Add --dry-run option to pull cmd

cmd/compose/pull.go

@@ -36,6 +36,8 @@ type pullOptions struct {
 	noParallel         bool
 	includeDeps        bool
 	ignorePullFailures bool
+	dryRun             bool
+	format             string
 }
 
 func pullCommand(p *projectOptions, backend api.Service) *cobra.Command {
@@ -63,6 +65,8 @@ func pullCommand(p *projectOptions, backend api.Service) *cobra.Command {
 	cmd.Flags().BoolVar(&opts.parallel, "no-parallel", true, "DEPRECATED disable parallel pulling.")
 	flags.MarkHidden("no-parallel") //nolint:errcheck
 	cmd.Flags().BoolVar(&opts.ignorePullFailures, "ignore-pull-failures", false, "Pull what it can and ignores images with pull failures")
+	cmd.Flags().BoolVar(&opts.dryRun, "dry-run", false, "Calc and print effects of execution of pull command without any actual effects")
+	cmd.Flags().StringVar(&opts.format, "format", "", `Format the output. Only compatible with "--dry-run". Values: [pretty | json]. (Default: pretty)`)
 	return cmd
 }
 
@@ -88,5 +92,7 @@ func runPull(ctx context.Context, backend api.Service, opts pullOptions, service
 	return backend.Pull(ctx, project, api.PullOptions{
 		Quiet:          opts.quiet,
 		IgnoreFailures: opts.ignorePullFailures,
+		DryRun:         opts.dryRun,
+		Format:         opts.format,
 	})
 }

local/e2e/compose/compose_dry_run_test.go

@@ -0,0 +1,51 @@
+/*
+   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 e2e
+
+import (
+	"strings"
+	"testing"
+
+	"gotest.tools/v3/assert"
+
+	. "github.com/docker/compose-cli/utils/e2e"
+)
+
+func TestComposePullDryRun(t *testing.T) {
+	c := NewParallelE2eCLI(t, binDir)
+
+	t.Run("compose pull dry run", func(t *testing.T) {
+		// ensure storing alpine image and deleting hello-world
+		c.RunDockerCmd("pull", "alpine")
+		c.RunDockerCmd("rmi", "hello-world", "-f")
+
+		res := c.RunDockerCmd("compose", "-f", "./fixtures/dry-run-test/pull/compose.yaml", "pull", "--dry-run")
+		lines := Lines(res.Stdout())
+		for _, line := range lines {
+			if strings.Contains(line, "expected-skip") {
+				assert.Assert(t, strings.Contains(line, " skip "))
+			}
+			if strings.Contains(line, "expected-fail") {
+				assert.Assert(t, strings.Contains(line, " fail "))
+			}
+			if strings.Contains(line, "expected-fetch") {
+				assert.Assert(t, strings.Contains(line, " fetch "))
+			}
+		}
+	})
+
+}

local/e2e/compose/fixtures/dry-run-test/pull/compose.yaml

@@ -0,0 +1,14 @@
+services:
+  expected-fetch:
+    image: hello-world
+    command: top
+  expected-skip-already-exist:
+    image: alpine
+    command: top
+  expected-fail:
+    # this image is not expected to be registered on any registries
+    image: expected-not-to-be-registered
+    command: top
+  expected-skip-build:
+    build: .
+    command: top

pkg/api/api.go

@@ -175,6 +175,8 @@ type PushOptions struct {
 type PullOptions struct {
 	Quiet          bool
 	IgnoreFailures bool
+	DryRun         bool
+	Format         string
 }
 
 // ImagesOptions group options of the Images API
@@ -308,6 +310,7 @@ type ImageSummary struct {
 	Repository    string
 	Tag           string
 	Size          int64
+	Digests       []string
 }
 
 // ServiceStatus hold status about a service

pkg/compose/build.go

@@ -20,6 +20,8 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"strings"
+	"sync"
 
