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</author>
</authorgroup>
- <pubdate>2005</pubdate>
+ <pubdate>2009</pubdate>
<title>Nagios plug-in development guidelines</title>
<revhistory>
<revision>
- <revnumber>$Revision$</revnumber>
- <date>$Date$</date>
+ <revnumber>1796</revnumber>
+ <date>2007-09-24 14:51:07 -0400 (Mon, 24 Sep 2007)</date>
</revision>
</revhistory>
<copyright>
- <year>2000 - 2005</year>
+ <year>2000 - 2009</year>
<holder>Nagios Plugins Development Team</holder>
</copyright>
the plug-in developers and encourage the standarization of the
different kind of plug-ins: C, shell, perl, python, etc.</para>
- <para>Nagios Plug-in Development Guidelines Copyright (C) 2000-2005
+ <para>Nagios Plug-in Development Guidelines Copyright (C) 2000-2009
(Nagios Plugins Team)</para>
<para>Permission is granted to make and distribute verbatim
<para>
Nagios plugins are developed to the GNU standard, so any OS which is supported by GNU
should run the plugins. While the requirements for compiling the Nagios plugins release
- is very small, to develop from CVS needs additional software to be installed. These are the
- minimum levels of software required:
+ are very basic, developing from the Git repository requires additional software to be
+ installed. These are the minimum levels of software required:
<literallayout>
- gnu make 3.79
- automake 1.8
- autoconf 2.58
- gettext 0.11.5
+ GNU make 3.79
+ GNU automake 1.9.2
+ GNU autoconf 2.59
+ GNU m4 1.4.2
+ GNU libtool 1.5
</literallayout>
- To compile from CVS, after you have checked out the code, run:
+ To compile from Git, after you have cloned the repository, run:
<literallayout>
tools/setup
./configure
the entire output to appear in a pager message, which will get chopped
off after a certain length.</para>
+ <para>As Nagios does not capture stderr output, you should only output to
+ STDOUT and not print to STDERR.</para>
+
<section><title>Print only one line of text</title>
<para>Nagios will only grab the first line of text from STDOUT
when it notifies contacts about potential problems. If you print
- multiple lines, you're out of luck. Remember, keep it short and
- to the point.</para>
+ multiple lines, you're out of luck (though this will be a feature of
+ Nagios 3). Remember, keep your output short and to the point.</para>
<para>Output should be in the format:</para>
<literallayout>
- METRIC STATUS: Information text
+ SERVICE STATUS: Information text
</literallayout>
<para>However, note that this is not a requirement of the API, so you cannot depend on this
being an accurate reflection of the status of the service - the status should always
<section><title>Screen Output</title>
<para>The plug-in should print the diagnostic and just the
- synopsis part of the help message. A well written plugin would
+ usage part of the help message. A well written plugin would
then have --help as a way to get the verbose help.</para>
+
<para>Code and output should try to respect the 80x25 size of a
crt (remember when fixing stuff in the server room!)</para>
</section>
- <section><title>Return the proper status code</title>
- <para>See <xref linkend="ReturnCodes"> below
- for the numeric values of status codes and their
- description. Remember to return an UNKNOWN state if bogus or
- invalid command line arguments are supplied or it you are unable
- to check the service.</para>
- </section>
-
<section><title>Plugin Return Codes</title>
<para>The return codes below are based on the POSIX spec of returning
a positive value. Netsaint prior to v0.0.7 supported non-POSIX
<entry align="center"><para>3</para></entry>
<entry valign="middle"><para>Unknown</para></entry>
<entry><para>Invalid command line arguments were supplied to the
- plugin or the plugin was unable to check the status of the given
- hosts/service</para></entry>
+ plugin or low-level failures internal to the plugin (such as unable to fork,
+ or open a tcp socket) that prevent it from performing the specified
+ operation. Higher-level errors (such as name resolution errors,
+ socket timeouts, etc) are outside of the control of plugins and should
+ generally NOT be reported as UNKNOWN states.
