chore: add Caddy config to ServiceSpec, load x-caddy to it

pkg/api/caddy.go

@@ -0,0 +1,8 @@
+package api
+
+// CaddySpec is the Caddy reverse proxy configuration for a service.
+type CaddySpec struct {
+	// Config contains the Caddy config (Caddyfile) content. It must not conflict with the Caddy configs
+	// of other services.
+	Config string
+}

pkg/api/service.go

@@ -6,6 +6,7 @@ import (
 	"maps"
 	"regexp"
 	"slices"
+	"strings"
 
 	"github.com/distribution/reference"
 	"github.com/google/go-cmp/cmp"
@@ -42,6 +43,10 @@ func ValidateServiceID(id string) bool {
 // ServiceSpec defines the desired state of a service.
 // ATTENTION: after changing this struct, verify if deploy.EvalContainerSpecChange needs to be updated.
 type ServiceSpec struct {
+	// Caddy is the optional Caddy reverse proxy configuration for the service.
+	// Caddy and Ports cannot be specified simultaneously.
+	Caddy *CaddySpec `json:",omitempty"`
+	// Container defines the desired state of each container in the service.
 	Container ContainerSpec
 	// Mode is the replication mode of the service. Default is ServiceModeReplicated if empty.
 	Mode string
@@ -49,6 +54,7 @@ type ServiceSpec struct {
 	// Placement defines the placement constraints for the service.
 	Placement Placement
 	// Ports defines what service ports to publish to make the service accessible outside the cluster.
+	// Caddy and Ports cannot be specified simultaneously.
 	Ports []PortSpec
 	// Replicas is the number of containers to run for the service. Only valid for a replicated service.
 	Replicas uint `json:",omitempty"`
@@ -112,10 +118,17 @@ func (s *ServiceSpec) Validate() error {
 			return fmt.Errorf("service name too long (max 63 characters): %q", s.Name)
 		}
 		if !dnsLabelRegexp.MatchString(s.Name) {
-			return fmt.Errorf("invalid service name: %q. must be 1-63 characters, lowercase letters, numbers, and dashes only; must start and end with a letter or number", s.Name)
+			return fmt.Errorf("invalid service name: %q. must be 1-63 characters, lowercase letters, numbers, "+
+				"and dashes only; must start and end with a letter or number", s.Name)
 		}
 	}
 
+	// Validate that Caddy and Ports are not used together.
+	if s.Caddy != nil && strings.TrimSpace(s.Caddy.Config) != "" && len(s.Ports) > 0 {
+		return fmt.Errorf("ports and Caddy configuration cannot be specified simultaneously: " +
+			"Caddy config is auto-generated from ports, use only one of them")
+	}
+
 	for _, p := range s.Ports {
 		if (p.Mode == "" || p.Mode == PortModeIngress) &&
 			p.Protocol != ProtocolHTTP && p.Protocol != ProtocolHTTPS {
@@ -151,11 +164,16 @@ func (s *ServiceSpec) Validate() error {
 func (s *ServiceSpec) Clone() ServiceSpec {
 	spec := *s
 
+	if s.Caddy != nil {
+		caddyCopy := *s.Caddy
+		spec.Caddy = &caddyCopy
+	}
+	spec.Container = s.Container.Clone()
+
 	if s.Ports != nil {
 		spec.Ports = make([]PortSpec, len(s.Ports))
 		copy(spec.Ports, s.Ports)
 	}
-	spec.Container = s.Container.Clone()
 
 	if s.Volumes != nil {
 		spec.Volumes = make([]VolumeSpec, len(s.Volumes))

