Logging (PSR-3)

Baseline: main 23.0+ · Verified: main 26.800.0

Code depends on Psr\Log\LoggerInterface; the implementation is chosen in .settings.php loggers. AddMessage2Log() — compat only.

Implementations (`Bitrix\Main\Diag\`)

Class	Notes
`FileLogger(string $fileName, ?int $maxSize = null)`	default max 1 MB, then renamed to `<file>.old`; `0` = no rotation
`SysLogger(string $prefix = '', int $flags = LOG_ODELAY, int $facility = LOG_USER)`	system syslog
`EventLogger(?string $module, ?string $auditType, ?callable $callback)`	`b_event_log` (Event log in admin) — low volume only
`LogFormatter($showArguments = false, $argMaxChars = 30)`	default; placeholders `{date}` `{host}` `{level}` `{delimiter}` `{exception}` `{trace}` + context keys
`JsonLinesFormatter` (Since main 25.300; older: `LogFormatter`)	writes only `$context` as one JSON line — the message text is dropped, put it into context

level and formatter settings apply only to Bitrix\Main\Diag\Logger subclasses, not to Monolog.