.\" Automatically generated by Pod::Man 2.25 (Pod::Simple 3.16)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings.  \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote.  \*(C+ will
.\" give a nicer C++.  Capital omega is used to do unbreakable dashes and
.\" therefore won't be available.  \*(C` and \*(C' expand to `' in nroff,
.\" nothing in troff, for use with C<>.
.tr \(*W-
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
.    ds -- \(*W-
.    ds PI pi
.    if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.    if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\"  diablo 12 pitch
.    ds L" ""
.    ds R" ""
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is turned on, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.ie \nF \{\
.    de IX
.    tm Index:\\$1\t\\n%\t"\\$2"
..
.    nr % 0
.    rr F
.\}
.el \{\
.    de IX
..
.\}
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear.  Run.  Save yourself.  No user-serviceable parts.
.    \" fudge factors for nroff and troff
.if n \{\
.    ds #H 0
.    ds #V .8m
.    ds #F .3m
.    ds #[ \f1
.    ds #] \fP
.\}
.if t \{\
.    ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.    ds #V .6m
.    ds #F 0
.    ds #[ \&
.    ds #] \&
.\}
.    \" simple accents for nroff and troff
.if n \{\
.    ds ' \&
.    ds ` \&
.    ds ^ \&
.    ds , \&
.    ds ~ ~
.    ds /
.\}
.if t \{\
.    ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.    ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.    ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.    ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.    ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.    ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
.    \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.    \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.    \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds : e
.    ds 8 ss
.    ds o a
.    ds d- d\h'-1'\(ga
.    ds D- D\h'-1'\(hy
.    ds th \o'bp'
.    ds Th \o'LP'
.    ds ae ae
.    ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ========================================================================
.\"
.IX Title "Perlbal::Manual::Logging 3pm"
.TH Perlbal::Manual::Logging 3pm "2012-03-23" "perl v5.14.2" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
Perlbal::Manual::Logging \- How Perlbal's logging system works
.SS "\s-1VERSION\s0"
.IX Subsection "VERSION"
Perlbal 1.78.
.SS "\s-1DESCRIPTION\s0"
.IX Subsection "DESCRIPTION"
Perlbal supports logging of a few messages (and you can log your messages in your plugins, for instance).
.PP
This document describes how to achieve that.
.SS "\s-1IMPORTANT:\s0 foreground vs. background"
.IX Subsection "IMPORTANT: foreground vs. background"
If Perlbal is running on the foreground, it logs by calling \f(CW\*(C`printf\*(C'\fR, which means you should get the logs on \f(CW\*(C`STDOUT\*(C'\fR.
.PP
If Perlbal is running on the background, it logs through Sys::Syslog. If Sys::Syslog is not available, there will be no logging, and \s-1THAT\s0'S \s-1THE\s0 \s-1MOST\s0 \s-1IMPORTANT\s0 \s-1THING\s0 \s-1TO\s0 \s-1KNOW\s0 \s-1ABOUT\s0 \s-1PERLBAL\s0'S \s-1LOGGING\s0 \s-1SYSTEM\s0.
.SS "How to log a message"
.IX Subsection "How to log a message"
You can log a message by calling \f(CW\*(C`Perlbal::log\*(C'\fR as you'd call Sys::Syslog's \f(CW\*(C`syslog\*(C'\fR:
.PP
.Vb 1
\&    Perlbal::log( $priority, $format, @args );
.Ve
.PP
You should read the documentation for Sys::Syslog for more information, but here's an example:
.PP
.Vb 1
\&    Perlbal::log( \*(Aqinfo\*(Aq, \*(Aqbeginning run\*(Aq );
.Ve
.PP
And here's another example:
.PP
.Vb 1
\&    Perlbal::log( \*(Aqcrit\*(Aq, "this thing crashed: $!" );
.Ve
.SS "What is logged?"
.IX Subsection "What is logged?"
