Add nginx config file and support for outlets

The nginx config file used to be copied from the discourse/discourse
repository, but it has been now moved in this project, closer to the
place where it is used.

The config has several 'include' statements that implement support for
outlets that templates can then use to extend the default configuration
for various features. This is an alternative to the "find & replace"
hacks.

image/base/etc/nginx/conf.d/discourse.conf

@@ -0,0 +1,289 @@
+# Additional MIME types that you'd like nginx to handle go in here
+types {
+  text/csv csv;
+  application/wasm wasm;
+}
+
+upstream discourse {
+  server 127.0.0.1:3000;
+}
+
+# inactive means we keep stuff around for 1440m minutes regardless of last access (1 week)
+# levels means it is a 2 deep hierarchy cause we can have lots of files
+# max_size limits the size of the cache
+proxy_cache_path /var/nginx/cache inactive=1440m levels=1:2 keys_zone=one:10m max_size=600m;
+
+# Increased from the default value to acommodate large cookies during oAuth2 flows
+# like in https://meta.discourse.org/t/x/74060 and large CSP and Link (preload) headers
+proxy_buffer_size 32k;
+proxy_buffers 4 32k;
+
+# Increased from the default value to allow for a large volume of cookies in request headers
+# Discourse itself tries to minimise cookie size, but we cannot control other cookies set by other tools on the same domain.
+large_client_header_buffers 4 32k;
+
+# attempt to preserve the proto, must be in http context
+map $http_x_forwarded_proto $thescheme {
+  default $scheme;
+  "~https$" https;
+}
+
+log_format log_discourse '[$time_local] "$http_host" $remote_addr "$request" "$http_user_agent" "$sent_http_x_discourse_route" $status $bytes_sent "$http_referer" $upstream_response_time $request_time "$upstream_http_x_discourse_username" "$upstream_http_x_discourse_trackview" "$upstream_http_x_queue_time" "$upstream_http_x_redis_calls" "$upstream_http_x_redis_time" "$upstream_http_x_sql_calls" "$upstream_http_x_sql_time"';
+
+# Allow bypass cache from localhost
+geo $bypass_cache {
+  default         0;
+  127.0.0.1       1;
+  ::1             1;
+}
+
+include conf.d/outlets/before-server/*.conf;
+
+server {
+  access_log /var/log/nginx/access.log log_discourse;
+
+  include conf.d/outlets/server/*.conf;
+
+  gzip on;
+  gzip_vary on;
+  gzip_min_length 1000;
+  gzip_comp_level 5;
+  gzip_types application/json text/css text/javascript application/x-javascript application/javascript image/svg+xml application/wasm;
+  gzip_proxied any;
+
+  server_name _;
+  server_tokens off;
+
+  sendfile on;
+
+  keepalive_timeout 65;
+
+  # maximum file upload size (keep up to date when changing the corresponding site setting)
+  client_max_body_size 10m;
+
+  # path to discourse's public directory
+  set $public /var/www/discourse/public;
+
+  # without weak etags we get zero benefit from etags on dynamically compressed content
+  # further more etags are based on the file in nginx not sha of data
+  # use dates, it solves the problem fine even cross server
+  etag off;
+
+  # prevent direct download of backups
+  location ^~ /backups/ {
+    internal;
+  }
+
+  # bypass rails stack with a cheap 204 for favicon.ico requests
+  location /favicon.ico {
+    return 204;
+    access_log off;
+    log_not_found off;
+  }
+
+  location / {
+    root $public;
+    add_header ETag "";
+
+    # auth_basic on;
+    # auth_basic_user_file /etc/nginx/htpasswd;
+
+    location ~ ^/uploads/short-url/ {
+      proxy_set_header Host $http_host;
+      proxy_set_header X-Real-IP $remote_addr;
+      proxy_set_header X-Request-Start "t=${msec}";
+      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+      proxy_set_header X-Forwarded-Proto $thescheme;
+      proxy_set_header X-Sendfile-Type "";
+      proxy_set_header X-Accel-Mapping "";
+      proxy_pass http://discourse;
+      break;
+    }
+
+    location ~ ^/(secure-media-uploads/|secure-uploads)/ {
+      proxy_set_header Host $http_host;
+      proxy_set_header X-Real-IP $remote_addr;
+      proxy_set_header X-Request-Start "t=${msec}";
+      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+      proxy_set_header X-Forwarded-Proto $thescheme;
+      proxy_set_header X-Sendfile-Type "";
+      proxy_set_header X-Accel-Mapping "";
+      proxy_pass http://discourse;
+      break;
+    }
+
+    location ~* (fonts|assets|plugins|uploads)/.*\.(eot|ttf|woff|woff2|ico|otf)$ {
+      expires 1y;
+      add_header Cache-Control public,immutable;
+      add_header Access-Control-Allow-Origin *;
+    }
+
+    location = /srv/status {
+      access_log off;
+      log_not_found off;
+      proxy_set_header Host $http_host;
+      proxy_set_header X-Real-IP $remote_addr;
+      proxy_set_header X-Request-Start "t=${msec}";
+      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+      proxy_set_header X-Forwarded-Proto $thescheme;
+      proxy_set_header X-Sendfile-Type "";
+      proxy_set_header X-Accel-Mapping "";
+      proxy_pass http://discourse;
+      break;
+    }
+
+    # some minimal caching here so we don't keep asking
+    # longer term we should increase probably to 1y
+    location ~ ^/javascripts/ {
+      expires 1d;
