Wait for server to respond, useful in pipeline to wait for service or app to start

wait-for-server.sh

#!/bin/sh


START=$(date '+%s')
TIMEOUT=$(($START + 30))

echo "Waiting for server $1 to start..."

until $(curl --output /dev/null --silent --head --insecure $1); do
    NOW=$(date '+%s')
    
    if [ "$NOW" -gt "$TIMEOUT" ]; then
        echo "Server $1 failed to start in 30 seconds"
        exit 1
    fi

    sleep 1
done

echo "Server $1 started"