doc/developer-guidelines.sgml

   1 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook V4.1//EN" >
   2 <book>
   3   <title>Nagios Plug-in Developer Guidelines</title>
   4
   5   <bookinfo>
   6     <authorgroup>
   7       <author>
   8         <affiliation>
   9           <orgname>Nagios Plugins Development Team</orgname>
  10         </affiliation>
  11       </author>
  12     </authorgroup>
  13
  14     <pubdate>2009</pubdate>
  15     <title>Nagios plug-in development guidelines</title>
  16
  17     <revhistory>
  18        <revision>
  19           <revnumber>1796</revnumber>
  20           <date>2007-09-24 14:51:07 -0400 (Mon, 24 Sep 2007)</date>
  21        </revision>
  22     </revhistory>
  23
  24         <copyright>
  25                 <year>2000 - 2009</year>
  26                 <holder>Nagios Plugins Development Team</holder>
  27         </copyright>
  28
  29 </bookinfo>
  30
  31
  32 <preface id="preface"><title>Preface</title>
  33     <para>The purpose of this guidelines is to provide a reference for
  34     the plug-in developers and encourage the standarization of the
  35     different kind of plug-ins: C, shell, perl, python, etc.</para>
  36
  37         <para>Nagios Plug-in Development Guidelines Copyright (C) 2000-2009
  38         (Nagios Plugins Team)</para>
  39
  40         <para>Permission is granted to make and distribute verbatim
  41         copies of this manual provided the copyright notice and this
  42         permission notice are preserved on all copies.</para>
  43
  44         <para>The plugins themselves are copyrighted by their respective
  45         authors.</para>
  46 </preface>
  47
  48 <article>
  49 <section id="DevRequirements"><title>Development platform requirements</title>
  50         <para>
  51         Nagios plugins are developed to the GNU standard, so any OS which is supported by GNU
  52         should run the plugins. While the requirements for compiling the Nagios plugins release
  53         are very basic, developing from the Git repository requires additional software to be
  54         installed. These are the minimum levels of software required:
  55
  56         <literallayout>
  57         GNU make 3.79
  58         GNU automake 1.9.2
  59         GNU autoconf 2.59
  60         GNU m4 1.4.2
  61         GNU libtool 1.5
  62         </literallayout>
  63
  64         To compile from Git, after you have cloned the repository, run:
  65         <literallayout>
  66         tools/setup
  67         ./configure
  68         make
  69         make install
  70         </literallayout>
  71         </para>
  72 </section>
  73
  74 <section id="PlugOutput"><title>Plugin Output for Nagios</title>
  75
  76                 <para>You should always print something to STDOUT that tells if the
  77                 service is working or why it is failing. Try to keep the output short -
  78                 probably less that 80 characters. Remember that you ideally would like
  79                 the entire output to appear in a pager message, which will get chopped
  80                 off after a certain length.</para>
  81
  82                 <para>As Nagios does not capture stderr output, you should only output to
  83                 STDOUT and not print to STDERR.</para>
  84
  85                 <section><title>Print only one line of text</title>
  86                 <para>Nagios will only grab the first line of text from STDOUT
  87                 when it notifies contacts about potential problems. If you print
  88                 multiple lines, you're out of luck (though this will be a feature of
  89                 Nagios 3). Remember, keep your output short and to the point.</para>
  90
  91                 <para>Output should be in the format:</para>
  92                 <literallayout>
  93                 SERVICE STATUS: Information text
  94                 </literallayout>
  95                 <para>However, note that this is not a requirement of the API, so you cannot depend on this
  96                 being an accurate reflection of the status of the service - the status should always
  97                 be determined by the return code.</para>
  98                 </section>
  99
 100                 <section><title>Verbose output</title>
 101                 <para>Use the -v flag for verbose output. You should allow multiple
 102                 -v options for additional verbosity, up to a maximum of 3. The standard
 103                 type of output should be:</para>
 104
 105                 <table id="verboselevels"><title>Verbose output levels</title>
 106                         <tgroup cols="2">
 107                                 <thead>
 108                                         <row>
 109                                                 <entry><para>Verbosity level</para></entry>
 110                                                 <entry><para>Type of output</para></entry>
 111                                         </row>
 112                                 </thead>
 113                                 <tbody>
 114                                         <row>
 115                                                 <entry align="center"><para>0</para></entry>
 116                                                 <entry><para>Single line, minimal output. Summary</para></entry>
 117                                         </row>
 118                                         <row>
 119                                                 <entry align="center"><para>1</para></entry>
 120                                                 <entry><para>Single line, additional information (eg list processes that fail)</para></entry>
 121                                         </row>
 122                                         <row>
 123                                                 <entry align="center"><para>2</para></entry>
 124                                                 <entry><para>Multi line, configuration debug output (eg ps command used)</para></entry>
