deploy.update_config.order support to start-first or stop-first when replacing containers (#248)

pkg/client/compose/service.go

@@ -97,6 +97,20 @@ func ServiceSpecFromCompose(project *types.Project, serviceName string) (api.Ser
 		default:
 			return spec, fmt.Errorf("unsupported deploy mode: '%s'", service.Deploy.Mode)
 		}
+
+		// Parse update_config.order
+		if cfg := service.Deploy.UpdateConfig; cfg != nil {
+			switch cfg.Order {
+			case "":
+				// No order specified, use default behavior.
+			case "start-first":
+				spec.UpdateConfig.Order = api.UpdateOrderStartFirst
+			case "stop-first":
+				spec.UpdateConfig.Order = api.UpdateOrderStopFirst
+			default:
+				return spec, fmt.Errorf("unsupported update_config.order: '%s'", cfg.Order)
+			}
+		}
 	}
 
 	// TODO: can service.tmpfs be handled as tmpfs volume mounts as well?

pkg/client/compose/service_test.go

@@ -787,6 +787,112 @@ services:
 	}
 }
 
+func TestServiceSpecFromCompose_UpdateConfig(t *testing.T) {
+	tests := []struct {
+		name        string
+		composeYAML string
+		expected    api.UpdateConfig
+		expectError bool
+	}{
+		{
+			name: "no update_config",
+			composeYAML: `
+services:
+  test:
+    image: nginx
+`,
+			expected: api.UpdateConfig{},
+		},
+		{
+			name: "update_config with stop-first order",
+			composeYAML: `
+services:
+  test:
+    image: postgres
+    deploy:
+      update_config:
+        order: stop-first
+`,
+			expected: api.UpdateConfig{
+				Order: api.UpdateOrderStopFirst,
+			},
+		},
+		{
+			name: "update_config with start-first order",
+			composeYAML: `
+services:
+  test:
+    image: nginx
+    deploy:
+      update_config:
+        order: start-first
+`,
+			expected: api.UpdateConfig{
+				Order: api.UpdateOrderStartFirst,
+			},
+		},
+		{
+			name: "update_config with invalid order",
+			composeYAML: `
+services:
+  test:
+    image: nginx
+    deploy:
+      update_config:
+        order: invalid-order
+`,
+			expectError: true,
+		},
+		{
+			name: "update_config with empty order",
+			composeYAML: `
+services:
+  test:
+    image: nginx
+    deploy:
+      update_config:
+        parallelism: 1
+`,
+			expected: api.UpdateConfig{},
+		},
+		{
+			name: "update_config with replicas and order",
+			composeYAML: `
+services:
+  test:
+    image: nginx
+    deploy:
+      replicas: 3
+      update_config:
+        order: stop-first
+`,
+			expected: api.UpdateConfig{
+				Order: api.UpdateOrderStopFirst,
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			project, err := LoadProjectFromContent(context.Background(), tt.composeYAML)
+			if tt.expectError {
+				require.Error(t, err)
+				return
+			}
+			require.NoError(t, err)
+
+			spec, err := ServiceSpecFromCompose(project, "test")
+			if tt.expectError {
+				assert.Error(t, err)
+				return
+			}
+			require.NoError(t, err)
+
+			assert.Equal(t, tt.expected, spec.UpdateConfig)
+		})
+	}
+}
+
 func TestServiceSpecFromCompose_XMachinesPlacement(t *testing.T) {
 	tests := []struct {
 		name        string