[CaddyExtensionKey]
+			require.True(t, ok, "x-caddy extension not found")
+
+			caddy, ok := caddyExt.(Caddy)
+			require.True(t, ok, "x-caddy extension is not Caddy type")
+
+			assert.Equal(t, tt.expectedConfig, caddy.Config)
+		})
+	}
+}

pkg/client/compose/project.go

@@ -24,6 +24,7 @@ func LoadProject(ctx context.Context, paths []string, opts ...composecli.Project
 		composecli.WithConfigFileEnv,
 		// If none was selected, get default Compose file names from current or parent folders.
 		composecli.WithDefaultConfigPath,
+		composecli.WithExtension(CaddyExtensionKey, Caddy{}),
 		composecli.WithExtension(PortsExtensionKey, PortsSource{}),
 		composecli.WithExtension(MachinesExtensionKey, MachinesSource{}),
 	}

pkg/client/compose/service_test.go

@@ -38,6 +38,7 @@ func loadProjectFromContent(t *testing.T, content string) (*types.Project, error
 		if o.KnownExtensions == nil {
 			o.KnownExtensions = map[string]any{}
 		}
+		o.KnownExtensions[CaddyExtensionKey] = Caddy{}
 		o.KnownExtensions[PortsExtensionKey] = PortsSource{}
 		o.KnownExtensions[MachinesExtensionKey] = MachinesSource{}
 	})