 125                                         </row>
 126                                         <row>
 127                                                 <entry align="center"><para>3</para></entry>
 128                                                 <entry><para>Lots of detail for plugin problem diagnosis</para></entry>
 129                                         </row>
 130                                 </tbody>
 131                         </tgroup>
 132                 </table>
 133                 </section>
 134
 135                 <section><title>Screen Output</title>
 136                 <para>The plug-in should print the diagnostic and just the
 137                 usage part of the help message.  A well written plugin would
 138                 then have --help as a way to get the verbose help.</para>
 139
 140                 <para>Code and output should try to respect the 80x25 size of a
 141                 crt (remember when fixing stuff in the server room!)</para>
 142                 </section>
 143
 144                 <section><title>Plugin Return Codes</title>
 145                 <para>The return codes below are based on the POSIX spec of returning
 146                 a positive value.  Netsaint prior to v0.0.7 supported non-POSIX
 147                 compliant return code of "-1" for unknown.  Nagios supports POSIX return
 148                 codes by default.</para>
 149
 150                 <para>Note: Some plugins will on occasion print on STDOUT that an error
 151                 occurred and error code is 138 or 255 or some such number.  These
 152                 are usually caused by plugins using system commands and having not
 153                 enough checks to catch unexpected output.  Developers should include a
 154                 default catch-all for system command output that returns an UNKNOWN
 155                 return code.</para>
 156
 157                 <table id="ReturnCodes"><title>Plugin Return Codes</title>
 158                         <tgroup cols="3">
 159                                 <thead>
 160                                         <row>
 161                                                 <entry><para>Numeric Value</para></entry>
 162                                                 <entry><para>Service Status</para></entry>
 163                                                 <entry><para>Status Description</para></entry>
 164                                         </row>
 165                                 </thead>
 166                                 <tbody>
 167                                         <row>
 168                                                 <entry align="center"><para>0</para></entry>
 169                                                 <entry valign="middle"><para>OK</para></entry>
 170                                                 <entry><para>The plugin was able to check the service and it
 171                                                 appeared to be functioning properly</para></entry>
 172                                         </row>
 173                                         <row>
 174                                                 <entry align="center"><para>1</para></entry>
 175                                                 <entry valign="middle"><para>Warning</para></entry>
 176                                                 <entry><para>The plugin was able to check the service, but it
 177                                                 appeared to be above some "warning" threshold or did not appear
 178                                                 to be working properly</para></entry>
 179                                         </row>
 180                                         <row>
 181                                                 <entry align="center"><para>2</para></entry>
 182                                                 <entry valign="middle"><para>Critical</para></entry>
 183                                                 <entry><para>The plugin detected that either the service was not
 184                                                 running or it was above some "critical" threshold</para></entry>
 185                                         </row>
 186                                         <row>
 187                                                 <entry align="center"><para>3</para></entry>
 188                                                 <entry valign="middle"><para>Unknown</para></entry>
 189                                                 <entry><para>Invalid command line arguments were supplied to the
 190                                                 plugin or low-level failures internal to the plugin (such as unable to fork,
 191                                                 or open a tcp socket) that prevent it from performing the specified
 192                                                 operation. Higher-level errors (such as name resolution errors,
 193                                                 socket timeouts, etc) are outside of the control of plugins and should
 194                                                 generally NOT be reported as UNKNOWN states.
 195                                                 </para></entry>
 196                                         </row>
 197                                 </tbody>
 198                         </tgroup>
 199                 </table>
 200
 201
 202                 </section>
 203
 204                 <section id="thresholdformat"><title>Threshold and ranges</title>
 205                 <para>A range is defined as a start and end point (inclusive) on a numeric scale (possibly
 206                 negative or positive infinity).
 207                 </para>
 208                 <para>A threshold is a range with an alert level (either warning or critical). Use the
 209                 set_thresholds(thresholds *, char *, char *) function to set the thresholds.
