Merge branch 'pull/collectd-4' into collectd-4

[collectd.git] / src / collectd.pod

diff --git a/src/collectd.pod b/src/collectd.pod
index 731a8c7..bc65f57 100644 (file)
--- a/src/collectd.pod
+++ b/src/collectd.pod
@@ -16,7 +16,7 @@ settings. The following features may be available:
 
 =item
 
-Apache server stats (I<apache>)
+Apache and lighttpd server statistics (I<apache>)
 
 =item
 
@@ -174,10 +174,10 @@ values.
 
 =head2 apache
 
-This module connects to an Apache webserver and expects the output produced by
-B<mod_status.c>. If requires B<libcurl> to set up the HTTP connection and issue
-the request(s). The following is a sample config for the Apache webserver. The
-use of C<ExtendedStatus on> is mandatory.
+This module connects to an Apache or lighttpd webserver and expects the output
+produced by B<mod_status.c>. If requires B<libcurl> to set up the HTTP
+connection and issue the request(s). The following is a sample config for the
+Apache webserver. Under Apache, the use of C<ExtendedStatus on> is mandatory.
 
   ExtendedStatus on
   <IfModule mod_status.c>
@@ -219,6 +219,39 @@ Successful spam checks (e.g. "BAYES_99", "SUBJECT_DRUG_GAP_C", ...):
 Each line is limited to 256 characters (including the newline character). 
 Longer lines will be ignored.
 
+=head2 exec
+
+The C<exec> plugin forks of an executable and reads back values that it writes
+to C<STDOUT>. The executable is forked kind of as L<init> does: It is forked
+once and not again until it exits. If it exited, it will be forked again after
+at most I<Interval> seconds. It is perfectly legal for the executable to run
+for a long time and continuously write values to C<STDOUT>.
+
+The forked executable is expected to print values to C<STDOUT>. The expected
+format is as follows:
+
+=over 4
+
+=item
+
+Each line beginning with a C<#> (hash mark) is ignored.
+
+=item
+
+Any other line must be of the form C<I<type>,I<type-instance>,I<value>>, where
+I<type> is either B<counter> or B<gauge>, I<type-instance> may not contain
+C<,> (comma), C</> (slash) and C<\0> (null byte) and I<value> is either an
+integer (if I<type> is B<counter>) or a floating-point number (if I<type> is
+B<gauge>).
+
+=back
+
+The values are always considered to be "fresh", i.E<nbsp>e. the time is set to
+"now".
+
+When collectd exits it sends a B<SIGTERM> to all still running
+child-processes upon which they have to quit.
+
 =head2 mysql
 
 Requires B<mysqlclient> to be installed. It connects to the database when