kilo/vendor/github.com/spf13/cobra/bash_completions.md

92 lines
3.5 KiB
Bash
Raw Normal View History

# Generating Bash Completions For Your cobra.Command
2019-01-18 01:50:10 +00:00
Please refer to [Shell Completions](shell_completions.md) for details.
2019-05-03 10:50:21 +00:00
## Bash legacy dynamic completions
2019-01-18 01:50:10 +00:00
For backward compatibility, Cobra still supports its legacy dynamic completion solution (described below). Unlike the `ValidArgsFunction` solution, the legacy solution will only work for Bash shell-completion and not for other shells. This legacy solution can be used along-side `ValidArgsFunction` and `RegisterFlagCompletionFunc()`, as long as both solutions are not used for the same command. This provides a path to gradually migrate from the legacy solution to the new solution.
2019-01-18 01:50:10 +00:00
The legacy solution allows you to inject bash functions into the bash completion script. Those bash functions are responsible for providing the completion choices for your own completions.
2019-01-18 01:50:10 +00:00
Some code that works in kubernetes:
2019-01-18 01:50:10 +00:00
```bash
const (
bash_completion_func = `__kubectl_parse_get()
{
local kubectl_output out
if kubectl_output=$(kubectl get --no-headers "$1" 2>/dev/null); then
out=($(echo "${kubectl_output}" | awk '{print $1}'))
COMPREPLY=( $( compgen -W "${out[*]}" -- "$cur" ) )
fi
}
__kubectl_get_resource()
{
if [[ ${#nouns[@]} -eq 0 ]]; then
return 1
fi
__kubectl_parse_get ${nouns[${#nouns[@]} -1]}
if [[ $? -eq 0 ]]; then
return 0
fi
}
2019-05-03 10:50:21 +00:00
__kubectl_custom_func() {
2019-01-18 01:50:10 +00:00
case ${last_command} in
kubectl_get | kubectl_describe | kubectl_delete | kubectl_stop)
__kubectl_get_resource
return
;;
*)
;;
esac
}
`)
```
And then I set that in my command definition:
```go
cmds := &cobra.Command{
Use: "kubectl",
Short: "kubectl controls the Kubernetes cluster manager",
Long: `kubectl controls the Kubernetes cluster manager.
Find more information at https://github.com/GoogleCloudPlatform/kubernetes.`,
Run: runHelp,
BashCompletionFunction: bash_completion_func,
}
```
2019-05-03 10:50:21 +00:00
The `BashCompletionFunction` option is really only valid/useful on the root command. Doing the above will cause `__kubectl_custom_func()` (`__<command-use>_custom_func()`) to be called when the built in processor was unable to find a solution. In the case of kubernetes a valid command might look something like `kubectl get pod [mypod]`. If you type `kubectl get pod [tab][tab]` the `__kubectl_customc_func()` will run because the cobra.Command only understood "kubectl" and "get." `__kubectl_custom_func()` will see that the cobra.Command is "kubectl_get" and will thus call another helper `__kubectl_get_resource()`. `__kubectl_get_resource` will look at the 'nouns' collected. In our example the only noun will be `pod`. So it will call `__kubectl_parse_get pod`. `__kubectl_parse_get` will actually call out to kubernetes and get any pods. It will then set `COMPREPLY` to valid pods!
2019-01-18 01:50:10 +00:00
Similarly, for flags:
2019-01-18 01:50:10 +00:00
```go
annotation := make(map[string][]string)
annotation[cobra.BashCompCustom] = []string{"__kubectl_get_namespaces"}
flag := &pflag.Flag{
Name: "namespace",
Usage: usage,
Annotations: annotation,
}
cmd.Flags().AddFlag(flag)
```
In addition add the `__kubectl_get_namespaces` implementation in the `BashCompletionFunction`
2019-01-18 01:50:10 +00:00
value, e.g.:
```bash
__kubectl_get_namespaces()
{
local template
template="{{ range .items }}{{ .metadata.name }} {{ end }}"
local kubectl_out
if kubectl_out=$(kubectl get -o template --template="${template}" namespace 2>/dev/null); then
COMPREPLY=( $( compgen -W "${kubectl_out}[*]" -- "$cur" ) )
fi
}
```