Ansible how to subtract two variables in a playbook?

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1

So I created a simple bash script to compare dates of the current date and last date of a directory that was last modified.

What I am looking for is something done in Ansible that can take the converted date string of two variables and subtract the difference.

We have these DAT MacAfee files, I just don’t like the bash script I created and looking for something that can be done with a yaml playbook.

So here is my script:

`

#!/bin/bash
# TO PRINT THE NUMBER OF DAYS SINCE LAST AV UPDATE
past_date=$(du -h --time testdate | grep -Eo '[[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}')

# Perform a subtraction of past_date string
# from today's string divided by seconds times 12 hour days  
diff=$((($(date +%s)-$(date +%s --date "$past_date"))/(3600*24)))
echo It has been $diff days since the last AV DAT update

`

Thanks in advance.

Andy Magana

Oklahoma, City OK

2

You could run a “shell” command and register the output to a variable using a command something like the following:

echo $((($(date +%s) - $(date +%s -r "$filename")) / 86400))

Alternatively, you could develop a action_plugin that could accept the filename as a parameter and perform the logic in python by first calling the stat module on the file as it also returns the last modification time of the file via mtime.

3

You could do something like this:

  • stat:
    path: “/path/to/file”
    register: result

  • debug:
    msg: “File was modified {{ days_ago }} days ago”
    vars:
    days_ago: “{{ ((result.stat.mtime - ansible_date_time.epoch|int)|int / 3600 / 24)|round(0, ‘floor’)|abs|int }}”

4

So I really have been racking my melon on this so your saying I can echo with the shell module what is the -r any way ?

5

Yeah, you can register the output of a shell command as a fact, below is simple example. Matts reply looks much nicer though, i would use his so you are not dependent on shell commands.

from the man page of date:

-r, --reference=FILE
display the last modification time of FILE

working example (replace filenametocheck with your actual filename)