docs: add structlog config

docs/howto/production/logging.md

@@ -7,7 +7,7 @@ messages, they are added as [extra] elements to the logs themselves.
 This way, you can adapt the logs to whatever format suits your needs the most, using
 a log filter:
 
-```
+```python
 import logging
 
 class ProcrastinateLogFilter(logging.Filter):
@@ -27,7 +27,55 @@ to see them is to use a structured logging library such as [`structlog`].
 
 If you want a minimal example of a logging setup that displays the extra
 attributes without using third party logging libraries, look at the
-[Django demo]
+[Django demo].
+
+:::{note}
+When using the `procrastinate` CLI, procrastinate sets up the logs for you,
+but the only customization available is `--log-format` and `--log-format-style`.
+If you want to customize the log format further, you will need run your own
+script that calls procrastinate's app methods.
+:::
+
+## `structlog`
+
+[`structlog`](https://www.structlog.org/en/stable/index.html) needs to be
+configured in order to have `procrastinate`'s logs be formatted uniformly
+with the rest of your application.
+
+The `structlog` docs has a [how to](https://www.structlog.org/en/stable/standard-library.html#rendering-using-structlog-based-formatters-within-logging).
+
+A minimal configuration would look like:
+
+```python
+shared_processors = [
+    structlog.contextvars.merge_contextvars,
+    structlog.stdlib.add_logger_name,
+    structlog.stdlib.add_log_level,
+    structlog.processors.StackInfoRenderer(),
+    structlog.dev.set_exc_info,
+]
+
+structlog.configure(
+    processors=shared_processors + [structlog.stdlib.ProcessorFormatter.wrap_for_formatter],
+    logger_factory=structlog.stdlib.LoggerFactory(),
+    cache_logger_on_first_use=True,
+)
+
+formatter = structlog.stdlib.ProcessorFormatter(
+    foreign_pre_chain=shared_processors,
+    processors=[
+        structlog.stdlib.ProcessorFormatter.remove_processors_meta,
+        structlog.dev.ConsoleRenderer(event_key="message"),
+    ],
+)
+
+handler = logging.StreamHandler()
+handler.setFormatter(formatter)
+
+root = logging.getLogger()
+root.addHandler(handler)
+root.setLevel(log_level)
+```
 
 [extra]: https://timber.io/blog/the-pythonic-guide-to-logging/#adding-context
 [`structlog`]: https://www.structlog.org/en/stable/