doc/developer-guidelines.sgml

   1 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook V4.1//EN" >
   2 <book>
   3   <title>Nagios Plugin Development 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>2013</pubdate>
  15     <title>Nagios Plugin 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 - 2013</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 plugin developers and encourage the standarization of the
  35     different kind of plugins: C, shell, perl, python, etc.</para>
  36
  37         <para>Nagios Plugin Development Guidelines Copyright (C) 2000-2013
  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>Starting with version 3, Nagios will process plugins' multiline
  87                 output, which should be formatted as:</para>
  88                 <literallayout>
  89                 SERVICE STATUS: First line of output | First part of performance data
  90                 Any number of subsequent lines of output, but note that buffers
  91                 may have a limited size | Second part of performance data, which
  92                 may have continuation lines, too
  93                 </literallayout>
  94                 <para>Note, however, that the default configs still do not include
  95                 the output's continuation lines into the notifications sent when
  96                 Nagios notifies contacts about potential problems.
  97                 Thus, keep your output short and to the point.</para>
  98
  99                 <para>Output should be in the format:</para>
 100                 <literallayout>
 101                 SERVICE STATUS: Information text
 102                 </literallayout>
 103                 <para>However, note that this is not a requirement of the API, so you cannot depend on this
 104                 being an accurate reflection of the status of the service - the status should always
 105                 be determined by the return code.</para>
 106                 </section>
 107
 108                 <section><title>Verbose output</title>
 109                 <para>Use the -v flag for verbose output. You should allow multiple
 110                 -v options for additional verbosity, up to a maximum of 3. The standard
 111                 type of output should be:</para>
 112
 113                 <table id="verboselevels"><title>Verbose output levels</title>
 114                         <tgroup cols="2">
 115                                 <thead>
 116                                         <row>
 117                                                 <entry><para>Verbosity level</para></entry>
 118                                                 <entry><para>Type of output</para></entry>
 119                                         </row>
 120                                 </thead>
 121                                 <tbody>
 122                                         <row>
 123                                                 <entry align="center"><para>0</para></entry>
 124                                                 <entry><para>Single line, minimal output. Summary</para></entry>
 125                                         </row>
 126                                         <row>
 127                                                 <entry align="center"><para>1</para></entry>
 128                                                 <entry><para>Single line, additional information (eg list processes that fail)</para></entry>
 129                                         </row>
 130                                         <row>
 131                                                 <entry align="center"><para>2</para></entry>
 132                                                 <entry><para>Multi line, configuration debug output (eg ps command used)</para></entry>
 133                                         </row>
 134                                         <row>
 135                                                 <entry align="center"><para>3</para></entry>
 136                                                 <entry><para>Lots of detail for plugin problem diagnosis</para></entry>
 137                                         </row>
 138                                 </tbody>
 139                         </tgroup>
 140                 </table>
 141                 </section>
 142
 143                 <section><title>Screen Output</title>
 144                 <para>The plugin should print the diagnostic and just the
 145                 usage part of the help message.  A well written plugin would
 146                 then have --help as a way to get the verbose help.</para>
 147
 148                 <para>Code and output should try to respect the 80x25 size of a
 149                 crt (remember when fixing stuff in the server room!)</para>
 150                 </section>
 151
 152                 <section><title>Plugin Return Codes</title>
 153                 <para>The return codes below are based on the POSIX spec of returning
 154                 a positive value.  Netsaint prior to v0.0.7 supported non-POSIX
 155                 compliant return code of "-1" for unknown.  Nagios supports POSIX return
 156                 codes by default.</para>
 157
 158                 <para>Note: Some plugins will on occasion print on STDOUT that an error
 159                 occurred and error code is 138 or 255 or some such number.  These
 160                 are usually caused by plugins using system commands and having not
 161                 enough checks to catch unexpected output.  Developers should include a
 162                 default catch-all for system command output that returns an UNKNOWN
 163                 return code.</para>
 164
