docker compose attach via RunAttach (from docker/cli's docker contain…

…er attach)

cmd/compose/attach.go

@@ -0,0 +1,79 @@
+/*
+   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 compose
+
+import (
+	"context"
+
+	"github.com/docker/cli/cli/command"
+	"github.com/docker/compose/v2/pkg/api"
+	"github.com/spf13/cobra"
+)
+
+type attachOpts struct {
+	*composeOptions
+
+	service string
+	index   int
+
+	detachKeys string
+
+	// todo docker container attach also has:
+	// --no-stdin  // whole point of attach is for STDIN (can already attach to STDOUT and STDERR via docker compose up)
+	// --sig-proxy
+
+}
+
+func attachCommand(p *ProjectOptions, dockerCli command.Cli, backend api.Service) *cobra.Command {
+	opts := attachOpts{
+		composeOptions: &composeOptions{
+			ProjectOptions: p,
+		},
+	}
+	runCmd := &cobra.Command{
+		Use:   "attach [OPTIONS] SERVICE",
+		Short: "Attach local standard input, output, and error streams to a service's running container.",
+		Args:  cobra.MinimumNArgs(1),
+		PreRunE: Adapt(func(ctx context.Context, args []string) error {
+			opts.service = args[0]
+			return nil
+		}),
+		RunE: Adapt(func(ctx context.Context, args []string) error {
+			return runAttach(ctx, dockerCli, backend, opts)
+		}),
+		ValidArgsFunction: completeServiceNames(dockerCli, p),
+	}
+
+	runCmd.Flags().IntVar(&opts.index, "index", 0, "index of the container if service has multiple replicas.")
+	runCmd.Flags().StringVarP(&opts.detachKeys, "detach-keys", "", "", "Override the key sequence for detaching from a container.")
+
+	return runCmd
+}
+
+func runAttach(ctx context.Context, dockerCli command.Cli, backend api.Service, opts attachOpts) error {
+	projectName, err := opts.toProjectName(dockerCli)
+	if err != nil {
+		return err
+	}
+
+	attachOpts := api.AttachOptions{
+		Service:    opts.service,
+		Index:      opts.index,
+		DetachKeys: opts.detachKeys,
+	}
+	return backend.Attach(ctx, projectName, attachOpts)
+}

cmd/compose/compose.go

@@ -444,6 +444,7 @@ func RootCommand(dockerCli command.Cli, backend api.Service) *cobra.Command { //
 		runCommand(&opts, dockerCli, backend),
 		removeCommand(&opts, dockerCli, backend),
 		execCommand(&opts, dockerCli, backend),
+		attachCommand(&opts, dockerCli, backend),
 		pauseCommand(&opts, dockerCli, backend),
 		unpauseCommand(&opts, dockerCli, backend),
 		topCommand(&opts, dockerCli, backend),

pkg/api/api.go

@@ -62,6 +62,8 @@ type Service interface {
 	Remove(ctx context.Context, projectName string, options RemoveOptions) error
 	// Exec executes a command in a running service container
 	Exec(ctx context.Context, projectName string, options RunOptions) (int, error)
+	// Attach STDIN,STDOUT,STDERR to a running service container
+	Attach(ctx context.Context, projectName string, options AttachOptions) error
 	// Copy copies a file/folder between a service container and the local filesystem
 	Copy(ctx context.Context, projectName string, options CopyOptions) error
 	// Pause executes the equivalent to a `compose pause`
@@ -340,6 +342,14 @@ type RunOptions struct {
 	Index int
 }
 
+// AttachOptions group options of the Attach API
+type AttachOptions struct {
+	Project    *types.Project
+	Service    string
+	Index      int
+	DetachKeys string
+}
+
 // EventsOptions group options of the Events API
 type EventsOptions struct {
 	Services []string

pkg/api/proxy.go

@@ -43,6 +43,7 @@ type ServiceProxy struct {
 	RunOneOffContainerFn func(ctx context.Context, project *types.Project, opts RunOptions) (int, error)
 	RemoveFn             func(ctx context.Context, project string, options RemoveOptions) error
 	ExecFn               func(ctx context.Context, project string, opts RunOptions) (int, error)
+	AttachFn             func(ctx context.Context, project string, opts AttachOptions) error
 	CopyFn               func(ctx context.Context, project string, options CopyOptions) error
 	PauseFn              func(ctx context.Context, project string, options PauseOptions) error
 	UnPauseFn            func(ctx context.Context, project string, options PauseOptions) error
@@ -87,6 +88,7 @@ func (s *ServiceProxy) WithService(service Service) *ServiceProxy {
 	s.RunOneOffContainerFn = service.RunOneOffContainer
 	s.RemoveFn = service.Remove
 	s.ExecFn = service.Exec
+	s.AttachFn = service.Attach
 	s.CopyFn = service.Copy
 	s.PauseFn = service.Pause
 	s.UnPauseFn = service.UnPause
@@ -267,6 +269,14 @@ func (s *ServiceProxy) Exec(ctx context.Context, projectName string, options Run
 	return s.ExecFn(ctx, projectName, options)
 }
 
+// Attach implements Service interface
+func (s *ServiceProxy) Attach(ctx context.Context, projectName string, options AttachOptions) error {
+	if s.AttachFn == nil {
+		return ErrNotImplemented
+	}
+	return s.AttachFn(ctx, projectName, options)
+}
+
 // Copy implements Service interface
 func (s *ServiceProxy) Copy(ctx context.Context, projectName string, options CopyOptions) error {
 	if s.CopyFn == nil {

pkg/compose/attach_service.go

@@ -0,0 +1,37 @@
+/*
+   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 compose
+
+import (
+	"context"
+	"strings"
+
+	"github.com/docker/cli/cli/command/container"
+	"github.com/docker/compose/v2/pkg/api"
+)
+
+func (s *composeService) Attach(ctx context.Context, projectName string, options api.AttachOptions) error {
+	projectName = strings.ToLower(projectName)
+	target, err := s.getSpecifiedContainer(ctx, projectName, oneOffInclude, false, options.Service, options.Index)
+	if err != nil {
+		return err
+	}
+
+	var attach container.AttachOptions
+	attach.DetachKeys = options.DetachKeys
+	return container.RunAttach(ctx, s.dockerCli, target.ID, &attach)
+}