Find all instances, and build a list

[John Harmon]

I have a file, as an example, with the following content:

disk = [file:/OVS/Repositories/0004fb0000030000df2ee11376f1cd94/VirtualDisks/b7558d7745c14b02806d08f8003906e1.img,xvda,w,phy:/OVS/Repositories/0004fb0000030000df2ee11376f1cd94/VirtualDisks/0004fb0000120000049ec392e534e039,xvdb,w,file:/OVS/Repositories/0004fb0000030000df2ee11376f1cd94/VirtualDisks/0004fb0000120000843bb7e2fe395f24.img,xvdc,w]

I wish to find all instances of image files, and build a list with them.  Here is my regexp:

(\w+.img)

Here is a regexp tester with all of the above:
https://regex101.com/r/UKcYIa/3

I know that I can do this with shell, or similar modules, but I wish to do this in a more ansible-native way (if there is one).   Is there a module that will allow me to search a file with a regular expression and then register the results to a variable?  I just want to build a list of *img files (can be more than 1 and probably wont exceed 10) so that I can manipulate them later.

[John Harmon]

I am trying the following, but it isn't quite working like I hoped:

    - name: Gather current virtual disks
      lineinfile:
        path: "{{ file }}"
        regexp: (\w+.img)
        line: ''
      check_mode: yes
      register: virt_disk

Result (debug of virt_disk):

ok: [myftpserver] => {
    "virt_disk": {
        "backup": "",
        "changed": true,
        "diff": [
            {
                "after": "",
                "after_header": "/var/ftp/vm.cfg (content)",
                "before": "",
                "before_header": "/var/ftp/vm.cfg (content)"
            },
            {
                "after_header": "/var/ftp/vm.cfg (file attributes)",
                "before_header": "/var/ftp/vm.cfg (file attributes)"
            }
        ],
        "failed": false,
        "msg": "line replaced"
    }
}

[Piotr Owcarz]

Hi

Read the file contents with the 'file' lookup https://docs.ansible.com/ansible/2.6/plugins/lookup/file.html then run regexp filter on the lookup result: https://docs.ansible.com/ansible/2.5/user_guide/playbooks_filters.html#regular-expression-filters

eg: "{{ lookup('file', '/path/to/file') | regex_findall('(\w+.img)') }}"

Piotr

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[John Harmon]

Great!  Thank you.

[John Harmon]

Perhaps I am doing this wrong, but it doesn't like my syntax.  If I escape the backslash ('\\w+.img') it tries to run but with a different error:

    - name: Find virtual Disks
      set_fact:
        virt_disks: "{{ lookup('file','/var/ftp/vm.cfg') | regex_findall('\w+.img') }}"

Result:

ERROR! Syntax Error while loading YAML.
  found unknown escape character

The error appears to have been in '/etc/ansible/playbooks/one-offs/sanitize_vm.yml': line 21, column 75, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

      set_fact:
        virt_disks: "{{ lookup('file','/var/ftp/vm.cfg') | regex_findall('\w+.img') }}"
                                                                          ^ here
We could be wrong, but this one looks like it might be an issue with
missing quotes.  Always quote template expression brackets when they
start a value. For instance:

    with_items:
      - {{ foo }}

Should be written as:

    with_items:
      - "{{ foo }}"

If I escape the backslash:

TASK [Find virtual Disks] ****************************************************************************************************************************************************************************************************************
 [WARNING]: Unable to find '/var/ftp/vm.cfg' in expected paths (use -vvvvv to see paths)

fatal: [ovmftp]: FAILED! => {"msg": "An unhandled exception occurred while running the lookup plugin 'file'. Error was a <class 'ansible.errors.AnsibleError'>, original message: could not locate file in lookup: /var/ftp/vm.cfg"}

I find the error strange on the last one, because I stat the file previous to it and can see it fine. 

[Kai Stian Olstad]

On Tuesday, 4 December 2018 18:21:23 CET John Harmon wrote:
> Perhaps I am doing this wrong, but it doesn't like my syntax. If I escape
> the backslash ('\\w+.img') it tries to run but with a different error:
> - name: Find virtual Disks
> set_fact:
> virt_disks: "{{ lookup('file','/var/ftp/vm.cfg') |
> regex_findall('\w+.img') }}"
>
> Result:
> ERROR! Syntax Error while loading YAML.
> found unknown escape character
>
> The error appears to have been in
> '/etc/ansible/playbooks/one-offs/sanitize_vm.yml': line 21, column 75, but
> may
> be elsewhere in the file depending on the exact syntax problem.
>
> The offending line appears to be:
>
> set_fact:
> virt_disks: "{{ lookup('file','/var/ftp/vm.cfg') | regex_findall('\w+.img') }}"

<snip />

>
>
> I find the error strange on the last one, because I stat the file previous
> to it and can see it fine.

In your set_fact, try to swap your single quotes to double quotes and you double to single quotes.


--
Kai Stian Olstad

[John Harmon]

Now, whether escaped or not it says it can't find the file.  Do I need to delegate_to in set_fact? or should it be looking on the host specified?

[Piotr Owcarz]

John, 

I just realized, that lookups read files on the Ansible control machine. I assume you are searching that file on remote machine - then lookup won't work. If this is the case, read on...

I was researchnig a similar issue today, and couldn't came up with other solution than:

- shell: "grep -Eo '\\w+.img'  {{ file }}"

  register: out

- debug: var=out.stdout_lines

Piotr

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[John Harmon]

Thx Piotr.  That works.  I was hoping to be able to do this without shell, but I haven't been able to find another way around it either.

[Kai Stian Olstad]

On Tuesday, 4 December 2018 19:02:13 CET John Harmon wrote:
>
> On Tuesday, December 4, 2018 at 10:32:41 AM UTC-7, Kai Stian Olstad wrote:
> >
> > >
> > > I find the error strange on the last one, because I stat the file
> > previous
> > > to it and can see it fine.
> >
> > In your set_fact, try to swap your single quotes to double quotes and you
> > double to single quotes.
> >
> >
> >
> >
> >

> Now, whether escaped or not it says it can't find the file. Do I need to
> delegate_to in set_fact? or should it be looking on the host specified?

lookup plugins run only on localhost not remote, if you file is on the host you can't use lookup.

--
Kai Stian Olstad

[Piotr Owcarz]

Yeah, I've turned a full circle... Sorry, but I don't have a better solution...

Piotr

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[Kai Stian Olstad]

On Tuesday, 4 December 2018 19:07:16 CET John Harmon wrote:
> Thx Piotr. That works. I was hoping to be able to do this without shell,
> but I haven't been able to find another way around it either.

A lot more code.
First use the slurp module to fetch the content and store it to a variable.
The result is base64 encode, so you need to use b64decode filer and then you can use the regex filter.


--
Kai Stian Olstad