+      add_header Cache-Control public,immutable;
+      add_header Access-Control-Allow-Origin *;
+    }
+
+    location ~ ^/assets/(?<asset_path>.+)$ {
+      expires 1y;
+      # asset pipeline enables this
+      brotli_static on;
+      gzip_static on;
+      add_header Cache-Control public,immutable;
+      # HOOK in asset location (used for extensibility)
+      # TODO I don't think this break is needed, it just breaks out of rewrite
+      break;
+    }
+
+    location ~ ^/plugins/ {
+      expires 1y;
+      add_header Cache-Control public,immutable;
+      add_header Access-Control-Allow-Origin *;
+    }
+
+    # cache emojis
+    location ~ /images/emoji/ {
+      expires 1y;
+      add_header Cache-Control public,immutable;
+      add_header Access-Control-Allow-Origin *;
+    }
+
+    location ~ ^/uploads/ {
+      # NOTE: it is really annoying that we can't just define headers
+      # at the top level and inherit.
+      #
+      # proxy_set_header DOES NOT inherit, by design, we must repeat it,
+      # otherwise headers are not set correctly
+      proxy_set_header Host $http_host;
+      proxy_set_header X-Real-IP $remote_addr;
+      proxy_set_header X-Request-Start "t=${msec}";
+      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+      proxy_set_header X-Forwarded-Proto $thescheme;
+      proxy_set_header X-Sendfile-Type X-Accel-Redirect;
+      proxy_set_header X-Accel-Mapping $public/=/downloads/;
+      expires 1y;
+      add_header Cache-Control public,immutable;
+
+      ## optional upload anti-hotlinking rules
+      #valid_referers none blocked mysite.com *.mysite.com;
+      #if ($invalid_referer) { return 403; }
+
+      # custom CSS
+      location ~ /stylesheet-cache/ {
+          add_header Access-Control-Allow-Origin *;
+          try_files $uri =404;
+      }
+
+      # this allows us to bypass rails
+      location ~* \.(gif|png|jpg|jpeg|bmp|tif|tiff|ico|webp|avif)$ {
+          add_header Access-Control-Allow-Origin *;
+          try_files $uri =404;
+      }
+
+      # SVG needs an extra header attached
+      location ~* \.(svg)$ {
+      }
+
+      # thumbnails & optimized images
+      location ~ /_?optimized/ {
+          add_header Access-Control-Allow-Origin *;
+          try_files $uri =404;
+      }
+
+      proxy_pass http://discourse;
+      break;
+    }
+
+    location ~ ^/admin/backups/ {
+      proxy_set_header Host $http_host;
+      proxy_set_header X-Real-IP $remote_addr;
+      proxy_set_header X-Request-Start "t=${msec}";
+      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+      proxy_set_header X-Forwarded-Proto $thescheme;
+      proxy_set_header X-Sendfile-Type X-Accel-Redirect;
+      proxy_set_header X-Accel-Mapping $public/=/downloads/;
+      proxy_pass http://discourse;
+      break;
+    }
+
+    # This big block is needed so we can selectively enable
+    # acceleration for backups, avatars, sprites and so on.
+    # see note about repetition above
+    location ~ ^/(svg-sprite/|letter_avatar/|letter_avatar_proxy/|user_avatar|highlight-js|stylesheets|theme-javascripts|favicon/proxied|service-worker|extra-locales/(mf|overrides)) {
+      proxy_set_header Host $http_host;
+      proxy_set_header X-Real-IP $remote_addr;
+      proxy_set_header X-Request-Start "t=${msec}";
+      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+      proxy_set_header X-Forwarded-Proto $thescheme;
+      proxy_set_header X-Sendfile-Type "";
+      proxy_set_header X-Accel-Mapping "";
+
+      # if Set-Cookie is in the response nothing gets cached
+      # this is double bad cause we are not passing last modified in
+      proxy_ignore_headers "Set-Cookie";
+      proxy_hide_header "Set-Cookie";
+      proxy_hide_header "X-Discourse-Username";
+      proxy_hide_header "X-Runtime";
+
+      # note x-accel-redirect can not be used with proxy_cache
+      proxy_cache one;
+      proxy_cache_key "$scheme,$host,$request_uri";
+      proxy_cache_valid 200 301 302 7d;
+      proxy_cache_bypass $bypass_cache;
+      proxy_pass http://discourse;
+      break;
+    }
+
+    # we need buffering off for message bus
+    location /message-bus/ {
+      proxy_set_header X-Request-Start "t=${msec}";
+      proxy_set_header Host $http_host;
+      proxy_set_header X-Real-IP $remote_addr;
+      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+      proxy_set_header X-Forwarded-Proto $thescheme;
+      proxy_set_header X-Sendfile-Type "";
+      proxy_set_header X-Accel-Mapping "";
+      proxy_http_version 1.1;
+      proxy_buffering off;
+      proxy_pass http://discourse;
+      break;
+    }
+
+    # this means every file in public is tried first
+    try_files $uri @discourse;
+  }
+
+  location /downloads/ {
+    internal;
+    alias $public/;
+  }
+
+  location @discourse {
+    include conf.d/outlets/discourse/*.conf;
+
+    proxy_set_header Host $http_host;
+    proxy_set_header X-Request-Start "t=${msec}";
+    proxy_set_header X-Real-IP $remote_addr;
+    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+    proxy_set_header X-Forwarded-Proto $thescheme;
+    proxy_set_header X-Sendfile-Type "";
+    proxy_set_header X-Accel-Mapping "";
+    proxy_pass http://discourse;
+  }
+}

