Reverse proxy with Apache HTTP Server

Requirements

For this you will need the Apache HTTP Server.

That is a fairly popular package so your distro will probably have it.

Ubuntu

sudo apt install apache2

Arch

sudo pacman -S apache

OpenSuse

sudo zypper install apache2

Install modules

You'll also need to install additional modules for Apache HTTP Server. You can do that with the following command:

sudo a2enmod proxy_http md ssl headers rewrite

Configure GoToSocial

We're going to have Apache handle LetsEncrypt certificates, so you need to turn off built-in LetsEncrypt support in your GoToSocial config.

First open the file in your text editor:

sudoedit /gotosocial/config.yaml

Then set letsencrypt-enabled: false.

If the reverse proxy will be running on the same machine, set the bind-address to "localhost" so that the GoToSocial server is only accessible via loopback. Otherwise it may be possible to bypass your proxy by connecting to GoToSocial directly, which might be undesirable.

If GoToSocial is already running, restart it.

sudo systemctl restart gotosocial.service

Or if you don't have a systemd service just restart it manually.

Set up Apache HTTP Server with SSL managed using MD module

Now we'll configure Apache HTTP Server to serve GoToSocial requests.

First we'll write a configuration for Apache HTTP Server and put it in /etc/apache2/sites-available:

sudo mkdir -p /etc/apache2/sites-available/
sudoedit /etc/apache2/sites-available/example.com.conf

In the above sudoedit command, replace example.com with the hostname of your GoToSocial server.

The file you're about to create should look a bit like this:

MDomain example.com auto
MDCertificateAgreement accepted

<VirtualHost *:80 >
  ServerName example.com
</VirtualHost>

<VirtualHost *:443>
  ServerName example.com

  RewriteEngine On
  RewriteCond %{HTTP:Upgrade} websocket [NC]
  RewriteCond %{HTTP:Connection} upgrade [NC]
  # set to 127.0.0.1 instead of localhost to work around https://stackoverflow.com/a/52550758
  RewriteRule ^/?(.*) "ws://127.0.0.1:8080/$1" [P,L]

  SSLEngine On
  ProxyPreserveHost On
  # set to 127.0.0.1 instead of localhost to work around https://stackoverflow.com/a/52550758
  ProxyPass / http://127.0.0.1:8080/
  ProxyPassReverse / http://127.0.0.1:8080/

  RequestHeader set "X-Forwarded-Proto" expr=https
</VirtualHost>

or, if you have Apache httpd 2.4.47+, you can get rid of both mod_rewrite and mod_proxy_wstunnel and simplify the whole config to:

MDomain example.com auto
MDCertificateAgreement accepted

<VirtualHost *:80 >
  ServerName example.com
</VirtualHost>

<VirtualHost *:443>
  ServerName example.com

  SSLEngine On
  ProxyPreserveHost On
  # set to 127.0.0.1 instead of localhost to work around https://stackoverflow.com/a/52550758
  ProxyPass / http://127.0.0.1:8080/ upgrade=websocket
  ProxyPassReverse / http://127.0.0.1:8080/

  RequestHeader set "X-Forwarded-Proto" expr=https
</VirtualHost>

Again, replace occurrences of example.com in the above config file with the hostname of your GtS server. If your domain name is gotosocial.example.com, then gotosocial.example.com would be the correct value.

You should also change http://127.0.0.1:8080 to the correct address and port (if it's not on 127.0.0.1:8080) of your GtS server. For example, if you're running GoToSocial on another machine with the local ip of 192.168.178.69 and on port 8080 then http://192.168.178.69:8080/ would be the correct value.

Rewrite* directives are needed to ensure that Websocket streaming connections also work. See the websocket document for more information on this.

ProxyPreserveHost On is essential: It guarantees that the proxy and the GoToSocial speak of the same Server name. If not, GoToSocial will build the wrong authentication headers, and all attempts at federation will be rejected with 401 Unauthorized.

By default, apache sets X-Forwarded-For in forwarded requests. To make this and rate limiting work, set the trusted-proxies configuration variable. See the rate limiting and general configuration docs

Save and close the config file.

Now we'll need to link the file we just created to the folder that Apache HTTP Server reads configurations for active sites from.

sudo mkdir /etc/apache2/sites-enabled
sudo ln -s /etc/apache2/sites-available/example.com.conf /etc/apache2/sites-enabled/

In the above ln command, replace example.com with the hostname of your GoToSocial server.

Now check for configuration errors.

sudo apachectl -t

If everything is fine you should get this as output:

Syntax OK

Everything working? Great! Then restart Apache HTTP Server to load your new config file.

sudo systemctl restart apache2

Now, monitor the logs to see when the new LetsEncrypt certificate arrives (tail -F /var/log/apache2/error.log), and then reload Apache one last time with the above systemctl restart command. After that you should be good to go!

