I'm trying to write completion functions for some custom functions I wrote, but seem to be really struggling with even the most basic ones.
An example function is:
function eb_instances() {
if [ "$#" -ne 2 ]; then
echo "Usage eb_instances <aws profile name> <environment name>"
echo "e.g.:"
echo " eb_instances production kraken-prod-api"
return 1
fi
aws ec2 describe-instances --filters "Name=instance-state-name,Values=running" "Name=tag:Name,Values=$2" --profile=$1 --output=json | jq -r ".Reservations[].Instances[].PrivateIpAddress"
}
This has two positional arguments, <aws profile name>
and <environment name>
I want the completion options for <aws profile name>
to be dynamically available by running
sed -n -E 's/\[([a-zA-Z0-9_\-]+)\]/\1/p' ~/.aws/credentials | tr \\n ' '
, and the completions for <environment name>
to be dynamically available by running another function I have called eb_names
.
I'm finding the documentation quite sparse and difficult to follow. I've also seen the zsh-completions repo for similar commands but can't seem to find something similar to what I need.
Any help getting started would be much appreciated!
Update
Based on @cuonglm's answer, I used:
#compdef ebinstances
_ebinstances() {
local state
_arguments \
'1: :->aws_profile'\
'*: :->eb_name'
case $state in
(aws_profile) _arguments '1:profiles:($(sed -n -E "s/\[([a-zA-Z0-9_\-]+)\]/\1/p" ~/.aws/credentials | tr \\n " "))' ;;
(*) compadd "$@" foo bar
esac
}
_ebinstances "$@"
What I forgot to mention in the original question was, that I also wanted the completion of the second argument be dependent on the first one (both of which are dynamic based executing some code), for example:
$ eb_instances <cursor>TAB
cuonglm test
gets the completions I want. Once I select say the first one, and try to auto complete:
$ eb_instances cuonglm <cursor>TAB
I want to generate the completion options by executing eb_names cuonglm
, and if possible, also, drilldown on the completions for example if the correct candidate was foo-bar
,
$ eb_instances cuonglm foo<cursor>TAB
I want to generate the completion options by executing eb_names cuonglm foo
Best Answer
At the first time, zsh Completion System seems to be very complex and difficult to grasp. Let try an example.
First thing you need to know,
zsh
completion system will load completion functions from$fpath
. Make sure your completions directory appear in:(If you used oh-my-zsh, there's
.oh-my-zsh/completions
existed in$fpath
, you can just create it and put your completion functions there)Now, you must create a completion file for your function, its name must start with underscore
_
, plus your function name. In your case, its name is_eb_instances
.Add theses lines to
_eb_instances
file:You are done. Save the file and start new session to test completion. You will see some thing like this:
You can read zsh completion system documentation about
_arguments
function,state
variable. Also you need to change(cuonglm test)
with yoursed
command and changeprod staging dev
to youreb_names
function.If you want to generate the 2nd argument base on what 1st argument passed, you can use
$words[2]
variable:Replace
echo
with your real function, in your case, it's$(eb_names $words[2])
.If you still feel hard to accomplish this, just define
_eb_instances
andeb_instances
in your.zshrc
then call completion as:You need to initialize completion system with:
(If you used
oh-my-zsh
, it have been loaded)