Create services in dependency order

Signed-off-by: Nicolas De Loof <nicolas.deloof@gmail.com>

local/compose.go

@@ -28,7 +28,6 @@ import (
 	"sync"
 
 	"github.com/opencontainers/go-digest"
-	"golang.org/x/sync/errgroup"
 
 	"github.com/compose-spec/compose-go/types"
 	"github.com/docker/compose-cli/api/compose"
@@ -71,16 +70,20 @@ func (s *local) Up(ctx context.Context, project *types.Project, detach bool) err
 		}
 	}
 
-	w := progress.ContextWriter(ctx)
-	eg, ctx := errgroup.WithContext(ctx)
 	for _, service := range project.Services {
-		service := service
-		eg.Go(func() error {
 		err := s.applyPullPolicy(ctx, service)
 		if err != nil {
 			return err
 		}
+	}
 
+	err := inDependencyOrder(ctx, project, func(service types.ServiceConfig) error {
+		return s.ensureService(ctx, project, service)
+	})
+	return err
+}
+
+func (s *local) ensureService(ctx context.Context, project *types.Project, service types.ServiceConfig) error {
 	actual, err := s.containerService.apiClient.ContainerList(ctx, moby.ContainerListOptions{
 		Filters: filters.NewArgs(
 			filters.Arg("label", "com.docker.compose.project="+project.Name),
@@ -96,6 +99,7 @@ func (s *local) Up(ctx context.Context, project *types.Project, detach bool) err
 		return err
 	}
 
+	w := progress.ContextWriter(ctx)
 	if len(actual) == 0 {
 		w.Event(progress.Event{
 			ID:         fmt.Sprintf("Service %q", service.Name),
@@ -175,9 +179,6 @@ func (s *local) Up(ctx context.Context, project *types.Project, detach bool) err
 		Done:       true,
 	})
 	return nil
-		})
-	}
-	return eg.Wait()
 }
 
 func getContainerName(c moby.Container) string {
@@ -711,3 +712,12 @@ func contains(slice []string, item string) bool {
 	}
 	return false
 }
+
+func containsAll(slice []string, items []string) bool {
+	for _, i := range items {
+		if !contains(slice, i) {
+			return false
+		}
+	}
+	return true
+}

local/dependencies.go

@@ -0,0 +1,60 @@
+// +build local
+
+/*
+   Copyright 2020 Docker Compose CLI authors
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package local
+
+import (
+	"context"
+	"github.com/compose-spec/compose-go/types"
+	"golang.org/x/sync/errgroup"
+)
+
+func inDependencyOrder(ctx context.Context, project *types.Project, fn func(types.ServiceConfig) error) error {
+	eg, ctx := errgroup.WithContext(ctx)
+	var (
+		scheduled []string
+		ready []string
+	)
+	results := make(chan string)
+	for len(ready) < len(project.Services) {
+		for _, service := range project.Services {
+			if contains(scheduled, service.Name) {
+				continue
+			}
+			if containsAll(ready, service.GetDependencies()) {
+				service := service
+				scheduled = append(scheduled, service.Name)
+				eg.Go(func() error {
+					err := fn(service)
+					if err != nil {
+						close(results)
+						return err
+					}
+					results <- service.Name
+					return nil
+				})
+			}
+		}
+		result, ok := <-results
+		if !ok {
+			break
+		}
+		ready = append(ready, result)
+	}
+	return eg.Wait()
+}

local/dependencies_test.go

@@ -0,0 +1,57 @@
+// +build local
+
+/*
+   Copyright 2020 Docker Compose CLI authors
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package local
+
+import (
+	"context"
+	"gotest.tools/v3/assert"
+	"testing"
+
+	"github.com/compose-spec/compose-go/types"
+)
+
+func TestInDependencyOrder(t *testing.T) {
+	order := make(chan string)
+	project := types.Project{
+		Services: []types.ServiceConfig{
+			{
+				Name:            "test1",
+				DependsOn: map[string]types.ServiceDependency{
+					"test2": {},
+				},
+			},
+			{
+				Name:            "test2",
+				DependsOn: map[string]types.ServiceDependency{
+					"test3": {},
+				},
+			},
+			{
+				Name:            "test3",
+			},
+		},
+	}
+	go inDependencyOrder(context.TODO(), &project, func(config types.ServiceConfig) error {
+		order <- config.Name
+		return nil
+	})
+	assert.Equal(t, <- order, "test3")
+	assert.Equal(t, <- order, "test2")
+	assert.Equal(t, <- order, "test1")
+}