Ansible - Unarchive module overwriting - ansible

Question

i am working with ansible and using a playbook.
In this playbook I am performing a download (from a web url) and unarchive of a file into hosts (using unarchive module), and after that I am copying some files from control machine into hosts (using copy module).
What is happening is that every time I use unarchive module, although every file is the same, ansible is overwriting files in hosts.
How can I make it so that it does not overwrite if contents are the same?
My playbook:
---
- hosts: group1
sudo: yes
tasks:
- name: Download and Extract apache
unarchive:
src: http://mirrors.up.pt/pub/apache/tomcat/tomcat-9/v9.0.1/bin/apache-tomcat-9.0.1.tar.gz
dest: /opt/
remote_src: yes
- name: Copy file to host
copy: src=/etc/ansible/files/myfile.xml dest=/opt/apache-tomcat-9.0.1/conf/myfile.xml

Answer 1

Add a creates option referencing something the unarchive places.
c.f. the documentation page here (check the version against what you are using.)
e.g.:
- unarchive:
remote_src : yes
src : "{{ url }}"
dest : "{{ install_dir }}/"
creates : "{{ flagFile }}"
If the unarchive creates a /tmp/foo directory with a file named bar, then flagFile can be /tmp/foo/bar, and unarchive won't run again if it's already there.

Answer 2

I've handled this multiple ways, depending on the situation.
Option 1:
One of the files created by the archive has a specific name, such as foo-version_no
In this case, I can add the option:
creates: 'foo=version_no'
If this file exists, ansible will not extract it.
Caveat:
If the extracted directory is supposed to contain 12 files, and at least 1 of them has been removed or altered, the unarchive module will not replace them.
Option 2:
If there is no version number in the file name, examine one of the files in the extract directory and asses if it is the correct file.
Perhaps a checksum on the file; a grep for a unique parameter; or executing a command with the '--version' option.
Register the results into a variable:
register: correct_file
The unarchive command can then have the when parameter:
unarchive:
. . .
. . .
when: (correct_file.stdout != My_Required_Version and correct_file is defined)
The last part, about being defined, is there because, if you determine the extracted files don;t exist at all, you would skip checking the version, so the variable 'correct_file' will be undefined.
Caveat:
See Caveat from Option 1.
Option 3:
Use an argument, or extract command that will not over write files if they have not changed.
Caveat:
There will still be a little over head, because the extract command needs to asses each file, but will not make a new one.
Option 4:
Have another way to assess the quality of the files in the extracted directory, and set a variable based upon that result.
A simple example would be to run a checksum on all files, the run a checksum on that output, yielding a "Checksum of Checksums"
Ex:
curr_sum=$( cksum $( cksum /path/to/extracted/files/* ) )
if [ $curr_sum -eq $Correct_Value ]
then
echo "This is OK"
exit 0
else
echo "This is not ok"
exit 1
fi
In ansible, you would run this command and register the result. Then compare the output to the pre-set value:
cmd: "script_name"
register: cksum_answer
failed_when: failed
. . .
unarchive:
. . .
. . .
when: cksum_answer.rc == 1