How can I find the user ID using ansible and use that in a jinja2 template?

Q: "Get the UID of each of the created users."

A: Module getent serves exactly this purpose. For example

- hosts: localhost
  vars:
    my_users: ['root', 'admin']
  tasks:
    - getent:
        database: passwd
    - debug:
        msg:
          - "{{ item }} uid: {{ getent_passwd[item].1 }}"
          - "{{ item }} gid: {{ getent_passwd[item].2 }}"
          - "{{ item }} home: {{ getent_passwd[item].4 }}"
          - "{{ item }} shell: {{ getent_passwd[item].5 }}"
      loop: "{{ my_users }}"

gives

ok: [localhost] => (item=root) => {
    "msg": [
        "root uid: 0", 
        "root gid: 0", 
        "root home: /root", 
        "root shell: /bin/bash"
    ]
}
ok: [localhost] => (item=admin) => {
    "msg": [
        "admin uid: 1002", 
        "admin gid: 1002", 
        "admin home: /home/admin", 
        "admin shell: /bin/bash"
    ]
}

Module getent automaticaly created the dictionary getent_passwd which can be used in a template. For example the template

shell> cat template.j2
{% for user in my_users %}
{{ user }} {{ getent_passwd[user].1 }}
{% endfor %}

    - template:
        src: template.j2
        dest: my_users.txt

gives

shell> cat my_users.txt 
root 0
admin 1002

I had the same question.

Unfortunately, the lookup plugin is only useful on the control node.
In other words, the subjected users (with the same uid) need to be on both the control node and all the managed nodes. Or the task will fail with return code 1.

For me, using the getent module is a decent solution.
Alternatively, everything is actually there in the returned value of the user module. I only need to register its returned value to access them.

The playbook below demonstrates how I compute uid from the returned value of the user module both in an arbitrary subsequent task (debug) and in the jinja template.

- name: Demonstrate How to Compute UID after User Creations
  hosts: all
  become: true
  gather_facts: no
  vars:
    my_users:
      - u1
      - u2
      - u3
  tasks:
    - name: Create users in loop
      user:
        name: "{{ item }}"
      loop: "{{ my_users }}"
      register: created_users

    - name: Display created users
      debug:
        msg: "User: uid:{{ item.uid }} name:{{ item.name }} group:{{ item.group }} home:{{ item.home }} shell:{{ item.shell }}"
      loop: "{{ created_users.results }}"
      # Use loop_control-label to suppress item verbosity
      loop_control:
        label: "{{ item.name }}"

    - name: Work with template
      template:
        src: myusers.j2
        dest: /tmp/myusers.txt

And here is myusers.j2 template.

{{ ansible_managed | comment }}
{% for item in created_users.results %}
User: uid:{{ item.uid }} name:{{ item.name }} group:{{ item.group }} home:{{ item.home }} shell:{{ item.shell }}
{% endfor %}

The output is as follows:

$ ansible-playbook compute-uid.yml

PLAY [Demonstrate How to Compute UID after User Creations] **********************************************************************************************

TASK [Create users in loop] *****************************************************************************************************************************
changed: [ansible1] => (item=u1)
changed: [ansible1] => (item=u2)
changed: [ansible1] => (item=u3)

TASK [Display created users] ****************************************************************************************************************************
ok: [ansible1] => (item=u1) => {
    "msg": "User: uid:1001 name:u1 group:1001 home:/home/u1 shell:/bin/bash"
}
ok: [ansible1] => (item=u2) => {
    "msg": "User: uid:1002 name:u2 group:1002 home:/home/u2 shell:/bin/bash"
}
ok: [ansible1] => (item=u3) => {
    "msg": "User: uid:1003 name:u3 group:1003 home:/home/u3 shell:/bin/bash"
}

TASK [Work with template] *******************************************************************************************************************************
changed: [ansible1]

PLAY RECAP **********************************************************************************************************************************************
ansible1                   : ok=3    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

$ ansible all -a "cat /tmp/myusers.txt"
ansible1 | CHANGED | rc=0 >>
#
# Ansible managed
#
User: uid:1001 name:u1 group:1001 home:/home/u1 shell:/bin/bash
User: uid:1002 name:u2 group:1002 home:/home/u2 shell:/bin/bash
User: uid:1003 name:u3 group:1003 home:/home/u3 shell:/bin/bash

What about using id command and subshell? You can then do something like

blobfuse $1 --tmp-path=/mnt/resource/{{ item }}/ -o attr_timeout=240 -o entry_timeout=240 -o negative_timeout=120 -o uid="$(id {{ item }})" -o allow_other --container-name={{ item }} --file-cache-timeout-in-seconds=120 --config-file=/root/connection-{{ item }}.cfg

If you are using command module - you'll have to replace it with shell.

Edit: If you are using templates and want to use lookup plugin, which seems cleaner, you can do something like this (this was tested on local linux machine):

template.yaml

{% for item in users %}
{{ item }} {{ lookup('pipe', "id -u " + item) }}
{% endfor %}

ansible command

ansible -m template -i localhost, all -c local -a "src=template.yaml dest=result.txt" -e "{ users: [nobody,root]}"

result.txt

nobody 65534
root 0

In your case the error was using the {{ item }} in lookup, you should use just variable names and concatenation inside {{}} block