how to periodically update segment for K8s info output ?

[gkoenig]

Hi,
I've written a small, simple script which outputs the k8s namespace and k8s server address to a segment, based on the output of command kubectl config view
It works great and I can see the desired output in the segment of the status bar.
The problem is, as soon as I change my $KUBECONFIG variable in the shell, the output in the segment shall update as well.....because changing this env variable also changes the output of the kubectl config view command.

How can I trigger the segment update periodically, so that it always reflects the current output of the kubectl command ? ....at the moment it doesn't update, it always shows the info of the time tmux was started.
In my .tmux.conf there is the status-interval option set =>
set-option -g status-interval 2

Thanks !

[erikw]

The way environmental variables and shells works is that a change of an envvar is local to the current shell. tmux-powerline works in a different shell than the one you changed $KUBECONFIG in. Thus, there must be some way to inform tmux-powerline on which value of $KUBECONFIG should be used.

Two ideas to solve this would be:

1. Let your segment read the value from a state file like ~/.kubeconfig. Instead of changing the envvar in your shell, you write the current value to a file. To make this easy, you can make a shell function that you source or include in your shell startup file like
   *

   kubeconfig() {
    local value="$1"
    export KUBECONFIG="$value"
    echo "$value" > $HOME/.kubeconfig
   }

   • Then in your shell, change the variable with $ kubeconfig new-value-of-envvar
   • Then in your segment just read this value

   export KUBECONFIG=$(cat ~/.kubeconfig)

2. Each time the prompt is rendered, copy the local $KUBECONFIG and send it to the tmux envvar with tmux setenv. This is documented at https://github.com/erikw/tmux-powerline#for-tmux-versions--21

[gkoenig]

Many thanks @erikw for those hints.
I went with option 1. => works great :D

[erikw]

Great, I'm glad I could help!