introduce pull --missing flag to only pull images not present in cache

Signed-off-by: Nicolas De Loof <[email protected]>

cmd/compose/pull.go

@@ -38,6 +38,7 @@ type pullOptions struct {
 	includeDeps        bool
 	ignorePullFailures bool
 	noBuildable        bool
+	missing            bool
 }
 
 func pullCommand(p *ProjectOptions, dockerCli command.Cli, backend api.Service) *cobra.Command {
@@ -67,6 +68,7 @@ func pullCommand(p *ProjectOptions, dockerCli command.Cli, backend api.Service)
 	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.noBuildable, "ignore-buildable", false, "Ignore images that can be built.")
+	cmd.Flags().BoolVar(&opts.missing, "missing", false, "Only pull images that are not present in local cache.")
 	return cmd
 }
 
@@ -83,6 +85,13 @@ func runPull(ctx context.Context, dockerCli command.Cli, backend api.Service, op
 		}
 	}
 
+	if opts.missing {
+		for i, service := range project.Services {
+			service.PullPolicy = types.PullPolicyMissing
+			project.Services[i] = service
+		}
+	}
+
 	return backend.Pull(ctx, project, api.PullOptions{
 		Quiet:           opts.quiet,
 		IgnoreFailures:  opts.ignorePullFailures,