fix(docker): Sync service.yml when compose expose is updated

The compose expose field was not parsed, so changes to it never
propagated to service.yml. Added Expose to composeService struct,
use it for container port extraction and primary service detection,
and regenerate service.yml metadata when compose file is updated.

Closes #104

Signed-off-by: nfebe <fenn25.fn@gmail.com>

Author: nfebe

internal/docker/discovery.go

@@ -28,6 +28,7 @@ type composeFile struct {
 type composeService struct {
 	Image    string        `yaml:"image"`
 	Ports    []interface{} `yaml:"ports"`
+	Expose   []interface{} `yaml:"expose"`
 	Networks []string      `yaml:"networks"`
 	Volumes  []string      `yaml:"volumes"`
 }
@@ -196,6 +197,12 @@ func (d *Discovery) parseComposeServices(composePath string) ([]models.Service,
 				service.Ports = append(service.Ports, portStr)
 			}
 		}
+		for _, p := range svc.Expose {
+			portStr := d.parsePort(p)
+			if portStr != "" {
+				service.Ports = append(service.Ports, portStr)
+			}
+		}
 
 		services = append(services, service)
 	}
@@ -538,7 +545,25 @@ func (d *Discovery) UpdateComposeFile(name string, content string) error {
 		_ = os.WriteFile(backup, data, 0644)
 	}
 
-	return os.WriteFile(composePath, []byte(content), 0644)
+	if err := os.WriteFile(composePath, []byte(content), 0644); err != nil {
+		return err
+	}
+
+	metadataPath := filepath.Join(dirPath, "service.yml")
+	if _, err := os.Stat(metadataPath); err == nil {
+		if newMeta := d.generateMetadataFromCompose(composePath, name); newMeta != nil {
+			existing, err := d.loadMetadata(metadataPath)
+			if err == nil {
+				existing.Networking.ContainerPort = newMeta.Networking.ContainerPort
+				if newMeta.Networking.Service != "" {
+					existing.Networking.Service = newMeta.Networking.Service
+				}
+				d.SaveMetadata(name, existing)
+			}
+		}
+	}
+
+	return nil
 }
 
 func (d *Discovery) SaveMetadata(name string, metadata *models.ServiceMetadata) error {
@@ -602,6 +627,12 @@ func (d *Discovery) generateMetadataFromCompose(composePath, name string) *model
 					metadata.Networking.ContainerPort = port
 				}
 			}
+		} else if len(svc.Expose) > 0 {
+			if portStr := d.parsePort(svc.Expose[0]); portStr != "" {
+				if port := d.extractContainerPort(portStr); port > 0 {
+					metadata.Networking.ContainerPort = port
+				}
+			}
 		}
 	}
 
@@ -618,7 +649,7 @@ func (d *Discovery) pickPrimaryService(services map[string]composeService) (stri
 		}
 	}
 	for name, svc := range services {
-		if len(svc.Ports) > 0 {
+		if len(svc.Ports) > 0 || len(svc.Expose) > 0 {
 			return name, svc
 		}
 	}

internal/docker/discovery_test.go

@@ -6,6 +6,9 @@ import (
 	"path/filepath"
 	"sort"
 	"testing"
+
+	"github.com/flatrun/agent/pkg/models"
+	"gopkg.in/yaml.v3"
 )
 
 func TestExtractBindMountPath(t *testing.T) {
@@ -408,6 +411,138 @@ func TestGenerateMetadataFromCompose_ServiceName(t *testing.T) {
 	}
 }
 
+func TestGenerateMetadataFromCompose_Expose(t *testing.T) {
+	tests := []struct {
+		name     string
+		compose  string
+		wantPort int
+	}{
+		{
+			name: "expose sets container port",
+			compose: `services:
+  app:
+    image: myapp:latest
+    expose:
+      - "80"
+`,
+			wantPort: 80,
+		},
+		{
+			name: "ports takes precedence over expose",
+			compose: `services:
+  app:
+    image: myapp:latest
+    ports:
+      - "8080:3000"
+    expose:
+      - "80"
+`,
+			wantPort: 3000,
+		},
+		{
+			name: "expose picks primary service in multi-service",
+			compose: `services:
+  app:
+    image: myapp:latest
+    expose:
+      - "8080"
+  db:
+    image: postgres:15
+`,
+			wantPort: 8080,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tmpDir, err := os.MkdirTemp("", "expose-test-*")
+			if err != nil {
+				t.Fatalf("Failed to create temp dir: %v", err)
+			}
+			defer os.RemoveAll(tmpDir)
+
+			composePath := filepath.Join(tmpDir, "docker-compose.yml")
+			if err := os.WriteFile(composePath, []byte(tt.compose), 0644); err != nil {
+				t.Fatalf("Failed to write compose file: %v", err)
+			}
+
+			d := NewDiscovery(tmpDir)
+			metadata := d.generateMetadataFromCompose(composePath, "test")
+			if metadata == nil {
+				t.Fatal("generateMetadataFromCompose returned nil")
+			}
+
+			if metadata.Networking.ContainerPort != tt.wantPort {
+				t.Errorf("ContainerPort = %d, want %d", metadata.Networking.ContainerPort, tt.wantPort)
+			}
+		})
+	}
+}
+
+func TestUpdateComposeFile_SyncsMetadata(t *testing.T) {
+	tmpDir, err := os.MkdirTemp("", "sync-test-*")
+	if err != nil {
+		t.Fatalf("Failed to create temp dir: %v", err)
+	}
+	defer os.RemoveAll(tmpDir)
+
+	deployDir := filepath.Join(tmpDir, "myapp")
+	if err := os.MkdirAll(deployDir, 0755); err != nil {
+		t.Fatalf("Failed to create deploy dir: %v", err)
+	}
+
+	compose := `services:
+  app:
+    image: myapp:latest
+    expose:
+      - "3000"
+`
+	composePath := filepath.Join(deployDir, "docker-compose.yml")
+	if err := os.WriteFile(composePath, []byte(compose), 0644); err != nil {
+		t.Fatalf("Failed to write compose: %v", err)
+	}
+
+	d := NewDiscovery(tmpDir)
+	metadata := &models.ServiceMetadata{
+		Name: "myapp",
+		Networking: models.NetworkingConfig{
+			ContainerPort: 3000,
+			Expose:        true,
+		},
+	}
+	if err := d.SaveMetadata("myapp", metadata); err != nil {
+		t.Fatalf("Failed to save metadata: %v", err)
+	}
+
+	updatedCompose := `services:
+  app:
+    image: myapp:latest
+    expose:
+      - "8080"
+`
+	if err := d.UpdateComposeFile("myapp", updatedCompose); err != nil {
+		t.Fatalf("UpdateComposeFile failed: %v", err)
+	}
+
+	metadataPath := filepath.Join(deployDir, "service.yml")
+	data, err := os.ReadFile(metadataPath)
+	if err != nil {
+		t.Fatalf("Failed to read service.yml: %v", err)
+	}
+
+	var updated models.ServiceMetadata
+	if err := yaml.Unmarshal(data, &updated); err != nil {
+		t.Fatalf("Failed to parse service.yml: %v", err)
+	}
+
+	if updated.Networking.ContainerPort != 8080 {
+		t.Errorf("ContainerPort = %d, want 8080", updated.Networking.ContainerPort)
+	}
+	if !updated.Networking.Expose {
+		t.Error("Expose should be preserved as true")
+	}
+}
+
 func TestExtractBindMounts(t *testing.T) {
 	tests := []struct {
 		name     string