 210                 </para>
 211                 <para>The theory is that the plugin will do some sort of check which returns
 212                 back a numerical value, or metric, which is then compared to the warning and
 213                 critical thresholds. Use the get_status(double, thresholds *) function to
 214                 compare the value against the thresholds.</para>
 215                 <para>This is the generalised format for ranges:</para>
 216
 217                 <literallayout>
 218                 [@]start:end
 219                 </literallayout>
 220
 221                 <para>Notes:</para>
 222                 <orderedlist>
 223                 <listitem><para>start &le; end</para>
 224                         </listitem>
 225                 <listitem><para>start and ":" is not required if start=0</para>
 226                         </listitem>
 227                 <listitem><para>if range is of format "start:" and end is not specified,
 228                         assume end is infinity</para>
 229                         </listitem>
 230                 <listitem><para>to specify negative infinity, use "~"</para>
 231                         </listitem>
 232                 <listitem><para>alert is raised if metric is outside start and end range
 233                         (inclusive of endpoints)</para>
 234                         </listitem>
 235                 <listitem><para>if range starts with "@", then alert if inside this range
 236                         (inclusive of endpoints)</para>
 237                         </listitem>
 238                 </orderedlist>
 239
 240                 <para>Note: Not all plugins are coded to expect ranges in this format yet.
 241                 There will be some work in providing multiple metrics.</para>
 242
 243                 <table id="ExampleRanges"><title>Example ranges</title>
 244                         <tgroup cols="2">
 245                                 <thead>
 246                                         <row>
 247                                                 <entry><para>Range definition</para></entry>
 248                                                 <entry><para>Generate an alert if x...</para></entry>
 249                                         </row>
 250                                 </thead>
 251                                 <tbody>
 252                                         <row>
 253                                                 <entry>10</entry>
 254                                                 <entry>&lt; 0 or &gt; 10, (outside the range of {0 .. 10})</entry>
 255                                         </row>
 256                                         <row>
 257                                                 <entry>10:</entry>
 258                                                 <entry>&lt; 10, (outside {10 .. &infin;})</entry>
 259                                         </row>
 260                                         <row>
 261                                                 <entry>~:10</entry>
 262                                                 <entry>&gt; 10, (outside the range of {-&infin; .. 10})</entry>
 263                                         </row>
 264                                         <row>
 265                                                 <entry>10:20</entry>
 266                                                 <entry>&lt; 10 or &gt; 20, (outside the range of {10 .. 20})</entry>
 267                                         </row>
 268                                         <row>
 269                                                 <entry>@10:20</entry>
 270                                                 <entry>&ge; 10 and &le; 20, (inside the range of {10 .. 20})</entry>
 271                                         </row>
 272                                         <row>
 273                                                 <entry>10</entry>
 274                                                 <entry>&lt; 0 or &gt; 10, (outside the range of {0 .. 10})</entry>
 275                                         </row>
 276                                 </tbody>
 277                         </tgroup>
 278                 </table>
 279                 <table id="CommandLineExamples"><title>Command line examples</title>
 280                         <tgroup cols="2">
 281                                 <thead>
 282                                         <row>
 283                                                 <entry><para>Command line</para></entry>
 284                                                 <entry><para>Meaning</para></entry>
 285                                         </row>
 286                                 </thead>
 287                                 <tbody>
 288                                         <row>
 289                                                 <entry>check_stuff -w10 -c20</entry>
 290                                                 <entry>Critical if "stuff" is over 20, else warn if over 10 (will be critical if "stuff" is less than 0)</entry>
 291                                         </row>
 292                                         <row>
 293                                                 <entry>check_stuff -w~:10 -c~:20</entry>
 294                                                 <entry>Same as above. Negative "stuff" is OK</entry>
 295                                         </row>
 296                                         <row>
 297                                                 <entry>check_stuff -w10: -c20</entry>
 298                                                 <entry>Critical if "stuff" is over 20, else warn if "stuff" is below 10 (will be critical if "stuff" is less than 0)</entry>
 299                                         </row>
 300                                         <row>
 301                                                 <entry>check_stuff -c1:</entry>
 302                                                 <entry>Critical if "stuff" is less than 1</entry>
 303                                         </row>
 304                                         <row>
 305                                                 <entry>check_stuff -w~:0 -c10</entry>
 306                                                 <entry>Critical if "stuff" is above 10; Warn if "stuff" is above zero</entry>
 307                                         </row>
 308                                         <row>
 309                                                 <entry>check_stuff -c5:6</entry>
 310                                                 <entry>The only noncritical range is 5:6</entry>
 311                                         </row>
 312                                         <row>
 313                                                 <entry>check_stuff -c10:20</entry>
 314                                                 <entry>Critical if "stuff" is 10 to 20</entry>
 315                                         </row>
 316                                 </tbody>
 317                         </tgroup>
 318                 </table>
 319                 </section>
 320
 321                 <section><title>Performance data</title>
 322                 <para>Performance data is defined by Nagios as "everything after the | of the plugin output" -
 323                 please refer to Nagios documentation for information on capturing this data to logfiles.
