# log_mf_h

###
Module

log_mf_h

###
Module Summary

An event handler that logs events to disk.

###
Description

This module is a gen_event handler module that can be installed in any gen_event process. It logs onto disk all events that are sent to an event manager. Each event is written as a binary, which makes the logging very fast. However, a tool such as the Report Browser (rb(3)) must be used to read the files. The events are written to multiple files. When all files have been used, the first one is reused and overwritten. The directory location, the number of files, and the size of each file are configurable. The directory will include one file called index, and report files 1, 2, ....

###
Data Types

####
args()

Term to be sent to gen_event:add_handler/3.

###
Exports

####
init(Dir, MaxBytes, MaxFiles) -> Args

####
init(Dir, MaxBytes, MaxFiles, Pred) -> Args

### Types

Dir = file:filename()
MaxBytes = integer() >= 0
MaxFiles = 1..255
Pred = fun((Event :: term()) -> boolean())
Args = args()

Initiates the event handler. Returns Args, which is to be used in a call to gen_event:add_handler(EventMgr, log_mf_h, Args).

Dir specifies which directory to use for the log files. MaxBytes specifies the size of each individual file. MaxFiles specifies how many files are used. Pred is a predicate function used to filter the events. If no predicate function is specified, all events are logged.

###
See Also

gen_event(3), rb(3)