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>2006</pubdate>
  15     <title>Nagios plug-in development guidelines</title>
  16
  17     <revhistory>
  18        <revision>
  19           <revnumber>$Revision$</revnumber>
  20           <date>$Date$</date>
  21        </revision>
  22     </revhistory>
  23
  24         <copyright>
  25                 <year>2000 - 2006</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) 2000-2006
  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         is very small, to develop from CVS needs additional software to be installed. These are the
  54         minimum levels of software required:
  55
  56         <literallayout>
  57         gnu make 3.79
  58         automake 1.9.2
  59         autoconf 2.59
  60         gnu m4 1.4.2
  61         gnu libtool 1.5
  62         </literallayout>
  63
  64         To compile from CVS, after you have checked out the code, run:
  65         <literallayout>
  66         tools/setup
  67         ./configure
  68         make
  69         make install
  70         </literallayout>
  71         </para>
  72
  73         <para>Note: gettext is no longer a developer platform requirement. A lot of the files in lib/ and m4/
  74         are synced with the coreutils project and we use the same levels of gettext that they
  75         distribute.
  76         </para>
  77         <para>Note: gnu libtool, which must be at version 1.5.22 or above, has files installed into CVS, so is not
  78         a development platform requirement.
  79         </para>
  80 </section>
  81
  82 <section id="PlugOutput"><title>Plugin Output for Nagios</title>
  83
  84                 <para>You should always print something to STDOUT that tells if the
  85                 service is working or why it is failing. Try to keep the output short -
  86                 probably less that 80 characters. Remember that you ideally would like
  87                 the entire output to appear in a pager message, which will get chopped
  88                 off after a certain length.</para>
  89
  90                 <para>As Nagios does not capture stderr output, you should only output to
  91                 STDOUT and not print to STDERR.</para>
  92
  93                 <section><title>Print only one line of text</title>
  94                 <para>Nagios will only grab the first line of text from STDOUT
  95                 when it notifies contacts about potential problems. If you print
  96                 multiple lines, you're out of luck (though this will be a feature of
  97                 Nagios 3). Remember, 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 plug-in 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                                         <row>
 281                                                 <entry>10</entry>
 282                                                 <entry>&lt; 0 or &gt; 10, (outside the range of {0 .. 10})</entry>
 283                                         </row>
 284                                 </tbody>
 285                         </tgroup>
 286                 </table>
 287                 <table id="CommandLineExamples"><title>Command line examples</title>
 288                         <tgroup cols="2">
 289                                 <thead>
 290                                         <row>
 291                                                 <entry><para>Command line</para></entry>
 292                                                 <entry><para>Meaning</para></entry>
 293                                         </row>
 294                                 </thead>
 295                                 <tbody>
 296                                         <row>
 297                                                 <entry>check_stuff -w10 -c20</entry>
 298                                                 <entry>Critical if "stuff" is over 20, else warn if over 10 (will be critical if "stuff" is less than 0)</entry>
 299                                         </row>
 300                                         <row>
 301                                                 <entry>check_stuff -w~:10 -c~:20</entry>
 302                                                 <entry>Same as above. Negative "stuff" is OK</entry>
 303                                         </row>
 304                                         <row>
 305                                                 <entry>check_stuff -w10: -c20</entry>
 306                                                 <entry>Critical if "stuff" is over 20, else warn if "stuff" is below 10 (will be critical if "stuff" is less than 0)</entry>
 307                                         </row>
 308                                         <row>
 309                                                 <entry>check_stuff -c1:</entry>
 310                                                 <entry>Critical if "stuff" is less than 1</entry>
 311                                         </row>
 312                                         <row>
 313                                                 <entry>check_stuff -w~:0 -c10</entry>
 314                                                 <entry>Critical if "stuff" is above 10; Warn if "stuff" is above zero</entry>
 315                                         </row>
 316                                         <row>
 317                                                 <entry>check_stuff -c5:6</entry>
 318                                                 <entry>The only noncritical range is 5:6</entry>
 319                                         </row>
 320                                         <row>
 321                                                 <entry>check_stuff -c10:20</entry>
 322                                                 <entry>Critical if "stuff" is 10 to 20</entry>
 323                                         </row>
 324                                 </tbody>
 325                         </tgroup>
 326                 </table>
 327                 </section>
 328
 329                 <section><title>Performance data</title>
 330                 <para>Performance data is defined by Nagios as "everything after the | of the plugin output" -
 331                 please refer to Nagios documentation for information on capturing this data to logfiles.
