Server setup script for Redis, HAProxy and Node.js

Question

I wrote a pretty basic setup script that handles most of the setup for a Three-server solution. The solution and setup file are available on GitHub

The three servers are Redis, HAProxy and Node / Cron.

All three options handle only solution specific stuff (not including installing the frameworks)

I felt like my usage of select statements was a little over the top, and newline as a constant seemed a little hacky, but nonetheless, it works.

n="
"
# From http://stackoverflow.com/a/246128
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
pass (){
 echo 1ドル | sha256sum | head -c 64
}
# Redis
redis (){
 ulimit -n 10032
 slave=false;
 echo "Enter the desired password for the Redis instance:"
 read -s password
 password=$(pass $password)
 echo "Is this a slave?"
 select yn in "Yes" "No"; do
 case $yn in
 Yes ) slave=1; break;;
 No ) slave=0; break;;
 esac
 done
 slave_text="";
 if [[ $slave -eq 1 ]]; then
 echo "Enter the Master IP address:"
 read master_ip
 echo "Enter the Redis Master password:"
 read -s master_password
 slave_text="slaveof $master_ip 6379
masterauth $master_password $n"
 fi
 echo "tcp-keepalive 60
port 6379
tcp-backlog 511
timeout 600
dir $DIR
supervised upstart
daemonize yes
#bind 127.0.0.1
maxmemory-policy noeviction
requirepass $password
$slave_text
" > "/etc/redis/redis.conf"
 echo "The password for Redis is $password"
 sudo service redis restart
}
# HAProxy
haproxy (){
 stats=1;
 stats_text="stats disable$n";
 echo "Please enter the IP address of the web server:"
 read initial_ip
 echo "Please enter the port of the web server:"
 read initial_port
 i=1
 web_servers="server web$i $initial_ip:$initial_port check$n"
 more_web_servers=1;
 while [ $more_web_servers -eq 1 ]
 do
 echo "Would you like to add another web server?"
 select yn in "Yes" "No"; do
 case $yn in
 Yes )
 echo "Please enter the IP address:"
 read repeat_ip
 echo "Please enter the port:"
 read repeat_port;
 ((i++))
 web_servers+=" server web$i $repeat_ip:$repeat_port check$n";
 break;;
 No ) more_web_servers=0; break;;
 esac
 done
 done
 echo "Do you want to turn HAProxy stats on?"
 select yn in "Yes" "No"; do
 case $yn in
 Yes ) stats=1; break;;
 No ) stats=0; break;;
 esac
 done
 if [[ $stats -eq 1 ]]; then
 echo "Enter the URL for stats:"
 read stats_uri
 echo "Please enter a user to access the stats page"
 echo "Please enter the Username:"
 read username
 echo "Please enter the Password:"
 read -s password
 users="stats auth $username:$password$n"
 more_users=1;
 while [ $more_users -eq 1 ]
 do
 echo "Would you like to add another user?"
 select yn in "Yes" "No"; do
 case $yn in
 Yes )
 echo "Please enter the Username:"
 read username
 echo "Please enter the Password:"
 read -s password
 users+=" stats auth $username:$password$n"
 break;;
 No ) more_users=0; break;;
 esac
 done
 done
 stats_text="stats enable
 stats uri $stats_uri
 stats realm Strictly\ Private
 $users"
 fi
 echo "global
 log 127.0.0.1 local0 notice
 maxconn 2000
 user haproxy
 group haproxy
defaults
 log global
 mode http
 option httplog
 option dontlognull
 retries 3
 option redispatch
 timeout connect 5000
 timeout client 10000
 timeout server 10000
listen web
 bind 0.0.0.0:80
 timeout connect 5000
 timeout client 10000
 timeout server 10000
 mode http
 $stats_text
 balance roundrobin
 option httpclose
 option forwardfor
 $web_servers $n" > "/etc/haproxy/haproxy.cfg"
 service haproxy restart
}
# web / cron
web (){
 cron_dir="$DIR/dist/cron";
 cron_content="#!/bin/bash
/usr/bin/node $cron_dir";
 echo "Please enter the Redis Master IP:"
 read redis_master_ip
 echo "Please enter the Redis Master Auth password:"
 read -s redis_master_password
 echo "Please enter the HAProxy IP address:"
 read HAProxy_IP
 echo "{
 \"redis\": {
 \"current_environment\": \"prod\",
 \"environments\": {
 \"prod\": {
 \"host\": \"$redis_master_ip\",
 \"port\": \"6379\",
 \"password\": \"$redis_master_password\"
 }
 }
 },
 \"haproxy\": {
 \"IP\": \"$HAProxy_IP\"
 }
}" > "$DIR/web.config.json"
 npm install -g webpack gulp > /dev/null 2 >&1
 npm install > /dev/null 2 >&1
 echo "Before continuing, we need to build the solution.
Have you done this, or would you like to now? (yes or no)"
 select yn in "Yes" "No"; do
 case $yn in
 Yes ) npm run install; break;;
 No ) break;;
 esac
 done
 if [ -f "$cron_dir/posts.js" ]
 then
 echo "30 * * * * $cron_content/posts.js > $DIR/posts.log" >> /etc/crontab
 echo "Posts CRON job added."
 fi
 if [ -f "$cron_dir/sites.js" ]
 then
 echo "0 23 * * * $cron_content/sites.js > $DIR/sites.log" >> /etc/crontab
 echo "Sites CRON job added."
 fi
 echo "start on runlevel [2345]
 start on filesystem
exec $DIR/node_modules/.bin/forever start $DIR/dist/web/index.js -o $DIR/out.log" > "/etc/init/web.conf"
 service web start
}
echo "StackNews setup script
-----------
Is this a Redis server, HAProxy server or web/cron server?"
select option in "Redis" "Web" "HAProxy"; do
 case $option in
 Redis ) redis; break;;
 Web ) web; break;;
 HAProxy ) haproxy; break;;
 esac
done

