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Build

We're now going to discuss how to build the binary for the groups.fiatjaf.com example provided by the relay29 repository which uses the Khatru29 wrapper.

Dependencies

Before building the binary, we need to install Go and Git.

Git

We need to install Git to be able to clone the relay29 repository:

apt install git

Go

We're now going to discuss how to install Go on your relay.

First, you need to determine which version of Go you want to install which you can do by going to the All releases page on the Go website.

Make sure to choose the appropriate download file for your relay's operating system (OS) and architecture. Since we're using Debian with an AMD processor, we're going to download the linux-amd64 file.

At the time of writing the current version of Go is 1.23.2, so we'll be downloading the go1.23.2.linux-amd64.tar.gz file.

We'll be downloading the file to the /tmp directory which is cleared when the system reboots. We’ll be downloading the file here because we won’t need this file after the installation process is completed.

Since we're using a headless server, we can use the wget command to download Go:

wget -P /tmp https://go.dev/dl/go1.23.2.linux-amd64.tar.gz

Be sure to replace go1.23.2.linux-amd64.tar.gz with whatever version of Go you're downloading and with whatever architecture you're using.

Before extracting the contents of the file, be sure to first remove any previously installed version of Go:

rm -rf /usr/local/go

You can now extract the contents of the file into the /usr/local directory:

tar -C /usr/local -xzf /tmp/go1.23.2.linux-amd64.tar.gz

Be sure to not extract the contents into an already existing /usr/local/go directory since this can break the Go installation.

After successfully extracting the contents, you should see a go directory in the /usr/local directory:

ls /usr/local

You can now add /usr/local/go/bin to the PATH environment variable by adding export PATH=$PATH:/usr/local/go/bin to your $HOME/.bashrc file.

First, open the file with a text editor of your choice, e.g., nano:

nano $HOME/.bashrc

Then add the following to the end of the file:

export PATH=$PATH:/usr/local/go/bin

Save the changes made to the .bashrc file and exit the editor.

The changes may not take effect until after you log back into the server.

To apply the changes immediately run:

source $HOME/.bashrc

Verify the installation was successful by running:

go version

The command should output:

go version go1.23.2 linux/amd64

Clone the Repository

Before cloning the relay29 repository, we're going to first create the following directories in the $HOME directory:

mkdir -p $HOME/nostr/relays

We can now navigate to the relays directory:

cd $HOME/nostr/relays

We're now ready to clone the relay29 repository:

git clone https://github.com/fiatjaf/relay29.git

After cloning the repository, navigate to the relay29/examples/groups.fiatjaf.com directory:

cd relay29/examples/groups.fiatjaf.com

You can use the repository to update Khatru29, so we're going to keep the repository on the relay.

Build Khatru29 Example

We're now ready to build the groups.fiatjaf.com example which uses the Khatru29 wrapper:

go build

The compilation could take a while depending on your server's specs, so be patient while the binary is being built.

When the compilation is finished the binary will be located in the relay29/examples/groups.fiatjaf.com directory.

You can list out the contents of that directory to see the binary:

ls

You should see the binary file which should be named groups.fiatjaf.com.

We're going to use a more general name for the binary by renaming it to khatru29:

mv groups.fiatjaf.com khatru29

Check Version

At the time of writing, the latest version of the relay29 library is v0.4.0 which is what the rest of the guide is currently based on.

Run Binary

To run Khatru29 you need to provide a secret key which will be used as the relay's private key.

Be sure to input your secret key securely, i.e., don't let anyone, any camera, etc. see your secret key, clear your clipboard if you're copying and pasting the value, turn off your terminal history on your server, etc.

The server terminal is using bash, so you can temporarily turn off the history for the current shell session by running:

set +o history

You can now run the binary:

DOMAIN="relay.relayrunner.xyz" RELAY_NAME="Relay Runner's Khatru29 Relay" RELAY_PRIVKEY="<your-secret-key>" ./khatru29

Be sure to replace the values of the following:

  • DOMAIN with the domain name of your server

  • RELAY_NAME with the name you're going to use with your relay

  • RELAY_PRIVKEY with the secret key you're going to use with your relay which should be passed as a 32-byte hex

Khatru29 should now be listening on 0.0.0.0:5577. A relay database will also be created in your current directory called db.

To stop the relay press Ctrl+C.

If you were able to successfully run the binary, you can turn on the history for the current shell session by running:

set -o history