pkg/api/service_test.go

@@ -0,0 +1,104 @@
+package api
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestServiceSpec_Validate_CaddyAndPorts(t *testing.T) {
+	tests := []struct {
+		name    string
+		spec    ServiceSpec
+		wantErr string
+	}{
+		{
+			name: "valid with neither Caddy nor Ports",
+			spec: ServiceSpec{
+				Name: "test",
+				Container: ContainerSpec{
+					Image: "nginx:latest",
+				},
+			},
+			wantErr: "",
+		},
+		{
+			name: "valid with Caddy only",
+			spec: ServiceSpec{
+				Name: "test",
+				Container: ContainerSpec{
+					Image: "nginx:latest",
+				},
+				Caddy: &CaddySpec{
+					Config: "example.com {\n  reverse_proxy :8080\n}",
+				},
+			},
+			wantErr: "",
+		},
+		{
+			name: "valid with Ports only",
+			spec: ServiceSpec{
+				Name: "test",
+				Container: ContainerSpec{
+					Image: "nginx:latest",
+				},
+				Ports: []PortSpec{
+					{
+						ContainerPort: 80,
+						Protocol:      ProtocolHTTP,
+					},
+				},
+			},
+			wantErr: "",
+		},
+		{
+			name: "valid with empty Caddy config and Ports",
+			spec: ServiceSpec{
+				Name: "test",
+				Container: ContainerSpec{
+					Image: "nginx:latest",
+				},
+				Caddy: &CaddySpec{
+					Config: "",
+				},
+				Ports: []PortSpec{
+					{
+						ContainerPort: 80,
+						Protocol:      ProtocolHTTP,
+					},
+				},
+			},
+			wantErr: "",
+		},
+		{
+			name: "invalid with both Caddy and Ports",
+			spec: ServiceSpec{
+				Name: "test",
+				Container: ContainerSpec{
+					Image: "nginx:latest",
+				},
+				Caddy: &CaddySpec{
+					Config: "example.com {\n  reverse_proxy :8080\n}",
+				},
+				Ports: []PortSpec{
+					{
+						ContainerPort: 80,
+						Protocol:      ProtocolHTTP,
+					},
+				},
+			},
+			wantErr: "ports and Caddy configuration cannot be specified simultaneously",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := tt.spec.Validate()
+			if tt.wantErr == "" {
+				require.NoError(t, err)
+			} else {
+				require.ErrorContains(t, err, tt.wantErr)
+			}
+		})
+	}
+}

pkg/client/compose/caddy_test.go

@@ -12,7 +12,7 @@ func TestCaddyExtension(t *testing.T) {
 		name        string
 		composeYAML string
 		wantConfig  string
-		wantErr     bool
+		wantErr     string
 	}{
 		{
 			name: "x-caddy as string",
@@ -93,7 +93,7 @@ services:
         }
       unknown_field: "should cause error"
 `,
-			wantErr: true,
+			wantErr: "invalid keys: unknown_field",
 		},
 		{
 			name: "x-caddy with non-string config field should fail",
@@ -104,7 +104,22 @@ services:
     x-caddy:
       config: 123
 `,
-			wantErr: true,
+			wantErr: "expected type 'string'",
+		},
+		{
+			name: "x-caddy with x-ports conflict",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+    x-caddy: |
+      example.com {
+        reverse_proxy web:80
+      }
+    x-ports:
+      - example.com:80/http
+`,
+			wantErr: "cannot specify both 'x-caddy' and 'x-ports'",
 		},
 	}
 
@@ -112,8 +127,8 @@ services:
 		t.Run(tt.name, func(t *testing.T) {
 			project, err := loadProjectFromContent(t, tt.composeYAML)
 
-			if tt.wantErr {
+			if tt.wantErr != "" {
-				require.Error(t, err, "expected error for test case with invalid extension")
+				require.ErrorContains(t, err, tt.wantErr)
 				return
 			}
 

pkg/client/compose/project.go

@@ -49,5 +49,10 @@ func LoadProject(ctx context.Context, paths []string, opts ...composecli.Project
 		return nil, err
 	}
 
+	// Validate extension combinations after all transformations.
+	if err = validateServicesExtensions(project); err != nil {
+		return nil, err
+	}
+
 	return project, nil
 }

pkg/client/compose/service.go

@@ -57,6 +57,12 @@ func ServiceSpecFromCompose(project *types.Project, serviceName string) (api.Ser
 		Mode: api.ServiceModeReplicated,
 	}
 
+	// Map x-caddy extension to spec.Caddy if specified.
+	if caddy, ok := service.Extensions[CaddyExtensionKey].(Caddy); ok && caddy.Config != "" {
+		spec.Caddy = &api.CaddySpec{
+			Config: caddy.Config,
+		}
+	}
 	if ports, ok := service.Extensions[PortsExtensionKey].([]api.PortSpec); ok {
 		spec.Ports = ports
 	}
@@ -242,3 +248,26 @@ func tmpfsVolumeSpecFromCompose(serviceVolume types.ServiceVolumeConfig) api.Vol
 
 	return spec
 }
+
+// validateServicesExtensions validates extension combinations across all services in the project.
+func validateServicesExtensions(project *types.Project) error {
+	for _, service := range project.Services {
+		// Check for x-caddy and x-ports conflict.
+		hasCaddy := false
+		if caddy, ok := service.Extensions[CaddyExtensionKey].(Caddy); ok && caddy.Config != "" {
+			hasCaddy = true
+		}
+
+		hasPorts := false
+		if ports, ok := service.Extensions[PortsExtensionKey].([]api.PortSpec); ok && len(ports) > 0 {
+			hasPorts = true
+		}
+
+		if hasCaddy && hasPorts {
+			return fmt.Errorf("service '%s' cannot specify both 'x-caddy' and 'x-ports': "+
+				"Caddy config is auto-generated from ports, use only one of them", service.Name)
+		}
+	}
+
+	return nil
+}

pkg/client/compose/service_test.go

@@ -2,6 +2,7 @@ package compose
 
 import (
 	"context"
+	"net/netip"
 	"path/filepath"
 	"slices"
 	"strings"
@@ -54,6 +55,11 @@ func loadProjectFromContent(t *testing.T, content string) (*types.Project, error
 		return nil, err
 	}
 
