oracular (3) logger_filters.3erl.gz
NAME
logger_filters - Filters to use with Logger.
DESCRIPTION
All functions exported from this module can be used as primary or handler filters. See
logger:add_primary_filter/2 and logger:add_handler_filter/3 for more information about how filters are
added.
Filters are removed with logger:remove_primary_filter/1 and logger:remove_handler_filter/2.
EXPORTS
domain(LogEvent, Extra) -> logger:filter_return()
Types:
LogEvent = logger:log_event()
Extra = {Action, Compare, MatchDomain}
Action = log | stop
Compare = super | sub | equal | not_equal | undefined
MatchDomain = [atom()]
This filter provides a way of filtering log events based on a domain field in Metadata. This field
is optional, and the purpose of using it is to group log events from, for example, a specific
functional area. This allows filtering or other specialized treatment in a Logger handler.
A domain field must be a list of atoms, creating smaller and more specialized domains as the list
grows longer. The greatest domain is [], which comprises all possible domains.
For example, consider the following domains:
D1 = [otp]
D2 = [otp, sasl]
D1 is the greatest of the two, and is said to be a super-domain of D2. D2 is a sub-domain D1. Both
D1 and D2 are sub-domains of [].
The above domains are used for logs originating from Erlang/OTP. D1 specifies that the log event
comes from Erlang/OTP in general, and D2 indicates that the log event is a so called SASL report.
The Extra parameter to the domain/2 function is specified when adding the filter via
logger:add_primary_filter/2 or logger:add_handler_filter/3.
The filter compares the value of the domain field in the log event's metadata (Domain) against
MatchDomain. The filter matches if the value of Compare is:
sub:
and Domain is equal to or a sub-domain of MatchDomain, that is, if MatchDomain is a prefix of
Domain.
super:
and Domain is equal to or a super-domain of MatchDomain, that is, if Domain is a prefix of
MatchDomain.
equal:
and Domain is equal to MatchDomain.
not_equal:
and Domain differs from MatchDomain, or if there is no domain field in metadata.
undefined:
and there is no domain field in metadata. In this case MatchDomain must be set to [].
If the filter matches and Action is log, the log event is allowed. If the filter matches and
Action is stop, the log event is stopped.
If the filter does not match, it returns ignore, meaning that other filters, or the value of the
configuration parameter filter_default, decide if the event is allowed or not.
Log events that do not contain any domain field, match only when Compare is equal to undefined or
not_equal.
Example: stop all events with domain [otp, sasl | _]
logger:set_handler_config(h1, filter_default, log). % this is the default
Filter = {fun logger_filters:domain/2, {stop, sub, [otp, sasl]}}.
logger:add_handler_filter(h1, no_sasl, Filter).
ok
level(LogEvent, Extra) -> logger:filter_return()
Types:
LogEvent = logger:log_event()
Extra = {Action, Operator, MatchLevel}
Action = log | stop
Operator = neq | eq | lt | gt | lteq | gteq
MatchLevel = logger:level()
This filter provides a way of filtering log events based on the log level. It matches log events
by comparing the log level with a specified MatchLevel
The Extra parameter is specified when adding the filter via logger:add_primary_filter/2 or
logger:add_handler_filter/3.
The filter compares the value of the event's log level (Level) to MatchLevel by calling
logger:compare_levels(Level, MatchLevel). The filter matches if the value of Operator is:
neq:
and the compare function returns lt or gt.
eq:
and the compare function returns eq.
lt:
and the compare function returns lt.
gt:
and the compare function returns gt.
lteq:
and the compare function returns lt or eq.
gteq:
and the compare function returns gt or eq.
If the filter matches and Action is log, the log event is allowed. If the filter matches and
Action is stop, the log event is stopped.
If the filter does not match, it returns ignore, meaning that other filters, or the value of the
configuration parameter filter_default, will decide if the event is allowed or not.
Example: only allow debug level log events
logger:set_handler_config(h1, filter_default, stop).
Filter = {fun logger_filters:level/2, {log, eq, debug}}.
logger:add_handler_filter(h1, debug_only, Filter).
ok
progress(LogEvent, Extra) -> logger:filter_return()
Types:
LogEvent = logger:log_event()
Extra = log | stop
This filter matches all progress reports from supervisor and application_controller.
If Extra is log, the progress reports are allowed. If Extra is stop, the progress reports are
stopped.
The filter returns ignore for all other log events.
remote_gl(LogEvent, Extra) -> logger:filter_return()
Types:
LogEvent = logger:log_event()
Extra = log | stop
This filter matches all events originating from a process that has its group leader on a remote
node.
If Extra is log, the matching events are allowed. If Extra is stop, the matching events are
stopped.
The filter returns ignore for all other log events.
SEE ALSO
logger(3erl)