provision-go-systemd-service.sh

#!/bin/bash -e
# 
# This script is a utility to provision easily a Linux machine with a new GO service.
#   1. Ensure the application home exists
#   2. Create a new systemd service file for given service's name
#   3. Create the symlink from the service name to the actual binary
#   4. Enable the systemd service (i.e. service restart on machine boot)
#   5. Reload the systemd daemon

APPS_HOME=~/goapps
SYSTEMD_DIR=/etc/systemd/system

usage(){
  echo "USAGE:
      `basename $0` -s <service>

    Options:
        -s <service>        Name of the new systemd service (i.e. GO app)"
  exit
}

if [ "$#" -ne 2 ] || [ "$1" == "--help" ] || [ "-h" == "$1" ]; then
    usage
    exit 0
fi

SERVICE_NAME=$2
SERVICE_HOME=$APPS_HOME/$SERVICE_NAME
SERVICE_FILE=$SYSTEMD_DIR/$SERVICE_NAME.service
SYMLINKED_BIN_NAME=$SERVICE_NAME-service

if [ -f $SERVICE_FILE ]; then
    echo "Systemd service definition file $SERVICE_FILE exists already!"
    echo "Exiting..."
    exit 0
fi

sudo mkdir -p $SERVICE_HOME

echo "Running for service name $SERVICE_NAME"
echo "  [+] Created service home: $SERVICE_HOME"

sudo bash -c "cat > $SERVICE_FILE" << EOF
[Unit]
Description=$SERVICE_NAME GO service
After=network.target

[Service]
Environment=MY_VAR=true
SyslogIdentifier=$SERVICE_NAME-service
ExecStart=${SERVICE_HOME}/${SYMLINKED_BIN_NAME}
Restart=on-failure

[Install]
WantedBy=multi-user.target
EOF
echo "  [+] Created systemd service file: $SERVICE_FILE"

sudo systemctl enable $SERVICE_FILE
echo "  [+] Enabled $SERVICE_NAME systemd service to restart automatically on machine boot"

sudo ln -fs ${SERVICE_HOME}/${SERVICE_NAME} ${SERVICE_HOME}/${SYMLINKED_BIN_NAME}
echo "  [+] Created symlink to binary file"

sudo systemctl daemon-reload
echo "  [+] Reload systemd daemon"

echo
echo "Useful service commands:
    $ sudo systemctl status $SERVICE_NAME
    $ sudo systemctl restart $SERVICE_NAME
    $ sudo systemctl stop $SERVICE_NAME
    $ sudo systemctl start $SERVICE_NAME
    $ journalctl -u $SERVICE_NAME            # tail application logs"