+ </para></entry>
</row>
</tbody>
</tgroup>
</section>
- <section id="thresholdformat"><title>Threshold range format</title>
- <para>Thresholds ranges define the warning and critical levels for plugins to
- alert on. The theory is that the plugin will do some sort of check which returns
+ <section id="thresholdformat"><title>Threshold and ranges</title>
+ <para>A range is defined as a start and end point (inclusive) on a numeric scale (possibly
+ negative or positive infinity).
+ </para>
+ <para>A threshold is a range with an alert level (either warning or critical). Use the
+ set_thresholds(thresholds *, char *, char *) function to set the thresholds.
+ </para>
+ <para>The theory is that the plugin will do some sort of check which returns
back a numerical value, or metric, which is then compared to the warning and
- critical thresholds.
- This is the generalised format for threshold ranges:</para>
+ critical thresholds. Use the get_status(double, thresholds *) function to
+ compare the value against the thresholds.</para>
+ <para>This is the generalised format for ranges:</para>
<literallayout>
[@]start:end
<para>Notes:</para>
<orderedlist>
- <listitem><para>start > end</para>
+ <listitem><para>start ≤ end</para>
</listitem>
<listitem><para>start and ":" is not required if start=0</para>
</listitem>
</listitem>
</orderedlist>
- <para>Note: Not all plugins are coded to expect ranges in this format. It is
- planned for a future release to
- provide standard libraries to parse and compare metrics against ranges. There
- will also be some work in providing multiple metrics.</para>
+ <para>Note: Not all plugins are coded to expect ranges in this format yet.
+ There will be some work in providing multiple metrics.</para>
+
+ <table id="ExampleRanges"><title>Example ranges</title>
+ <tgroup cols="2">
+ <thead>
+ <row>
+ <entry><para>Range definition</para></entry>
+ <entry><para>Generate an alert if x...</para></entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>10</entry>
+ <entry>< 0 or > 10, (outside the range of {0 .. 10})</entry>
+ </row>
+ <row>
+ <entry>10:</entry>
+ <entry>< 10, (outside {10 .. ∞})</entry>
+ </row>
+ <row>
+ <entry>~:10</entry>
+ <entry>> 10, (outside the range of {-∞ .. 10})</entry>
+ </row>
+ <row>
+ <entry>10:20</entry>
+ <entry>< 10 or > 20, (outside the range of {10 .. 20})</entry>
+ </row>
+ <row>
+ <entry>@10:20</entry>
+ <entry>≥ 10 and ≤ 20, (inside the range of {10 .. 20})</entry>
+ </row>
+ <row>
+ <entry>10</entry>
+ <entry>< 0 or > 10, (outside the range of {0 .. 10})</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ <table id="CommandLineExamples"><title>Command line examples</title>
+ <tgroup cols="2">
+ <thead>
+ <row>
+ <entry><para>Command line</para></entry>
+ <entry><para>Meaning</para></entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>check_stuff -w10 -c20</entry>
+ <entry>Critical if "stuff" is over 20, else warn if over 10 (will be critical if "stuff" is less than 0)</entry>
+ </row>
+ <row>
+ <entry>check_stuff -w~:10 -c~:20</entry>
+ <entry>Same as above. Negative "stuff" is OK</entry>
+ </row>
+ <row>
+ <entry>check_stuff -w10: -c20</entry>
+ <entry>Critical if "stuff" is over 20, else warn if "stuff" is below 10 (will be critical if "stuff" is less than 0)</entry>
+ </row>
+ <row>
+ <entry>check_stuff -c1:</entry>
+ <entry>Critical if "stuff" is less than 1</entry>
+ </row>
+ <row>
+ <entry>check_stuff -w~:0 -c10</entry>
+ <entry>Critical if "stuff" is above 10; Warn if "stuff" is above zero</entry>
+ </row>
+ <row>
+ <entry>check_stuff -c5:6</entry>
+ <entry>The only noncritical range is 5:6</entry>
+ </row>
+ <row>
+ <entry>check_stuff -c10:20</entry>
+ <entry>Critical if "stuff" is less than 10 or over 20</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
</section>
<section><title>Performance data</title>
<orderedlist>
<listitem><para>space separated list of label/value pairs</para>
</listitem>
- <listitem><para>label can contain any characters</para>
+ <listitem><para>label can contain any characters except the equals sign or single quote (')</para>
</listitem>
<listitem><para>the single quotes for the label are optional. Required if
- spaces, = or ' are in the label</para>
+ spaces are in the label</para>
</listitem>
<listitem><para>label length is arbitrary, but ideally the first 19 characters
are unique (due to a limitation in RRD). Be aware of a limitation in the
</section>
<section><title>Translations</title>
- <para>If possible, use translation tools for all output. Currently, most of the core C plugins
- use gettext for translation. General guidelines are:</para>
-
- <orderedlist>
- <listitem><para>short help is not translated</para></listitem>
- <listitem><para>long help has options in English language, but text translated</para></listitem>
- <listitem><para>"Copyright" kept in English</para></listitem>
- <listitem><para>copyright holder names kept in original text</para></listitem>
- </orderedlist>
+ <para>If possible, use translation tools for all output to respect the user's language
+ settings. See <xref linkend="translationsdevelopers"> for guidelines
+ for the core plugins.
