feat(iac): establish Ansible baseline for Nginx, SearXNG, Valkey, and Certbot

- Reverse-engineer live Debian 13 (trixie) VPS state at miguelpedro.xyz.br
- Add modular Ansible roles: common, certbot, valkey, searxng, and nginx
- Encrypt SearXNG secret_key using ansible-vault in group_vars/all/vault.yml
- Cleanly remove unused example.com Nginx stub symlink (sites-enabled/miguelpedro.xyz.br)
- Scaffold cgit + fcgiwrap role (cgit_enabled: false) for upcoming deployment
- Add DISCOVERY_REPORT.md, COMMAND_LOG.md, README.md, and AGENT_INSTRUCTIONS.md with Self-Updating Protocol

6 files changed, 425 insertions, 0 deletions

diff --git a/roles/nginx/handlers/main.yml b/roles/nginx/handlers/main.yml
new file mode 100644
index 0000000..3940edb
--- /dev/null
+++ b/roles/nginx/handlers/main.yml
@@ -0,0 +1,11 @@
+---
+- name: Validate and reload nginx
+  ansible.builtin.command: /usr/sbin/nginx -t
+  changed_when: false
+  notify: Reload nginx service
+
+- name: Reload nginx service
+  ansible.builtin.systemd:
+    name: nginx.service
+    state: reloaded
+  listen: Reload nginx
diff --git a/roles/nginx/tasks/main.yml b/roles/nginx/tasks/main.yml
new file mode 100644
index 0000000..c4f55b6
--- /dev/null
+++ b/roles/nginx/tasks/main.yml
@@ -0,0 +1,87 @@
+---
+- name: Ensure nginx is installed
+  ansible.builtin.apt:
+    name:
+      - nginx
+    state: present
+
+- name: Ensure Nginx directories exist
+  ansible.builtin.file:
+    path: "{{ item }}"
+    state: directory
+    owner: root
+    group: root
+    mode: "0755"
+  loop:
+    - /etc/nginx/sites-available
+    - /etc/nginx/sites-enabled
+    - /etc/nginx/default.apps-available
+    - /etc/nginx/default.d
+    - "{{ default_web_root }}"
+
+- name: Deploy /etc/nginx/nginx.conf
+  ansible.builtin.template:
+    src: nginx.conf.j2
+    dest: /etc/nginx/nginx.conf
+    owner: root
+    group: root
+    mode: "0644"
+    validate: "/usr/sbin/nginx -t -c %s"
+  notify: Reload nginx
+
+- name: Deploy /etc/nginx/default.apps-available/searxng.conf
+  ansible.builtin.template:
+    src: default-app-searxng.conf.j2
+    dest: /etc/nginx/default.apps-available/searxng.conf
+    owner: root
+    group: root
+    mode: "0644"
+  notify: Reload nginx
+
+- name: Enable /etc/nginx/default.d/searxng.conf symlink
+  ansible.builtin.file:
+    src: /etc/nginx/default.apps-available/searxng.conf
+    dest: /etc/nginx/default.d/searxng.conf
+    state: link
+  notify: Reload nginx
+
+- name: Deploy /etc/nginx/sites-available/default
+  ansible.builtin.template:
+    src: site-default.conf.j2
+    dest: /etc/nginx/sites-available/default
+    owner: root
+    group: root
+    mode: "0644"
+  notify: Reload nginx
+
+- name: Deploy /etc/nginx/sites-available/searxng.conf
+  ansible.builtin.template:
+    src: site-searxng.conf.j2
+    dest: /etc/nginx/sites-available/searxng.conf
+    owner: root
+    group: root
+    mode: "0644"
+  notify: Reload nginx
+
+- name: Enable active Nginx sites
+  ansible.builtin.file:
+    src: "/etc/nginx/sites-available/{{ item }}"
+    dest: "/etc/nginx/sites-enabled/{{ item }}"
+    state: link
+  loop:
+    - default
+    - searxng.conf
+  notify: Reload nginx
+
+- name: Remove unused/stub Nginx site symlinks (clean tracking)
+  ansible.builtin.file:
+    path: "/etc/nginx/sites-enabled/{{ item }}"