 332                 However, it is the responsibility of the plugin writer to ensure the
 333                 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</para>
 345                         </listitem>
 346                 <listitem><para>the single quotes for the label are optional. Required if
 347                         spaces, = or ' 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</para>
 363                         </listitem>
 364                 <listitem><para>warn and crit are in the range format (see
 365                         <xref linkend="thresholdformat">). Must be the same UOM</para>
 366                         </listitem>
 367                 <listitem><para>UOM (unit of measurement) is one of:</para>
 368                         <orderedlist>
 369                         <listitem><para>no unit specified - assume a number (int or float)
 370                                 of things (eg, users, processes, load averages)</para>
 371                                 </listitem>
 372                         <listitem><para>s - seconds (also us, ms)</para></listitem>
 373                         <listitem><para>% - percentage</para></listitem>
 374                         <listitem><para>B - bytes (also KB, MB, TB)</para></listitem>
 375                         <listitem><para>c - a continous counter (such as bytes
 376                                 transmitted on an interface)</para></listitem>
 377                         </orderedlist>
 378                         </listitem>
 379                 </orderedlist>
 380
 381                 <para>It is up to third party programs to convert the Nagios plugins
 382                 performance data into graphs.</para>
 383                 </section>
 384
 385         <section><title>Translations</title>
 386         <para>If possible, use translation tools for all output to respect the user's language
 387                 settings. See <xref linkend="translationsdevelopers"> for guidelines
 388                 for the core plugins.
 389         </para>
 390         </section>
 391 </section>
 392
 393 <section id="SysCmdAuxFiles"><title>System Commands and Auxiliary Files</title>
 394
 395                 <section><title>Don't execute system commands without specifying their
 396                 full path</title>
 397                 <para>Don't use exec(), popen(), etc. to execute external
 398                 commands without explicity using the full path of the external
 399                 program.</para>
 400
 401                 <para>Doing otherwise makes the plugin vulnerable to hijacking
 402                 by a trojan horse earlier in the search path. See the main
 403                 plugin distribution for examples on how this is done.</para>
 404                 </section>
 405
 406                 <section><title>Use spopen() if external commands must be executed</title>
 407
 408             <para>If you have to execute external commands from within your
 409         plugin and you're writing it in C, use the spopen() function
 410                 that Karl DeBisschop has written.</para>
 411
 412                 <para>The code for spopen() and spclose() is included with the
 413                 core plugin distribution.</para>
 414                 </section>
 415
 416                 <section><title>Don't make temp files unless absolutely required</title>
 417
 418                 <para>If temp files are needed, make sure that the plugin will
 419                 fail cleanly if the file can't be written (e.g., too few file
 420                 handles, out of disk space, incorrect permissions, etc.) and
 421                 delete the temp file when processing is complete.</para>
 422                 </section>
 423
 424         <section><title>Don't be tricked into following symlinks</title>
 425
 426                 <para>If your plugin opens any files, take steps to ensure that
 427                 you are not following a symlink to another location on the
 428                 system.</para>
 429                 </section>
 430
 431                 <section><title>Validate all input</title>
 432
 433                 <para>use routines in utils.c or utils.pm and write more as needed</para>
 434                 </section>
 435
 436 </section>
 437
 438
 439
 440
 441 <section id="PerlPlugin"><title>Perl Plugins</title>
 442
 443                 <para>Perl plugins are coded a little more defensively than other
 444                 plugins because of embedded Perl.  When configured as such, embedded