+ </para>
</section>
</section>
</section>
</section>
+<section id="Testcases"><title>Test cases</title>
+<para>
+Tests are the best way of knowing if the plugins work as expected. Please
+create and update test cases where possible.
+</para>
+
+<para>
+To run a test, from the top level directory, run "make test". This will run
+all the current tests and report an overall success rate.
+</para>
+
+<para>
+See the <ulink url="http://tinderbox.opsera.com">Nagios Plugins Tinderbox server</ulink>
+for the daily test results.
+</para>
+
+<section><title>Test cases for plugins</title>
+<para>These use perl's Test::More. To do a one time test, run "cd plugins && perl t/check_disk.t".
+</para>
+
+<para>There will somtimes be failures seen in this output which are known failures that
+need to be fixed. As long as the return code is 0, it will be reported as "test pass".
+(If you have a fix so that the specific test passes, that will be gratefully received!)
+</para>
+
+<para>
+If you want a summary test, run: "cd plugins && prove t/check_disk.t".
+This runs the test in a summary format.
+</para>
+
+<para>
+For a good and amusing tutorial on using Test::More, see this
+<ulink url="http://search.cpan.org/~mschwern/Test-Simple-0.62/lib/Test/Tutorial.pod">
+link</ulink>
+</para>
+
+</section>
+
+<section><title>Testing the C library functions</title>
+<para>
+We use <ulink url="http://jc.ngo.org.uk/trac-bin/trac.cgi/wiki/LibTap">the libtap library</ulink>, which gives
+perl's TAP
+(Test Anything Protocol) output. This is used by the FreeBSD team for their regression testing.
+</para>
+
+<para>
+To run tests using the libtap library, download the latest tar ball and extract.
+There is a problem with tap-1.01 where
+<ulink url="http://jc.ngo.org.uk/trac-bin/trac.cgi/ticket/25">pthread support doesn't appear to work</ulink>
+properly on non-FreeBSD systems. Install with 'CPPFLAGS="-UHAVE_LIBPTHREAD" ./configure && make && make check && make install'.
+</para>
+
+<para>
+When you run Nagios Plugins' configure, it will look for the tap library and will automatically
+setup the tests. Run "make test" to run all the tests.
