Add bash autocompletion generator
Given a (potentially annotated) cobra command you can generate a bash completion script.
This commit is contained in:
Eric Paris
parent
f576d29563
commit
9b2e6822e5
@ -348,6 +348,9 @@ Like help the function and template are over ridable through public methods.
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command.SetUsageTemplate(s string)
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## Generating bash completions for your command
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Cobra can generate a bash completions file. If you add more information to your command these completions can be amazingly powerful and flexible. Read more about [Bash Completions](bash_completions.md)
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## Debugging
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330
bash_completions.go
Normal file
330
bash_completions.go
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@ -0,0 +1,330 @@
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package cobra
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import (
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"bytes"
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"fmt"
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"os"
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"strings"
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"github.com/spf13/pflag"
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)
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const (
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BashCompFilenameExt = "cobra_annotation_bash_completion_filename_extentions"
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BashCompOneRequiredFlag = "cobra_annotation_bash_completion_one_required_flag"
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)
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func preamble(out *bytes.Buffer) {
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fmt.Fprintf(out, `#!/bin/bash
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__debug()
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{
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if [[ -n ${BASH_COMP_DEBUG_FILE} ]]; then
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echo "$*" >> ${BASH_COMP_DEBUG_FILE}
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fi
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}
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__index_of_word()
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{
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local w word=$1
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shift
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index=0
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for w in "$@"; do
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[[ $w = "$word" ]] && return
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index=$((index+1))
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done
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index=-1
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}
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__contains_word()
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{
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local w word=$1; shift
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for w in "$@"; do
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[[ $w = "$word" ]] && return
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done
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return 1
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}
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__handle_reply()
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{
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__debug "${FUNCNAME}"
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case $cur in
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-*)
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compopt -o nospace
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local allflags
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if [ ${#must_have_one_flag[@]} -ne 0 ]; then
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allflags=("${must_have_one_flag[@]}")
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else
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allflags=("${flags[*]} ${two_word_flags[*]}")
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fi
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COMPREPLY=( $(compgen -W "${allflags[*]}" -- "$cur") )
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[[ $COMPREPLY == *= ]] || compopt +o nospace
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return 0;
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;;
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esac
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# check if we are handling a flag with special work handling
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local index
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__index_of_word "${prev}" "${flags_with_completion[@]}"
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if [[ ${index} -ge 0 ]]; then
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${flags_completion[${index}]}
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return
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fi
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# we are parsing a flag and don't have a special handler, no completion
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if [[ ${cur} != "${words[cword]}" ]]; then
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return
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fi
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local completions
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if [[ ${#must_have_one_flag[@]} -ne 0 ]]; then
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completions=("${must_have_one_flag[@]}")
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elif [[ ${#must_have_one_noun[@]} -ne 0 ]]; then
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completions=("${must_have_one_noun[@]}")
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else
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completions=("${commands[@]}")
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fi
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COMPREPLY=( $(compgen -W "${completions[*]}" -- "$cur") )
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if [[ ${#COMPREPLY[@]} -eq 0 ]]; then
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declare -F __custom_func >/dev/null && __custom_func
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fi
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}
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__handle_flag()
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{
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__debug "${FUNCNAME}: c is $c words[c] is ${words[c]}"
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# if a command required a flag, and we found it, unset must_have_one_flag()
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local flagname=${words[c]}
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# if the word contained an =
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if [[ ${words[c]} == *"="* ]]; then
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flagname=${flagname%%=*} # strip everything after the =
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flagname="${flagname}=" # but put the = back
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fi
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__debug "${FUNCNAME}: looking for ${flagname}"
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if __contains_word "${flagname}" "${must_have_one_flag[@]}"; then
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must_have_one_flag=()
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fi
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# skip the argument to a two word flag
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if __contains_word "${words[c]}" "${two_word_flags[@]}"; then
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c=$((c+1))
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# if we are looking for a flags value, don't show commands
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if [[ $c -eq $cword ]]; then
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commands=()
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fi
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fi
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# skip the flag itself
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c=$((c+1))
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}
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__handle_noun()
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{
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__debug "${FUNCNAME}: c is $c words[c] is ${words[c]}"
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if __contains_word "${words[c]}" "${must_have_one_noun[@]}"; then
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must_have_one_noun=()
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fi
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nouns+=("${words[c]}")
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c=$((c+1))
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}
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__handle_command()
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{
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__debug "${FUNCNAME}: c is $c words[c] is ${words[c]}"
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local next_command
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if [[ -n ${last_command} ]]; then
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next_command="_${last_command}_${words[c]}"
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else
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next_command="_${words[c]}"
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fi
