fix(wg): improve generation of keypairs

Signed-off-by: Matej Focko <me@mfocko.xyz>

roles/wg/tasks/generate_keypair.yml

@@ -0,0 +1,20 @@
+---
+- name: Generate private key
+  ansible.builtin.command:
+    cmd: wg genkey
+  changed_when: false
+  check_mode: false
+  register: _generated_private_key
+
+- name: Derive public key
+  ansible.builtin.command:
+    cmd: wg pubkey
+    stdin: "{{ _generated_private_key.stdout }}"
+  changed_when: false
+  check_mode: false
+  register: _derived_public_key
+
+- name: Set key/pair facts
+  ansible.builtin.set_fact:
+    wg_private_key: _generated_private_key.stdout
+    wg_public_key: _derived_public_key.stdout

roles/wg/tasks/main.yml

@@ -3,25 +3,36 @@
   ansible.builtin.include_tasks: install.yml
   tags: install
 
-- name: Generate private key
-  ansible.builtin.shell:
-    cmd: |
-      set -e -o pipefail
-      umask 077
-      wg genkey | tee private.key | wg pubkey > public.key
+- name: Check for existence of private key
+  ansible.builtin.stat:
+    path: /etc/wireguard/private.key
+  register: _private_key_stat
 
-    chdir: /etc/wireguard
-    creates: /etc/wireguard/private.key
-  when: wg_generate_keypair
+- name: Generate keypair
+  ansible.builtin.include_tasks: tasks/generate_keypair.yml
+  when: not _private_key_stat.exists
 
-- name: Get public key
-  ansible.builtin.command: cat /etc/wireguard/public.key
-  register: public_key
-  changed_when: False
+- name: Save private key
+  ansible.builtin.template:
+    src: templates/keyfile.j2
+    dest: /etc/wireguard/private.key
+    owner: root
+    group: root
+    mode: 0700
+  vars:
+    key: "{{ wg_private_key }}"
+  when: not _private_key_stat.exists
 
-- name: Set public key fact
-  ansible.builtin.set_fact:
-    public_key: "{{ public_key.stdout }}"
+- name: Save public key
+  ansible.builtin.template:
+    src: templates/keyfile.j2
+    dest: /etc/wireguard/public.key
+    owner: root
+    group: root
+    mode: 0700
+  vars:
+    key: "{{ wg_public_key }}"
+  when: not _private_key_stat.exists
 
 - name: Set dns_command for co-openSUSE
   ansible.builtin.set_fact:

roles/wg/templates/keyfile.j2

@@ -0,0 +1 @@
+{{ key }}