add scale command as alpha

Signed-off-by: Guillaume Lours <705411+glours@users.noreply.github.com>

cmd/compose/alpha.go

@@ -32,6 +32,7 @@ func alphaCommand(p *ProjectOptions, backend api.Service) *cobra.Command {
 	cmd.AddCommand(
 		watchCommand(p, backend),
 		vizCommand(p, backend),
+		scaleCommand(p, backend),
 	)
 	return cmd
 }

cmd/compose/scale.go

@@ -0,0 +1,103 @@
+/*
+   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/compose-spec/compose-go/types"
+	"github.com/pkg/errors"
+	"golang.org/x/exp/maps"
+	"strconv"
+	"strings"
+
+	"github.com/docker/compose/v2/pkg/api"
+	"github.com/spf13/cobra"
+)
+
+type scaleOptions struct {
+	*ProjectOptions
+	noDeps bool
+}
+
+func scaleCommand(p *ProjectOptions, backend api.Service) *cobra.Command {
+	opts := scaleOptions{
+		ProjectOptions: p,
+	}
+	scaleCmd := &cobra.Command{
+		Use:   "scale [SERVICE=REPLICAS...]",
+		Short: "Scale services ",
+		Args:  cobra.MinimumNArgs(1),
+		RunE: Adapt(func(ctx context.Context, args []string) error {
+			serviceTuples, err := parseServicesReplicasArgs(args)
+			if err != nil {
+				return err
+			}
+			return runScale(ctx, backend, opts, serviceTuples)
+		}),
+		ValidArgsFunction: completeServiceNames(p),
+	}
+	flags := scaleCmd.Flags()
+	flags.BoolVar(&opts.noDeps, "no-deps", false, "Don't start linked services.")
+
+	return scaleCmd
+}
+
+func runScale(ctx context.Context, backend api.Service, opts scaleOptions, serviceReplicaTuples map[string]int) error {
+	services := maps.Keys(serviceReplicaTuples)
+	project, err := opts.ToProject(services)
+	if err != nil {
+		return err
+	}
+
+	if opts.noDeps {
+		project.ForServices(services, types.IgnoreDependencies)
+	}
+
+tuplesLoop:
+	for key, value := range serviceReplicaTuples {
+		for i, service := range project.Services {
+			if service.Name == key {
+				if service.Deploy == nil {
+					service.Deploy = &types.DeployConfig{}
+				}
+				scale := uint64(value)
+				service.Deploy.Replicas = &scale
+				project.Services[i] = service
+				continue tuplesLoop
+			}
+		}
+	}
+
+	return backend.Scale(ctx, project, api.ScaleOptions{Services: services})
+}
+
+func parseServicesReplicasArgs(args []string) (map[string]int, error) {
+	serviceReplicaTuples := map[string]int{}
+	for _, arg := range args {
+		key, val, ok := strings.Cut(arg, "=")
+		if !ok || key == "" || val == "" {
+			return nil, errors.Errorf("Invalide scale specifier %q.", arg)
+		}
+		intValue, err := strconv.Atoi(val)
+
+		if err != nil {
+			return nil, errors.Errorf("Invalide scale specifier, can't parse replicate value to int %q.", arg)
+		}
+		serviceReplicaTuples[key] = intValue
+	}
+	return serviceReplicaTuples, nil
+}

docs/reference/compose_alpha_scale.md

@@ -0,0 +1,15 @@
+# docker compose alpha scale
+
+<!---MARKER_GEN_START-->
+Scale services 
+
+### Options
+
+| Name        | Type | Default | Description                     |
+|:------------|:-----|:--------|:--------------------------------|
+| `--dry-run` |      |         | Execute command in dry run mode |
+| `--no-deps` |      |         | Don't start linked services.    |
+
+
+<!---MARKER_GEN_END-->
+

docs/reference/docker_compose_alpha.yaml

@@ -4,9 +4,11 @@ long: Experimental commands
 pname: docker compose
 plink: docker_compose.yaml
 cname:
+    - docker compose alpha scale
     - docker compose alpha viz
     - docker compose alpha watch
 clink:
+    - docker_compose_alpha_scale.yaml
     - docker_compose_alpha_viz.yaml
     - docker_compose_alpha_watch.yaml
 inherited_options:

