Some updates about tpl

tpl is a little project I started nearly two years ago out of the need to dynamically generate a couple of files based on a simple template and some secret data coming from a Vault server.

Since then it has been extended to read environment and eventually execute external shell commands and use their output during the rendering phase. Well, but even that was now nearly 12 months ago with not much happening therafter.

Until last week when a coworker of mine discovered the tool and started to use it. He also opened a PR for allowing tpl to read the source template from stdin instead of from a file:

$ cat template.tpl
{{ index .Env "HOME" }}

$ cat template.tpl | tpl -
/Users/zerok

After I merged this, I released tpl v2.6.0 🙂

While working on the same project that had caused kautsig to extend tpl, I felt the need for something that I love when using Hugo: Data files. Wouldn’t it be nice to use JSON or YAML data without first having to jump through some hoops (i.e. using the system command to cat the file and the using some parsing logic in the template)?

Let’s say, you have a users.yaml file that you generated in some other step containing all the users you have in your system:

- zerok
- admin
- superadmin
- bossofsuperadmin

The template should now generate a new YAML file that contains the username but also the home-directory of that user:

{{ range .Data.users }}
- name: {{ . }}
  home: /home/{{ . }}
{{ end }}

That’s pretty much what was added with v2.7.0 later that day:

$ tpl --data 'users=users.yaml' template.yaml.tpl

- name: zerok
  home: /home/zerok

- name: admin
  home: /home/admin

- name: superadmin
  home: /home/superadmin

- name: bossofsuperadmin
  home: /home/bossofsuperadmin

Let’s see if it takes another 12 months for someone to come up with another feature for tpl. I’m not sure yet but perhaps something related to nushell perhaps? 😉