 165                 <table id="ReturnCodes"><title>Plugin Return Codes</title>
 166                         <tgroup cols="3">
 167                                 <thead>
 168                                         <row>
 169                                                 <entry><para>Numeric Value</para></entry>
 170                                                 <entry><para>Service Status</para></entry>
 171                                                 <entry><para>Status Description</para></entry>
 172                                         </row>
 173                                 </thead>
 174                                 <tbody>
 175                                         <row>
 176                                                 <entry align="center"><para>0</para></entry>
 177                                                 <entry valign="middle"><para>OK</para></entry>
 178                                                 <entry><para>The plugin was able to check the service and it
 179                                                 appeared to be functioning properly</para></entry>
 180                                         </row>
 181                                         <row>
 182                                                 <entry align="center"><para>1</para></entry>
 183                                                 <entry valign="middle"><para>Warning</para></entry>
 184                                                 <entry><para>The plugin was able to check the service, but it
 185                                                 appeared to be above some "warning" threshold or did not appear
 186                                                 to be working properly</para></entry>
 187                                         </row>
 188                                         <row>
 189                                                 <entry align="center"><para>2</para></entry>
 190                                                 <entry valign="middle"><para>Critical</para></entry>
 191                                                 <entry><para>The plugin detected that either the service was not
 192                                                 running or it was above some "critical" threshold</para></entry>
 193                                         </row>
 194                                         <row>
 195                                                 <entry align="center"><para>3</para></entry>
 196                                                 <entry valign="middle"><para>Unknown</para></entry>
 197                                                 <entry><para>Invalid command line arguments were supplied to the
 198                                                 plugin or low-level failures internal to the plugin (such as unable to fork,
 199                                                 or open a tcp socket) that prevent it from performing the specified
 200                                                 operation. Higher-level errors (such as name resolution errors,
 201                                                 socket timeouts, etc) are outside of the control of plugins and should
 202                                                 generally NOT be reported as UNKNOWN states.
 203                                                 </para></entry>
 204                                         </row>
 205                                 </tbody>
 206                         </tgroup>
 207                 </table>
 208
 209
 210                 </section>
 211
 212                 <section id="thresholdformat"><title>Threshold and ranges</title>
 213                 <para>A range is defined as a start and end point (inclusive) on a numeric scale (possibly
 214                 negative or positive infinity).
 215                 </para>
 216                 <para>A threshold is a range with an alert level (either warning or critical). Use the
 217                 set_thresholds(thresholds *, char *, char *) function to set the thresholds.
 218                 </para>
 219                 <para>The theory is that the plugin will do some sort of check which returns
 220                 back a numerical value, or metric, which is then compared to the warning and
 221                 critical thresholds. Use the get_status(double, thresholds *) function to
 222                 compare the value against the thresholds.</para>
 223                 <para>This is the generalised format for ranges:</para>
 224
 225                 <literallayout>
 226                 [@]start:end
 227                 </literallayout>
 228
 229                 <para>Notes:</para>
 230                 <orderedlist>
 231                 <listitem><para>start &le; end</para>
 232                         </listitem>
 233                 <listitem><para>start and ":" is not required if start=0</para>
 234                         </listitem>
 235                 <listitem><para>if range is of format "start:" and end is not specified,
 236                         assume end is infinity</para>
 237                         </listitem>
 238                 <listitem><para>to specify negative infinity, use "~"</para>
 239                         </listitem>
 240                 <listitem><para>alert is raised if metric is outside start and end range
 241                         (inclusive of endpoints)</para>
 242                         </listitem>
 243                 <listitem><para>if range starts with "@", then alert if inside this range
 244                         (inclusive of endpoints)</para>
 245                         </listitem>
 246                 </orderedlist>
 247
 248                 <para>Note: Not all plugins are coded to expect ranges in this format yet.
