How check a file exists in ansible?

问题

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)

If the file.txt exists then I have to skip the task.

回答1:

You can first check that the destination file exists or not and then make a decision based on the output of it's 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: stat_result.stat.exists == False

回答2:

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

回答3:

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

回答4:

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

回答5:

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

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

回答6:

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

- 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

回答7:

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

来源：https://stackoverflow.com/questions/35654286/how-check-a-file-exists-in-ansible

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ansible