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helm
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fix(comp): Prepare plugin completion for Cobra 1.0

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Cobra 1.0.0 introduces support for Custom Go Completions.  However,
there is a small difference compared to helm's existing solution.
The difference is that Cobra will not complete sub-commands if there
are any dynamic completion functions registered.

The way helm implemented plugin completions had the dynamic completion
function associated with the root plugin command (e.g. 2to3); with
Cobra, this prevents any of the sub-commands of the plugin to be
completed (i.e., 2to3 <TAB> will not show the static sub-commands).

The solution is to only register the dynamic completion function for a
plugin command that doesn't have any further sub-commands.  This allows
all sub-commands to be completed properly, and when there are no more
levels of sub-commands, the dynamic completion is called.

This commit had to make two changes to achieve this:
1- refactor the load_plugins.go file to extract the logic to call
   the plugin.complete executable (for dynamic completions), so that
   it could be added to each final sub-command.
2- load the static completion not only for the "completion" command like
   before, but also for the "__complete" command, so that when the
   __complete command is called for dynamic completion of a sub-command,
   it is aware of the sub-command in question.

The second change is also valuable for the future support of completion
for the Fish shell.  Completion for the fish shell uses the __complete
command not only for dynamic completions but also for basic command and
flag completion. This implies that the __complete command must be aware
of the plugins sub-commands, and therefore that the plugin's static
completion be loaded.

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>
pull/8134/head
Marc Khouzam 5 years ago committed by Marc Khouzam
parent 88f6991fff
commit 0366f9970f
1 changed files with 142 additions and 121 deletions
Show Stats Download Patch File Download Diff File

