curl probe

curl-probe.sh

#!/bin/bash

# -------------------------------------------------------------
# Repeatedly probe a url forever with curl, only keeping the HTTP response code or the failure message from curl. Discard all other output.
# Any args passed to this script will be forwarded to the curl command as-is.
# Activity is profusely logged. 
#
# Examples:
#
#   Probe from the internet, limiting execution time:
#     ./curl-probe.sh  https://www.example.com/ --max-time 15
#
#   Probe from inside the server:
#    ./curl-probe.sh  https://www.example.com/ --resolve www.example.com:443:127.0.0.1
#
#  Send all probe output (stdout + stderr) to a log file:
#    ./curl-probe.sh  https://www.example.com/ > ./curl.log 2>&1
# -------------------------------------------------------------

ARGS=$*

if [ -z "$ARGS" ]; then
  >&2 echo "Which URL do you want to probe?"
  exit 1
fi

while true; do
  echo ''
  echo -n "BEGIN "
  /bin/date --iso-8601=seconds;
  (set -x && /usr/bin/time  --format "COMMAND_TIME\t%E" -- /usr/bin/curl -sS -w '%{http_code}\n' "$@" -o /dev/null);
  echo -n "END "
  /bin/date --iso-8601=seconds;
  /bin/sleep 3;
done