+</para>
+</section>
+
+</section>
<section id="CodingGuidelines"><title>Coding guidelines</title>
<para>See <ulink url="http://www.gnu.org/prep/standards_toc.html">GNU
Coding standards</ulink> for general guidelines.</para>
- <section><title>Comments</title>
+ <section><title>C coding</title>
+
+ <para>Variables should be declared at the beginning of code blocks and
+ not inline because of portability with older compilers.</para>
+
<para>You should use /* */ for comments and not // as some compilers
do not handle the latter form.</para>
+
+ <para>You should also avoid using the type "bool" and its values
+ "true" and "false". Instead use the "int" type and the plugins' own
+ "TRUE"/"FALSE" values to keep the code uniformly.</para>
+ </section>
+
+ <section><title>Crediting sources</title>
<para>If you have copied a routine from another source, make sure the licence
from your source allows this. Add a comment referencing the ACKNOWLEDGEMENTS
file, where you can put more detail about the source.</para>
</para>
</section>
- <section><title>CVS comments</title>
- <para>When adding CVS comments at commit time, you can use the following prefixes:
- <variablelist>
- <varlistentry><term>- comment</term>
- <listitem>
- <para>for a comment that can be removed from the Changelog</para>
- </listitem>
- </varlistentry>
- <varlistentry><term>* comment</term>
- <listitem>
- <para>for an important amendment to be included into a features list</para>
- </listitem>
- </varlistentry>
- </variablelist>
- </para>
+ <section><title>Commit Messages</title>
<para>If the change is due to a contribution, please quote the contributor's name
and, if applicable, add the SourceForge Tracker number. Don't forget to
update the THANKS.in file.</para>
+ <para>If you have a change that is useful for noting in the next release, please
+ update the NEWS file.</para>
+ <para>All commits will be written to a ChangeLog at release time.
+ </para>
+ </section>
+
+ <section id="translationsdevelopers"><title>Translations for developers</title>
+ <para>To make the job easier for translators, please follow these guidelines:</para>
+ <orderedlist>
+ <listitem><para>
+ Before creating new strings, check the po/nagios-plugins.pot file to
+ see if a similar string
+ already exists
+ </para></listitem>
+ <listitem><para>
+ For help texts, break into individual options so that these can be reused
+ between plugins
+ </para></listitem>
+ <listitem><para>Try to avoid linefeeds unless you are working on a block of text</para></listitem>
+ <listitem><para>Short help is not translated</para></listitem>
+ <listitem><para>Long help has options in English language, but text translated</para></listitem>
+ <listitem><para>"Copyright" kept in English</para></listitem>
+ <listitem><para>Copyright holder names kept in original text</para></listitem>
+ <listitem><para>Debugging output does not need to be translated</para></listitem>
+ </orderedlist>
+ </section>
+
+ <section><title>Translations for translators</title>
+ <para>To create an up to date list of translatable strings, run: tools/gen_locale.sh</para>
</section>
+
</section>
<section id="SubmittingChanges"><title>Submission of new plugins and patches</title>
<section id="Patches"><title>Patches</title>
<para>If you have a bug patch, please supply a unified or context diff against the
version you are using. For new features, please supply a diff against
- the CVS HEAD version.</para>
+ the Git "master" branch.</para>
<para>Patches should be submitted via
<ulink url="http://sourceforge.net/tracker/?group_id=29880&atid=397599">SourceForge's
Credit will always be given for any patches through a THANKS file in the distribution.</para>
</section>
- <section id="Newplugins"><title>New plugins</title>
+ <section id="Contributedplugins"><title>Contributed plugins</title>
+ <para>Plugins that have been contributed to the project and
+ distributed with the Nagios Plugin files are held in the contrib/ directory and are not installed
+ by default. These plugins are not officially supported by the team.
+ The current policy is that these plugins should be owned and maintained by the original
+ contributor, preferably hosted on <ulink url="http://exchange.nagios.org">Nagios Exchange</ulink>.
+ </para>
+ <para>If patches or bugs are raised to an contributed plugin, we will start communications with the
+ original contributor, but seek to remove the plugin from our distribution.
+ </para>
+ <para>The aim is to distribute only code that the Nagios Plugin team are responsible for.
+ </para>
+ </section>
+
+ <section id="Newplugins"><title>New plugins</title>
<para>If you would like others to use your plugins, please add it to
the official 3rd party plugin repository,
- <ulink url="http://www.nagiosexchange.org">NagiosExchange</ulink>.
+ <ulink url="http://exchange.nagios.org">Nagios Exchange</ulink>.
</para>
<para>We are not accepting requests for inclusion of plugins into
</para>
<orderedlist>
+ <listitem>
+ <para>Include copyright and license information in all files. Copyright must be solely
+ granted to the Nagios Plugin Development Team</para>
+ </listitem>
<listitem>
<para>The standard command options are supported (--help, --version,
--timeout, --warning, --critical)</para>