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Relayer
Running a Relayer
Running with Systemd

Running with Systemd

The following guide will walk you through setting up a relayer as a system service. By the end of this document, you will have set up a Webb Relayer at a publicly accessible via an endpoint behind a reverse proxy, and fulfill the requirements for listing your relayer on app.webb.tools.

Getting Started

These instructions assume the user has access to a server on any Linux VM, and is logged into a user with sudo permissions.

Prerequisites

It is a requirement to have Nginx installed on the Linux machine, for instructions on how to install Nginx on the machine please visit the offical Nginx installation documentation here (opens in a new tab).

Basic Environment Setup

Following the instructions below, you will be able to run the relayer as a system service.

Update Ubuntu packages

# Update ubuntu packages
sudo apt update && sudo apt upgrade

Update Snap package

# Update snap packages
sudo apt install -y snapd
sudo snap install core; sudo snap refresh core

Install dependencies

# Install dependencies
sudo apt install gcc cmake pkg-config libssl-dev git clang libclang-dev
sudo apt install build-essential

Install Rust

# Install rust
curl https://sh.rustup.rs -sSf | sh -s -- -y
export PATH=~/.cargo/bin:$PATH
source ~/.cargo/env

Install Certbot

# Install certbot
sudo snap install --classic certbot && sudo ln -s /snap/bin/certbot /usr/bin/certbot

Build Relayer from source

# Build from source
git clone https://github.com/webb-tools/relayer.git
cd relayer && cargo build --release --features cli

Creating a System Service

  1. Setup the relayer as a system service:

Let's first create a service file for the relayer:

# Create the service file
sudo touch /etc/systemd/system/webb-relayer.service

Next, we will paste the following into the service file, and replace the <user> with the user that will be running the relayer:

# This assumes the repo has been cloned in the home directory of the user
# Paste the following into the service file, and replace the <user>:

[Unit]
Description=WebbRelayer

[Service]
Type=exec
WorkingDirectory=/home/<user>/relayer
ExecStart=cargo run --features cli --bin webb-relayer -- -c /home/<user>/relayer/config/<configs> -vvv

[Install]
WantedBy=multi-user.target
  1. Enable and start the system service:
sudo systemctl enable webb-relayer && sudo systemctl start webb-relayer

Nginx Setup

  1. Configure your registered domain name with your cloud service provider.

  2. Install nginx if it isn't already on your machine:

sudo apt install nginx

First, we will configure the endpoint linked to your domain name at port 80 for certificate generation

  1. Create nginx site files for your domain:
cd /etc/nginx/sites-available &&

sudo cp default <domain name> &&

sudo ln -s /etc/nginx/sites-available/<domain name> /etc/nginx/sites-enabled/
  1. Modify the nginx sites-available file to:
server {
    listen 80;
    listen [::]:80;

    root /var/www/<domain name>/html;
    index index.html index.htm index.nginx-debian.html;

    server_name <domain name>;

    location / {
            try_files $uri $uri/ =404;
    }
}
  1. Check the nginx configuration
sudo nginx -t
  1. If no issues exist, restart the nginx service:
sudo systemctl restart nginx

Next we will create the self-signed certificate and reconfigure for https and wss support

  1. Create the self-signed certificate:
sudo certbot certonly --nginx
  1. Modify the nginx site file:
map $http_upgrade $connection_upgrade {
    default upgrade;
    '' close;
}

server {

    # SSL configuration
    #
    listen 443 ssl;
    listen [::]:443 ssl;

    root /var/www/<domain name>/html;

    server_name <domain name>;
    ssl_certificate /etc/letsencrypt/live/<domain name>/cert.pem;
    ssl_certificate_key /etc/letsencrypt/live/<domain name>/privkey.pem;
    ssl_session_timeout 5m;
    ssl_protocols SSLv2 SSLv3 TLSv1 TLSv1.1 TLSv1.2;
    ssl_ciphers   HIGH:!aNULL:!MD5;
    ssl_prefer_server_ciphers on;

    location / {
        proxy_pass http://127.0.0.1:9955;
        proxy_pass_request_headers on;
        proxy_http_version 1.1;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;
    }
}
  1. Check Nginx configuration and restart the service:
sudo nginx -t && sudo systemctl restart nginx

Monitoring Setup

Relayers will want to setup monitoring to ensure maximum uptime and automatic restarts when things go awry.

  1. sudo apt install -y monit

  2. modify the monitrc file at: /etc/monit/monitrc

set httpd port 2812 and
use address localhost
allow localhost

set daemon 10
set log /var/log/monit.log
set idfile /var/lib/monit/id
set statefile /var/lib/monit/state
set eventqueue
    basedir /var/lib/monit/events
    slots 100

check process webb-relayer matching target/release/webb-relayer
    start program = "/bin/systemctl restart webb-relayer"
    stop program = "/bin/systemctl kill webb-relayer"
    if cpu > 90% for 20 cycles then exec "/bin/systemctl stop webb-relayer" and repeat every 10 cycles
    if cpu > 90% for 64 cycles then exec "/bin/systemctl kill webb-relayer" and repeat every 10 cycles
    if cpu > 90% for 64 cycles then alert
    if does not exist for 1 cycles then start
  1. restart monit and validate:
sudo monit reload && sudo monit validate

Dapp Integration

After completing the above steps, submit a PR with changes for your https endpoint in the Webb Dapp (opens in a new tab) repo.

Running with DockerConfiguration Options