Answer 1

shellcheck it!

There is this wonderful site called shellcheck.net that tells you all kinds of common mistakes.

The newline in a string

n="
"

n is an unusual name for something that's a newline. How about newline?

Here's another writing style that you might like:

n=$'\n'

For more details on this syntax, search for \$' in man bash.

Embedding variables in a string

The linebreak is odd in the middle of the string, especially considering the $n variable that you have:

 slave_text="slaveof $master_ip 6379
masterauth $master_password $n"

I'm wondering if you didn't use $n because you were not sure how to make it work. Here are some equivalent ways to write the statement on a single line:

 slave_text="slaveof $master_ip 6379${n}masterauth $master_password $n"
 slave_text="slaveof $master_ip 6379$n""masterauth $master_password $n"

Embedding variables in text

This is very tedious, as you had to escape all the ":

echo "{
 \"redis\": {
 \"current_environment\": \"prod\",
 \"environments\": {
 \"prod\": {
 \"host\": \"$redis_master_ip\",
 \"port\": \"6379\",
 \"password\": \"$redis_master_password\"
 }
 }
 },
 \"haproxy\": {
 \"IP\": \"$HAProxy_IP\"
 }
}" > "$DIR/web.config.json"

A simpler approach would have been to enclose in single quotes instead, and break out of it in front of variables, like this:

echo '{
 "redis": {
 "current_environment": "prod",
 "environments": {
 "prod": {
 "host": "'$redis_master_ip'",
 "port": "6379",
 "password": "'$redis_master_password'"
 }
 }
 },
 "haproxy": {
 "IP": "'$HAProxy_IP'"
 }
}' > "$DIR/web.config.json"

But an even better way is to use a here-string:

cat << EOF > "$DIR/web.config.json"
{
 "redis": {
 "current_environment": "prod",
 "environments": {
 "prod": {
 "host": "$redis_master_ip",
 "port": "6379",
 "password": "$redis_master_password"
 }
 }
 },
 "haproxy": {
 "IP": "$HAProxy_IP"
 }
}
EOF

Redirecting both stdout and stderr

Instead of this:

npm install -g webpack gulp > /dev/null 2 >&1

A simpler way to redirect both stdout and stderr is this:

npm install -g webpack gulp &> /dev/null

The shebang

Don't forget to start your script with the correct shebang:

#!/usr/bin/env bash

Inconsistent use of [ and [[

In some places you use [ and in others [[. I think it will be slightly easier to read the script if you used a consistent writing style. [ is considered obsolete, [[ is recommended.

Trailing ;

A ; at the end of a line is pointless (unless it's part of a ;; in a case statement). I suggest to remove those.

Tedious -eq

The -eq operator is kind of tedious here:

if [[ $slave -eq 1 ]]; then

A simple = would work just as well, so I recommend to write that way.

Writing style

This is a bit unusual:

pass (){

A more common writing style is this:

pass() {