 445                 Perl Nagios (ePN) requires stricter use of the some of Perl's features.
 446                 This section outlines some of the steps needed to use ePN
 447                 effectively.</para>
 448
 449                 <orderedlist>
 450
 451                         <listitem><para> Do not use BEGIN and END blocks since they will be called
 452                         only once (when Nagios starts and shuts down) with Embedded Perl (ePN).  In
 453                         particular, do not use BEGIN blocks to initialize variables.</para>
 454                         </listitem>
 455
 456                         <listitem><para>To use utils.pm, you need to provide a full path to the
 457                         module in order for it to work.</para>
 458
 459           <literallayout>
 460           e.g.
 461                 use lib "/usr/local/nagios/libexec";
 462                 use utils qw(...);
 463           </literallayout>
 464                         </listitem>
 465
 466                         <listitem><para>Perl scripts should be called with "-w"</para>
 467                         </listitem>
 468
 469                         <listitem><para>All Perl plugins must compile cleanly under "use strict" - i.e. at
 470                         least explicitly package names as in "$main::x" or predeclare every
 471                         variable. </para>
 472
 473
 474                         <para>Explicitly initialize each variable in use.  Otherwise with
 475                         caching enabled, the plugin will not be recompiled each time, and
 476                         therefore Perl will not reinitialize all the variables.  All old
 477                         variable values will still be in effect.</para>
 478                         </listitem>
 479
 480                         <listitem><para>Do not use &gt;DATA&lt; handles (these simply do not compile under ePN).</para>
 481                         </listitem>
 482
 483                         <listitem><para>Do not use global variables in named subroutines. This is bad practise anyway, but with ePN the
 484                         compiler will report an error "&lt;global_var&gt; will not stay shared ..". Values used by
 485                         subroutines should be passed in the argument list.</para>
 486                         </listitem>
 487
 488                         <listitem><para>If writing to a file (perhaps recording
 489                         performance data) explicitly close close it.  The plugin never
 490                         calls <emphasis role="strong">exit</emphasis>; that is caught by
 491                         p1.pl, so output streams are never closed.</para>
 492                         </listitem>
 493
 494                         <listitem><para>As in <xref linkend="runtime"> all plugins need
 495                         to monitor their runtime, specially if they are using network
 496                         resources.  Use of the <emphasis>alarm</emphasis> is recommended
 497                         noting that some Perl modules (eg LWP) manage timers, so that an alarm
 498                         set by a plugin using such a module is overwritten by the module.
 499                         (workarounds are cunning (TM) or using the module timer)
 500                         Plugins may import a default time out ($TIMEOUT) from utils.pm.
 501                         </para>
 502                         </listitem>
 503
 504                         <listitem><para>Perl plugins should import %ERRORS from utils.pm
 505                         and then "exit $ERRORS{'OK'}" rather than "exit 0"
 506                         </para>
 507                         </listitem>
 508
 509                 </orderedlist>
 510
 511 </section>
 512
 513 <section id="runtime"><title>Runtime Timeouts</title>
 514
 515                 <para>Plugins have a very limited runtime - typically 10 sec.
 516                 As a result, it is very important for plugins to maintain internal
 517                 code to exit if runtime exceeds a threshold. </para>
 518
 519                 <para>All plugins should timeout gracefully, not just networking
 520                 plugins. For instance, df may lock if you have automounted
 521                 drives and your network fails - but on first glance, who'd think
 522                 df could lock up like that.  Plus, it should just be more error
 523                 resistant to be able to time out rather than consume
 524                 resources.</para>
 525
 526                 <section><title>Use DEFAULT_SOCKET_TIMEOUT</title>
 527
 528                 <para>All network plugins should use DEFAULT_SOCKET_TIMEOUT to timeout</para>
 529
 530                 </section>
 531
 532
 533                 <section><title>Add alarms to network plugins</title>
 534
 535                 <para>If you write a plugin which communicates with another
 536                 networked host, you should make sure to set an alarm() in your
 537                 code that prevents the plugin from hanging due to abnormal
 538                 socket closures, etc. Nagios takes steps to protect itself
 539                 against unruly plugins that timeout, but any plugins you create
 540                 should be well behaved on their own.</para>
 541
 542                 </section>
 543
 544
 545
 546 </section>
 547
 548 <section id="PlugOptions"><title>Plugin Options</title>
 549
 550                 <para>A well written plugin should have --help as a way to get
 551                 verbose help. Code and output should try to respect the 80x25 size of a
 552                 crt (remember when fixing stuff in the server room!)</para>
 553
 554                 <section><title>Option Processing</title>
 555
 556                 <para>For plugins written in C, we recommend the C standard
 557                 getopt library for short options. Getopt_long is always available.
