[erlang-questions] error_logger heap overflow
Mon Jan 7 18:35:29 CET 2013
On 01/07/2013 10:01 AM, Bogdan Andu wrote:
> Sorry for delayed response.
> Unfortunately, I cannot use the work around presented because is experimental and the system is ready to be launched into production, so I cannot anymore switch back to lager, although is more heap overflow resistant than error_logger is.
> I stick with error_logger because errors are easier to read and I am accustomed with it.
> log rotation is solved with newsyslog.
> What makes lager's messages 'hard to read' is the lack of error formatting.
> What I would expect from lager:
> 1. lager:notice() send the message in /var/log/notice_log
> lager:error() send the message in /var/log/error_log
> lager:info() send the message in /va/log/info_log
> 2. crash messages to appear only in /var/log/crash_log
> 3. this sould be configurable
> 4. more error formatting, like error_log has, in order to be easier to read
> Why I want that? Because error has higher priority that notice, so all messages founded in /var/log/error_log are also founded in
> /var/log/notice_log. I do not want duplicated error messages even if they are truncated.
> ----- Original Message -----
> From: Andrew Thompson <>
> Cc: Bogdan Andu <>
> Sent: Wednesday, November 28, 2012 8:47 AM
> Subject: Re: [erlang-questions] error_logger heap overflow
> On Tue, Nov 20, 2012 at 03:28:57AM -0800, Bogdan Andu wrote:
>> I used that, lager, but it is hard to read error messages, and the errors are duplicated across all log files.
>> One cannot say to lager: commit notice messages to /var/log/notice_log, because all error messages with higher prority get written there, too.
> I decided to tinker around this week in relation to this issue and came
> up with this:
> Does that address your concern on that front?
>> I like how error_logger prints the errors and I am used to it.
>> Please give me an advice of how to overcome this situation.
> One thing you could do would be to fork the stdlib (or SASL)
> error_logger gen_event handlers to use lager_format instead of io_lib
> (lager_format is a fork of io_lib with size based truncation added to
> avoid the OOM issues). The only downside to this is that lager_format
> currently lacks the line-wrapping support ~p and friends have in io_lib,
> so stacktraces, for example, end up on one big line rather than being
> line wrapped nicely.
> Also, with regard to lager and formatting OTP errors, lager will try to
> rewrite common OTP errors into more 'friendly' log messages, but it will
> also write a truncated version of the original log format to the
> 'crash.log', if more information is required.
Recent lager allows you to do just that:
=debug - only the debug level
Doesn't seem to be talked about in the README unfortunately.
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