+	// Validate extension combinations after all transformations.
+	if err = validateServicesExtensions(project); err != nil {
+		return nil, err
+	}
+
 	return project, nil
 }
 
@@ -186,6 +192,25 @@ func TestServiceSpecFromCompose(t *testing.T) {
 							},
 						},
 					},
+					Ports: []api.PortSpec{
+						{
+							Hostname:      "test.example.com",
+							ContainerPort: 80,
+							Protocol:      api.ProtocolHTTPS,
+							Mode:          api.PortModeIngress,
+						},
+						{
+							ContainerPort: 8000,
+							Protocol:      api.ProtocolHTTP,
+							Mode:          api.PortModeIngress,
+						},
+						{
+							ContainerPort: 3000,
+							PublishedPort: 5000,
+							Protocol:      "tcp",
+							Mode:          api.PortModeHost,
+						},
+					},
 					Replicas: 3,
 					Volumes: []api.VolumeSpec{
 						{
@@ -229,6 +254,20 @@ func TestServiceSpecFromCompose(t *testing.T) {
 						},
 					},
 				},
+				"test-caddy-config": {
+					Name: "test-caddy-config",
+					Mode: api.ServiceModeReplicated,
+					Container: api.ContainerSpec{
+						Image:      "myapp:1.2.3",
+						PullPolicy: api.PullPolicyMissing,
+					},
+					Caddy: &api.CaddySpec{
+						Config: `test-caddy-config.example.com {
+  reverse_proxy {{ upstreams 80 }}
+}
+`,
+					},
+				},
 			},
 		},
 	}
@@ -249,13 +288,115 @@ func TestServiceSpecFromCompose(t *testing.T) {
 					return strings.Compare(a.Name, b.Name)
 				})
 
-				assert.True(t, cmp.Equal(spec, expectedSpec, cmpopts.EquateEmpty()),
+				cmpOpts := cmp.Options{cmpopts.EquateEmpty(), cmpopts.EquateComparable(netip.Addr{})}
-					cmp.Diff(spec, expectedSpec, cmpopts.EquateEmpty()))
+				assert.True(t, cmp.Equal(spec, expectedSpec, cmpOpts...), cmp.Diff(spec, expectedSpec, cmpOpts...))
 			}
 		})
 	}
 }
 
+func TestServiceSpecFromCompose_Caddy(t *testing.T) {
+	tests := []struct {
+		name        string
+		composeYAML string
+		want        *api.CaddySpec
+	}{
+		{
+			name: "x-caddy as string",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+    x-caddy: |
+      example.com {
+        reverse_proxy web:80
+      }
+`,
+			want: &api.CaddySpec{
+				Config: `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
+        }
+`,
+			want: &api.CaddySpec{
+				Config: `example.com {
+  reverse_proxy web:80
+}
+`,
+			},
+		},
+		{
+			name: "x-caddy with path to Caddyfile",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+    x-caddy: testdata/Caddyfile
+`,
+			want: &api.CaddySpec{
+				Config: `test.example.com {
+  reverse_proxy test:8000
+}
+`,
+			},
+		},
+		{
+			name: "x-caddy with empty string",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+    x-caddy: ""
+`,
+			want: nil,
+		},
+		{
+			name: "no x-caddy extension",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+`,
+			want: nil,
+		},
+		{
+			name: "x-caddy with empty object",
+			composeYAML: `
+services:
+  web:
+    image: nginx
+    x-caddy: {}
+`,
+			want: nil,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			project, err := loadProjectFromContent(t, tt.composeYAML)
+			require.NoError(t, err)
+
+			spec, err := ServiceSpecFromCompose(project, "web")
+			require.NoError(t, err)
+
+			assert.Equal(t, tt.want, spec.Caddy)
+		})
+	}
+}
+
 func TestServiceSpecFromCompose_XMachinesPlacement(t *testing.T) {
 	tests := []struct {
 		name        string

pkg/client/compose/testdata/compose-full-spec.yaml

@@ -31,6 +31,18 @@ services:
         target: /tmpfs
         tmpfs:
           size: 10485760
+    x-ports:
+      - test.example.com:80/https
+      - 8000/http
+      - 5000:3000@host
+
+  test-caddy-config:
+    image: myapp:1.2.3
+    # x-ports and x-caddy are mutually exclusive.
+    x-caddy: |
+      test-caddy-config.example.com {
+        reverse_proxy {{ upstreams 80 }}
+      }
 
 volumes:
   data1: