[Python] How to use the default value of a param when import a rule in Snakemake?

I am trying to generalize my snakemake workflow, but I see a weird behavior, which I am not sure if I am doing something wrong or if it is by default. I created a file analysis.smk rules and the evariable I tried to make a generic rule, to import it in many of my snakemake workflows, so I have, for instance in my analysis.smk rule:

rule analysis:
output: test.root
input: input_test.root
params:
variable: "SvB"
rebin: 10
shell: `python run_analysis.py {params.variable} {params.rebin}`


In another Snakefile, I am importing this rule and using it as:

module analysis:
snakefile: "analysis.smk"
config: config

use rule analysis from analysis as run_analysis with:
output: f"{config['output']}/hist.root"
input: f"{config['output']}/input_hist.root"
params:
rebin: 20


And when I run my workflow, I am getting errors like:

AttributeError: 'Params' object has no attribute 'variable', when formatting the following:


Because I didn't define the variable. Is this expected? I would just like to change the value of some params, and use the default in others.

I am using snakemake version 8.27.1

Continue reading...