How to create a loop in bash that is waiting for a webserver to respond?

The poster asks a specific question about printing ., but I think most people coming here are looking for the solution below, as it is a single command that supports finite retries.

curl --head -X GET --retry 5 --retry-connrefused --retry-delay 1 http://myhost:myport

httping is nice for this. simple, clean, quiet.

while ! httping -qc1 http://myhost:myport ; do sleep 1 ; done

while/until etc is a personal pref.


I wanted to limit the maximum number of attempts. Based on Thomas's accepted answer I made this:

attempt_counter=0
max_attempts=5

until $(curl --output /dev/null --silent --head --fail http://myhost:myport); do
    if [ ${attempt_counter} -eq ${max_attempts} ];then
      echo "Max attempts reached"
      exit 1
    fi

    printf '.'
    attempt_counter=$(($attempt_counter+1))
    sleep 5
done

Combining the question with chepner's answer, this worked for me:

until $(curl --output /dev/null --silent --head --fail http://myhost:myport); do
    printf '.'
    sleep 5
done

Tags:

Bash