EmbedAPI: log success requests (#8689)
* EmbedAPI: log success requests
Log success requests using `django-structlog` and send them New Relic to know
what projects are using EmbedAPI, if they are using sphinx-hoverxref and what
version of it.
This is the minimum configuration required to start using structlog + New Relic.
If we are happy with the results we can migrate the other logs to structlog,
which should be simple, but a little tedious to do search&replace.
In the future, we can also set up django-structlog to log Celery tasks as well.
* Minimal implementation of structlog for EmbedAPI
Use structlog _only_ for EmbedAPI v2/v3 for now. We will do a test in production
to this and decide the migration path for the whole codebase.
* structlog: migrate application code to better logging
Initial work to migrate our application to structlog for better logging, making
them compatible with New Relic's integration.
There are more work that can be done here to make it better. For example, more
usage of `log.bind` to avoid repetition. Besides, rewriting some log message and
reduce them to have more Canonical Log
Lines (https://www.structlog.org/en/stable/logging-best-practices.html#canonical-log-lines)
instead.
* Make logs from `logging.getLogger` to look better
Logs coming from `logging.getLogger` (from other applications) have the same
structure that the ones logged by us via `structlog`.
* Lint
* Colored console locally and plain console in production
* Use `SysLogProcessor` and `SysLogRenderer` to format the logs
Use a custom renderer to match the structure we want:
```
%programname[%processid] [%level] %message [%logger:%linenumber] %structureddata
```
By default, rsyslog will prepend
```
%timestamp %hostname
```
and it will look exactly as we want.
* Missing imports
* Ignore `request_started` and `request_finished` events
Co-authored-by: Eric Holscher <25510+ericholscher@users.noreply.github.com>
