nginx: Add option for installing extra modules

This will be used for installing the geoip2 module, so we can make it
more difficult for Chinese bots to crawl the wiki.

The name of the shared object file can be overridden in case it is not
named ngx_http_{{ module.name }}_module.so, e.g. srcache where the
shared object is named ngx_http_srcache_filter_module.so.

roles/nginx/defaults/main.yml

 letsencrypt_validation_dir: "/var/lib/letsencrypt"
 nginx_firewall_zone:
+nginx_extra_modules: []

roles/nginx/meta/main.yml

+dependencies:
+  - role: geoipupdate
+    when: "'geoip2' in (nginx_extra_modules | map(attribute='name') )"

roles/nginx/tasks/main.yml

 - name: Install nginx
   pacman: name=nginx,nginx-mod-brotli state=present
 
+- name: Install extra nginx modules
+  pacman: name={{ nginx_extra_modules | map(attribute='name') | map('regex_replace', '^', 'nginx-mod-') }} state=present
+
 - name: Install nginx.service snippet
   copy: src=nginx.service.d dest=/etc/systemd/system owner=root group=root mode=0644
 

roles/nginx/templates/nginx.conf.j2

@@ -2,6 +2,13 @@ worker_processes  auto;
 
 load_module /usr/lib/nginx/modules/ngx_http_brotli_filter_module.so;
 load_module /usr/lib/nginx/modules/ngx_http_brotli_static_module.so;
+{% for module in nginx_extra_modules %}
+{% if module.so_name is not defined %}
+load_module /usr/lib/nginx/modules/ngx_http_{{ module.name }}_module.so;
+{% else %}
+load_module /usr/lib/nginx/modules/{{ module.so_name | replace('-', '_') }};
+{% endif %}
+{% endfor %}
 include toplevel-snippets/*.conf;
 
 events {