+    state: absent
+  loop: "{{ nginx_remove_unused_sites | default([]) }}"
+  notify: Reload nginx
+
+- name: Ensure nginx service is enabled and running
+  ansible.builtin.systemd:
+    name: nginx.service
+    enabled: true
+    state: started
diff --git a/roles/nginx/templates/default-app-searxng.conf.j2 b/roles/nginx/templates/default-app-searxng.conf.j2
new file mode 100644
index 0000000..66b1f86
--- /dev/null
+++ b/roles/nginx/templates/default-app-searxng.conf.j2
@@ -0,0 +1,23 @@
+location /searxng {
+
+    uwsgi_pass unix://{{ searxng_socket_path }};
+
+    include uwsgi_params;
+
+    uwsgi_param    HTTP_HOST             $host;
+    uwsgi_param    HTTP_CONNECTION       $http_connection;
+
+    # see flaskfix.py
+    uwsgi_param    HTTP_X_FORWARDED_PROTO  $scheme;
+    uwsgi_param    HTTP_X_SCRIPT_NAME    /searxng;
+
+    # see botdetection/trusted_proxies.py
+    uwsgi_param    HTTP_X_REAL_IP        $remote_addr;
+    uwsgi_param    HTTP_X_FORWARDED_FOR  $proxy_add_x_forwarded_for;
+}
+
+# To serve the static files via the HTTP server
+#
+# location /searxng/static/ {
+#     alias /usr/local/searxng/searxng-src/searx/static/;
+# }
diff --git a/roles/nginx/templates/nginx.conf.j2 b/roles/nginx/templates/nginx.conf.j2
new file mode 100644
index 0000000..68a8fd4
--- /dev/null
+++ b/roles/nginx/templates/nginx.conf.j2
@@ -0,0 +1,84 @@
+user www-data;
+worker_processes auto;
+worker_cpu_affinity auto;
+pid /run/nginx.pid;
+error_log /var/log/nginx/error.log;
+include /etc/nginx/modules-enabled/*.conf;
+
+events {
+	worker_connections 768;
+	# multi_accept on;
+}
+
+http {
+
+	##
+	# Basic Settings
+	##
+
+	sendfile on;
+	tcp_nopush on;
+	types_hash_max_size 2048;
+	server_tokens off; # Recommended practice is to turn this off
+
+	# server_names_hash_bucket_size 64;
+	# server_name_in_redirect off;
+
+	include /etc/nginx/mime.types;
+	default_type application/octet-stream;
+
+	##
+	# SSL Settings
+	##
+
+	ssl_protocols TLSv1.2 TLSv1.3; # Dropping SSLv3 (POODLE), TLS 1.0, 1.1
+	ssl_prefer_server_ciphers off; # Don't force server cipher order.
+
+	##
+	# Logging Settings
+	##
+
+	access_log /var/log/nginx/access.log;
+
+	##
+	# Gzip Settings
+	##
+
+	gzip on;
+
+	# gzip_vary on;
+	# gzip_proxied any;
+	# gzip_comp_level 6;
+	# gzip_buffers 16 8k;
+	# gzip_http_version 1.1;
+	# gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;
+
+	##
+	# Virtual Host Configs
+	##
+
+	include /etc/nginx/conf.d/*.conf;
+	include /etc/nginx/sites-enabled/*;
+}
+
+
+#mail {
+#	# See sample authentication script at:
+#	# http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
+#
+#	# auth_http localhost/auth.php;
+#	# pop3_capabilities "TOP" "USER";
+#	# imap_capabilities "IMAP4rev1" "UIDPLUS";
+#
+#	server {
+#		listen     localhost:110;
+#		protocol   pop3;
+#		proxy      on;
+#	}
+#
+#	server {
+#		listen     localhost:143;
+#		protocol   imap;
+#		proxy      on;
+#	}
+#}
diff --git a/roles/nginx/templates/site-default.conf.j2 b/roles/nginx/templates/site-default.conf.j2
new file mode 100644
index 0000000..2542a3a
--- /dev/null
+++ b/roles/nginx/templates/site-default.conf.j2
@@ -0,0 +1,173 @@
+##
+# You should look at the following URL's in order to grasp a solid understanding
+# of Nginx configuration files in order to fully unleash the power of Nginx.