 324                 However, it is the responsibility of the plugin writer to ensure the
 325                 performance data is in a "Nagios plugins" format.
 326                 This is the expected format:</para>
 327
 328                 <literallayout>
 329                 'label'=value[UOM];[warn];[crit];[min];[max]
 330                 </literallayout>
 331
 332                 <para>Notes:</para>
 333                 <orderedlist>
 334                 <listitem><para>space separated list of label/value pairs</para>
 335                         </listitem>
 336                 <listitem><para>label can contain any characters except the equals sign or single quote (')</para>
 337                         </listitem>
 338                 <listitem><para>the single quotes for the label are optional. Required if
 339                         spaces are in the label</para>
 340                         </listitem>
 341                 <listitem><para>label length is arbitrary, but ideally the first 19 characters
 342                         are unique (due to a limitation in RRD). Be aware of a limitation in the
 343                         amount of data that NRPE returns to Nagios</para>
 344                         </listitem>
 345                 <listitem><para>to specify a quote character, use two single quotes</para>
 346                         </listitem>
 347                 <listitem><para>warn, crit, min or max may be null (for example, if the threshold is
 348                         not defined or min and max do not apply). Trailing unfilled semicolons can be
 349                         dropped</para>
 350                         </listitem>
 351                 <listitem><para>min and max are not required if UOM=%</para>
 352                         </listitem>
 353                 <listitem><para>value, min and max in class [-0-9.]. Must all be the
 354                         same UOM</para>
 355                         </listitem>
 356                 <listitem><para>warn and crit are in the range format (see
 357                         <xref linkend="thresholdformat">). Must be the same UOM</para>
 358                         </listitem>
 359                 <listitem><para>UOM (unit of measurement) is one of:</para>
 360                         <orderedlist>
 361                         <listitem><para>no unit specified - assume a number (int or float)
 362                                 of things (eg, users, processes, load averages)</para>
 363                                 </listitem>
 364                         <listitem><para>s - seconds (also us, ms)</para></listitem>
 365                         <listitem><para>% - percentage</para></listitem>
 366                         <listitem><para>B - bytes (also KB, MB, TB)</para></listitem>
 367                         <listitem><para>c - a continous counter (such as bytes
 368                                 transmitted on an interface)</para></listitem>
 369                         </orderedlist>
 370                         </listitem>
 371                 </orderedlist>
 372
 373                 <para>It is up to third party programs to convert the Nagios plugins
 374                 performance data into graphs.</para>
 375                 </section>
 376
 377         <section><title>Translations</title>
 378         <para>If possible, use translation tools for all output to respect the user's language
 379                 settings. See <xref linkend="translationsdevelopers"> for guidelines
 380                 for the core plugins.
 381         </para>
 382         </section>
 383 </section>
 384
 385 <section id="SysCmdAuxFiles"><title>System Commands and Auxiliary Files</title>
 386
 387                 <section><title>Don't execute system commands without specifying their
 388                 full path</title>
 389                 <para>Don't use exec(), popen(), etc. to execute external
 390                 commands without explicity using the full path of the external
 391                 program.</para>
 392
 393                 <para>Doing otherwise makes the plugin vulnerable to hijacking
 394                 by a trojan horse earlier in the search path. See the main
 395                 plugin distribution for examples on how this is done.</para>
 396                 </section>
 397
 398                 <section><title>Use spopen() if external commands must be executed</title>
 399
 400             <para>If you have to execute external commands from within your
 401         plugin and you're writing it in C, use the spopen() function
 402                 that Karl DeBisschop has written.</para>
 403
 404                 <para>The code for spopen() and spclose() is included with the
 405                 core plugin distribution.</para>
 406                 </section>
 407
 408                 <section><title>Don't make temp files unless absolutely required</title>
 409
 410                 <para>If temp files are needed, make sure that the plugin will
 411                 fail cleanly if the file can't be written (e.g., too few file
 412                 handles, out of disk space, incorrect permissions, etc.) and
 413                 delete the temp file when processing is complete.</para>
 414                 </section>
 415
 416         <section><title>Don't be tricked into following symlinks</title>
 417
 418                 <para>If your plugin opens any files, take steps to ensure that
 419                 you are not following a symlink to another location on the
 420                 system.</para>
 421                 </section>
 422
 423                 <section><title>Validate all input</title>
 424
 425                 <para>use routines in utils.c or utils.pm and write more as needed</para>
 426                 </section>
 427
 428 </section>
 429
 430
 431
 432
 433 <section id="PerlPlugin"><title>Perl Plugins</title>
 434
 435                 <para>Perl plugins are coded a little more defensively than other
 436                 plugins because of embedded Perl.  When configured as such, embedded