.IP "\(bu" 4
When we try to read from or write to a filehandle that is undefined, Perlbal::AIO logs a critical message:
.Sp
.Vb 1
\&    Perlbal::log("crit", "Undef \e$fh: $stack_trace");
.Ve
.IP "\(bu" 4
When failing to create a socket, Perlbal::BackendHTTP logs a critical message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqcrit\*(Aq, "Error creating socket: $!");
.Ve
.IP "\(bu" 4
When \f(CW\*(C`inet_aton\*(C'\fR fails to create a socket, Perlbal::BackendHTTP logs a critical message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqcrit\*(Aq, "inet_aton failed creating socket for $ip");
.Ve
.IP "\(bu" 4
When writing to a client, if we try to read more than we should from the backend, Perlbal::ClientHTTPBase logs a warning message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqwarning\*(Aq, "tried to readahead negative bytes.  filesize=$self\->{reproxy_file_size}, offset=$self\->{reproxy_file_offset}");
.Ve
.IP "\(bu" 4
When opening a file being \s-1PUT\s0 for writing to disk, if there's an error (which is going to originate a 500 server error), Perlbal::ClientHTTPBase logs a warning message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqwarning\*(Aq, "system error: $msg ($info)");
.Ve
.IP "\(bu" 4
If we receive a request with a content length different from the actual length of the request, Perlbal::ClientProxy logs a critical message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqcrit\*(Aq, "Content length of $clen declared but $self\->{buoutpos} bytes written to disk");
.Ve
.IP "\(bu" 4
When trying to buffer data to disk, if the operation fails Perlbal::ClientProxy logs a critical message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqcrit\*(Aq, "Failure to open $fn for buffered upload output");
.Ve
.IP "\(bu" 4
After buffering data to disk, if the file is empty, Perlbal::ClientProxy logs a critical message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqcrit\*(Aq, "Error writing buffered upload: $!.  Tried to do $len bytes at $self\->{buoutpos}.");
.Ve
.IP "\(bu" 4
When purging a buffered upload on the disk, if an error occurs, Perlbal::ClientProxy logs a critical message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqwarning\*(Aq, "Unable to link $self\->{bufilename}: $!");
.Ve
.IP "\(bu" 4
When marking a backend as pending, if there's already another one in that ip/port, Perlbal::Service will log a couple of warning messages:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqwarning\*(Aq, "Warning: attempting to spawn backend connection that already existed.");
\&
\&    Perlbal::log(\*(Aqwarning\*(Aq, "          \-\- [$filename:$line] $package::$subroutine");
.Ve
.IP "\(bu" 4
When deciding whether we should spawn one or more backend connections, if the total of pending conections is negative, Perlbal::Service will log a critical message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqcrit\*(Aq, "Bogus: service $self\->{name} has pending connect count of $self\->{pending_connect_count}?!  Resetting.");
.Ve
.IP "\(bu" 4
When spawning a backend connection, if there is no \s-1IP\s0 address for the backend, Perlbal::Service will log a critical message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqcrit\*(Aq, "No backend IP for service $self\->{name}");
.Ve
.IP "\(bu" 4
When starting, Perlbal will log an info message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqinfo\*(Aq, \*(Aqbeginning run\*(Aq);
.Ve
.IP "\(bu" 4
When shutting down, Perlbal will log an info message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqinfo\*(Aq, \*(Aqending run\*(Aq);
.Ve
.IP "\(bu" 4
After each loop, is some error occurred, Perlbal will log a critical message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqcrit\*(Aq, "crash log: $_") foreach split(/\er?\en/, $@);
.Ve
.IP "\(bu" 4
When attempting to create the pidfile, if unsuccessful, Perlbal will log an info message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqinfo\*(Aq, "couldn\*(Aqt create pidfile \*(Aq$file\*(Aq: $!" );
.Ve
.IP "\(bu" 4
When attempting to write to the pidfile, if unsuccessful, Perlbal will log an info message:
.Sp
.Vb 1
\&    Perlbal::log(\*(Aqinfo\*(Aq, "couldn\*(Aqt write into pidfile \*(Aq$file\*(Aq: $!" );
.Ve
.SS "Generating more logs by sending a \s-1USR1\s0 signal to perlbal"
.IX Subsection "Generating more logs by sending a USR1 signal to perlbal"
If you send a \s-1USR1\s0 signal to perlbal, that tells it to log some basic statistics to the syslog.
.PP
It's similar to connecting to a management service and issue a \f(CW\*(C`show service\*(C'\fR for each service, plus a \f(CW\*(C`states\*(C'\fR and a \f(CW\*(C`queues\*(C'\fR commands.
.SS "Where is it logged to?"
.IX Subsection "Where is it logged to?"
The way Perlbal opens Sys::Syslog, it logs to \fI/var/log/daemon.log\fR by default.
.SS "\s-1SEE\s0 \s-1ALSO\s0"
.IX Subsection "SEE ALSO"
You can tweek Sys::Syslog's configuration under \fI/etc/syslog.conf\fR. See Sys::Syslog for more details.