 558                 </para>
 559
 560                 <para>For plugins written in Perl, we recommend Getopt::Long module.</para>
 561
 562                 <para>Positional arguments are strongly discouraged.</para>
 563
 564                 <para>There are a few reserved options that should not be used
 565                 for other purposes:</para>
 566
 567                 <literallayout>
 568           -V version (--version)
 569           -h help (--help)
 570           -t timeout (--timeout)
 571           -w warning threshold (--warning)
 572           -c critical threshold (--critical)
 573           -H hostname (--hostname)
 574           -v verbose (--verbose)
 575                 </literallayout>
 576
 577                 <para>In addition to the reserved options above, some other standard options are:</para>
 578
 579                 <literallayout>
 580           -C SNMP community (--community)
 581           -a authentication password (--authentication)
 582           -l login name (--logname)
 583           -p port or password (--port or --passwd/--password)monitors operational
 584           -u url or username (--url or --username)
 585                 </literallayout>
 586
 587                 <para>Look at check_pgsql and check_procs to see how I currently
 588                 think this can work.  Standard options are:</para>
 589
 590
 591                 <para>The option -V or --version should be present in all
 592                 plugins. For C plugins it should result in a call to print_revision, a
 593                 function in utils.c which takes two character arguments, the
 594                 command name and the plugin revision.</para>
 595
 596                 <para>The -? option, or any other unparsable set of options,
 597                 should print out a short usage statement. Character width should
 598                 be 80 and less and no more that 23 lines should be printed (it
 599                 should display cleanly on a dumb terminal in a server
 600                 room).</para>
 601
 602                 <para>The option -h or --help should be present in all plugins.
 603                 In C plugins, it should result in a call to print_help (or
 604                 equivalent).  The function print_help should call print_revision,
 605                 then print_usage, then should provide detailed
 606                 help. Help text should fit on an 80-character width display, but
 607                 may run as many lines as needed.</para>
 608
 609                 <para>The option -v or --verbose should be present in all plugins.
 610                 The user should be allowed to specify -v multiple times to increase
 611                 the verbosity level, as described in <xref linkend="verboselevels">.</para>
 612     </section>
 613
 614     <section>
 615       <title>Plugins with more than one type of threshold, or with
 616       threshold ranges</title>
 617
 618       <para>Old style was to do things like -ct for critical time and
 619       -cv for critical value. That goes out the window with POSIX
 620       getopt. The allowable alternatives are:</para>
 621
 622       <orderedlist>
 623         <listitem>
 624           <para>long options like -critical-time (or -ct and -cv, I
 625           suppose).</para>
 626         </listitem>
 627
 628         <listitem>
 629           <para>repeated options like `check_load -w 10 -w 6 -w 4 -c
 630           16 -c 10 -c 10`</para>
 631         </listitem>
 632
 633         <listitem>
 634           <para>for brevity, the above can be expressed as `check_load
 635           -w 10,6,4 -c 16,10,10`</para>
 636         </listitem>
 637
 638         <listitem>
 639           <para>ranges are expressed with colons as in `check_procs -C
 640           httpd -w 1:20 -c 1:30` which will warn above 20 instances,
 641           and critical at 0 and above 30</para>
 642         </listitem>
 643
 644         <listitem>
 645           <para>lists are expressed with commas, so Jacob's check_nmap
 646           uses constructs like '-p 1000,1010,1050:1060,2000'</para>
 647         </listitem>
 648
 649         <listitem>
 650           <para>If possible when writing lists, use tokens to make the
 651           list easy to remember and non-order dependent - so
 652           check_disk uses '-c 10000,10%' so that it is clear which is
 653           the precentage and which is the KB values (note that due to
 654           my own lack of foresight, that used to be '-c 10000:10%' but
 655           such constructs should all be changed for consistency,
 656           though providing reverse compatibility is fairly
 657           easy).</para>
 658         </listitem>
 659
 660       </orderedlist>
 661
 662       <para>As always, comments are welcome - making this consistent
 663       without a host of long options was quite a hassle, and I would
 664       suspect that there are flaws in this strategy.
