feat(compose): Support depends_on property (#1634)

Reviewed-by: Alexander Jung <alex@unikraft.io>
Approved-by: Alexander Jung <alex@unikraft.io>

compose/project.go

@@ -240,3 +240,85 @@ func (project *Project) AssignIPs(ctx context.Context) error {
 
 	return nil
 }
+
+// ServicesOrderedByDependencies receives a list of services and generates a
+// new list ordered by dependencies. If expand is set, it will also include
+// dependencies not present in the original list.
+func (project *Project) ServicesOrderedByDependencies(ctx context.Context, services types.Services, expand bool) []types.ServiceConfig {
+	added := map[string]struct{}{}
+
+	var addDependenciesRecursevly func(service types.ServiceConfig)
+
+	orderedServices := []types.ServiceConfig{}
+	addDependenciesRecursevly = func(service types.ServiceConfig) {
+		added[service.Name] = struct{}{}
+		for name, dependency := range service.DependsOn {
+			_, ok := services[name]
+			if !ok && !expand {
+				continue
+			}
+
+			log.G(ctx).
+				WithField("service", service.Name).
+				WithField("on", name).
+				Debug("depends")
+
+			_, ok = added[name]
+			if !ok && dependency.Required {
+				addDependenciesRecursevly(project.Services[name])
+			}
+		}
+
+		orderedServices = append(orderedServices, service)
+	}
+
+	for _, service := range services {
+		_, ok := added[service.Name]
+		if !ok {
+			addDependenciesRecursevly(service)
+		}
+	}
+
+	return orderedServices
+}
+
+// ServicesReversedWithDependants receives a list of services and generates a
+// new list reverse ordered by dependencies. If expand is set, it will also
+// include dependendants not present in the original list.
+func (project *Project) ServicesReversedByDependencies(ctx context.Context, services types.Services, expand bool) []types.ServiceConfig {
+	added := map[string]struct{}{}
+
+	var addDependantsRecursevly func(service types.ServiceConfig)
+
+	reversedServices := []types.ServiceConfig{}
+	addDependantsRecursevly = func(service types.ServiceConfig) {
+		added[service.Name] = struct{}{}
+		for _, name := range service.GetDependents(project.Project) {
+			_, ok := services[name]
+			if !ok && !expand {
+				continue
+			}
+
+			log.G(ctx).
+				WithField("service", name).
+				WithField("on", service.Name).
+				Debug("depends")
+
+			_, ok = added[name]
+			if !ok && project.Services[name].DependsOn[service.Name].Required {
+				addDependantsRecursevly(project.Services[name])
+			}
+		}
+
+		reversedServices = append(reversedServices, service)
+	}
+
+	for _, service := range services {
+		_, ok := added[service.Name]
+		if !ok {
+			addDependantsRecursevly(service)
+		}
+	}
+
+	return reversedServices
+}

internal/cli/kraft/compose/create/create.go

@@ -274,7 +274,9 @@ func (opts *CreateOptions) Run(ctx context.Context, args []string) error {
 		return err
 	}
 
-	for _, service := range services {
+	orderedServices := project.ServicesOrderedByDependencies(ctx, services, true)
+	for _, service := range orderedServices {
+		log.G(ctx).Debugf("creating service %s...", service.Name)
 		alreadyCreated := false
 		for _, machine := range machines.Items {
 			if service.ContainerName != machine.Name {

internal/cli/kraft/compose/down/down.go

@@ -99,7 +99,8 @@ func (opts *DownOptions) Run(ctx context.Context, args []string) error {
 		return err
 	}
 
-	for _, service := range project.Services {
+	orderedServices := project.ServicesReversedByDependencies(ctx, project.Services, false)
+	for _, service := range orderedServices {
 		for _, machine := range machines.Items {
 			if service.ContainerName == machine.Name {
 				if err := removeService(ctx, service); err != nil {

internal/cli/kraft/compose/pause/pause.go

@@ -91,8 +91,9 @@ func (opts *PauseOptions) Run(ctx context.Context, args []string) error {
 		return err
 	}
 
+	orderedServices := project.ServicesReversedByDependencies(ctx, services, false)
 	machinesToPause := []string{}
-	for _, service := range services {
+	for _, service := range orderedServices {
 		for _, machine := range machines.Items {
 			if service.ContainerName == machine.Name && machine.Status.State == machineapi.MachineStateRunning {
 				machinesToPause = append(machinesToPause, machine.Name)

internal/cli/kraft/compose/start/start.go

@@ -91,8 +91,9 @@ func (opts *StartOptions) Run(ctx context.Context, args []string) error {
 		return err
 	}
 
+	orderedServices := project.ServicesOrderedByDependencies(ctx, services, true)
 	machinesToStart := []string{}
-	for _, service := range services {
+	for _, service := range orderedServices {
 		for _, machine := range machines.Items {
 			if service.ContainerName == machine.Name {
 				if machine.Status.State == machineapi.MachineStateCreated || machine.Status.State == machineapi.MachineStateExited {

internal/cli/kraft/compose/stop/stop.go

@@ -91,8 +91,9 @@ func (opts *StopOptions) Run(ctx context.Context, args []string) error {
 		return err
 	}
 
+	orderedServices := project.ServicesReversedByDependencies(ctx, services, false)
 	machinesToStop := []string{}
-	for _, service := range services {
+	for _, service := range orderedServices {
 		for _, machine := range machines.Items {
 			if service.ContainerName == machine.Name &&
 				(machine.Status.State == machineapi.MachineStateRunning ||

internal/cli/kraft/compose/unpause/unpause.go

@@ -91,8 +91,9 @@ func (opts *UnpauseOptions) Run(ctx context.Context, args []string) error {
 		return err
 	}
 
+	orderedServices := project.ServicesOrderedByDependencies(ctx, services, true)
 	machinesToUnpause := []string{}
-	for _, service := range services {
+	for _, service := range orderedServices {
 		for _, machine := range machines.Items {
 			if service.ContainerName == machine.Name {
 				if machine.Status.State == machineapi.MachineStatePaused {