Right now, Boulder expects to be able to connect to syslog, and panics
if it's not available. We'd like to be able to log to stdout/stderr as a
replacement for syslog.
- Add a detailed timestamp (down to microseconds, same as we collect in
prod via syslog).
- Remove the escape codes for colorizing output.
- Report the severity level numerically rather than with a letter prefix.
Add locking for stdout/stderr and syslog logs. Neither the [syslog] package
nor the [os] package document concurrency-safety, and the Go rule is: if
it's not documented to be concurrent-safe, it's not. Notably the [log.Logger]
package is documented to be concurrent-safe, and a look at its implementation
shows it uses a Mutex internally.
Remove places that use the singleton `blog.Get()`, and instead pass through
a logger from main in all the places that need it.
[syslog]: https://pkg.go.dev/log/syslog
[os]: https://pkg.go.dev/os
[log.Logger]: https://pkg.go.dev/log#Logger