docs/reference/docker_compose_alpha_scale.yaml

@@ -0,0 +1,35 @@
+command: docker compose alpha scale
+short: Scale services
+long: Scale services
+usage: docker compose alpha scale [SERVICE=REPLICAS...]
+pname: docker compose alpha
+plink: docker_compose_alpha.yaml
+options:
+    - option: no-deps
+      value_type: bool
+      default_value: "false"
+      description: Don't start linked services.
+      deprecated: false
+      hidden: false
+      experimental: false
+      experimentalcli: false
+      kubernetes: false
+      swarm: false
+inherited_options:
+    - option: dry-run
+      value_type: bool
+      default_value: "false"
+      description: Execute command in dry run mode
+      deprecated: false
+      hidden: false
+      experimental: false
+      experimentalcli: false
+      kubernetes: false
+      swarm: false
+deprecated: false
+hidden: false
+experimental: false
+experimentalcli: true
+kubernetes: false
+swarm: false
+

go.mod

@@ -50,6 +50,8 @@ require (
 	gotest.tools/v3 v3.5.0
 )
 
+require golang.org/x/exp v0.0.0-20230713183714-613f0c0eb8a1
+
 require (
 	github.com/AdaLogics/go-fuzz-headers v0.0.0-20230106234847-43070de90fa1 // indirect
 	github.com/Azure/go-ansiterm v0.0.0-20210617225240-d185dfc1b5a1 // indirect
@@ -155,7 +157,6 @@ require (
 	go.opentelemetry.io/otel/metric v0.37.0 // indirect
 	go.opentelemetry.io/proto/otlp v0.19.0 // indirect
 	golang.org/x/crypto v0.7.0 // indirect
-	golang.org/x/exp v0.0.0-20230713183714-613f0c0eb8a1 // indirect
 	golang.org/x/mod v0.11.0 // indirect
 	golang.org/x/net v0.9.0 // indirect
 	golang.org/x/oauth2 v0.7.0 // indirect

pkg/api/api.go

@@ -86,6 +86,12 @@ type Service interface {
 	Viz(ctx context.Context, project *types.Project, options VizOptions) (string, error)
 	// Wait blocks until at least one of the services' container exits
 	Wait(ctx context.Context, projectName string, options WaitOptions) (int64, error)
+	// Scale manages numbers of container instances running per service
+	Scale(ctx context.Context, project *types.Project, options ScaleOptions) error
+}
+
+type ScaleOptions struct {
+	Services []string
 }
 
 type WaitOptions struct {

pkg/api/proxy.go

@@ -55,6 +55,7 @@ type ServiceProxy struct {
 	DryRunModeFn         func(ctx context.Context, dryRun bool) (context.Context, error)
 	VizFn                func(ctx context.Context, project *types.Project, options VizOptions) (string, error)
 	WaitFn               func(ctx context.Context, projectName string, options WaitOptions) (int64, error)
+	ScaleFn              func(ctx context.Context, project *types.Project, options ScaleOptions) error
 	interceptors         []Interceptor
 }
 
@@ -97,6 +98,7 @@ func (s *ServiceProxy) WithService(service Service) *ServiceProxy {
 	s.DryRunModeFn = service.DryRunMode
 	s.VizFn = service.Viz
 	s.WaitFn = service.Wait
+	s.ScaleFn = service.Scale
 	return s
 }
 
@@ -343,6 +345,13 @@ func (s *ServiceProxy) Wait(ctx context.Context, projectName string, options Wai
 	return s.WaitFn(ctx, projectName, options)
 }
 
+func (s *ServiceProxy) Scale(ctx context.Context, project *types.Project, options ScaleOptions) error {
+	if s.ScaleFn == nil {
+		return ErrNotImplemented
+	}
+	return s.ScaleFn(ctx, project, options)
+}
+
 func (s *ServiceProxy) MaxConcurrency(i int) {
 	s.MaxConcurrencyFn(i)
 }

pkg/compose/scale.go

@@ -0,0 +1,35 @@
+/*
+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/compose-spec/compose-go/types"
+	"github.com/docker/compose/v2/internal/tracing"
+	"github.com/docker/compose/v2/pkg/api"
+	"github.com/docker/compose/v2/pkg/progress"
+)
+
+func (s *composeService) Scale(ctx context.Context, project *types.Project, options api.ScaleOptions) error {
+	return progress.Run(ctx, tracing.SpanWrapFunc("project/scale", tracing.ProjectOptions(project), func(ctx context.Context) error {
+		err := s.create(ctx, project, api.CreateOptions{Services: options.Services})
+		if err != nil {
+			return err
+		}
+		return s.start(ctx, project.Name, api.StartOptions{Project: project, Services: options.Services}, nil)
+
+	}), s.stdinfo())
+}