 249                 There will be some work in providing multiple metrics.</para>
 250
 251                 <table id="ExampleRanges"><title>Example ranges</title>
 252                         <tgroup cols="2">
 253                                 <thead>
 254                                         <row>
 255                                                 <entry><para>Range definition</para></entry>
 256                                                 <entry><para>Generate an alert if x...</para></entry>
 257                                         </row>
 258                                 </thead>
 259                                 <tbody>
 260                                         <row>
 261                                                 <entry>10</entry>
 262                                                 <entry>&lt; 0 or &gt; 10, (outside the range of {0 .. 10})</entry>
 263                                         </row>
 264                                         <row>
 265                                                 <entry>10:</entry>
 266                                                 <entry>&lt; 10, (outside {10 .. &infin;})</entry>
 267                                         </row>
 268                                         <row>
 269                                                 <entry>~:10</entry>
 270                                                 <entry>&gt; 10, (outside the range of {-&infin; .. 10})</entry>
 271                                         </row>
 272                                         <row>
 273                                                 <entry>10:20</entry>
 274                                                 <entry>&lt; 10 or &gt; 20, (outside the range of {10 .. 20})</entry>
 275                                         </row>
 276                                         <row>
 277                                                 <entry>@10:20</entry>
 278                                                 <entry>&ge; 10 and &le; 20, (inside the range of {10 .. 20})</entry>
 279                                         </row>
 280                                 </tbody>
 281                         </tgroup>
 282                 </table>
 283                 <table id="CommandLineExamples"><title>Command line examples</title>
 284                         <tgroup cols="2">
 285                                 <thead>
 286                                         <row>
 287                                                 <entry><para>Command line</para></entry>
 288                                                 <entry><para>Meaning</para></entry>
 289                                         </row>
 290                                 </thead>
 291                                 <tbody>
 292                                         <row>
 293                                                 <entry>check_stuff -w10 -c20</entry>
 294                                                 <entry>Critical if "stuff" is over 20, else warn if over 10 (will be critical if "stuff" is less than 0)</entry>
 295                                         </row>
 296                                         <row>
 297                                                 <entry>check_stuff -w~:10 -c~:20</entry>
 298                                                 <entry>Same as above. Negative "stuff" is OK</entry>
 299                                         </row>
 300                                         <row>
 301                                                 <entry>check_stuff -w10: -c20</entry>
 302                                                 <entry>Critical if "stuff" is over 20, else warn if "stuff" is below 10 (will be critical if "stuff" is less than 0)</entry>
 303                                         </row>
 304                                         <row>
 305                                                 <entry>check_stuff -c1:</entry>
 306                                                 <entry>Critical if "stuff" is less than 1</entry>
 307                                         </row>
 308                                         <row>
 309                                                 <entry>check_stuff -w~:0 -c10</entry>
 310                                                 <entry>Critical if "stuff" is above 10; Warn if "stuff" is above zero (will be critical if "stuff" is less than 0)</entry>
 311                                         </row>
 312                                         <row>
 313                                                 <entry>check_stuff -c5:6</entry>
 314                                                 <entry>Critical if "stuff" is less than 5 or more than 6</entry>
 315                                         </row>
 316                                         <row>
 317                                                 <entry>check_stuff -c@10:20</entry>
 318                                                 <entry>OK if stuff is less than 10 or higher than 20, otherwise critical </entry>
 319                                         </row>
 320                                 </tbody>
 321                         </tgroup>
 322                 </table>
 323                 </section>
 324
 325                 <section><title>Performance data</title>
 326                 <para>Nagios 3 and newer will concatenate the parts following a "|" in a) the first
 327                 line output by the plugin, and b) in the second to last line, into a string it
 328                 passes to whatever performance data processing it has configured. (Note that it
 329                 currently does not insert additional whitespace between both, so the plugin needs
 330                 to provide some to prevent the last pair of a) and the first of b) getting run
 331                 together.) Please refer to the Nagios documentation for information on how to
 332                 configure such processing. However, it is the responsibility of the plugin writer
 333                 to ensure the performance data is in a "Nagios Plugins" format.
