How to loop multiple tasks in Ansible? [duplicate] - ansible

Question

I need to check if a file named deploy.db exists. If it does not exist, I need to perform a set of tasks for which I am using a block.
Below is how I run the playbook
ansible-playbook test.yml \
-e Layer=APP \
-e BASEPATH="/logs" \
-e Filenames="file1,file2,file3"
Here is the playbook test.yml:
---
- name: "Play 1"
hosts: localhost
gather_facts: false
tasks:
- name: Construct
debug:
msg: "Run"
- block:
- stat: path="{{ BASEPATH }}/deploy.db"
register: currdb
- file: path="{{ BASEPATH }}/deploy.db" state=touch recurse=no
when: currdb.stat.exists == False
- shell: "echo done>>{{ BASEPATH }}/deploy.db"
when: currdb.stat.exists == False
when: Layer == 'APP'
with_items:
- "{{ Filenames.split(',') }}"
I am getting the below error running the playbook:
ERROR! 'with_items' is not a valid attribute for a Block
The error appears to be in '/app/test.yml': line 9, column 6, but may
be elsewhere in the file depending on the exact syntax problem.
The offending line appears to be:
- block:
^ here
After researching a bit, I understand that neither with_items nor loop is supported by a block and the solution is to include a tasks file.
I am, however, not sure how to get that to work. Can you suggest what tweaks I need in order to make my playbook work?
Considering I am on the latest version of Ansible, are there other solutions?

Answer 1

TL;DR
'with_items' is not a valid attribute for a Block
The error message says it all: you cannot loop over a block.
If you need to loop over a set of tasks, put them in a separate file and use include_tasks
Implementation (and some good practice...)
Below is an implementation based on your example illustrating the solution.
Since your question and code lacks some precision and since I pointed out some bad practices, please note that:
I fixed the looped code to effectively use the filenames you loop on (I inferred it was supposed to the deploy.db file). Note the use of loop_control to disambiguate the variable name in the included file (i.e. db_filename).
I made the code idempotent as much as possible by using the ansible module copy in place of shell and dropped the touch phase.
I transformed the var names to all lowercase and underscore separator.
To make sure the copy task works on all occasion, I replaced the removed tasks with a single making sure the basepath dir exists.
I added a unique filter after filenames.split(',') as well as a trim filter on each value to remove possible duplicates and eventual spaces added by error in the coma separated list.
I used not keyword and bool filter (for extra security) rather than a bare compare to a boolean False value.
Here is the included file create_db_each.yml
---
- name: Check if file exists
stat:
path: "{{ basepath }}/{{ db_filename }}"
register: currdb
- name: Create the file with "done" line if not present
copy:
content: "done"
dest: "{{ basepath }}/{{ db_filename }}"
when: not currdb.stat.exists | bool
used in the following create_db.yml playbook
---
- name: "Create my dbs"
hosts: localhost
gather_facts: false
tasks:
- name: Make sure the base directory exists
file:
path: "{{ basepath }}"
state: directory
- name: load each db
include_tasks: "create_db_each.yml"
when: layer == 'APP'
loop: "{{ filenames.split(',') | unique | map('trim') }}"
loop_control:
loop_var: db_filename
which gives
notes:
first run only, run it again on your side to witness it reports OK everywhere
see the filenames parameter value to illustrate the use of unique and trim
$ ansible-playbook -e basepath=/tmp/my/base/path -e "filenames='a.bla, b.toto, c , z.txt,a.bla'" -e layer=APP create_db.yml
PLAY [Create my dbs] ************************************************
TASK [Make sure the base directory exists] **************************
changed: [localhost]
TASK [load each db] *************************************************
included: /home/olcla/Sources/ZZ_tests/ansitests/create_db_each.yml for localhost => (item=a.bla)
included: /home/olcla/Sources/ZZ_tests/ansitests/create_db_each.yml for localhost => (item=b.toto)
included: /home/olcla/Sources/ZZ_tests/ansitests/create_db_each.yml for localhost => (item=c)
included: /home/olcla/Sources/ZZ_tests/ansitests/create_db_each.yml for localhost => (item=z.txt)
TASK [Check if file exists] *****************************************
ok: [localhost]
TASK [Create the file with "done" line if not present] **************
changed: [localhost]
TASK [Check if file exists] *****************************************
ok: [localhost]
TASK [Create the file with "done" line if not present] **************
changed: [localhost]
TASK [Check if file exists] *****************************************
ok: [localhost]
TASK [Create the file with "done" line if not present] **************
changed: [localhost]
TASK [Check if file exists] *****************************************
ok: [localhost]
TASK [Create the file with "done" line if not present] **************
changed: [localhost]
PLAY RECAP **********************************************************
localhost: ok=13 changed=5 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
$ tree /tmp/my/base/path/
/tmp/my/base/path/
├── a.bla
├── b.toto
├── c
└── z.txt
$ for f in /tmp/my/base/path/*; do cat $f; echo; done
done
done
done
done