+# https://www.nginx.com/resources/wiki/start/
+# https://www.nginx.com/resources/wiki/start/topics/tutorials/config_pitfalls/
+# https://wiki.debian.org/Nginx/DirectoryStructure
+#
+# In most cases, administrators will remove this file from sites-enabled/ and
+# leave it as reference inside of sites-available where it will continue to be
+# updated by the nginx packaging team.
+#
+# This file will automatically load configuration files provided by other
+# applications, such as Drupal or Wordpress. These applications will be made
+# available underneath a path with that package name, such as /drupal8.
+#
+# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
+##
+
+# Default server configuration
+#
+server {
+        # Load configuration files for the default server block.
+        include /etc/nginx/default.d/*.conf;
+
+	listen 80 default_server;
+	listen [::]:80 default_server;
+
+	# SSL configuration
+	#
+	# listen 443 ssl default_server;
+	# listen [::]:443 ssl default_server;
+	#
+	# Note: You should disable gzip for SSL traffic.
+	# See: https://bugs.debian.org/773332
+	#
+	# Read up on ssl_ciphers to ensure a secure configuration.
+	# See: https://bugs.debian.org/765782
+	#
+	# Self signed certs generated by the ssl-cert package
+	# Don't use them in a production server!
+	#
+	# include snippets/snakeoil.conf;
+
+	root {{ default_web_root }};
+
+	# Add index.php to the list if you are using PHP
+	index index.html index.htm index.nginx-debian.html;
+
+	server_name _;
+
+	location / {
+		# First attempt to serve request as file, then
+		# as directory, then fall back to displaying a 404.
+		try_files $uri $uri/ =404;
+	}
+
+	# pass PHP scripts to FastCGI server
+	#
+	#location ~ \.php$ {
+	#	include snippets/fastcgi-php.conf;
+	#
+	#	# With php-fpm (or other unix sockets):
+	#	fastcgi_pass unix:/run/php/php7.4-fpm.sock;
+	#	# With php-cgi (or other tcp sockets):
+	#	fastcgi_pass 127.0.0.1:9000;
+	#}
+
+	# deny access to .htaccess files, if Apache's document root
+	# concurs with nginx's one
+	#
+	#location ~ /\.ht {
+	#	deny all;
+	#}
+}
+
+
+# Virtual Host configuration for example.com
+#
+# You can move that to a different file under sites-available/ and symlink that
+# to sites-enabled/ to enable it.
+#
+#server {
+#	listen 80;
+#	listen [::]:80;
+#
+#	server_name example.com;
+#
+#	root /var/www/example.com;
+#	index index.html;
+#
+#	location / {
+#		try_files $uri $uri/ =404;
+#	}
+#}
+
+server {
+
+	# SSL configuration
+	#
+	# listen 443 ssl default_server;
+	# listen [::]:443 ssl default_server;
+	#
+	# Note: You should disable gzip for SSL traffic.
+	# See: https://bugs.debian.org/773332
+	#
+	# Read up on ssl_ciphers to ensure a secure configuration.
+	# See: https://bugs.debian.org/765782
+	#
+	# Self signed certs generated by the ssl-cert package
+	# Don't use them in a production server!
