Update the apt cache when the repo changes.

tasks/main.yml

@@ -1,25 +1,4 @@
 ---
-- name: Remove grafana
-  when: not grafana_enabled
-  tags: [grafana]
-  block:
-    - name: Ensure that grafana is stopped and disabled
-      ansible.builtin.service:
-        name: grafana-server
-        state: stopped
-        enabled: false
-
-    - name: Remove the grafana deb packages
-      ansible.builtin.apt:
-        name: "{{ grafana_packages }}"
-        state: absent
-
-    - name: Install the grafana deb repository
-      ansible.builtin.apt_repository:
-        repo: '{{ grafana_repo }}'
-        state: absent
-        update_cache: true
-
 - name: Install grafana
   when: grafana_enabled
   tags: [grafana]
@@ -49,6 +28,11 @@
         signed_by: "{{ grafana_repo_key_file }}"
         state: present
         enabled: true
+      register: grafana_repo
+    - name: Update the apt cache
+      ansible.builtin.apt:
+        update_cache: yes
+      when: grafana_repo is changed
     - name: Install the grafana packages
       ansible.builtin.apt:
         pkg: "{{ grafana_packages }}"