image/base/etc/nginx/conf.d/outlets/server/http.conf

@@ -0,0 +1 @@
+listen 80;

samples/standalone.yml

@@ -11,8 +11,6 @@ templates:
   - "templates/postgres.template.yml"
   - "templates/redis.template.yml"
   - "templates/web.template.yml"
-  ## Uncomment the next line to enable the IPv6 listener
-  #- "templates/web.ipv6.template.yml"
   - "templates/web.ratelimited.template.yml"
   ## Uncomment these two lines if you wish to add Lets Encrypt (https)
   #- "templates/web.ssl.template.yml"

samples/web_only.yml

@@ -3,8 +3,6 @@
 
 templates:
   - "templates/web.template.yml"
-  ## Uncomment the next line to enable the IPv6 listener
-  #- "templates/web.ipv6.template.yml"
   - "templates/web.ratelimited.template.yml"
   ## Uncomment these two lines if you wish to add Lets Encrypt (https)
   #- "templates/web.ssl.template.yml"

templates/offline-page.template.yml

@@ -7,17 +7,14 @@ params:
   offline_page_repository: https://github.com/discourse/discourse-offline-page.git
 
 run:
-  - replace:
-     filename: "/etc/nginx/conf.d/discourse.conf"
-     global: true
-     from: /server.+{/
-     to: |
-       server {
-         error_page 502 /error_page.html;
-         location /error_page.html {
-           root /var/www/discourse-offline-page/html;
-           internal;
-         }
+  - file:
+     path: "/etc/nginx/conf.d/outlets/server/offline-page.conf"
+     contents: |
+        error_page 502 /error_page.html;
+        location /error_page.html {
+          root /var/www/discourse-offline-page/html;
+          internal;
+        }
 
   - exec:
       cmd: git clone $offline_page_repository /var/www/discourse-offline-page

templates/web.ipv6.template.yml

@@ -1,8 +1,2 @@
+# This file is deprecated; you can remove it from your app.yml
 run:
-  - exec: echo "Enabling IPv6 listener"
-  - replace:
-      filename: "/etc/nginx/conf.d/discourse.conf"
-      from: listen 80;
-      to: |
-        listen 80;
-        listen [::]:80;

templates/web.letsencrypt.ssl.template.yml

@@ -106,28 +106,22 @@ hooks:
 
         /usr/sbin/nginx -c /etc/nginx/letsencrypt.conf -s stop
 
-    - replace:
-       filename: "/etc/nginx/conf.d/discourse.conf"
-       from: /ssl_certificate.+/
-       to: |
-         ssl_certificate /shared/ssl/$$ENV_DISCOURSE_HOSTNAME.cer;
-         ssl_certificate /shared/ssl/$$ENV_DISCOURSE_HOSTNAME_ecc.cer;
-
     - replace:
        filename: /shared/letsencrypt/account.conf
        from: /#?ACCOUNT_EMAIL=.+/
        to: |
          ACCOUNT_EMAIL=$$ENV_LETSENCRYPT_ACCOUNT_EMAIL
 
     - replace:
-       filename: "/etc/nginx/conf.d/discourse.conf"
-       from: /ssl_certificate_key.+/
+       filename: "/etc/nginx/conf.d/outlets/server/https.conf"
+       from: /ssl_certificate.+/
        to: |
-         ssl_certificate_key /shared/ssl/$$ENV_DISCOURSE_HOSTNAME.key;
-         ssl_certificate_key /shared/ssl/$$ENV_DISCOURSE_HOSTNAME_ecc.key;
+         ssl_certificate /shared/ssl/$$ENV_DISCOURSE_HOSTNAME.cer;
+         ssl_certificate /shared/ssl/$$ENV_DISCOURSE_HOSTNAME_ecc.cer;
 
     - replace:
-       filename: "/etc/nginx/conf.d/discourse.conf"
-       from: /add_header.+/
+       filename: "/etc/nginx/conf.d/outlets/server/https.conf"
+       from: /ssl_certificate_key.+/
        to: |
-         add_header Strict-Transport-Security 'max-age=63072000';
+         ssl_certificate_key /shared/ssl/$$ENV_DISCOURSE_HOSTNAME.key;
+         ssl_certificate_key /shared/ssl/$$ENV_DISCOURSE_HOSTNAME_ecc.key;