 334                 This is the expected format:</para>
 335
 336                 <literallayout>
 337                 'label'=value[UOM];[warn];[crit];[min];[max]
 338                 </literallayout>
 339
 340                 <para>Notes:</para>
 341                 <orderedlist>
 342                 <listitem><para>space separated list of label/value pairs</para>
 343                         </listitem>
 344                 <listitem><para>label can contain any characters except the equals sign or single quote (')</para>
 345                         </listitem>
 346                 <listitem><para>the single quotes for the label are optional. Required if
 347                         spaces are in the label</para>
 348                         </listitem>
 349                 <listitem><para>label length is arbitrary, but ideally the first 19 characters
 350                         are unique (due to a limitation in RRD). Be aware of a limitation in the
 351                         amount of data that NRPE returns to Nagios</para>
 352                         </listitem>
 353                 <listitem><para>to specify a quote character, use two single quotes</para>
 354                         </listitem>
 355                 <listitem><para>warn, crit, min or max may be null (for example, if the threshold is
 356                         not defined or min and max do not apply). Trailing unfilled semicolons can be
 357                         dropped</para>
 358                         </listitem>
 359                 <listitem><para>min and max are not required if UOM=%</para>
 360                         </listitem>
 361                 <listitem><para>value, min and max in class [-0-9.]. Must all be the
 362                         same UOM. value may be a literal "U" instead, this would indicate that the
 363                         actual value couldn't be determined</para>
 364                         </listitem>
 365                 <listitem><para>warn and crit are in the range format (see
 366                         <xref linkend="thresholdformat">). Must be the same UOM</para>
 367                         </listitem>
 368                 <listitem><para>UOM (unit of measurement) is one of:</para>
 369                         <orderedlist>
 370                         <listitem><para>no unit specified - assume a number (int or float)
 371                                 of things (eg, users, processes, load averages)</para>
 372                                 </listitem>
 373                         <listitem><para>s - seconds (also us, ms)</para></listitem>
 374                         <listitem><para>% - percentage</para></listitem>
 375                         <listitem><para>B - bytes (also KB, MB, TB)</para></listitem>
 376                         <listitem><para>c - a continous counter (such as bytes
 377                                 transmitted on an interface)</para></listitem>
 378                         </orderedlist>
 379                         </listitem>
 380                 </orderedlist>
 381
 382                 <para>It is up to third party programs to convert the Nagios Plugins
 383                 performance data into graphs.</para>
 384                 </section>
 385
 386         <section><title>Translations</title>
 387         <para>If possible, use translation tools for all output to respect the user's language
 388                 settings. See <xref linkend="translationsdevelopers"> for guidelines
 389                 for the core plugins.
 390         </para>
 391         </section>
 392 </section>
 393
 394 <section id="SysCmdAuxFiles"><title>System Commands and Auxiliary Files</title>
 395
 396                 <section><title>Don't execute system commands without specifying their
 397                 full path</title>
 398                 <para>Don't use exec(), popen(), etc. to execute external
 399                 commands without explicity using the full path of the external
 400                 program.</para>
 401
 402                 <para>Doing otherwise makes the plugin vulnerable to hijacking
 403                 by a trojan horse earlier in the search path. See the main
 404                 plugin distribution for examples on how this is done.</para>
 405                 </section>
 406
 407                 <section><title>Use spopen() if external commands must be executed</title>
 408
 409             <para>If you have to execute external commands from within your
 410         plugin and you're writing it in C, use the spopen() function
 411                 that Karl DeBisschop has written.</para>
 412
 413                 <para>The code for spopen() and spclose() is included with the
 414                 core plugin distribution.</para>
 415                 </section>
 416
 417                 <section><title>Don't make temp files unless absolutely required</title>
 418
 419                 <para>If temp files are needed, make sure that the plugin will
 420                 fail cleanly if the file can't be written (e.g., too few file
 421                 handles, out of disk space, incorrect permissions, etc.) and
 422                 delete the temp file when processing is complete.</para>
 423                 </section>
 424
 425         <section><title>Don't be tricked into following symlinks</title>
 426
 427                 <para>If your plugin opens any files, take steps to ensure that
 428                 you are not following a symlink to another location on the
 429                 system.</para>
 430                 </section>
 431
 432                 <section><title>Validate all input</title>
 433
 434                 <para>use routines in utils.c or utils.pm and write more as needed</para>
 435                 </section>
 436
 437 </section>
 438
 439
 440
 441
 442 <section id="PerlPlugin"><title>Perl Plugins</title>
 443
 444                 <para>Perl plugins are coded a little more defensively than other
 445                 plugins because of embedded Perl.  When configured as such, embedded
 446                 Perl Nagios (ePN) requires stricter use of the some of Perl's features.
 447                 This section outlines some of the steps needed to use ePN
 448                 effectively.</para>
 449
 450                 <orderedlist>
 451
 452                         <listitem><para> Do not use BEGIN and END blocks since they will be called
 453                         only once (when Nagios starts and shuts down) with Embedded Perl (ePN).  In
 454                         particular, do not use BEGIN blocks to initialize variables.</para>
 455                         </listitem>
 456
 457                         <listitem><para>To use utils.pm, you need to provide a full path to the
 458                         module in order for it to work.</para>
 459
 460           <literallayout>
 461           e.g.
