This adds a "policy" hook into the logging framework's streams and
filters to replace the existing log filter predicates. The hook
signature is as follows:
hook(rec: any, id: Log::ID, filter: Log::Filter);
The logging manager invokes hooks on each log record. Hooks can veto
log records via a break, and modify them if necessary. Log filters
inherit the stream-level hook, but can override or remove the hook as
needed.
The distribution's existing log streams now come with pre-defined
hooks that users can add handlers to. Their name is standardized as
"log_policy" by convention, with additional suffixes when a module
provides multiple streams. The following adds a handler to the Conn
module's default log policy hook:
hook Conn::log_policy(rec: Conn::Info, id: Log::ID, filter: Log::Filter)
{
if ( some_veto_reason(rec) )
break;
}
By default, this handler will get invoked for any log filter
associated with the Conn::LOG stream.
The existing predicates are deprecated for removal in 4.1 but continue
to work.
``NetControl::DROP`` had 3 conflicting definitions that could potentially
be used incorrectly without any warnings or type-checking errors.
Such enum redefinition conflicts are now caught and treated as errors,
so the ``NetControl::DROP`` enums had to be renamed:
* The use as enum of type ``Log::ID`` is renamed to ``NetControl::DROP_LOG``
* The use as enum of type ``NetControl::CatchReleaseInfo`` is renamed to
``NetControl::DROP_REQUESTED``
* The use as enum of type ``NetControl::RuleType`` is unchanged and still
named ``NetControl::DROP``
For event/hook handlers that had a previous declaration, any &default
arguments are ineffective. Only &default uses in the initial
prototype's arguments have an effect (that includes if the handler
is actually the site at which the declaration occurs).
These are no longer loaded by default due to the performance impact they
cause simply by being loaded (they have event handlers for commonly
generated events) and they aren't generally useful enough to justify it.
