loop a curl call & count successful responses before an error

Question

I'm trying to test and quantify a intermittent error response from an http server. I have a curl call constructed that can make the necessary request, but I'm getting tired up typing up arrow and return.

How can I tell curl to repeatedly make the request until it encounters an error and then output the number of success responses before the error?

Answer 1

This bash recipe should do what you're looking for.

i=0 ; while true ; do curl -o /dev/null -s https://www.google.com/ ; if [ $? -ne 0 ] ; then echo $i ; break ; fi ; i=$(($i+1)) ; echo -en "$i        \r" ; sleep 1 ; done

Broken out into multiple lines:

i=0 # set counter to 0
while true  # infinite loop
do
    curl -o /dev/null -s https://www.google.com/  # silent curl request to site
    if [ $? -ne 0 ]
    then
        # curl didn't return 0 - failure
        echo $i
        break # terminate loop
    fi
    i=$(($i+1))  # increment counter
    echo -en "$i        \r"   # display # of requests each iteration
    sleep 1  # short pause between requests
done

You can optionally redirect cURL output to a file, so when it fails you can see the output using something like this:

 curl -v -o /dev/null https://google.com &> /tmp/output.txt