 462                 use lib "/usr/local/nagios/libexec";
 463                 use utils qw(...);
 464           </literallayout>
 465                         </listitem>
 466
 467                         <listitem><para>Perl scripts should be called with "-w"</para>
 468                         </listitem>
 469
 470                         <listitem><para>All Perl plugins must compile cleanly under "use strict" - i.e. at
 471                         least explicitly package names as in "$main::x" or predeclare every
 472                         variable. </para>
 473
 474
 475                         <para>Explicitly initialize each variable in use.  Otherwise with
 476                         caching enabled, the plugin will not be recompiled each time, and
 477                         therefore Perl will not reinitialize all the variables.  All old
 478                         variable values will still be in effect.</para>
 479                         </listitem>
 480
 481                         <listitem><para>Do not use &gt;DATA&lt; handles (these simply do not compile under ePN).</para>
 482                         </listitem>
 483
 484                         <listitem><para>Do not use global variables in named subroutines. This is bad practise anyway, but with ePN the
 485                         compiler will report an error "&lt;global_var&gt; will not stay shared ..". Values used by
 486                         subroutines should be passed in the argument list.</para>
 487                         </listitem>
 488
 489                         <listitem><para>If writing to a file (perhaps recording
 490                         performance data) explicitly close close it.  The plugin never
 491                         calls <emphasis role="strong">exit</emphasis>; that is caught by
 492                         p1.pl, so output streams are never closed.</para>
 493                         </listitem>
 494
 495                         <listitem><para>As in <xref linkend="runtime"> all plugins need
 496                         to monitor their runtime, specially if they are using network
 497                         resources.  Use of the <emphasis>alarm</emphasis> is recommended
 498                         noting that some Perl modules (eg LWP) manage timers, so that an alarm
 499                         set by a plugin using such a module is overwritten by the module.
 500                         (workarounds are cunning (TM) or using the module timer)
 501                         Plugins may import a default time out ($TIMEOUT) from utils.pm.
 502                         </para>
 503                         </listitem>
 504
 505                         <listitem><para>Perl plugins should import %ERRORS from utils.pm
 506                         and then "exit $ERRORS{'OK'}" rather than "exit 0"
 507                         </para>
 508                         </listitem>
 509
 510                 </orderedlist>
 511
 512 </section>
 513
 514 <section id="runtime"><title>Runtime Timeouts</title>
 515
 516                 <para>Plugins have a very limited runtime - typically 10 sec.
 517                 As a result, it is very important for plugins to maintain internal
 518                 code to exit if runtime exceeds a threshold. </para>
 519
 520                 <para>All plugins should timeout gracefully, not just networking
 521                 plugins. For instance, df may lock if you have automounted
 522                 drives and your network fails - but on first glance, who'd think
 523                 df could lock up like that.  Plus, it should just be more error
 524                 resistant to be able to time out rather than consume
 525                 resources.</para>
 526
 527                 <section><title>Use DEFAULT_SOCKET_TIMEOUT</title>
 528
 529                 <para>All network plugins should use DEFAULT_SOCKET_TIMEOUT to timeout</para>
 530
 531                 </section>
 532
 533
 534                 <section><title>Add alarms to network plugins</title>
 535
 536                 <para>If you write a plugin which communicates with another
 537                 networked host, you should make sure to set an alarm() in your
 538                 code that prevents the plugin from hanging due to abnormal
 539                 socket closures, etc. Nagios takes steps to protect itself
 540                 against unruly plugins that timeout, but any plugins you create
 541                 should be well behaved on their own.</para>
 542
 543                 </section>
 544
 545
 546
 547 </section>
 548
 549 <section id="PlugOptions"><title>Plugin Options</title>
 550
 551                 <para>A well written plugin should have --help as a way to get
 552                 verbose help. Code and output should try to respect the 80x25 size of a
 553                 crt (remember when fixing stuff in the server room!)</para>
 554
 555                 <section><title>Option Processing</title>
 556
 557                 <para>For plugins written in C, we recommend the C standard
 558                 getopt library for short options. Getopt_long is always available.
