Script run time and file time have fallen out of sync

[beauremus]

If the script fails to generate a data file. The next run of the script will generate a data file from the previous hour. This has happened enough times that we are currently 9 hours behind.

I propose having nanny.py generate files from the calculated start time, the end time of the last found file, until now.

Consider:

    if path.exists(output_file):
        os.remove(output_file)

    with pd.HDFStore(output_file) as hdf:

We remove an existing file because otherwise, we append it to the existing file. If an existing process holds the output_file open, and a new process attempts to remove it, it should fail. Consider failing gracefully.

[beauremus]

Time estimates:

• Best case - half a day
• Worse case - a week
• Best guess - 2 days