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Plack::Middleware::LogErrors(3pm) User Contributed Perl Documentation Plack::Middleware::LogErrors(3pm)


Plack::Middleware::LogErrors - Map psgi.errors to psgix.logger or other logger


version 0.003


Using a logger you have already configured (using Log::Dispatch as an example):

    use Log::Dispatch;
    my $logger = Log::Dispatch->new;
    $logger->add( Log::Dispatch::File->new(...) );
    builder {
        enable 'LogDispatch', logger => $logger;
        enable 'LogErrors';

Using an explicitly defined logger:

    builder {
        enable 'LogErrors', logger => sub {
            my $args = shift;


"psgi.errors" defaults to "STDERR" in most backends, which results in content going somewhere unhelpful like the server console.

This middleware simply remaps the "psgi.errors" stream to the "psgix.logger" stream, or an explicit logger that you provide.

This is especially handy when used in combination with other middlewares such as Plack::Middleware::LogWarn (which diverts Perl warnings to "psgi.errors"); Plack::Middleware::HTTPExceptions (which diverts uncaught exceptions to "psgi.errors"); and Plack::Middleware::AccessLog, which defaults to "psgi.errors" when not passed a logger -- which is also automatically applied via plackup (so if you provided no "--access-log" option indicating a filename, "psgi.errors" is used).



A code reference for logging messages, that conforms to the psgix.logger specification. If not provided, "psgix.logger" is used, or the application will generate an error at runtime if there is no such logger configured.


  • PSGI::Extensions - the definition of "psgix.logger"
  • "The Error Stream" in PSGI - the definition of "psgi.errors"
  • Plack::Middleware::LogWarn - maps warnings to "psgi.errors"
  • Plack::Middleware::HTTPExceptions - maps exceptions to "psgi.errors"
  • Plack::Middleware::LogDispatch - use a Log::Dispatch logger for "psgix.logger"
  • Plack::Middleware::Log4perl - use a Log::Log4perl logger for "psgix.logger"
  • Plack::Middleware::SimpleLogger - essentially the opposite of this module!


Bugs may be submitted through the RT bug tracker <> (or <>).

There is also a mailing list available for users of this distribution, at <!forum/psgi-plack>.

There is also an irc channel available for users of this distribution, at "#plack" on "" <irc://>.

I am also usually active on irc, as 'ether' at "".


Karen Etheridge <>


This software is copyright (c) 2013 by Karen Etheridge.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

2018-05-22 perl v5.40.0