Reverse proxy with Caddy 2

Requirements

For this guide you will need Caddy 2, there are no other dependencies. Caddy manages Lets Encrypt certificates and renewal for them.

Caddy is in the most popular package managers, or you can get a static binary. For all latest installation guides, refer to their manual.

Debian, Ubuntu, Raspbian

# Add the keyring for their custom repository.
sudo apt install -y debian-keyring debian-archive-keyring apt-transport-https
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/gpg.key' | sudo gpg --dearmor -o /usr/share/keyrings/caddy-stable-archive-keyring.gpg
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/debian.deb.txt' | sudo tee /etc/apt/sources.list.d/caddy-stable.list

# Update packages and install it
sudo apt update
sudo apt install caddy

Fedora, Redhat, Centos

dnf install 'dnf-command(copr)'
dnf copr enable @caddy/caddy
dnf install caddy

Arch

pacman -Syu caddy

FreeBSD

sudo pkg install caddy

Configure GoToSocial

If GoToSocial is already running, stop it.

sudo systemctl stop gotosocial

In your GoToSocial config turn off Lets Encrypt by setting letsencrypt-enabled to false.

If you we running GoToSocial on port 443, change the port value back to the default 8080.

Set up Caddy

We will configure Caddy 2 to use GoToSocial on our main domain example.org. Since Caddy takes care of obtaining the Lets Encrypt certificate, we only need to configure it properly once.

In most simple use cases Caddy defaults to a file called Caddyfile. It can reload on changes, or can be configured through an HTTP API for zero downtime, but this is out of our current scope.

sudo mkdir -p /etc/caddy
sudo vim /etc/caddy/Caddyfile

While editing the file above, you should replace 'example.org' with your domain. Your domain should occur twice in the current configuration. If you have chosen another port number for GoToSocial other than port 8080, change the port number on the reverse proxy line to match that.

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

# Because we use a reverse proxy, Caddy won't redirect port 80 to 443 by default unless we tell it to.
example.org:80 {
    redir https://example.org/{uri}
}

# The actual host configuration
example.org:443 {
    # Optional, but recommended, compress the traffic using proper protocols
    encode zstd gzip

    # The actual proxy configuration to port 8080 (unless you've chosen another port number)
    reverse_proxy * http://127.0.0.1:8080 {
        # Flush immediatly, to prevent buffered response to the client
        flush_interval -1
    }
}

For advanced configuration check the reverse_proxy directive at the Caddy documentation.

Now check for configuration errors.

sudo caddy validate

If everything is fine, you should get some info lines as output. Unless there are lines marked with [err] in front of them, you are all set.

Everything working? Great! Then restart caddy to load your new config file.

sudo systemctl restart caddy

If everything went right, you're now all set to enjoy your GoToSocial instance, so we are going to start it again.

sudo systemctl start gotosocial

Results

You should now be able to open the splash page for your instance in your web browser, and will see that it runs under HTTPS!