 559                 </para>
 560
 561                 <para>For plugins written in Perl, we recommend Getopt::Long module.</para>
 562
 563                 <para>Positional arguments are strongly discouraged.</para>
 564
 565                 <para>There are a few reserved options that should not be used
 566                 for other purposes:</para>
 567
 568                 <literallayout>
 569           -V version (--version)
 570           -h help (--help)
 571           -t timeout (--timeout)
 572           -w warning threshold (--warning)
 573           -c critical threshold (--critical)
 574           -H hostname (--hostname)
 575           -v verbose (--verbose)
 576                 </literallayout>
 577
 578                 <para>In addition to the reserved options above, some other standard options are:</para>
 579
 580                 <literallayout>
 581           -C SNMP community (--community)
 582           -a authentication password (--authentication)
 583           -l login name (--logname)
 584           -p port or password (--port or --passwd/--password)monitors operational
 585           -u url or username (--url or --username)
 586                 </literallayout>
 587
 588                 <para>Look at check_pgsql and check_procs to see how I currently
 589                 think this can work.  Standard options are:</para>
 590
 591
 592                 <para>The option -V or --version should be present in all
 593                 plugins. For C plugins it should result in a call to print_revision, a
 594                 function in utils.c which takes two character arguments, the
 595                 command name and the plugin revision.</para>
 596
 597                 <para>The -? option, or any other unparsable set of options,
 598                 should print out a short usage statement. Character width should
 599                 be 80 and less and no more that 23 lines should be printed (it
 600                 should display cleanly on a dumb terminal in a server
 601                 room).</para>
 602
 603                 <para>The option -h or --help should be present in all plugins.
 604                 In C plugins, it should result in a call to print_help (or
 605                 equivalent).  The function print_help should call print_revision,
 606                 then print_usage, then should provide detailed
 607                 help. Help text should fit on an 80-character width display, but
 608                 may run as many lines as needed.</para>
 609
 610                 <para>The option -v or --verbose should be present in all plugins.
 611                 The user should be allowed to specify -v multiple times to increase
 612                 the verbosity level, as described in <xref linkend="verboselevels">.</para>
 613     </section>
 614
 615     <section>
 616       <title>Plugins with more than one type of threshold, or with
 617       threshold ranges</title>
 618
 619       <para>Old style was to do things like -ct for critical time and
 620       -cv for critical value. That goes out the window with POSIX
 621       getopt. The allowable alternatives are:</para>
 622
 623       <orderedlist>
 624         <listitem>
 625           <para>long options like -critical-time (or -ct and -cv, I
 626           suppose).</para>
 627         </listitem>
 628
 629         <listitem>
 630           <para>repeated options like `check_load -w 10 -w 6 -w 4 -c
 631           16 -c 10 -c 10`</para>
 632         </listitem>
 633
 634         <listitem>
 635           <para>for brevity, the above can be expressed as `check_load
 636           -w 10,6,4 -c 16,10,10`</para>
 637         </listitem>
 638
 639         <listitem>
 640           <para>ranges are expressed with colons as in `check_procs -C
 641           httpd -w 1:20 -c 1:30` which will warn above 20 instances,
 642           and critical at 0 and above 30</para>
 643         </listitem>
 644
 645         <listitem>
 646           <para>lists are expressed with commas, so Jacob's check_nmap
 647           uses constructs like '-p 1000,1010,1050:1060,2000'</para>
 648         </listitem>
 649
 650         <listitem>
 651           <para>If possible when writing lists, use tokens to make the
 652           list easy to remember and non-order dependent - so
 653           check_disk uses '-c 10000,10%' so that it is clear which is
 654           the precentage and which is the KB values (note that due to
 655           my own lack of foresight, that used to be '-c 10000:10%' but
 656           such constructs should all be changed for consistency,
 657           though providing reverse compatibility is fairly
 658           easy).</para>
 659         </listitem>
 660
 661       </orderedlist>
 662
 663       <para>As always, comments are welcome - making this consistent
 664       without a host of long options was quite a hassle, and I would
 665       suspect that there are flaws in this strategy.
 666       </para>
 667     </section>
 668 </section>
 669
 670 <section id="Testcases"><title>Test cases</title>
 671 <para>
 672 Tests are the best way of knowing if the plugins work as expected. Please
 673 create and update test cases where possible.
 674 </para>
 675
 676 <para>
 677 To run a test, from the top level directory, run "make test". This will run
 678 all the current tests and report an overall success rate.
