report browser and error_logger

[Hal Snyder]

Martin Bjorklund <mbj@REDACTED> writes:

> Since I implemented this in OTP, I've done some rethinking - why
> bother to store the logs in binary format anyway? In most cases it's
> better to store the error log in plain text, but using a wrap log so
> the log won't grow. This is what we do in our systems.
> 
> I've attached disk_log_h, a module which should have been
> implemented years ago. It's a gen_event handler for disk_log. This
> handler can be used e.g. for an error log, or whatever. This module
> could very well be part of OTP (it's intended to be).

Great! This looks quite interesting.

One small question, however. Attempts to use disk_log_h result in
event handler crashes. Is it correct that disk_log:do_log/2 returns an
integer? It returns 1 in the tests, and disk_log_h doesn't seem to
like that.

Also, what would be a good way to flush cached log entries to disk?
Hope I'm not being a pest.

The setup:

1. Using kit built from otp_src_R8B-20011015 plus the disk_log
   patch you provided.

2. Then in a directory where disk_log_h.beam and logger.beam exist,
   start an erl node as follows.

>erl          
Erlang (BEAM) emulator version 5.1 [source]

Eshell V5.1  (abort with ^G)
1> logger:add_error_logger_mf("/tmp/glotz", 10000, 4, all).
ok
2> error_logger:error_msg("foo~n").   
ok

=ERROR REPORT==== 20-Jan-2002::18:05:05 ===
foo
3> 
=ERROR REPORT==== 20-Jan-2002::18:05:05 ===
** gen_event handler {disk_log_h,logger} crashed.
** Was installed in error_logger
** Last event was: {error,<0.21.0>,{<0.23.0>,"foo~n",[]}}
** When handler state == {state,{log,ok,
                                     logger,
                                     none,
                                     0,
                                     "/tmp/glotz",
                                     [],
                                     wrap,
                                     external,
                                     wrap_ext,
                                     none,
                                     read_write,
                                     {10000,4},
                                     {handle,
                                         "/tmp/glotz",
                                         10000,
                                         4,
                                         0,
                                         1,
                                         {cache,
                                             {file_descriptor,
                                                 prim_file,
                                                 {#Port<0.32>,3}},
                                             0,
                                             []},
                                         "/tmp/glotz.1",
                                         0,
                                         0,
                                         0,
                                         0,
                                         0}},
                                0,
                                {logger,form_all}}
** Reason == 1