Apache HTTP Server needs to be restart (or reloaded), every time mod_md gets a new certificate; see the module's docs for more information.

Depending on your version of Apache HTTP Server, you may see the following error: error (specific information not available): acme problem urn:ietf:params:acme:error:invalidEmail: Error creating new account :: contact email "webmaster@localhost" has invalid domain : Domain name needs at least one dot

If this happens, you'll need to do one (or all) of the below:

  1. Update /etc/apache2/sites-enabled/000-default.conf and change the ServerAdmin value to a valid email address (then reload Apache HTTP Server).
  2. Add the line MDContactEmail your.email.address@whatever.com below the MDomain line in /etc/apache2/sites-available/example.com.conf, replacing your.email.address@whatever.com with a valid email address, and example.com with your GtS host name.

Set up Apache HTTP Server with SSL managed manually or by an external software (e.g. Certbot or acme.sh)

If you prefer to have a manual setup or setting SSL using a different service to manage it (Certbot, etc), then you can use a simpler setup for your Apache HTTP Server.

First we'll write a configuration for Apache HTTP Server and put it in /etc/apache2/sites-available:

sudo mkdir -p /etc/apache2/sites-available/
sudoedit /etc/apache2/sites-available/example.com.conf

In the above sudoedit command, replace example.com with the hostname of your GoToSocial server.

The file you're about to create should look initially for both 80 (required) and 443 ports (optional) a bit like this:

<VirtualHost *:80>
  ServerName example.com

  RewriteEngine On
  RewriteCond %{HTTP:Upgrade} websocket [NC]
  RewriteCond %{HTTP:Connection} upgrade [NC]
  # set to 127.0.0.1 instead of localhost to work around https://stackoverflow.com/a/52550758
  RewriteRule ^/?(.*) "ws://127.0.0.1:8080/$1" [P,L]

  ProxyPreserveHost On
  # set to 127.0.0.1 instead of localhost to work around https://stackoverflow.com/a/52550758
  ProxyPass / http://127.0.0.1:8080/
  ProxyPassReverse / http://127.0.0.1:8080/

</VirtualHost>

Again, replace occurrences of example.com in the above config file with the hostname of your GtS server. If your domain name is gotosocial.example.com, then gotosocial.example.com would be the correct value.

You should also change http://127.0.0.1:8080 to the correct address and port (if it's not on 127.0.0.1:8080) of your GtS server. For example, if you're running GoToSocial on another machine with the local ip of 192.168.178.69 and on port 8080 then http://192.168.178.69:8080/ would be the correct value.

Rewrite* directives are needed to ensure that Websocket streaming connections also work. See the websocket document for more information on this.

ProxyPreserveHost On is essential: It guarantees that the proxy and the GoToSocial speak of the same Server name. If not, GoToSocial will build the wrong authentication headers, and all attempts at federation will be rejected with 401 Unauthorized.

In the case of providing an initial setup for the 443 port looking for additional managing by an external tool, you could use default certificates provided by the server which you can find referenced in the default-ssl.conf file at /etc/apache2/sites-available/.

Save and close the config file.

Now we'll need to link the file we just created to the folder that Apache HTTP Server reads configurations for active sites from.

sudo mkdir /etc/apache2/sites-enabled
sudo ln -s /etc/apache2/sites-available/example.com.conf /etc/apache2/sites-enabled/

In the above ln command, replace example.com with the hostname of your GoToSocial server.

Now check for configuration errors.

sudo apachectl -t

If everything is fine you should get this as output:

Syntax OK

Everything working? Great! Then restart Apache HTTP Server to load your new config file.

sudo systemctl restart apache2

Troubleshooting

If you cannot connect to the site in your browser, the reverse proxy setup doesn't work. Compare the Apache log file (tail -F /var/log/apache2/access.log) with the GoToSocial log file. Requests made must show up in both places. Double check the ProxyPass setting.

If you can connect but your posts don't federate and your account cannot be found from elsewhere, check your logs. Federation is broken if you see messages attempting to read your profile (something like level=INFO … method=GET statusCode=401 path=/users/your_username msg="Unauthorized: …") or post to your inbox (something like level=INFO … method=POST statusCode=404 path=/your_username/inbox msg="Not Found: …"). Double check the ProxyPreserveHost setting.

If you can connect but you cannot authorize your account in a Mastodon client app, check your headers. Use curl -I https://example.com and look for the Content-Security-Policy header. If your webserver sets it, you might have to unset it. One way to do that is to use Header unset Content-Security-Policy in the Apache site config file (something like example.com.conf).