[ansible] How to check if a file exists in Ansible?

I have to check whether a file exists in /etc/. If the file exists then I have to skip the task. Here is the code I am using:

- name: checking the file exists
  command: touch file.txt
  when: $(! -s /etc/file.txt)

I find it can be annoying and error prone to do a lot of these .stat.exists type checks. For example they require extra care to get check mode (--check) working.

Many answers here suggest

• get and register
• apply when register expression is true

However, sometimes this is a code smell so always look for better ways to use Ansible, specifically there are many advantages to using the correct module. e.g.

- name: install ntpdate
  package:
    name: ntpdate

or

- file:
    path: /etc/file.txt
    owner: root
    group: root
    mode: 0644

But when it is not possible use one module, also investigate if you can register and check the result of a previous task. e.g.

# jmeter_version: 4.0 
- name: Download Jmeter archive
  get_url:
    url: "http://archive.apache.org/dist/jmeter/binaries/apache-jmeter-{{ jmeter_version }}.tgz"
    dest: "/opt/jmeter/apache-jmeter-{{ jmeter_version }}.tgz"
    checksum: sha512:eee7d68bd1f7e7b269fabaf8f09821697165518b112a979a25c5f128c4de8ca6ad12d3b20cd9380a2b53ca52762b4c4979e564a8c2ff37196692fbd217f1e343
  register: download_result

- name: Extract apache-jmeter
  unarchive:
    src: "/opt/jmeter/apache-jmeter-{{ jmeter_version }}.tgz"
    dest: "/opt/jmeter/"
    remote_src: yes
    creates: "/opt/jmeter/apache-jmeter-{{ jmeter_version }}"
  when: download_result.state == 'file'

Note the when: but also the creates: so --check doesn't error out

I mention this because often these less-than-ideal practices come in pairs i.e. no apt/yum package so we have to 1) download and 2) unzip

Hope this helps

If you just want to make sure a certain file exists (f.ex. because it shoud be created in a different way than via ansible) and fail if it doesn't, then you can do this:

- name: sanity check that /some/path/file exists
  command: stat /some/path/file
  check_mode: no # always run
  changed_when: false # doesn't change anything

**

How to check if a file exists in Ansible using when condition

**

Below is the ansible play i used to remove the file when the file exists in the OS end.

 - name: find out /etc/init.d/splunk file exists or not'
      stat:
        path: /etc/init.d/splunk
      register: splunkresult
      tags:
        - always

    - name: 'Remove splunk from init.d file if splunk already running'
      file:
        path: /etc/init.d/splunk
        state: absent
      when: splunkresult.stat.exists == true
      ignore_errors: yes
      tags:
        - always

I have used play condition as like below

when: splunkresult.stat.exists == true --> Remove the file

you can give true/false based on your requirement

when: splunkresult.stat.exists == false
when: splunkresult.stat.exists == true

You can use Ansible stat module to register the file, and when module to apply the condition.

- name: Register file
      stat:
        path: "/tmp/test_file"
      register: file_path

- name: Create file if it doesn't exists
      file: 
        path: "/tmp/test_file"
        state: touch
      when: file_path.stat.exists == False

This can be achieved with the stat module to skip the task when file exists.

- hosts: servers
  tasks:
  - name: Ansible check file exists.
    stat:
      path: /etc/issue
    register: p
  - debug:
      msg: "File exists..."
    when: p.stat.exists
  - debug:
      msg: "File not found"
    when: p.stat.exists == False

You can first check that the destination file exists or not and then make a decision based on the output of its result:

    tasks:
      - name: Check that the somefile.conf exists
        stat:
          path: /etc/file.txt
        register: stat_result

      - name: Create the file, if it doesnt exist already
        file:
          path: /etc/file.txt
          state: touch
        when: not stat_result.stat.exists

In general you would do this with the stat module. But the command module has the creates option which makes this very simple:

- name: touch file
  command: touch /etc/file.txt
  args:
    creates: /etc/file.txt

I guess your touch command is just an example? Best practice would be to not check anything at all and let ansible do its job - with the correct module. So if you want to ensure the file exists you would use the file module:

- name: make sure file exists
  file:
    path: /etc/file.txt
    state: touch

The stat module will do this as well as obtain a lot of other information for files. From the example documentation:

- stat: path=/path/to/something
  register: p

- debug: msg="Path exists and is a directory"
  when: p.stat.isdir is defined and p.stat.isdir

Discovered that calling stat is slow and collects a lot of info that is not required for file existence check.
After spending some time searching for solution, i discovered following solution, which works much faster:

- raw: test -e /path/to/something && echo true || echo false
  register: file_exists

- debug: msg="Path exists"
  when: file_exists == true

vars:
  mypath: "/etc/file.txt"

tasks:
  - name: checking the file exists
    command: touch file.txt
    when: mypath is not exists

A note on relative paths to complement the other answers.

When doing infrastructure as code I'm usually using roles and tasks that accept relative paths, specially for files defined in those roles.

Special variables like playbook_dir and role_path are very useful to create the absolute paths needed to test for existence.