 679 </para>
 680
 681 <para>
 682 See the <ulink url="http://tinderbox.opsera.com">Nagios Plugins Tinderbox server</ulink>
 683 for the daily test results.
 684 </para>
 685
 686 <section><title>Test cases for plugins</title>
 687 <para>These use perl's Test::More. To do a one time test, run "cd plugins && perl t/check_disk.t".
 688 </para>
 689
 690 <para>There will somtimes be failures seen in this output which are known failures that
 691 need to be fixed. As long as the return code is 0, it will be reported as "test pass".
 692 (If you have a fix so that the specific test passes, that will be gratefully received!)
 693 </para>
 694
 695 <para>
 696 If you want a summary test, run: "cd plugins && prove t/check_disk.t".
 697 This runs the test in a summary format.
 698 </para>
 699
 700 <para>
 701 For a good and amusing tutorial on using Test::More, see this
 702 <ulink url="http://search.cpan.org/~mschwern/Test-Simple-0.62/lib/Test/Tutorial.pod">
 703 link</ulink>
 704 </para>
 705
 706 </section>
 707
 708 <section><title>Testing the C library functions</title>
 709 <para>
 710 We use <ulink url="http://jc.ngo.org.uk/trac-bin/trac.cgi/wiki/LibTap">the libtap library</ulink>, which gives
 711 perl's TAP
 712 (Test Anything Protocol) output. This is used by the FreeBSD team for their regression testing.
 713 </para>
 714
 715 <para>
 716 To run tests using the libtap library, download the latest tar ball and extract.
 717 There is a problem with tap-1.01 where
 718 <ulink url="http://jc.ngo.org.uk/trac-bin/trac.cgi/ticket/25">pthread support doesn't appear to work</ulink>
 719 properly on non-FreeBSD systems. Install with 'CPPFLAGS="-UHAVE_LIBPTHREAD" ./configure && make && make check && make install'.
 720 </para>
 721
 722 <para>
 723 When you run Nagios Plugins' configure, it will look for the tap library and will automatically
 724 setup the tests. Run "make test" to run all the tests.
 725 </para>
 726 </section>
 727
 728 </section>
 729 <section id="CodingGuidelines"><title>Coding guidelines</title>
 730         <para>See <ulink url="http://www.gnu.org/prep/standards_toc.html">GNU
 731         Coding standards</ulink> for general guidelines.</para>
 732         <section><title>C coding</title>
 733
 734         <para>Variables should be declared at the beginning of code blocks and
 735         not inline because of portability with older compilers.</para>
 736
 737         <para>You should use /* */ for comments and not // as some compilers
 738         do not handle the latter form.</para>
 739
 740         <para>You should also avoid using the type "bool" and its values
 741         "true" and "false". Instead use the "int" type and the plugins' own
 742         "TRUE"/"FALSE" values to keep the code uniformly.</para>
 743         </section>
 744
 745         <section><title>Crediting sources</title>
 746         <para>If you have copied a routine from another source, make sure the licence
 747         from your source allows this. Add a comment referencing the ACKNOWLEDGEMENTS
 748         file, where you can put more detail about the source.</para>
 749         <para>For contributed code, do not add any named credits in the source code
 750         - contributors should be added into the THANKS.in file instead.
 751         </para>
 752         </section>
 753
 754         <section><title>Commit Messages</title>
 755         <para>If the change is due to a contribution, please quote the contributor's name
 756         and, if applicable, add the SourceForge Tracker number. Don't forget to
 757 update the THANKS.in file.</para>
 758         <para>If you have a change that is useful for noting in the next release, please
 759         update the NEWS file.</para>
 760         <para>All commits will be written to a ChangeLog at release time.