263
cmd/helm/load_plugins.go
Unescape View File

@ -64,21 +64,6 @@ func loadPlugins(baseCmd *cobra.Command, out io.Writer) {
return
}
processParent := func(cmd *cobra.Command, args []string) ([]string, error) {
k, u := manuallyProcessArgs(args)
if err := cmd.Parent().ParseFlags(k); err != nil {
return nil, err
}
return u, nil
}
// If we are dealing with the completion command, we try to load more details about the plugins
// if available, so as to allow for command and flag completion
if subCmd, _, err := baseCmd.Find(os.Args[1:]); err == nil && subCmd.Name() == "completion" {
loadPluginsForCompletion(baseCmd, found)
return
}
// Now we create commands for all of these.
for _, plug := range found {
plug := plug
@ -87,33 +72,6 @@ func loadPlugins(baseCmd *cobra.Command, out io.Writer) {
md.Usage = fmt.Sprintf("the %q plugin", md.Name)
}
// This function is used to setup the environment for the plugin and then
// call the executable specified by the parameter 'main'
callPluginExecutable := func(cmd *cobra.Command, main string, argv []string, out io.Writer) error {
env := os.Environ()
for k, v := range settings.EnvVars() {
env = append(env, fmt.Sprintf("%s=%s", k, v))
}
prog := exec.Command(main, argv...)
prog.Env = env
prog.Stdin = os.Stdin
prog.Stdout = out
prog.Stderr = os.Stderr
if err := prog.Run(); err != nil {
if eerr, ok := err.(*exec.ExitError); ok {
os.Stderr.Write(eerr.Stderr)
status := eerr.Sys().(syscall.WaitStatus)
return pluginError{
error: errors.Errorf("plugin %q exited with error", md.Name),
code: status.ExitStatus(),
}
}
return err
}
return nil
}
c := &cobra.Command{
Use: md.Name,
Short: md.Usage,
@ -134,62 +92,59 @@ func loadPlugins(baseCmd *cobra.Command, out io.Writer) {
return errors.Errorf("plugin %q exited with error", md.Name)
}
return callPluginExecutable(cmd, main, argv, out)
return callPluginExecutable(md.Name, main, argv, out)
},
// This passes all the flags to the subcommand.
DisableFlagParsing: true,
}
// TODO: Make sure a command with this name does not already exist.
baseCmd.AddCommand(c)
// Setup dynamic completion for the plugin
completion.RegisterValidArgsFunc(c, func(cmd *cobra.Command, args []string, toComplete string) ([]string, completion.BashCompDirective) {
u, err := processParent(cmd, args)
if err != nil {
return nil, completion.BashCompDirectiveError
}
// We will call the dynamic completion script of the plugin
main := strings.Join([]string{plug.Dir, pluginDynamicCompletionExecutable}, string(filepath.Separator))
argv := []string{}
if !md.IgnoreFlags {
argv = append(argv, u...)
argv = append(argv, toComplete)
}
plugin.SetupPluginEnv(settings, md.Name, plug.Dir)
// For completion, we try to load more details about the plugins so as to allow for command and
// flag completion of the plugin itself.
// We only do this when necessary (for the "completion" and "__complete" commands) to avoid the
// risk of a rogue plugin affecting Helm's normal behavior.
subCmd, _, err := baseCmd.Find(os.Args[1:])
if (err == nil && (subCmd.Name() == "completion" || subCmd.Name() == completion.CompRequestCmd)) ||
/* for the tests */ subCmd == baseCmd.Root() {
loadCompletionForPlugin(c, plug)
}
}
}
completion.CompDebugln(fmt.Sprintf("calling %s with args %v", main, argv))
buf := new(bytes.Buffer)
if err := callPluginExecutable(cmd, main, argv, buf); err != nil {
return nil, completion.BashCompDirectiveError
}
func processParent(cmd *cobra.Command, args []string) ([]string, error) {
k, u := manuallyProcessArgs(args)
if err := cmd.Parent().ParseFlags(k); err != nil {
return nil, err
}
return u, nil
}
var completions []string
for _, comp := range strings.Split(buf.String(), "\n") {
// Remove any empty lines
if len(comp) > 0 {
completions = append(completions, comp)
}
}
// This function is used to setup the environment for the plugin and then
// call the executable specified by the parameter 'main'
func callPluginExecutable(pluginName string, main string, argv []string, out io.Writer) error {
env := os.Environ()
for k, v := range settings.EnvVars() {
env = append(env, fmt.Sprintf("%s=%s", k, v))
}
// Check if the last line of output is of the form :<integer>, which
// indicates the BashCompletionDirective.
directive := completion.BashCompDirectiveDefault
if len(completions) > 0 {
lastLine := completions[len(completions)-1]
if len(lastLine) > 1 && lastLine[0] == ':' {
if strInt, err := strconv.Atoi(lastLine[1:]); err == nil {
directive = completion.BashCompDirective(strInt)
completions = completions[:len(completions)-1]
}
}
prog := exec.Command(main, argv...)
prog.Env = env
prog.Stdin = os.Stdin
prog.Stdout = out
prog.Stderr = os.Stderr
if err := prog.Run(); err != nil {
if eerr, ok := err.(*exec.ExitError); ok {
os.Stderr.Write(eerr.Stderr)
status := eerr.Sys().(syscall.WaitStatus)
return pluginError{
error: errors.Errorf("plugin %q exited with error", pluginName),
code: status.ExitStatus(),
}
return completions, directive
})
// TODO: Make sure a command with this name does not already exist.
baseCmd.AddCommand(c)
}
return err
}
return nil
}
// manuallyProcessArgs processes an arg array, removing special args.
@ -246,35 +201,31 @@ type pluginCommand struct {
Commands []pluginCommand `json:"commands"`
}
// loadPluginsForCompletion will load and parse any completion.yaml provided by the plugins
func loadPluginsForCompletion(baseCmd *cobra.Command, plugins []*plugin.Plugin) {
for _, plug := range plugins {
// Parse the yaml file providing the plugin's subcmds and flags
cmds, err := loadFile(strings.Join(
[]string{plug.Dir, pluginStaticCompletionFile}, string(filepath.Separator)))
if err != nil {
// The file could be missing or invalid. Either way, we at least create the command
// for the plugin name.
if settings.Debug {
log.Output(2, fmt.Sprintf("[info] %s\n", err.Error()))
}
cmds = &pluginCommand{Name: plug.Metadata.Name}
