#!/bin/bash
# Hashicorp Consul bootstrap script
# Params:
#   server       : if present, bootstraps a server
#   bind         : bind interface address
#   server-ip    : server ip address

# exit on error
set -e

if [ "$#" -eq 0 ]; then
  echo "No options specified, exiting."
  exit 1
elif [ "$#" -eq 1 ] && [ "$1" == "-h" ]; then
  echo "HashiCorp Consul Bootstrap Script. Provide:"
  echo "-server for server install,"
  echo "-bind for the bind interface address,"
  echo "-server-ip for the server ip address."
  exit 1
fi

# create consul user
useradd --system --home /etc/consul.d --shell /bin/false consul

# create directory if doesn't exist and set permissions
mkdir -p /etc/consul.d/ && chown -R consul:consul /etc/consul.d/

# create consul data dir and set permissions
mkdir -p /opt/consul && chown -R consul:consul /opt/consul

# write systemd conf
cat >/etc/systemd/system/consul.service <<EOF
[Unit]
Description="HashiCorp Consul - A service mesh solution"
Documentation=https://www.consul.io/
Requires=network-online.target
After=network-online.target

[Service]
User=consul
Group=consul
ExecStart=/usr/bin/consul agent -config-dir=/etc/consul.d/
ExecReload=/bin/kill --signal HUP $MAINPID
KillMode=process
KillSignal=SIGTERM
Restart=on-failure
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

# reload systemd
systemctl daemon-reload

# parameter setup
consultype="client"
bind_ip=null
server_ip=null

# read parameters
while [[ "$#" -gt 0 ]]
do
  case $1 in
    -server)
      consultype="server"
      ;;
    -bind)
      bind_ip="$2"
      ;;
    -server-ip)
      server_ip="$2"
      ;;
  esac
  shift
done

# write config file

if [ $consultype == "client" ]
then

  cat >/etc/consul.d/consul.hcl <<EOF
datacenter = "dc1"
data_dir = "/opt/consul"
bind_addr = "$bind_ip"
retry_join = ["$server_ip"]
EOF
  chmod 640 /etc/consul.d/consul.hcl

else

  cat >/etc/consul.d/server.hcl <<EOF
datacenter = "dc1"
data_dir = "/opt/consul"
bind_addr = "$bind_ip"
server = true
bootstrap_expect = 1
ui_config {
  enabled = true
}
EOF
  chmod 640 /etc/consul.d/server.hcl

fi

echo "Done! Please launch with systemctl start consul"