 437                 Perl Nagios (ePN) requires stricter use of the some of Perl's features.
 438                 This section outlines some of the steps needed to use ePN
 439                 effectively.</para>
 440
 441                 <orderedlist>
 442
 443                         <listitem><para> Do not use BEGIN and END blocks since they will be called
 444                         only once (when Nagios starts and shuts down) with Embedded Perl (ePN).  In
 445                         particular, do not use BEGIN blocks to initialize variables.</para>
 446                         </listitem>
 447
 448                         <listitem><para>To use utils.pm, you need to provide a full path to the
 449                         module in order for it to work.</para>
 450
 451           <literallayout>
 452           e.g.
 453                 use lib "/usr/local/nagios/libexec";
 454                 use utils qw(...);
 455           </literallayout>
 456                         </listitem>
 457
 458                         <listitem><para>Perl scripts should be called with "-w"</para>
 459                         </listitem>
 460
 461                         <listitem><para>All Perl plugins must compile cleanly under "use strict" - i.e. at
 462                         least explicitly package names as in "$main::x" or predeclare every
 463                         variable. </para>
 464
 465
 466                         <para>Explicitly initialize each variable in use.  Otherwise with
 467                         caching enabled, the plugin will not be recompiled each time, and
 468                         therefore Perl will not reinitialize all the variables.  All old
 469                         variable values will still be in effect.</para>
 470                         </listitem>
 471
 472                         <listitem><para>Do not use &gt;DATA&lt; handles (these simply do not compile under ePN).</para>
 473                         </listitem>
 474
 475                         <listitem><para>Do not use global variables in named subroutines. This is bad practise anyway, but with ePN the
 476                         compiler will report an error "&lt;global_var&gt; will not stay shared ..". Values used by
 477                         subroutines should be passed in the argument list.</para>
 478                         </listitem>
 479
 480                         <listitem><para>If writing to a file (perhaps recording
 481                         performance data) explicitly close close it.  The plugin never
 482                         calls <emphasis role="strong">exit</emphasis>; that is caught by
 483                         p1.pl, so output streams are never closed.</para>
 484                         </listitem>
 485
 486                         <listitem><para>As in <xref linkend="runtime"> all plugins need
 487                         to monitor their runtime, specially if they are using network
 488                         resources.  Use of the <emphasis>alarm</emphasis> is recommended
 489                         noting that some Perl modules (eg LWP) manage timers, so that an alarm
 490                         set by a plugin using such a module is overwritten by the module.
 491                         (workarounds are cunning (TM) or using the module timer)
 492                         Plugins may import a default time out ($TIMEOUT) from utils.pm.
 493                         </para>
 494                         </listitem>
 495
 496                         <listitem><para>Perl plugins should import %ERRORS from utils.pm
 497                         and then "exit $ERRORS{'OK'}" rather than "exit 0"
 498                         </para>
 499                         </listitem>
 500
 501                 </orderedlist>
 502
 503 </section>
 504
 505 <section id="runtime"><title>Runtime Timeouts</title>
 506
 507                 <para>Plugins have a very limited runtime - typically 10 sec.
 508                 As a result, it is very important for plugins to maintain internal
 509                 code to exit if runtime exceeds a threshold. </para>
 510
 511                 <para>All plugins should timeout gracefully, not just networking
 512                 plugins. For instance, df may lock if you have automounted
 513                 drives and your network fails - but on first glance, who'd think
 514                 df could lock up like that.  Plus, it should just be more error
 515                 resistant to be able to time out rather than consume
 516                 resources.</para>
 517
 518                 <section><title>Use DEFAULT_SOCKET_TIMEOUT</title>
 519
 520                 <para>All network plugins should use DEFAULT_SOCKET_TIMEOUT to timeout</para>
 521
 522                 </section>
 523
 524
 525                 <section><title>Add alarms to network plugins</title>
 526
 527                 <para>If you write a plugin which communicates with another
 528                 networked host, you should make sure to set an alarm() in your
 529                 code that prevents the plugin from hanging due to abnormal
 530                 socket closures, etc. Nagios takes steps to protect itself
 531                 against unruly plugins that timeout, but any plugins you create
 532                 should be well behaved on their own.</para>
 533
 534                 </section>
 535
 536
 537
 538 </section>
 539
 540 <section id="PlugOptions"><title>Plugin Options</title>
 541
 542                 <para>A well written plugin should have --help as a way to get
 543                 verbose help. Code and output should try to respect the 80x25 size of a
 544                 crt (remember when fixing stuff in the server room!)</para>
 545
 546                 <section><title>Option Processing</title>
 547
 548                 <para>For plugins written in C, we recommend the C standard
 549                 getopt library for short options. Getopt_long is always available.
