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added loglevel option for plugins

Plugins can now use a 'loglevel' argument in config/plugins entry

Includes user instructions prepended to docs/logging.pod

Already works for all plugins that use named arguments
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1 parent 15bf425 commit efbaf2ec6f3b809eb03a062bd603e89b57e442d6 @msimerson msimerson committed May 21, 2012
Showing with 146 additions and 4 deletions.
  1. +119 −2 docs/logging.pod
  2. +27 −2 lib/Qpsmtpd/
121 docs/logging.pod
@@ -1,7 +1,124 @@
-# read this with 'perldoc README.logging' ...
+# read this with 'perldoc docs/logging.pod'
+=head1 qpsmtpd logging; user documentation
+Qpsmtpd has a modular logging system. Here's a few things you need to know:
+ * The built-in logging prints log messages to STDERR.
+ * A variety of logging plugins is included, each with its own behavior.
+ * When a logging plugin is enabled, the built-in logging is disabled.
+ * plugins/logging/warn mimics the built-in logging.
+ * Multiple logging plugins can be enabled simultaneously.
+Read the POD within each logging plugin (perldoc plugins/logging/B<NAME>)
+to learn if it tickles your fancy.
+=head2 enabling plugins
+To enable logging plugins, edit the file I<config/logging> and uncomment the
+entries for the plugins you wish to use.
+=head2 logging level
+The 'master switch' for loglevel is I<config/loglevel>. Qpsmtpd and active
+plugins will output all messages that are less than or equal to the value
+specified. The log levels correspond to syslog levels:
+Level 6, LOGINFO, is the level at which most servers should start logging. At
+level 6, each plugin should log one and occasionally two entries that
+summarize their activity. Here's a few sample lines:
+ (connect) ident::geoip: SA, Saudi Arabia
+ (connect) ident::p0f: Windows 7 or 8
+ (connect) earlytalker: pass: remote host said nothing spontaneous
+ (data_post) domainkeys: skip: unsigned
+ (data_post) spamassassin: pass, Spam, 21.7 < 100
+ (data_post) dspam: fail: agree, Spam, 1.00 c
+ 552 we agree, no spam please (#5.6.1)
+Three plugins fired during the SMTP connection phase and 3 more ran during the
+data_post phase. Each plugin emitted one entry stating their findings.
+If you aren't processing the logs, you can save some disk I/O by reducing the
+loglevel, so that the only messages logged are ones that indicate a human
+should be taking some corrective action.
+=head2 log location
+If qpsmtpd is started using the distributed run file (cd ~smtpd; ./run), then
+you will see the log entries printed to your terminal. This solution works
+great for initial setup and testing and is the simplest case.
+A typical way to run qpsmtpd is as a supervised process with daemontools. If
+daemontools is already set up, setting up qpsmtpd may be as simple as:
+C<ln -s /usr/home/smtpd /var/service/>
+If svcscan is running, the symlink will be detected and tcpserver will
+run the 'run' files in the ./ and ./log directories. Any log entries
+emitted will get handled per the instructions in log/run. The default
+location specified in log/run is log/main/current.
+=head2 plugin loglevel
+Most plugins support a loglevel argument after their config/plugins entry.
+The value can be a whole number (N) or a relative number (+/-N), where
+N is a whole number from 0-7. See the descriptions of each below.
+C<ident/p0f loglevel 5>
+C<ident/p0f loglevel -1>
+ATTN plugin authors: To support loglevel in your plugin, you must store the
+loglevel settings from the plugins/config entry $self->{_args}{loglevel}. A
+simple and recommended example is as follows:
+ sub register {
+ my ( $self, $qp ) = shift, shift;
+ $self->log(LOGERROR, "Bad arguments") if @_ % 2;
+ $self->{_args} = { @_ };
+ }
+=head3 whole number
+If loglevel is a whole number, then all log activity in the plugin is logged
+at that level, regardless of the level the plugin author selected. This can
+be easily understood with a couple examples:
+The master loglevel is set at 6 (INFO). The mail admin sets a plugin loglevel
+to 7 (DEBUG). No messages from that plugin are emitted because DEBUG log
+entries are not <= 6 (INFO).
+The master loglevel is 6 (INFO) and the plugin loglevel is set to 5 or 6. All
+log entries will be logged because 5 is <= 6.
+This behavior is very useful to plugin authors. While testing and monitoring
+a plugin, they can set the level of their plugin to log everything. To return
+to 'normal' logging, they just update their config/plugins entry.
+=head3 relative
+Relative loglevel arguments adjust the loglevel of each logging call within
+a plugin. A value of I<loglevel +1> would make every logging entry one level
+less severe, where a value of I<loglevel -1> would make every logging entry
+one level more severe.
+For example, if a plugin has a loglevel setting of -1 and that same plugin
+logged a LOGDEBUG, it would instead be a LOGINFO message. Relative values
+makes it easy to control the verbosity and/or severity of individual plugins.
=head1 qpsmtpd logging system; developer documentation
Qpsmtpd now (as of 0.30-dev) supports a plugable logging architecture, so
@@ -62,7 +179,7 @@ plugin (the system will not infinitely recurse in any case).
=item C<@log>
The remaining arguments are as passed by the caller, which may be a single
-term or may be a list of values. It is usually sufficient to call
+term or may be a list of values. It is usually sufficient to call
C<join(" ",@log)> to deal with these terms, but it is possible that some
plugin might pass additional arguments with signficance.
29 lib/Qpsmtpd/
@@ -63,10 +63,35 @@ sub qp {
sub log {
my $self = shift;
- $self->{_qp}->varlog(shift, $self->{_hook}, $self->plugin_name, @_)
- unless defined $self->{_hook} and $self->{_hook} eq 'logging';
+ return if defined $self->{_hook} && $self->{_hook} eq 'logging';
+ my $level = $self->adjust_log_level( shift, $self->plugin_name );
+ $self->{_qp}->varlog($level, $self->{_hook}, $self->plugin_name, @_);
+sub adjust_log_level {
+ my ( $self, $cur_level, $plugin_name) = @_;
+ my $adj = $self->{_args}{loglevel} or return $cur_level;
+ return $adj if $adj =~ m/^[01234567]$/; # a raw syslog numeral
+ if ( $adj !~ /^[\+\-][\d]$/ ) {
+ $self->log( LOGERROR, $self-"invalid $plugin_name loglevel setting ($adj)" );
+ undef $self->{_args}{loglevel}; # only complain once per plugin
+ return $cur_level;
+ };
+ my $operator = substr($adj, 0, 1);
+ my $adjust = substr($adj, -1, 1);
+ my $new_level = $operator eq '+' ? $cur_level + $adjust : $cur_level - $adjust;
+ $new_level = 7 if $new_level > 7;
+ $new_level = 0 if $new_level < 0;
+ return $new_level;
sub transaction {
# not sure if this will work in a non-forking or a threaded daemon

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