Repeatedly fetching a URL until the response contains "state: INIT"

I am working on a project in which I need to make a URL call to one of my servers from a bash shell script.

http://hostname.domain.com:8080/beat

After hitting the above URL, I will be getting the below response, from which I need to parse and extract the value of state:

num_retries_allowed: 3 count: 30 count_behind: 100 state: INIT num_rounds: 60 hour_col: 2 day_col: 0

Now I will keep on hitting the above URL every 10 seconds until the value of the state variable is equal to INIT:

state = INIT

If the state is equal to INIT then I will exit successfully out of the shell script, otherwise I will keep on trying until the state becomes INIT.

Also, if the state: string is missing in the $DATA variable by any chance, then I want to assign 0 to the state variable. So if state is equal to 0, then I will also exit out of the shell script successfully.

I am hitting the above URL and checking whether I got a successful response or not. If I got a successful response, then I am breaking out (which means server is running fine), but if I didn't got successful response, then I am checking whether my server is running or not on port 8080. If it is not running, then I will start the server. And I am retrying this for a period of 15 times, and after 15 tries if the server hasn't come back up, then exit out of the shell script with a non-zero status code.

Is the below shell script correct?

```
#!/bin/bash

HOSTNAME=$hostname
DATA=""
RETRY=15

echo $HOSTNAME

sleep 1m

while true; do

while [ $RETRY -gt 0 ]
do
DATA=$(wget -O - -q -t 1 http://$HOSTNAME:8080/beat)
if [ $? -eq 0 ]
then
break
else
if lsof -Pi :8080 -sTCP:LISTEN -t >/dev/null ;
then
echo "Server is running"
else
echo "Server is not running so re-starting the server here"
# starting server here
fi
let RETRY-=1

Inconsistent logic

In one place the script checks http://$HOSTNAME:8080/beat,
in another, it checks for a local process listening on port 8080.
This only makes sense if $HOSTNAME the name of the local machine.
It will make more sense to replace $HOSTNAME with hard-coded localhost.

Use exit code directly

Instead of this:

DATA=$(wget -O - -q -t 1 http://$HOSTNAME:8080/beat)
if [ $? -eq 0 ]
then
    break

You could use the exit code directly like this:

if DATA=$(wget -O - -q -t 1 http://$HOSTNAME:8080/beat)
then
    break

Another way:

DATA=$(wget -O - -q -t 1 http://$HOSTNAME:8080/beat) && break

Math in Bash

Instead of this:

let RETRY-=1

There are slightly simpler alternatives:

((RETRY -= 1))
((RETRY--))

StackExchange Code Review Q#79495, answer score: 2