chore: handle x-caddy: path/to/Caddyfile to read Caddy config in compose from file

pkg/client/compose/caddy.go

@@ -2,7 +2,11 @@ package compose
 
 import (
 	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
 
+	"github.com/compose-spec/compose-go/v2/types"
 	"github.com/mitchellh/mapstructure"
 )
 
@@ -41,3 +45,48 @@ func (c *Caddy) DecodeMapstructure(value any) error {
 	}
 	return nil
 }
+
+// isCaddyfilePath determines if a string is likely a file path rather than inline Caddyfile config.
+func isCaddyfilePath(s string) bool {
+	s = strings.TrimSpace(s)
+	if s == "" {
+		return false
+	}
+
+	// For simplicity, multi-line string is considered an inline Caddyfile content.
+	return !strings.Contains(s, "\n")
+}
+
+// transformServicesCaddyExtension processes Caddy extensions to load configs from files if needed.
+func transformServicesCaddyExtension(project *types.Project) (*types.Project, error) {
+	return project.WithServicesTransform(func(name string, service types.ServiceConfig) (types.ServiceConfig, error) {
+		ext, ok := service.Extensions[CaddyExtensionKey]
+		if !ok {
+			return service, nil
+		}
+
+		caddy, ok := ext.(Caddy)
+		if !ok {
+			return service, nil
+		}
+
+		// Load the Caddyfile config from file if it's a path and replace the path with its content.
+		if isCaddyfilePath(caddy.Config) {
+			configPath := caddy.Config
+			if !filepath.IsAbs(configPath) {
+				configPath = filepath.Join(project.WorkingDir, configPath)
+			}
+
+			content, err := os.ReadFile(configPath)
+			if err != nil {
+				return service, fmt.Errorf("read Caddy config (Caddyfile) from file '%s' for service '%s': %w",
+					caddy.Config, name, err)
+			}
+
+			caddy.Config = string(content)
+			service.Extensions[CaddyExtensionKey] = caddy
+		}
+
+		return service, nil
+	})
+}

pkg/client/compose/caddy_test.go

@@ -9,10 +9,10 @@ import (
 
 func TestCaddyExtension(t *testing.T) {
 	tests := []struct {
-		name           string
-		composeYAML    string
-		expectedConfig string
-		wantErr        bool
+		name        string
+		composeYAML string
+		wantConfig  string
+		wantErr     bool
 	}{
 		{
 			name: "x-caddy as string",
@@ -25,7 +25,7 @@ services:
         reverse_proxy web:80
       }
 `,
-			expectedConfig: `example.com {
+			wantConfig: `example.com {
   reverse_proxy web:80
 }
 `,
@@ -42,12 +42,24 @@ services:
           reverse_proxy web:80
         }
 `,
-			expectedConfig: `example.com {
+			wantConfig: `example.com {
   reverse_proxy web:80
 }
 `,
 		},
-
+		{
+			name: "x-caddy with path to Caddyfile",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+    x-caddy: testdata/Caddyfile
+`,
+			wantConfig: `test.example.com {
+  reverse_proxy test:8000
+}
+`,
+		},
 		{
 			name: "x-caddy with empty object",
 			composeYAML: `
@@ -56,7 +68,7 @@ services:
     image: nginx
     x-caddy: {}
 `,
-			expectedConfig: "",
+			wantConfig: "",
 		},
 		{
 			name: "x-caddy with empty string",
@@ -66,7 +78,7 @@ services:
     image: nginx
     x-caddy: ""
 `,
-			expectedConfig: "",
+			wantConfig: "",
 		},
 		{
 			name: "x-caddy with extra unknown field should fail",
@@ -117,7 +129,40 @@ services:
 			caddy, ok := caddyExt.(Caddy)
 			require.True(t, ok, "x-caddy extension is not Caddy type")
 
-			assert.Equal(t, tt.expectedConfig, caddy.Config)
+			assert.Equal(t, tt.wantConfig, caddy.Config)
+		})
+	}
+}
+
+func TestIsCaddyfilePath(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  bool
+	}{
+		// Should be detected as file paths.
+		{"relative path with slash", "./Caddyfile", true},
+		{"relative path parent", "../Caddyfile", true},
+		{"relative path", "relative/path/to/file", true},
+		{"absolute path", "/etc/caddy/Caddyfile", true},
+		{"just Caddyfile", "Caddyfile", true},
+		{"Caddyfile with suffix", "Caddyfile.app", true},
+		{"caddyfile lowercase", "caddyfile", true},
+		{"with .caddyfile extension", "my.caddyfile", true},
+		{"with .Caddyfile extension", "my.Caddyfile", true},
+		{"with .caddy extension", "config.caddy", true},
+		{"with .conf extension", "caddy.conf", true},
+		{"simple filename", "config", true},
+
+		// Should NOT be detected as file paths.
+		{"multiline config", "example.com {\n  reverse_proxy :8080\n}", false},
+		{"empty string", "", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := isCaddyfilePath(tt.input)
+			assert.Equal(t, tt.want, result, "isCaddyfilePath(%q) should be %v", tt.input, tt.want)
 		})
 	}
 }

pkg/client/compose/project.go

@@ -25,8 +25,8 @@ func LoadProject(ctx context.Context, paths []string, opts ...composecli.Project
 		// 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{}),
+		composecli.WithExtension(PortsExtensionKey, PortsSource{}),
 	}
 
 	options, err := composecli.NewProjectOptions(
@@ -42,6 +42,9 @@ func LoadProject(ctx context.Context, paths []string, opts ...composecli.Project
 		return nil, err
 	}
 
+	if project, err = transformServicesCaddyExtension(project); err != nil {
+		return nil, err
+	}
 	if project, err = transformServicesPortsExtension(project); err != nil {
 		return nil, err
 	}

pkg/client/compose/service_test.go

@@ -46,7 +46,10 @@ func loadProjectFromContent(t *testing.T, content string) (*types.Project, error
 		return nil, err
 	}
 
-	// Apply ports extension transformation since we're not using LoadProject
+	// Apply extension transformations since we're not using LoadProject.
+	if project, err = transformServicesCaddyExtension(project); err != nil {
+		return nil, err
+	}
 	if project, err = transformServicesPortsExtension(project); err != nil {
 		return nil, err
 	}

pkg/client/compose/testdata/Caddyfile

@@ -0,0 +1,3 @@
+test.example.com {
+  reverse_proxy test:8000
+}