Server-Sent Events as a standalone service

In some languages such as PHP it's not easy to keep connection between a client and a server open. This standalone service is made to solve that problem.

• go, the programming language;
• gb, the project based build tool for GO;

• make vendor to download all required libraries;
• make build to build the project;
• make serve to run the server;
• make kill to kill the server;
• make restart to restart the server;

curl -X POST -H "X-Token:secret" -d 'hello world' http://localhost:9090/event/:event/:id

Create a non-root user named go-pusher:

sudo useradd -m -G www-data -s /bin/bash go-pusher

Add the following lines to the end of the /home/go-pusher/.bashrc file:

export GOPATH=/home/go-pusher/go
export GOROOT=/usr/local/src/go
export PATH=${PATH}:$GOROOT/bin:$GOPATH/bin

Then download latest complied version of Go from its website and unarchive it into $GOROOT directory:

sudo curl -H 'Accept-encoding:gzip' https://storage.googleapis.com/golang/go1.5.1.linux-amd64.tar.gz | gzip -dc | tar -xf - -C /usr/local/src

Install GB:

go get github.com/constabulary/gb/...

Create a directory for the log files to live in:

sudo mkdir -p /usr/local/var/log/goPusher
sudo chown go-pusher -R /usr/local/var/log/goPusher

Clone source code of goPusher project into ~/goPusher folder:

git clone https://github.com/mrded/goPusher ~/goPusher; cd ~/goPusher

Install all dependencies and build the project: make {vendor,build}

Ubuntu come pre-packaged with a service called Upstart. A daemon for automatically starting services on system start-up and monitoring them to ensure they are restarted if they fail.

cat /etc/init/go-pusher.conf

description     "go-pusher"
author          "Dmitry Demenchuk"

start on (net-device-up
  and local-filesystems
  and runlevel [2345])

stop on runlevel [016]

respawn

script
  chdir /home/go-pusher/goPusher
  exec ./bin/goPusher
end script

• Run the service: sudo service go-pusher start
• Add the service to autoload: sudo update-rc.d go-pusher defaults
• Remove the service from autoload: sudo update-rc.d -f go-pusher remove

You can also use supervisor to manage the service.

Add a configuration file for Supervisor: cat /etc/supervisor/conf.d/go-pusher.conf

[program:go-pusher]
directory=/home/go-pusher/goPusher/
command=/home/go-pusher/goPusher//bin/goPusher
autostart=true
autorestart=true
startsecs=10
stdout_logfile=/usr/local/var/log/goPusher/stdout.log
stdout_logfile_maxbytes=1MB
stdout_logfile_backups=10
stdout_capture_maxbytes=1MB
stderr_logfile=/usr/local/var/log/goPusher/stderr.log
stderr_logfile_maxbytes=1MB
stderr_logfile_backups=10
stderr_capture_maxbytes=1MB
environment = HOME="/home/go-pusher", USER="go-pusher"
user = go-pusher

This section defines the command we want to execute to start goPusher, automatically starts it with Supervisor, and specifies the locations of log files and corresponding environment variables.

Now restart Supervisor: sudo service supervisor restart