// loadCompletionForPlugin will load and parse any completion.yaml provided by the plugin
// and add the dynamic completion hook to call the optional plugin.complete
func loadCompletionForPlugin(pluginCmd *cobra.Command, plugin *plugin.Plugin) {
// Parse the yaml file providing the plugin's sub-commands and flags
cmds, err := loadFile(strings.Join(
[]string{plugin.Dir, pluginStaticCompletionFile}, string(filepath.Separator)))
if err != nil {
// The file could be missing or invalid. No static completion for this plugin.
if settings.Debug {
log.Output(2, fmt.Sprintf("[info] %s\n", err.Error()))
}
// Continue to setup dynamic completion.
cmds = &pluginCommand{}
}
// We know what the plugin name must be.
// Let's set it in case the Name field was not specified correctly in the file.
// This insures that we will at least get the plugin name to complete, even if
// there is a problem with the completion.yaml file
cmds.Name = plug.Metadata.Name
// Preserve the Usage string specified for the plugin
cmds.Name = pluginCmd.Use
addPluginCommands(baseCmd, cmds)
}
addPluginCommands(plugin, pluginCmd, cmds)
}
// addPluginCommands is a recursive method that adds the different levels
// of sub-commands and flags for the plugins that provide such information
func addPluginCommands(baseCmd *cobra.Command, cmds *pluginCommand) {
// addPluginCommands is a recursive method that adds each different level
// of sub-commands and flags for the plugins that have provided such information
func addPluginCommands(plugin *plugin.Plugin, baseCmd *cobra.Command, cmds *pluginCommand) {
if cmds == nil {
return
}
@ -287,14 +238,19 @@ func addPluginCommands(baseCmd *cobra.Command, cmds *pluginCommand) {
return
}
// Create a fake command just so the completion script will include it
c := &cobra.Command{
Use: cmds.Name,
ValidArgs: cmds.ValidArgs,
// A Run is required for it to be a valid command without subcommands
Run: func(cmd *cobra.Command, args []string) {},
baseCmd.Use = cmds.Name
baseCmd.ValidArgs = cmds.ValidArgs
// Setup the same dynamic completion for each plugin sub-command.
// This is because if dynamic completion is triggered, there is a single executable
// to call (plugin.complete), so every sub-commands calls it in the same fashion.
if cmds.Commands == nil {
// Only setup dynamic completion if there are no sub-commands. This avoids
// calling plugin.complete at every completion, which greatly simplifies
// development of plugin.complete for plugin developers.
completion.RegisterValidArgsFunc(baseCmd, func(cmd *cobra.Command, args []string, toComplete string) ([]string, completion.BashCompDirective) {
return pluginDynamicComp(plugin, cmd, args, toComplete)
})
}
baseCmd.AddCommand(c)
// Create fake flags.
if len(cmds.Flags) > 0 {
@ -314,7 +270,7 @@ func addPluginCommands(baseCmd *cobra.Command, cmds *pluginCommand) {
}
}
f := c.Flags()
f := baseCmd.Flags()
if len(longs) >= len(shorts) {
for i := range longs {
if i < len(shorts) {
@ -338,7 +294,16 @@ func addPluginCommands(baseCmd *cobra.Command, cmds *pluginCommand) {
// Recursively add any sub-commands
for _, cmd := range cmds.Commands {
addPluginCommands(c, &cmd)
// Create a fake command so that completion can be done for the sub-commands of the plugin
subCmd := &cobra.Command{
// This prevents Cobra from removing the flags. We want to keep the flags to pass them
// to the dynamic completion script of the plugin.
DisableFlagParsing: true,
// A Run is required for it to be a valid command without subcommands
Run: func(cmd *cobra.Command, args []string) {},
}
baseCmd.AddCommand(subCmd)
addPluginCommands(plugin, subCmd, &cmd)
}
}
@ -353,3 +318,59 @@ func loadFile(path string) (*pluginCommand, error) {
err = yaml.Unmarshal(b, cmds)
return cmds, err
}
// pluginDynamicComp call the plugin.complete script of the plugin (if available)
// to obtain the dynamic completion choices. It must pass all the flags and sub-commands
// specified in the command-line to the plugin.complete executable (except helm's global flags)
func pluginDynamicComp(plug *plugin.Plugin, cmd *cobra.Command, args []string, toComplete string) ([]string, completion.BashCompDirective) {
md := plug.Metadata
u, err := processParent(cmd, args)
if err != nil {
return nil, completion.BashCompDirectiveError
}
// We will call the dynamic completion script of the plugin
main := strings.Join([]string{plug.Dir, pluginDynamicCompletionExecutable}, string(filepath.Separator))
// We must include all sub-commands passed on the command-line.
// To do that, we pass-in the entire CommandPath, except the first two elements
// which are 'helm' and 'pluginName'.
argv := strings.Split(cmd.CommandPath(), " ")[2:]
if !md.IgnoreFlags {
argv = append(argv, u...)
argv = append(argv, toComplete)
}
plugin.SetupPluginEnv(settings, md.Name, plug.Dir)
completion.CompDebugln(fmt.Sprintf("calling %s with args %v", main, argv))
buf := new(bytes.Buffer)
if err := callPluginExecutable(md.Name, main, argv, buf); err != nil {
// The dynamic completion file is optional for a plugin, so this error is ok.
completion.CompDebugln(fmt.Sprintf("Unable to call %s: %v", main, err.Error()))
return nil, completion.BashCompDirectiveDefault
}
var completions []string
for _, comp := range strings.Split(buf.String(), "\n") {
// Remove any empty lines
if len(comp) > 0 {
completions = append(completions, comp)
}
}
// Check if the last line of output is of the form :<integer>, which
// indicates the BashCompletionDirective.
directive := completion.BashCompDirectiveDefault
if len(completions) > 0 {
lastLine := completions[len(completions)-1]
if len(lastLine) > 1 && lastLine[0] == ':' {
if strInt, err := strconv.Atoi(lastLine[1:]); err == nil {
directive = completion.BashCompDirective(strInt)
completions = completions[:len(completions)-1]
}
}
}
return completions, directive
}

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