+	#
+	# include snippets/snakeoil.conf;
+
+	root {{ default_web_root }};
+
+	# Add index.php to the list if you are using PHP
+	index index.html index.htm index.nginx-debian.html;
+    server_name {{ primary_domain_aliases | join(' ') }} {{ primary_domain }}; # managed by Certbot
+
+
+	location / {
+		# First attempt to serve request as file, then
+		# as directory, then fall back to displaying a 404.
+		try_files $uri $uri/ =404;
+	}
+
+	# pass PHP scripts to FastCGI server
+	#
+	#location ~ \.php$ {
+	#	include snippets/fastcgi-php.conf;
+	#
+	#	# With php-fpm (or other unix sockets):
+	#	fastcgi_pass unix:/run/php/php7.4-fpm.sock;
+	#	# With php-cgi (or other tcp sockets):
+	#	fastcgi_pass 127.0.0.1:9000;
+	#}
+
+	# deny access to .htaccess files, if Apache's document root
+	# concurs with nginx's one
+	#
+	#location ~ /\.ht {
+	#	deny all;
+	#}
+
+
+    listen 443 ssl; # managed by Certbot
+    listen [::]:443 ssl ipv6only=on; # managed by Certbot
+    ssl_certificate /etc/letsencrypt/live/{{ primary_domain }}/fullchain.pem; # managed by Certbot
+    ssl_certificate_key /etc/letsencrypt/live/{{ primary_domain }}/privkey.pem; # managed by Certbot
+    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
+    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
+
+
+
+}
+server {
+{% for alias in primary_domain_aliases %}
+    if ($host = {{ alias }}) {
+        return 301 https://$host$request_uri;
+    } # managed by Certbot
+
+
+{% endfor %}
+    if ($host = {{ primary_domain }}) {
+        return 301 https://$host$request_uri;
+    } # managed by Certbot
+
+
+	listen 80 ;
+	listen [::]:80 ;
+    server_name {{ primary_domain_aliases | join(' ') }} {{ primary_domain }};
+    return 404; # managed by Certbot
+}
diff --git a/roles/nginx/templates/site-searxng.conf.j2 b/roles/nginx/templates/site-searxng.conf.j2
new file mode 100644
index 0000000..67a5a2d
--- /dev/null
+++ b/roles/nginx/templates/site-searxng.conf.j2
@@ -0,0 +1,47 @@
+server {
+    server_name {{ searxng_domain }};
+
+    # Disable logging for user privacy
+    access_log /dev/null;
+    error_log  /dev/null;
+
+    # Security headers
+    add_header X-Frame-Options "SAMEORIGIN" always;
+    add_header X-Content-Type-Options "nosniff" always;
+    add_header Referrer-Policy "no-referrer" always;
+    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
+
+    location / {
+        uwsgi_pass unix://{{ searxng_socket_path }};
+
+        include uwsgi_params;
+
+        uwsgi_param    HTTP_HOST             $host;
+        uwsgi_param    HTTP_CONNECTION       $http_connection;
+
+        # see flaskfix.py
+        uwsgi_param    HTTP_X_SCHEME         $scheme;
+
+        # see limiter.py
+        uwsgi_param    HTTP_X_REAL_IP        $remote_addr;
+        uwsgi_param    HTTP_X_FORWARDED_FOR  $proxy_add_x_forwarded_for;
+    }
+
+    listen 443 ssl; # managed by Certbot
+    listen [::]:443 ssl; # managed by Certbot
+    ssl_certificate /etc/letsencrypt/live/{{ searxng_domain }}/fullchain.pem; # managed by Certbot
+    ssl_certificate_key /etc/letsencrypt/live/{{ searxng_domain }}/privkey.pem; # managed by Certbot
+    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
+    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
+}
+
+server {
+    if ($host = {{ searxng_domain }}) {
+        return 301 https://$host$request_uri;
+    } # managed by Certbot
+
+    listen 80;
+    listen [::]:80;
+    server_name {{ searxng_domain }};
+    return 404; # managed by Certbot
+}