 550                 </para>
 551
 552                 <para>For plugins written in Perl, we recommend Getopt::Long module.</para>
 553
 554                 <para>Positional arguments are strongly discouraged.</para>
 555
 556                 <para>There are a few reserved options that should not be used
 557                 for other purposes:</para>
 558
 559                 <literallayout>
 560           -V version (--version)
 561           -h help (--help)
 562           -t timeout (--timeout)
 563           -w warning threshold (--warning)
 564           -c critical threshold (--critical)
 565           -H hostname (--hostname)
 566           -v verbose (--verbose)
 567                 </literallayout>
 568
 569                 <para>In addition to the reserved options above, some other standard options are:</para>
 570
 571                 <literallayout>
 572           -C SNMP community (--community)
 573           -a authentication password (--authentication)
 574           -l login name (--logname)
 575           -p port or password (--port or --passwd/--password)monitors operational
 576           -u url or username (--url or --username)
 577                 </literallayout>
 578
 579                 <para>Look at check_pgsql and check_procs to see how I currently
 580                 think this can work.  Standard options are:</para>
 581
 582
 583                 <para>The option -V or --version should be present in all
 584                 plugins. For C plugins it should result in a call to print_revision, a
 585                 function in utils.c which takes two character arguments, the
 586                 command name and the plugin revision.</para>
 587
 588                 <para>The -? option, or any other unparsable set of options,
 589                 should print out a short usage statement. Character width should
 590                 be 80 and less and no more that 23 lines should be printed (it
 591                 should display cleanly on a dumb terminal in a server
 592                 room).</para>
 593
 594                 <para>The option -h or --help should be present in all plugins.
 595                 In C plugins, it should result in a call to print_help (or
 596                 equivalent).  The function print_help should call print_revision,
 597                 then print_usage, then should provide detailed
 598                 help. Help text should fit on an 80-character width display, but
 599                 may run as many lines as needed.</para>
 600
 601                 <para>The option -v or --verbose should be present in all plugins.
 602                 The user should be allowed to specify -v multiple times to increase
 603                 the verbosity level, as described in <xref linkend="verboselevels">.</para>
 604     </section>
 605
 606     <section>
 607       <title>Plugins with more than one type of threshold, or with
 608       threshold ranges</title>
 609
 610       <para>Old style was to do things like -ct for critical time and
 611       -cv for critical value. That goes out the window with POSIX
 612       getopt. The allowable alternatives are:</para>
 613
 614       <orderedlist>
 615         <listitem>
 616           <para>long options like -critical-time (or -ct and -cv, I
 617           suppose).</para>
 618         </listitem>
 619
 620         <listitem>
 621           <para>repeated options like `check_load -w 10 -w 6 -w 4 -c
 622           16 -c 10 -c 10`</para>
 623         </listitem>
 624
 625         <listitem>
 626           <para>for brevity, the above can be expressed as `check_load
 627           -w 10,6,4 -c 16,10,10`</para>
 628         </listitem>
 629
 630         <listitem>
 631           <para>ranges are expressed with colons as in `check_procs -C
 632           httpd -w 1:20 -c 1:30` which will warn above 20 instances,
 633           and critical at 0 and above 30</para>
 634         </listitem>
 635
 636         <listitem>
 637           <para>lists are expressed with commas, so Jacob's check_nmap
 638           uses constructs like '-p 1000,1010,1050:1060,2000'</para>
 639         </listitem>
 640
 641         <listitem>
 642           <para>If possible when writing lists, use tokens to make the
 643           list easy to remember and non-order dependent - so
 644           check_disk uses '-c 10000,10%' so that it is clear which is
 645           the precentage and which is the KB values (note that due to
 646           my own lack of foresight, that used to be '-c 10000:10%' but
 647           such constructs should all be changed for consistency,
 648           though providing reverse compatibility is fairly
 649           easy).</para>
 650         </listitem>
 651
 652       </orderedlist>
 653
 654       <para>As always, comments are welcome - making this consistent
 655       without a host of long options was quite a hassle, and I would
 656       suspect that there are flaws in this strategy.
