Instead of writing log errors to stderr, write them to a file in the state directory. When reporting a health check failure, include the path to the file and the last several lines.
Log files are named by date, and the last 7 days are kept.
Closes#106
Specifically, certspotter no longer terminates unless it receives SIGTERM
or SIGINT or there is a serious error.
Although using cron made sense in the early days of Certificate
Transparency, certspotter now needs to run continuously to reliably keep
up with the high growth rate of contemporary CT logs, and to gracefully
handle the many transient errors that can arise when monitoring CT.
Closes: #63Closes: #37Closes: #32 (presumably by eliminating $DNS_NAMES and $IP_ADDRESSES)
Closes: #21 (with $WATCH_ITEM)
Closes: #25
