compute-engine

Deploy Go web app

This document explains how to create a web service using Nginx and Go to host it in Google Compute Engine.

Prerequisites

• Update the SO
• Install Go 1.21
• Install Nginx

sudo apt update && sudo apt upgrade -y
wget https://go.dev/dl/go1.21.11.linux-amd64.tar.gz && sudo tar -C /usr/local -xzf go1.21.11.linux-amd64.tar.gz
sudo apt-get install nginx -y

Verify that Go works:

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

Configure the web server

We only want Nginx to work as a proxy for our application, so we will disable the default server page, and create a new one. For this, we will modify /etc/nginx/sites-available/default and add the following:

server {
    listen 80;
    server_name "";
    access_log /var/log/nginx/webapp.access.log;
    location / {
        proxy_pass http://127.0.0.1:8080;
    }       
}

Enable the site configuration by creating a symlink to it in sites-enabled, and telling Nginx to reload:

cd /etc/nginx/sites-enabled
sudo ln -s ../sites-available/default
sudo /etc/init.d/nginx reload

Now the Nginx proxy is created but nothing is listening on http://127.0.0.1:8080. Upload webserver.go to the VM and run the Go web server:

cd ~/
export PATH=$PATH:/usr/local/go/bin
go run webserver.go -http=127.0.0.1:8080

Now the server should be available and working.

Automate startup

We’ve now accomplished what we set out to do. But what if the machine restarts? We need to configure the system to run the goto process on start-up. Firt let's build the server and move it to a shared directory:

go build webserver.go
sudo mv webserver /usr/sbin/webserver
sudo chown root:root /usr/sbin/webserver

Now let's create a basic init.d script in /etc/init.d/webserver:

#!/bin/bash

NAME="webserver"
GO_BINARY_PATH="/usr/sbin/webserver"
PIDFILE="/var/run/webserver.pid"

start() {
  "$GO_BINARY_PATH"
}

stop() {
  pkill -f "^$GO_BINARY_PATH" -TERM
  sleep 10
  pkill -f "^$GO_BINARY_PATH" -KILL
}

case "$1" in
  start)
    echo -n "Starting $NAME server: "
    start-stop-daemon --start --make-pidfile --background --pidfile $PIDFILE --exec $GO_BINARY_PATH
    echo "started."
    ;;
  stop)
    echo -n "Stopping $NAME server: "
    start-stop-daemon --stop --quiet --pidfile $PIDFILE --exec $GO_BINARY_PATH
    rm -f $PIDFILE
    echo "stopped."
    ;;
  restart)
    echo -n "Restarting $NAME server: "
    stop
    start
    echo "restarted."
    ;;
  *)
    echo "Usage: $0 {start|stop|restart}"
    exit 1
    ;;
esac

exit 0

Now we can execute it:

sudo chmod +x /etc/init.d/webserver
sudo /etc/init.d/webserver start

And last add the service to rc.d so that it is launched on start-up:

sudo update-rc.d webserver defaults

Verify the link has been created, otherwise create it:

sudo ls -l /etc/rc[0-6].d/S*webserver
sudo ln -s /etc/init.d/webserver /etc/rc2.d/S02webserver

And that’s it. There is more you could do, but these are the bare essentials to reliably run a Go (or any other) web service behind Nginx under Debian.