 	"github.com/compose-spec/compose-go/types"
 	"github.com/containerd/containerd/platforms"
@@ -29,10 +31,12 @@ import (
 	"github.com/docker/buildx/util/buildflags"
 	xprogress "github.com/docker/buildx/util/progress"
 	moby "github.com/docker/docker/api/types"
+	"github.com/docker/docker/registry"
 	bclient "github.com/moby/buildkit/client"
 	"github.com/moby/buildkit/session"
 	"github.com/moby/buildkit/session/auth/authprovider"
 	specs "github.com/opencontainers/image-spec/specs-go/v1"
+	"golang.org/x/sync/errgroup"
 
 	"github.com/docker/compose-cli/pkg/api"
 	"github.com/docker/compose-cli/pkg/progress"
@@ -97,7 +101,7 @@ func (s *composeService) ensureImagesExists(ctx context.Context, project *types.
 		}
 	}
 
-	images, err := s.getLocalImagesDigests(ctx, project)
+	images, err := s.getLocalImagesIDs(ctx, project)
 	if err != nil {
 		return err
 	}
@@ -163,7 +167,19 @@ func (s *composeService) getBuildOptions(project *types.Project, images map[stri
 
 }
 
-func (s *composeService) getLocalImagesDigests(ctx context.Context, project *types.Project) (map[string]string, error) {
+func (s *composeService) getLocalImagesIDs(ctx context.Context, project *types.Project) (map[string]string, error) {
+	imgs, err := s.getLocalImageSummaries(ctx, project)
+	if err != nil {
+		return nil, err
+	}
+	images := map[string]string{}
+	for name, info := range imgs {
+		images[name] = info.ID
+	}
+	return images, nil
+}
+
+func (s *composeService) getLocalImageSummaries(ctx context.Context, project *types.Project) (map[string]api.ImageSummary, error) {
 	imageNames := []string{}
 	for _, s := range project.Services {
 		imgName := getImageName(s, project.Name)
@@ -175,13 +191,64 @@ func (s *composeService) getLocalImagesDigests(ctx context.Context, project *typ
 	if err != nil {
 		return nil, err
 	}
-	images := map[string]string{}
-	for name, info := range imgs {
-		images[name] = info.ID
+	return imgs, nil
+}
+
+func (s *composeService) getLocalImagesDigests(ctx context.Context, project *types.Project) (map[string][]string, error) {
+	imgs, err := s.getLocalImageSummaries(ctx, project)
+	if err != nil {
+		return nil, err
+	}
+	images := map[string][]string{}
+	for name, summary := range imgs {
+		for _, d := range summary.Digests {
+			s := strings.Split(d, "@")
+			images[name] = append(images[name], s[len(s)-1])
+		}
 	}
 	return images, nil
 }
 
+func (s *composeService) getDistributionImagesDigests(ctx context.Context, project *types.Project) (map[string]string, error) {
+	images := map[string]string{}
+
+	for _, service := range project.Services {
+		if service.Image == "" {
+			continue
+		}
+		images[service.Image] = ""
+	}
+
+	info, err := s.apiClient.Info(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	if info.IndexServerAddress == "" {
+		info.IndexServerAddress = registry.IndexServer
+	}
+
+	l := sync.Mutex{}
+	eg, ctx := errgroup.WithContext(ctx)
+	for img := range images {
+		img := img
+		eg.Go(func() error {
+			registryAuth, err := getEncodedRegistryAuth(img, info, s.configFile)
+			if err != nil {
+				return err
+			}
+			inspect, _ := s.apiClient.DistributionInspect(ctx, img, registryAuth)
+			// Ignore error here.
+			// If you catch error here, all inspect requests will fail.
+			l.Lock()
+			images[img] = inspect.Descriptor.Digest.String()
+			l.Unlock()
+			return nil
+		})
+	}
+	return images, eg.Wait()
+}
+
 func (s *composeService) doBuild(ctx context.Context, project *types.Project, opts map[string]build.Options, observedState Containers, mode string) (map[string]string, error) {
 	info, err := s.apiClient.Info(ctx)
 	if err != nil {

pkg/compose/images.go

@@ -105,6 +105,7 @@ func (s *composeService) getImages(ctx context.Context, images []string) (map[st
 				Repository: repository,
 				Tag:        tag,
 				Size:       inspect.Size,
+				Digests:    inspect.RepoDigests,
 			}
 			l.Unlock()
 			return nil