example data dump with retry on failure

backup.sh

#!/bin/bash

while true ; do

  # there is no way to distinguish node's (1) exit code on SIGINT (and SIGTERM)
  # from a (1) exit code due to normal exit call in userland.
  # if node preserved SIGINT/SIGTERM, then the shell would detect node's
  # "abnormal exit" status, and the script would terminate immediately after 
  # node returns
  
  # as it stands, it will be very difficult to terminate this script
  # using Ctrl-C (SIGINT).

  if node dump-data.js > backup.json ; then
    break
  fi
  echo -e "\nbackup failed. retrying..."
done
echo "backup complete. $(date)"

echo "transferring to permanent storage..."
scp "backup.json" "somehost.example.com:~/backup-$(date +%Y%m%d).json"
echo "transfer complete. $(date)"

dump-data.js

    process.stderr.write("simulating backup action (sleep for 20 seconds). "+
        "Press Ctrl-C.. see what happens.");

    setTimeout(function() {
      process.stderr.write('ok - success!\n');
      process.exit(0);
    }, 20000);