cli: add completion to list builder names

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

commands/inspect.go

@@ -113,7 +113,7 @@ func inspectCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 			}
 			return runInspect(dockerCli, options)
 		},
-		ValidArgsFunction: completion.Disable,
+		ValidArgsFunction: completion.BuilderNames(dockerCli),
 	}
 
 	flags := cmd.Flags()

commands/rm.go

@@ -93,7 +93,7 @@ func rmCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 			}
 			return runRm(dockerCli, options)
 		},
-		ValidArgsFunction: completion.Disable,
+		ValidArgsFunction: completion.BuilderNames(dockerCli),
 	}
 
 	flags := cmd.Flags()

commands/root.go

@@ -5,6 +5,7 @@ import (
 
 	imagetoolscmd "github.com/docker/buildx/commands/imagetools"
 	"github.com/docker/buildx/controller/remote"
+	"github.com/docker/buildx/util/cobrautil/completion"
 	"github.com/docker/buildx/util/logutil"
 	"github.com/docker/cli-docs-tool/annotation"
 	"github.com/docker/cli/cli"
@@ -93,6 +94,11 @@ func addCommands(cmd *cobra.Command, dockerCli command.Cli) {
 	if isExperimental() {
 		remote.AddControllerCommands(cmd, dockerCli)
 	}
+
+	cmd.RegisterFlagCompletionFunc( //nolint:errcheck
+		"builder",
+		completion.BuilderNames(dockerCli),
+	)
 }
 
 func rootFlags(options *rootOptions, flags *pflag.FlagSet) {

commands/stop.go

@@ -47,7 +47,7 @@ func stopCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 			}
 			return runStop(dockerCli, options)
 		},
-		ValidArgsFunction: completion.Disable,
+		ValidArgsFunction: completion.BuilderNames(dockerCli),
 	}
 
 	return cmd

commands/use.go

@@ -79,7 +79,7 @@ func useCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 			}
 			return runUse(dockerCli, options)
 		},
-		ValidArgsFunction: completion.Disable,
+		ValidArgsFunction: completion.BuilderNames(dockerCli),
 	}
 
 	flags := cmd.Flags()

util/cobrautil/completion/completion.go

@@ -4,6 +4,9 @@ import (
 	"strings"
 
 	"github.com/docker/buildx/bake"
+	"github.com/docker/buildx/builder"
+	"github.com/docker/buildx/store/storeutil"
+	"github.com/docker/cli/cli/command"
 	"github.com/spf13/cobra"
 )
 
@@ -36,3 +39,24 @@ func BakeTargets(files []string) ValidArgsFn {
 		return filtered, cobra.ShellCompDirectiveNoFileComp
 	}
 }
+
+func BuilderNames(dockerCli command.Cli) ValidArgsFn {
+	return func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+		txn, release, err := storeutil.GetStore(dockerCli)
+		if err != nil {
+			return nil, cobra.ShellCompDirectiveError
+		}
+		defer release()
+		builders, err := builder.GetBuilders(dockerCli, txn)
+		if err != nil {
+			return nil, cobra.ShellCompDirectiveError
+		}
+		var filtered []string
+		for _, b := range builders {
+			if toComplete == "" || strings.HasPrefix(b.Name, toComplete) {
+				filtered = append(filtered, b.Name)
+			}
+		}
+		return filtered, cobra.ShellCompDirectiveNoFileComp
+	}
+}