DockerCLI/command/service/scale.go

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package service
import (
"fmt"
"strconv"
"strings"
"golang.org/x/net/context"
"github.com/docker/docker/api/types"
"github.com/docker/docker/cli"
"github.com/docker/docker/cli/command"
"github.com/spf13/cobra"
)
func newScaleCommand(dockerCli *command.DockerCli) *cobra.Command {
return &cobra.Command{
Use: "scale SERVICE=REPLICAS [SERVICE=REPLICAS...]",
Short: "Scale one or multiple services",
Args: scaleArgs,
RunE: func(cmd *cobra.Command, args []string) error {
return runScale(dockerCli, args)
},
}
}
func scaleArgs(cmd *cobra.Command, args []string) error {
if err := cli.RequiresMinArgs(1)(cmd, args); err != nil {
return err
}
for _, arg := range args {
if parts := strings.SplitN(arg, "=", 2); len(parts) != 2 {
return fmt.Errorf(
"Invalid scale specifier '%s'.\nSee '%s --help'.\n\nUsage: %s\n\n%s",
arg,
cmd.CommandPath(),
cmd.UseLine(),
cmd.Short,
)
}
}
return nil
}
func runScale(dockerCli *command.DockerCli, args []string) error {
var errors []string
for _, arg := range args {
parts := strings.SplitN(arg, "=", 2)
serviceID, scaleStr := parts[0], parts[1]
// validate input arg scale number
scale, err := strconv.ParseUint(scaleStr, 10, 64)
if err != nil {
errors = append(errors, fmt.Sprintf("%s: invalid replicas value %s: %v", serviceID, scaleStr, err))
continue
}
if err := runServiceScale(dockerCli, serviceID, scale); err != nil {
errors = append(errors, fmt.Sprintf("%s: %v", serviceID, err))
}
}
if len(errors) == 0 {
return nil
}
return fmt.Errorf(strings.Join(errors, "\n"))
}
func runServiceScale(dockerCli *command.DockerCli, serviceID string, scale uint64) error {
client := dockerCli.Client()
ctx := context.Background()
service, _, err := client.ServiceInspectWithRaw(ctx, serviceID)
if err != nil {
return err
}
serviceMode := &service.Spec.Mode
if serviceMode.Replicated == nil {
return fmt.Errorf("scale can only be used with replicated mode")
}
serviceMode.Replicated.Replicas = &scale
err = client.ServiceUpdate(ctx, service.ID, service.Version, service.Spec, types.ServiceUpdateOptions{})
if err != nil {
return err
}
fmt.Fprintf(dockerCli.Out(), "%s scaled to %d\n", serviceID, scale)
return nil
}