Refine a bit dnsmasq role

An assertion block was missing a condition, leading to issue when we
wanted to just remove a network from the configuration.

In the network configuration template, the test to know more about ipv4
and ipv6 ranges was a bit too loose, leading to issues under certain
conditions.

We faced the same issue in the host management, leading to potentially
wrong DHCP configuration. In order to ease debugging, we now generate a
fact, display its content, and use that content to inject the host data
in the configuration.

During a re-run, the service is already stopped/disabled, and the unit
file is removed. Ansible will then fail, since systemd can't find the
service to stop.

roles/dnsmasq/tasks/configure.yml

@@ -74,10 +74,14 @@
   become: true
   when:
     - _act == 'cleanup'
+  register: _dnsmasq_stop
   ansible.builtin.systemd_service:
     name: cifmw-dnsmasq.service
     state: stopped
     enabled: false
+  failed_when:
+    - _dnsmasq_stop.msg is defined and
+      _dnsmasq_stop.msg is not match('Could not find the requested service cifmw-dnsmasq.service')
 
 - name: Remove unit file
   become: true

roles/dnsmasq/tasks/manage_host.yml

@@ -39,28 +39,36 @@
       - _network_exists.stat.exists
     quiet: true
     msg: >-
-      You must create the network first, calling
+      You must create {{ cifmw_dnsmasq_host_network }} network first, calling
       dnsmasq/manage_network.yml task.
 
-- name: Manage host entry
-  become: true
-  notify: Restart dnsmasq
-  ansible.builtin.blockinfile:
-    block: |
-      {% if cifmw_dnsmasq_host_ipv4 is defined                -%}
-      {% set data = [cifmw_dnsmasq_host_mac]                  -%}
-      {% set _ = data.append(cifmw_dnsmasq_host_ipv4)         -%}
+- name: Compute entry
+  ansible.builtin.set_fact:
+    _host_entry: |
+      {% if cifmw_dnsmasq_host_ipv4 is defined and cifmw_dnsmasq_host_ipv4 | length > 0       -%}
+      {% set data = [cifmw_dnsmasq_host_mac]                                                  -%}
+      {% set _ = data.append(cifmw_dnsmasq_host_ipv4)                                         -%}
       {% set _ = data.append(cifmw_dnsmasq_host_name) if
-                 cifmw_dnsmasq_host_name is defined           -%}
+                 cifmw_dnsmasq_host_name is defined and cifmw_dnsmasq_host_name | length > 0  -%}
       dhcp-host={{ data | join(',') }}
       {% endif -%}
-      {% if cifmw_dnsmasq_host_ipv6 is defined                -%}
-      {% set data = [cifmw_dnsmasq_host_mac]                  -%}
-      {% set _ = data.append('['~cifmw_dnsmasq_host_ipv6~']') -%}
+      {% if cifmw_dnsmasq_host_ipv6 is defined and cifmw_dnsmasq_host_ipv6 | length > 0       -%}
+      {% set data = [cifmw_dnsmasq_host_mac]                                                  -%}
+      {% set _ = data.append('['~cifmw_dnsmasq_host_ipv6~']')                                 -%}
       {% set _ = data.append(cifmw_dnsmasq_host_name) if
-                 cifmw_dnsmasq_host_name is defined           -%}
+                 cifmw_dnsmasq_host_name is defined and cifmw_dnsmasq_host_name | length > 0  -%}
       dhcp-host={{ data | join(',') }}
       {% endif -%}
+
+- name: Debug _host_entry
+  ansible.builtin.debug:
+    var: _host_entry
+
+- name: Manage host entry
+  become: true
+  notify: Restart dnsmasq
+  ansible.builtin.blockinfile:
+    block: "{{ _host_entry }}"
     dest: "{{ cifmw_dnsmasq_basedir }}/{{ cifmw_dnsmasq_host_network }}-hosts.conf"
     create: true
     mode: "0644"

roles/dnsmasq/tasks/manage_network.yml

@@ -22,6 +22,8 @@
       - cifmw_dnsmasq_network_state in ['present', 'absent']
 
 - name: Assert mandatory parameters for new network
+  when:
+    - cifmw_dnsmasq_network_state == 'present'
   ansible.builtin.assert:
     that:
       - cifmw_dnsmasq_network_definition is defined

roles/dnsmasq/templates/network.conf.j2

@@ -1,9 +1,9 @@
 # Managed by ci-framework/dnsmasq
 {% for range in cifmw_dnsmasq_network_definition['ranges']                                      %}
-{%   if range.start_v4 is defined                                                               %}
+{%   if range.start_v4 is defined and range.start_v4 | length > 0                               %}
 dhcp-range=set:{{ range.label }},{{ range.start_v4 }},static,{{ (range.start_v4 + "/" + range.prefix_length_v4 | default(24) | string) |  ansible.utils.ipaddr('netmask') }},{{ range.ttl | default('1h') }}
 {%   endif                                                                                      %}
-{%   if range.start_v6 is defined                                                               %}
+{%   if range.start_v6 is defined and range.start_v6 | length > 0                               %}
 dhcp-range=set:{{ range.label }},{{ range.start_v6 }},static,{{ range.prefix_length_v6 | default('64') }},{{ range.ttl | default('1h') }}
 {%   endif                                                                                      %}
 {%   for option in range['options'] | default([])                                               %}