1Perlbal::Manual::LogginUgs(e3r)Contributed Perl DocumentPaetrilobnal::Manual::Logging(3)
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NAME

6       Perlbal::Manual::Logging - How Perlbal's logging system works
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8   VERSION
9       Perlbal 1.78.
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11   DESCRIPTION
12       Perlbal supports logging of a few messages (and you can log your
13       messages in your plugins, for instance).
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15       This document describes how to achieve that.
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17   IMPORTANT: foreground vs. background
18       If Perlbal is running on the foreground, it logs by calling "printf",
19       which means you should get the logs on "STDOUT".
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21       If Perlbal is running on the background, it logs through Sys::Syslog.
22       If Sys::Syslog is not available, there will be no logging, and THAT'S
23       THE MOST IMPORTANT THING TO KNOW ABOUT PERLBAL'S LOGGING SYSTEM.
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25   How to log a message
26       You can log a message by calling "Perlbal::log" as you'd call
27       Sys::Syslog's "syslog":
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29           Perlbal::log( $priority, $format, @args );
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31       You should read the documentation for Sys::Syslog for more information,
32       but here's an example:
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34           Perlbal::log( 'info', 'beginning run' );
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36       And here's another example:
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38           Perlbal::log( 'crit', "this thing crashed: $!" );
39
40   What is logged?
41       •   When we try to read from or write to a filehandle that is
42           undefined, Perlbal::AIO logs a critical message:
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44               Perlbal::log("crit", "Undef \$fh: $stack_trace");
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46       •   When failing to create a socket, Perlbal::BackendHTTP logs a
47           critical message:
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49               Perlbal::log('crit', "Error creating socket: $!");
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51       •   When "inet_aton" fails to create a socket, Perlbal::BackendHTTP
52           logs a critical message:
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54               Perlbal::log('crit', "inet_aton failed creating socket for $ip");
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56       •   When writing to a client, if we try to read more than we should
57           from the backend, Perlbal::ClientHTTPBase logs a warning message:
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59               Perlbal::log('warning', "tried to readahead negative bytes.  filesize=$self->{reproxy_file_size}, offset=$self->{reproxy_file_offset}");
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61       •   When opening a file being PUT for writing to disk, if there's an
62           error (which is going to originate a 500 server error),
63           Perlbal::ClientHTTPBase logs a warning message:
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65               Perlbal::log('warning', "system error: $msg ($info)");
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67       •   If we receive a request with a content lenght different from the
68           actual length of the request, Perlbal::ClientProxy logs a critical
69           message:
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71               Perlbal::log('crit', "Content length of $clen declared but $self->{buoutpos} bytes written to disk");
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73       •   When trying to buffer data to disk, if the operation fails
74           Perlbal::ClientProxy logs a critical message:
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76               Perlbal::log('crit', "Failure to open $fn for buffered upload output");
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78       •   After buffering data to disk, if the file is empty,
79           Perlbal::ClientProxy logs a critical message:
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81               Perlbal::log('crit', "Error writing buffered upload: $!.  Tried to do $len bytes at $self->{buoutpos}.");
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83       •   When purging a buffered upload on the disk, if an error occurs,
84           Perlbal::ClientProxy logs a critical message:
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86               Perlbal::log('warning', "Unable to link $self->{bufilename}: $!");
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88       •   When marking a backend as pending, if there's already another one
89           in that ip/port, Perlbal::Service will log a couple of warning
90           messages:
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92               Perlbal::log('warning', "Warning: attempting to spawn backend connection that already existed.");
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94               Perlbal::log('warning', "          -- [$filename:$line] $package::$subroutine");
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96       •   When deciding whether we should spawn one or more backend
97           connections, if the total of pending conections is negative,
98           Perlbal::Service will log a critical message:
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100               Perlbal::log('crit', "Bogus: service $self->{name} has pending connect count of $self->{pending_connect_count}?!  Resetting.");
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102       •   When spawning a backend connection, if there is no IP address for
103           the backend, Perlbal::Service will log a critical message:
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105               Perlbal::log('crit', "No backend IP for service $self->{name}");
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107       •   When starting, Perlbal will log an info message:
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109               Perlbal::log('info', 'beginning run');
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111       •   When shutting down, Perlbal will log an info message:
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113               Perlbal::log('info', 'ending run');
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115       •   After each loop, is some error occurred, Perlbal will log a
116           critical message:
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118               Perlbal::log('crit', "crash log: $_") foreach split(/\r?\n/, $@);
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120       •   When attempting to create the pidfile, if unsuccessful, Perlbal
121           will log an info message:
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123               Perlbal::log('info', "couldn't create pidfile '$file': $!" );
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125       •   When attempting to write to the pidfile, if unsuccessful, Perlbal
126           will log an info message:
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128               Perlbal::log('info', "couldn't write into pidfile '$file': $!" );
129
130   Generating more logs by sending a USR1 signal to perlbal
131       If you send a USR1 signal to perlbal, that tells it to log some basic
132       statistics to the syslog.
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134       It's similar to connecting to a management service and issue a "show
135       service" for each service, plus a "states" and a "queues" commands.
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137   Where is it logged to?
138       The way Perlbal opens Sys::Syslog, it logs to /var/log/daemon.log by
139       default.
140
141   SEE ALSO
142       You can tweek Sys::Syslog's configuration under /etc/syslog.conf. See
143       Sys::Syslog for more details.
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147perl v5.36.0                      2023-01-18       Perlbal::Manual::Logging(3)