logger can emit invalid json in some cases

[ceejbot]

If you log a string variable using the debug formatter, kv-log-macro does not escape the double-quotes properly, resulting in invalid json in the log line. E.g.,

let foo = "bar";
log::info!("log some data; foo={:?}",  foo);

produces:
{"level":"info","pid":1837,"message":"log some data; foo="bar"","target":"geolocality::endpoints::foo","hostname":"example.com","time":"2021-12-15T06:41:28.325Z"}

The individual fix is to log displayable types with the display formatter, but we should see why kv-log-macro isn't escaping strings correctly and act somehow. update? file bug? switch loggers? other?

[chrisdickinson]

I think the fix would be in here: https://github.com/eaze/preroll/blob/latest/src/logging/json.rs