 657       </para>
 658     </section>
 659 </section>
 660
 661 <section id="Testcases"><title>Test cases</title>
 662 <para>
 663 Tests are the best way of knowing if the plugins work as expected. Please
 664 create and update test cases where possible.
 665 </para>
 666
 667 <para>
 668 To run a test, from the top level directory, run "make test". This will run
 669 all the current tests and report an overall success rate.
 670 </para>
 671
 672 <para>
 673 See the <ulink url="http://tinderbox.opsera.com">Nagios Plugins Tinderbox server</ulink>
 674 for the daily test results.
 675 </para>
 676
 677 <section><title>Test cases for plugins</title>
 678 <para>These use perl's Test::More. To do a one time test, run "cd plugins && perl t/check_disk.t".
 679 </para>
 680
 681 <para>There will somtimes be failures seen in this output which are known failures that
 682 need to be fixed. As long as the return code is 0, it will be reported as "test pass".
 683 (If you have a fix so that the specific test passes, that will be gratefully received!)
 684 </para>
 685
 686 <para>
 687 If you want a summary test, run: "cd plugins && prove t/check_disk.t".
 688 This runs the test in a summary format.
 689 </para>
 690
 691 <para>
 692 For a good and amusing tutorial on using Test::More, see this
 693 <ulink url="http://search.cpan.org/~mschwern/Test-Simple-0.62/lib/Test/Tutorial.pod">
 694 link</ulink>
 695 </para>
 696
 697 </section>
 698
 699 <section><title>Testing the C library functions</title>
 700 <para>
 701 We use <ulink url="http://jc.ngo.org.uk/trac-bin/trac.cgi/wiki/LibTap">the libtap library</ulink>, which gives
 702 perl's TAP
 703 (Test Anything Protocol) output. This is used by the FreeBSD team for their regression testing.
 704 </para>
 705
 706 <para>
 707 To run tests using the libtap library, download the latest tar ball and extract.
 708 There is a problem with tap-1.01 where
 709 <ulink url="http://jc.ngo.org.uk/trac-bin/trac.cgi/ticket/25">pthread support doesn't appear to work</ulink>
 710 properly on non-FreeBSD systems. Install with 'CPPFLAGS="-UHAVE_LIBPTHREAD" ./configure && make && make check && make install'.
 711 </para>
 712
 713 <para>
 714 When you run Nagios Plugins' configure, it will look for the tap library and will automatically
 715 setup the tests. Run "make test" to run all the tests.
 716 </para>
 717 </section>
 718
 719 </section>
 720 <section id="CodingGuidelines"><title>Coding guidelines</title>
 721         <para>See <ulink url="http://www.gnu.org/prep/standards_toc.html">GNU
 722         Coding standards</ulink> for general guidelines.</para>
 723         <section><title>C coding</title>
 724
 725         <para>Variables should be declared at the beginning of code blocks and
 726         not inline because of portability with older compilers.</para>
 727
 728         <para>You should use /* */ for comments and not // as some compilers
 729         do not handle the latter form.</para>
 730
 731         <para>You should also avoid using the type "bool" and its values
 732         "true" and "false". Instead use the "int" type and the plugins' own
 733         "TRUE"/"FALSE" values to keep the code uniformly.</para>
 734         </section>
 735
 736         <section><title>Crediting sources</title>
 737         <para>If you have copied a routine from another source, make sure the licence
 738         from your source allows this. Add a comment referencing the ACKNOWLEDGEMENTS
 739         file, where you can put more detail about the source.</para>
 740         <para>For contributed code, do not add any named credits in the source code
 741         - contributors should be added into the THANKS.in file instead.
 742         </para>
 743         </section>
 744
 745         <section><title>CVS comments</title>
 746         <para>If the change is due to a contribution, please quote the contributor's name
 747         and, if applicable, add the SourceForge Tracker number. Don't forget to
 748 update the THANKS.in file.</para>
 749         <para>If you have a change that is useful for noting in the next release, please
 750         update the NEWS file.</para>
 751         <para>All commit comments will be written to a ChangeLog at release time.