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c=$((c+1))
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__debug "${FUNCNAME}: looking for ${next_command}"
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declare -F $next_command >/dev/null && $next_command
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}
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__handle_word()
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{
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if [[ $c -ge $cword ]]; then
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__handle_reply
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return
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fi
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__debug "${FUNCNAME}: c is $c words[c] is ${words[c]}"
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if [[ "${words[c]}" == -* ]]; then
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__handle_flag
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elif __contains_word "${words[c]}" "${commands[@]}"; then
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__handle_command
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else
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__handle_noun
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fi
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__handle_word
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}
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`)
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}
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func postscript(out *bytes.Buffer, name string) {
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fmt.Fprintf(out, "__start_%s()\n", name)
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fmt.Fprintf(out, `{
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local cur prev words cword split
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_init_completion -s || return
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local completions_func
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local c=0
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local flags=()
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local two_word_flags=()
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local flags_with_completion=()
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local flags_completion=()
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local commands=("%s")
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local must_have_one_flag=()
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local must_have_one_noun=()
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local last_command
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local nouns=()
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__handle_word
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}
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`, name)
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fmt.Fprintf(out, "complete -F __start_%s %s\n", name, name)
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fmt.Fprintf(out, "# ex: ts=4 sw=4 et filetype=sh\n")
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}
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func writeCommands(cmd *Command, out *bytes.Buffer) {
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fmt.Fprintf(out, " commands=()\n")
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for _, c := range cmd.Commands() {
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fmt.Fprintf(out, " commands+=(%q)\n", c.Name())
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}
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fmt.Fprintf(out, "\n")
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}
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func writeFlagHandler(name string, annotations map[string][]string, out *bytes.Buffer) {
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for key, value := range annotations {
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switch key {
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case BashCompFilenameExt:
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fmt.Fprintf(out, " flags_with_completion+=(%q)\n", name)
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ext := strings.Join(value, "|")
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ext = "_filedir '@(" + ext + ")'"
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fmt.Fprintf(out, " flags_completion+=(%q)\n", ext)
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}
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}
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}
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func writeShortFlag(flag *pflag.Flag, out *bytes.Buffer) {
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b := (flag.Value.Type() == "bool")
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name := flag.Shorthand
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format := " "
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if !b {
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format += "two_word_"
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}
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format += "flags+=(\"-%s\")\n"
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fmt.Fprintf(out, format, name)
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writeFlagHandler("-"+name, flag.Annotations, out)
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}
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func writeFlag(flag *pflag.Flag, out *bytes.Buffer) {
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b := (flag.Value.Type() == "bool")
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name := flag.Name
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format := " flags+=(\"--%s"
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if !b {
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format += "="
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}
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format += "\")\n"
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fmt.Fprintf(out, format, name)
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writeFlagHandler("--"+name, flag.Annotations, out)
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}
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func writeFlags(cmd *Command, out *bytes.Buffer) {
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fmt.Fprintf(out, ` flags=()
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two_word_flags=()
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flags_with_completion=()
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flags_completion=()
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`)
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cmd.NonInheritedFlags().VisitAll(func(flag *pflag.Flag) {
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writeFlag(flag, out)
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if len(flag.Shorthand) > 0 {
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writeShortFlag(flag, out)
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}
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})
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fmt.Fprintf(out, "\n")
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}
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func writeRequiredFlag(cmd *Command, out *bytes.Buffer) {
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fmt.Fprintf(out, " must_have_one_flag=()\n")
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flags := cmd.NonInheritedFlags()
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flags.VisitAll(func(flag *pflag.Flag) {
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for key, _ := range flag.Annotations {
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switch key {
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case BashCompOneRequiredFlag:
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format := " must_have_one_flag+=(\"--%s"
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b := (flag.Value.Type() == "bool")
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if !b {
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format += "="
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}
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format += "\")\n"
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fmt.Fprintf(out, format, flag.Name)
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if len(flag.Shorthand) > 0 {
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fmt.Fprintf(out, " must_have_one_flag+=(\"-%s\")\n", flag.Shorthand)
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}
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}
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}
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})
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}
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func writeRequiredNoun(cmd *Command, out *bytes.Buffer) {
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fmt.Fprintf(out, " must_have_one_noun=()\n")
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for _, value := range cmd.ValidArgs {
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fmt.Fprintf(out, " must_have_one_noun+=(%q)\n", value)
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}
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}
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func gen(cmd *Command, out *bytes.Buffer) {
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for _, c := range cmd.Commands() {
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gen(c, out)
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}
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commandName := cmd.CommandPath()
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commandName = strings.Replace(commandName, " ", "_", -1)
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fmt.Fprintf(out, "_%s()\n{\n", commandName)
