Use multiple statements in the same Jinja block {% ... %}

Here is an example code from an SLS (salt stack) file, using Jinja:

{% set here = 'some-value' -%}
{%- set user = 'my_user' -%}
{%- set group = 'my_group' -%}

{%- set all_users = salt['user.list_users']() -%}
{%- if user in all_users -%}
{%- set usr_home = salt['user.info'](user).home -%}
{%- set prefix = 'some_prefix' ~ '_' ~ user %}

# This is just an example state
{{ prefix }}-dotvnc:
  file.directory:
    - name: {{ usr_home }}/.vnc
    - user: {{ user }}
    - group: {{ group }}
    - mode: '0700'

{% endif -%}

This looks very ugly, I would like to do something like this:

{% 
set here = 'some-value'
set user = 'my_user'
set group = 'my_group'

set all_users = salt['user.list_users']()
if user in all_users
  set usr_home = salt['user.info'](user).home
  set prefix = 'some_prefix' ~ '_' ~ user
%}

# This is just an example state
{{ prefix }}-dotvnc:
  file.directory:
    - name: {{ usr_home }}/.vnc
    - user: {{ user }}
    - group: {{ group }}
    - mode: '0700'

{% endif -%}

Multiple variables and commands cannot be avoided, this example shows a template that uses the home directory of a user from Jinja, but, the user may not exists when the template is rendered, and so its home directory may not exist.

While the first version works, it is very ugly, and hard to read.

Is there way to make this less cryptic?

This is not a duplicate of Code blocks in Jinja templates in salt, because dictionary lookups cannot be used in this case. E.g. the code is arbitrary.

Solution

One alternative syntax you could use is the line statement one — but if it is less cryptic or not is, off course, to your liking.

With it, your template could look like this:

% set user = 'my_user'
% set group = 'my_group'

% set all_users = salt['user.list_users']()
% if user in all_users
  % set usr_home = salt['user.info'](user).home
  % set prefix = 'some_prefix' ~ '_' ~ user

# This is just an example state
{{ prefix }}-dotvnc:
  file.directory:
    - name: {{ usr_home }}/.vnc
    - user: {{ user }}
    - group: {{ group }}
    - mode: '0700'
% endif

Which would render to something like

some_prefix_my_user-dotvnc:
  file.directory:
    - name: /home/my_user/.vnc
    - user: my_user
    - group: my_group
    - mode: '0700'

This possibility is offered via the parameters line_statement_prefix and line_comment_prefix.

In SaltStack, this can be configured in the Salt configurations files, under the keys jinja_env and jinja_sls_env.
E.g.:
```
jinja_sls_env:
  line_statement_prefix: '%'
  line_comment_prefix: '#'
```

In an Ansible template, this can be passed as the first line of the template:

#jinja2:line_statement_prefix: '%', line_comment_prefix: '#'
% set user = 'my_user'
# ... the rest of the template goes here

In a Python / Jinja project, this would be configured via parameters set at the environment initialisation.

from jinja2 import Environment, PackageLoader, select_autoescape
env = Environment(
    loader=PackageLoader("yourapp"),
    line_statement_prefix='%', 
    line_comment_prefix='#'
)