 761         </para>
 762         </section>
 763
 764         <section id="translationsdevelopers"><title>Translations for developers</title>
 765         <para>To make the job easier for translators, please follow these guidelines:</para>
 766         <orderedlist>
 767           <listitem><para>
 768             Before creating new strings, check the po/nagios-plugins.pot file to
 769             see if a similar string
 770             already exists
 771           </para></listitem>
 772           <listitem><para>
 773             For help texts, break into individual options so that these can be reused
 774             between plugins
 775           </para></listitem>
 776           <listitem><para>Try to avoid linefeeds unless you are working on a block of text</para></listitem>
 777           <listitem><para>Short help is not translated</para></listitem>
 778           <listitem><para>Long help has options in English language, but text translated</para></listitem>
 779           <listitem><para>"Copyright" kept in English</para></listitem>
 780           <listitem><para>Copyright holder names kept in original text</para></listitem>
 781           <listitem><para>Debugging output does not need to be translated</para></listitem>
 782         </orderedlist>
 783         </section>
 784
 785         <section><title>Translations for translators</title>
 786         <para>To create an up to date list of translatable strings, run: tools/gen_locale.sh</para>
 787         </section>
 788
 789 </section>
 790
 791 <section id="SubmittingChanges"><title>Submission of new plugins and patches</title>
 792
 793         <section id="Patches"><title>Patches</title>
 794         <para>If you have a bug patch, please supply a unified or context diff against the
 795         version you are using. For new features, please supply a diff against
 796         the Git "master" branch.</para>
 797
 798         <para>Patches should be submitted via
 799         <ulink url="http://sourceforge.net/tracker/?group_id=29880&amp;atid=397599">SourceForge's
 800         tracker system for Nagiosplug patches</ulink>
 801         and be announced to the nagiosplug-devel mailing list.</para>
 802
 803         <para>Submission of a patch implies that the submmitter acknowledges that they
 804         are the author of the code (or have permission from the author to release the code)
 805         and agree that the code can be released under the GPL. The copyright for the changes will
 806         then revert to the Nagios Plugin Development Team - this is required so that any copyright
 807         infringements can be investigated quickly without contacting a huge list of copyright holders.
 808         Credit will always be given for any patches through a THANKS file in the distribution.</para>
 809         </section>
 810
 811
 812         <section id="Contributedplugins"><title>Contributed plugins</title>
 813         <para>Plugins that have been contributed to the project and
 814         distributed with the Nagios Plugin files are held in the contrib/ directory and are not installed
 815         by default. These plugins are not officially supported by the team.
 816         The current policy is that these plugins should be owned and maintained by the original
 817         contributor, preferably hosted on <ulink url="http://exchange.nagios.org">Nagios Exchange</ulink>.
 818         </para>
 819         <para>If patches or bugs are raised to an contributed plugin, we will start communications with the
 820         original contributor, but seek to remove the plugin from our distribution.
 821         </para>
 822         <para>The aim is to distribute only code that the Nagios Plugin team are responsible for.
 823         </para>
 824         </section>
 825
 826         <section id="Newplugins"><title>New plugins</title>
 827         <para>If you would like others to use your plugins, please add it to
 828         the official 3rd party plugin repository,
 829         <ulink url="http://exchange.nagios.org">Nagios Exchange</ulink>.
 830         </para>
 831
 832         <para>We are not accepting requests for inclusion of plugins into
 833         our distribution at the moment, but when we do, these are the minimum
 834         requirements:
 835         </para>
 836
 837       <orderedlist>
 838         <listitem>
 839           <para>Include copyright and license information in all files. Copyright must be solely
 840                 granted to the Nagios Plugin Development Team</para>
 841         </listitem>
 842         <listitem>
 843           <para>The standard command options are supported (--help, --version,
 844           --timeout, --warning, --critical)</para>
 845         </listitem>
 846         <listitem>
 847           <para>It is determined to be not redundant (for instance, we would not
 848                 add a new version of check_disk just because someone had provide
 849                 a plugin that had perf checking - we would incorporate the features
 850                 into an exisiting plugin)</para>
 851         </listitem>
 852         <listitem>
 853           <para>One of the developers has had the time to audit the code and declare
 854                 it ready for core</para>
 855         </listitem>
 856         <listitem>
 857           <para>It should also follow code format guidelines, and use functions from
 858 utils (perl or c or sh) rather than using its own</para>
 859         </listitem>
 860         <listitem>
 861           <para>Includes patches to configure.in if required (via the EXTRAS list if
 862           it will only work on some platforms)</para>
 863         </listitem>
 864         <listitem>
 865           <para>If possible, please submit a test harness. Documentation on sample
 866           tests coming soon</para>
 867         </listitem>
 868       </orderedlist>
 869
 870         </section>
 871
 872 </section>
 873 </article>
 874
 875 </book>