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fmt.Fprintf(out, " last_command=%q\n", commandName)
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writeCommands(cmd, out)
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writeFlags(cmd, out)
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writeRequiredFlag(cmd, out)
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writeRequiredNoun(cmd, out)
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fmt.Fprintf(out, "}\n\n")
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}
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func (cmd *Command) GenBashCompletion(out *bytes.Buffer) {
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preamble(out)
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if len(cmd.BashCompletionFunction) > 0 {
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fmt.Fprintf(out, "%s\n", cmd.BashCompletionFunction)
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}
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gen(cmd, out)
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postscript(out, cmd.Name())
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}
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func (cmd *Command) GenBashCompletionFile(filename string) error {
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out := new(bytes.Buffer)
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cmd.GenBashCompletion(out)
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outFile, err := os.Create(filename)
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if err != nil {
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return err
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}
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defer outFile.Close()
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_, err = outFile.Write(out.Bytes())
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if err != nil {
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return err
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}
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return nil
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}
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146
bash_completions.md
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146
bash_completions.md
Normal file
@ -0,0 +1,146 @@
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# Generating Bash Completions For Your Own cobra.Command
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Generating bash completions from a cobra command is incredibly easy. An actual program which does so for the kubernetes kubectl binary is as follows:
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```go
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package main
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import (
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"io/ioutil"
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"os"
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"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl/cmd"
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)
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func main() {
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kubectl := cmd.NewFactory(nil).NewKubectlCommand(os.Stdin, ioutil.Discard, ioutil.Discard)
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kubectl.GenBashCompletionFile("out.sh")
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}
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```
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That will get you completions of subcommands and flags. If you make additional annotations to your code, you can get even more intelligent and flexible behavior.
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## Creating your own custom functions
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Some more actual code that works in kubernetes:
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```bash
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const (
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bash_completion_func = `__kubectl_parse_get()
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{
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local kubectl_output out
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if kubectl_output=$(kubectl get --no-headers "$1" 2>/dev/null); then
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out=($(echo "${kubectl_output}" | awk '{print $1}'))
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COMPREPLY=( $( compgen -W "${out[*]}" -- "$cur" ) )
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fi
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}
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__kubectl_get_resource()
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{
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if [[ ${#nouns[@]} -eq 0 ]]; then
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return 1
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fi
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__kubectl_parse_get ${nouns[${#nouns[@]} -1]}
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if [[ $? -eq 0 ]]; then
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return 0
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fi
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}
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__custom_func() {
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case ${last_command} in
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kubectl_get | kubectl_describe | kubectl_delete | kubectl_stop)
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__kubectl_get_resource
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return
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;;
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*)
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;;
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esac
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}
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`)
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```
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And then I set that in my command definition:
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```go
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cmds := &cobra.Command{
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Use: "kubectl",
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Short: "kubectl controls the Kubernetes cluster manager",
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Long: `kubectl controls the Kubernetes cluster manager.
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Find more information at https://github.com/GoogleCloudPlatform/kubernetes.`,
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Run: runHelp,
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BashCompletionFunction: bash_completion_func,
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}
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```
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The `BashCompletionFunction` option is really only valid/useful on the root command. Doing the above will cause `__custom_func()` to be called when the built in processor was unable to find a solution. In the case of kubernetes a valid command might look something like `kubectl get pod [mypod]`. If you type `kubectl get pod [tab][tab]` the `__customc_func()` will run because the cobra.Command only understood "kubectl" and "get." `__custom_func()` will see that the cobra.Command is "kubectl_get" and will thus call another helper `__kubectl_get_resource()`. `__kubectl_get_resource` will look at the 'nouns' collected. In our example the only noun will be `pod`. So it will call `__kubectl_parse_get pod`. `__kubectl_parse_get` will actually call out to kubernetes and get any pods. It will then set `COMPREPLY` to valid pods!
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## Have the completions code complete your 'nouns'
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In the above example "pod" was assumed to already be typed. But if you want `kubectl get [tab][tab]` to show a list of valid "nouns" you have to set them. Simplified code from `kubectl get` looks like:
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```go
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validArgs []string = { "pods", "nodes", "services", "replicationControllers" }
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cmd := &cobra.Command{
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Use: "get [(-o|--output=)json|yaml|template|...] (RESOURCE [NAME] | RESOURCE/NAME ...)",
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Short: "Display one or many resources",
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Long: get_long,
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Example: get_example,
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Run: func(cmd *cobra.Command, args []string) {
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err := RunGet(f, out, cmd, args)
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util.CheckErr(err)
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},
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ValidArgs: validArgs,
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}
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```
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Notice we put the "ValidArgs" on the "get" subcommand. Doing so will give results like
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```bash
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# kubectl get [tab][tab]
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nodes pods replicationControllers services
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```
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## Mark flags as required
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Most of the time completions will only show subcommands. But if a flag is required to make a subcommand work, you probably want it to show up when the user types [tab][tab]. Marking a flag as 'Required' is incredibly easy.