 752         </para>
 753         </section>
 754
 755         <section id="translationsdevelopers"><title>Translations for developers</title>
 756         <para>To make the job easier for translators, please follow these guidelines:</para>
 757         <orderedlist>
 758           <listitem><para>
 759             Before creating new strings, check the po/nagios-plugins.pot file to
 760             see if a similar string
 761             already exists
 762           </para></listitem>
 763           <listitem><para>
 764             For help texts, break into individual options so that these can be reused
 765             between plugins
 766           </para></listitem>
 767           <listitem><para>Try to avoid linefeeds unless you are working on a block of text</para></listitem>
 768           <listitem><para>Short help is not translated</para></listitem>
 769           <listitem><para>Long help has options in English language, but text translated</para></listitem>
 770           <listitem><para>"Copyright" kept in English</para></listitem>
 771           <listitem><para>Copyright holder names kept in original text</para></listitem>
 772           <listitem><para>Debugging output does not need to be translated</para></listitem>
 773         </orderedlist>
 774         </section>
 775
 776         <section><title>Translations for translators</title>
 777         <para>To create an up to date list of translatable strings, run: tools/gen_locale.sh</para>
 778         </section>
 779
 780 </section>
 781
 782 <section id="SubmittingChanges"><title>Submission of new plugins and patches</title>
 783
 784         <section id="Patches"><title>Patches</title>
 785         <para>If you have a bug patch, please supply a unified or context diff against the
 786         version you are using. For new features, please supply a diff against
 787         the Git "master" branch.</para>
 788
 789         <para>Patches should be submitted via
 790         <ulink url="http://sourceforge.net/tracker/?group_id=29880&amp;atid=397599">SourceForge's
 791         tracker system for Nagiosplug patches</ulink>
 792         and be announced to the nagiosplug-devel mailing list.</para>
 793
 794         <para>Submission of a patch implies that the submmitter acknowledges that they
 795         are the author of the code (or have permission from the author to release the code)
 796         and agree that the code can be released under the GPL. The copyright for the changes will
 797         then revert to the Nagios Plugin Development Team - this is required so that any copyright
 798         infringements can be investigated quickly without contacting a huge list of copyright holders.
 799         Credit will always be given for any patches through a THANKS file in the distribution.</para>
 800         </section>
 801
 802
 803         <section id="Contributedplugins"><title>Contributed plugins</title>
 804         <para>Plugins that have been contributed to the project and
 805         distributed with the Nagios Plugin files are held in the contrib/ directory and are not installed
 806         by default. These plugins are not officially supported by the team.
 807         The current policy is that these plugins should be owned and maintained by the original
 808         contributor, preferably hosted on <ulink url="http://exchange.nagios.org">Nagios Exchange</ulink>.
 809         </para>
 810         <para>If patches or bugs are raised to an contributed plugin, we will start communications with the
 811         original contributor, but seek to remove the plugin from our distribution.
 812         </para>
 813         <para>The aim is to distribute only code that the Nagios Plugin team are responsible for.
 814         </para>
 815         </section>
 816
 817         <section id="Newplugins"><title>New plugins</title>
 818         <para>If you would like others to use your plugins, please add it to
 819         the official 3rd party plugin repository,
 820         <ulink url="http://exchange.nagios.org">Nagios Exchange</ulink>.
 821         </para>
 822
 823         <para>We are not accepting requests for inclusion of plugins into
 824         our distribution at the moment, but when we do, these are the minimum
 825         requirements:
 826         </para>
 827
 828       <orderedlist>
 829         <listitem>
 830           <para>Include copyright and license information in all files. Copyright must be solely
 831                 granted to the Nagios Plugin Development Team</para>
 832         </listitem>
 833         <listitem>
 834           <para>The standard command options are supported (--help, --version,
 835           --timeout, --warning, --critical)</para>
 836         </listitem>
 837         <listitem>
 838           <para>It is determined to be not redundant (for instance, we would not
 839                 add a new version of check_disk just because someone had provide
 840                 a plugin that had perf checking - we would incorporate the features
 841                 into an exisiting plugin)</para>
 842         </listitem>
 843         <listitem>
 844           <para>One of the developers has had the time to audit the code and declare
 845                 it ready for core</para>
 846         </listitem>
 847         <listitem>
 848           <para>It should also follow code format guidelines, and use functions from
 849 utils (perl or c or sh) rather than using its own</para>
 850         </listitem>
 851         <listitem>
 852           <para>Includes patches to configure.in if required (via the EXTRAS list if
 853           it will only work on some platforms)</para>
 854         </listitem>
 855         <listitem>
 856           <para>If possible, please submit a test harness. Documentation on sample
 857           tests coming soon</para>
 858         </listitem>
 859       </orderedlist>
 860
 861         </section>
 862
 863 </section>
 864 </article>
 865
 866 </book>