Advanced usage

Here are some more advanced design patterns that you can take advantage of.

Recursive

By default, the fmf files are copied over in the output, and if there are new .fmf files created, the generation is re-run. This allows to create arbitrarily complex template structures. The simplest example here is creating 2D array of outputs:

/main.fmf

vars:
  var1: [2, 3]
  var2:  [x, y]
templates:
  path: /template

/template/main.fmf.j2

{% for A in var1 -%}
/A_{{ A }}:
  varA: {{ A }}
{% for B in var2 -%}
/A_{{ A }}/B_{{ B }}:
  varB: {{ B }}
{% endfor -%}
{% endfor -%}

Which expands to an intermediate fmf tree of

/main.fmf

/A_2:
  varA: 2
/A_2/B_x:
  varB: x
/A_2/B_y:
  varB: y
/A_3:
  varA: 3
/A_3/B_x:
  varB: x
/A_3/B_y:
  varB: y

$ fmf show
/A_2/B_x
varA: 2
varB: x

/A_2/B_y
varA: 2
varB: y

/A_3/B_x
varA: 3
varB: x

/A_3/B_y
varA: 3
varB: y

Note

If a templated file like main.fmf.j2 clashes with an original main.fmf file in the original fmf tree, the generated file overwrites the

The recursive feature can be turned off with the --no-recursive flag.

fmf-jinja bomb

If you want an equivalent fork bomb while running fmf-jinja, here you are:

$ fmf init
$ touch main.fmf
$ ln -s main.fmf main.fmf.j2
$ fmf-jinja generate -o whatever