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```go
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cmd.MarkFlagRequired("pod")
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cmd.MarkFlagRequired("container")
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```
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and you'll get something like
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```bash
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# kubectl exec [tab][tab][tab]
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-c --container= -p --pod=
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```
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# Specify valid filename extentions for flags that take a filename
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In this example we use --filename= and expect to get a json or yaml file as the argument. To make this easier we annotate the --filename flag with valid filename extensions.
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```go
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annotations := make([]string, 3)
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annotations[0] = "json"
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annotations[1] = "yaml"
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annotations[2] = "yml"
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annotation := make(map[string][]string)
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annotation[cobra.BashCompFilenameExt] = annotations
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flag := &pflag.Flag{"filename", "f", usage, value, value.String(), false, annotation}
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cmd.Flags().AddFlag(flag)
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```
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Now when you run a command with this filename flag you'll get something like
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```bash
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# kubectl create -f
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test/ example/ rpmbuild/
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hello.yml test.json
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```
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So while there are many other files in the CWD it only shows me subdirs and those with valid extensions.
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74
bash_completions_test.go
Normal file
74
bash_completions_test.go
Normal file
@ -0,0 +1,74 @@
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package cobra
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import (
|
||||
"bytes"
|
||||
"fmt"
|
||||
"os"
|
||||
"strings"
|
||||
"testing"
|
||||
)
|
||||
|
||||
var _ = fmt.Println
|
||||
var _ = os.Stderr
|
||||
|
||||
func check(t *testing.T, found, expected string) {
|
||||
if !strings.Contains(found, expected) {
|
||||
t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
|
||||
}
|
||||
}
|
||||
|
||||
// World worst custom function, just keep telling you to enter hello!
|
||||
const (
|
||||
bash_completion_func = `__custom_func() {
|
||||
COMPREPLY=( "hello" )
|
||||
}
|
||||
`
|
||||
)
|
||||
|
||||
func TestBashCompletions(t *testing.T) {
|
||||
c := initializeWithRootCmd()
|
||||
cmdEcho.AddCommand(cmdTimes)
|
||||
c.AddCommand(cmdEcho, cmdPrint)
|
||||
|
||||
// custom completion function
|
||||
c.BashCompletionFunction = bash_completion_func
|
||||
|
||||
// required flag
|
||||
c.MarkFlagRequired("introot")
|
||||
|
||||
// valid nounds
|
||||
validArgs := []string{"pods", "nodes", "services", "replicationControllers"}
|
||||
c.ValidArgs = validArgs
|
||||
|
||||
// filename extentions
|
||||
annotations := make([]string, 3)
|
||||
annotations[0] = "json"
|
||||
annotations[1] = "yaml"
|
||||
annotations[2] = "yml"
|
||||
|
||||
annotation := make(map[string][]string)
|
||||
annotation[BashCompFilenameExt] = annotations
|
||||
|
||||
var flagval string
|
||||
c.Flags().StringVar(&flagval, "filename", "", "Enter a filename")
|
||||
flag := c.Flags().Lookup("filename")
|
||||
flag.Annotations = annotation
|
||||
|
||||
out := new(bytes.Buffer)
|
||||
c.GenBashCompletion(out)
|
||||
str := out.String()
|
||||
|
||||
check(t, str, "_cobra-test")
|
||||
check(t, str, "_cobra-test_echo")
|
||||
check(t, str, "_cobra-test_echo_times")
|
||||
check(t, str, "_cobra-test_print")
|
||||
|
||||
// check for required flags
|
||||
check(t, str, `must_have_one_flag+=("--introot=")`)
|
||||
// check for custom completion function
|
||||
check(t, str, `COMPREPLY=( "hello" )`)
|
||||
// check for required nouns
|
||||
check(t, str, `must_have_one_noun+=("pods")`)
|
||||
// check for filename extention flags
|
||||
check(t, str, `flags_completion+=("_filedir '@(json|yaml|yml)'")`)
|
||||
}
|
||||
@ -44,6 +44,10 @@ type Command struct {
|
||||
Long string
|
||||
// Examples of how to use the command
|
||||
Example string
|
||||
// List of all valid non-flag arguments, used for bash completions *TODO* actually validate these
|
||||
ValidArgs []string
|
||||
// Custom functions used by the bash autocompletion generator
|
||||
BashCompletionFunction string
|
||||
// Full set of flags
|
||||
flags *flag.FlagSet
|
||||
// Set of flags childrens of this command will inherit
|
||||
|
||||
Loading…
Reference in New Issue
Block a user