 665       </para>
 666     </section>
 667 </section>
 668
 669 <section id="Testcases"><title>Test cases</title>
 670 <para>
 671 Tests are the best way of knowing if the plugins work as expected. Please
 672 create and update test cases where possible.
 673 </para>
 674
 675 <para>
 676 To run a test, from the top level directory, run "make test". This will run
 677 all the current tests and report an overall success rate.
 678 </para>
 679
 680 <para>
 681 See the <ulink url="http://tinderbox.altinity.org">Nagios Plugins Tinderbox server</ulink>
 682 for the daily test results.
 683 </para>
 684
 685 <section><title>Test cases for plugins</title>
 686 <para>These use perl's Test::More. To do a one time test, run "cd plugins && perl t/check_disk.t".
 687 </para>
 688
 689 <para>There will somtimes be failures seen in this output which are known failures that
 690 need to be fixed. As long as the return code is 0, it will be reported as "test pass".
 691 (If you have a fix so that the specific test passes, that will be gratefully received!)
 692 </para>
 693
 694 <para>
 695 If you want a summary test, run: "cd plugins && prove t/check_disk.t".
 696 This runs the test in a summary format.
 697 </para>
 698
 699 <para>
 700 For a good and amusing tutorial on using Test::More, see this
 701 <ulink url="http://search.cpan.org/~mschwern/Test-Simple-0.62/lib/Test/Tutorial.pod">
 702 link</ulink>
 703 </para>
 704
 705 </section>
 706
 707 <section><title>Testing the C library functions</title>
 708 <para>
 709 We use <ulink url="http://jc.ngo.org.uk/trac-bin/trac.cgi/wiki/LibTap">the libtap library</ulink>, which gives
 710 perl's TAP
 711 (Test Anything Protocol) output. This is used by the FreeBSD team for their regression testing.
 712 </para>
 713
 714 <para>
 715 To run tests using the libtap library, download the latest tar ball and extract.
 716 There is a problem with tap-1.01 where
 717 <ulink url="http://jc.ngo.org.uk/trac-bin/trac.cgi/ticket/25">pthread support doesn't appear to work</ulink>
 718 properly on non-FreeBSD systems. Install with 'CPPFLAGS="-UHAVE_LIBPTHREAD" ./configure && make && make check && make install'.
 719 </para>
 720
 721 <para>
 722 When you run Nagios Plugins' configure, it will look for the tap library and will automatically
 723 setup the tests. Run "make test" to run all the tests.
 724 </para>
 725 </section>
 726
 727 </section>
 728 <section id="CodingGuidelines"><title>Coding guidelines</title>
 729         <para>See <ulink url="http://www.gnu.org/prep/standards_toc.html">GNU
 730         Coding standards</ulink> for general guidelines.</para>
 731         <section><title>C coding</title>
 732
 733         <para>Variables should be declared at the beginning of code blocks and
 734         not inline because of portability with older compilers.</para>
 735
 736         <para>You should use /* */ for comments and not // as some compilers
 737         do not handle the latter form.</para>
 738
 739         <para>You should also avoid using the type "bool" and its values
 740         "true" and "false". Instead use the "int" type and the plugins' own
 741         "TRUE"/"FALSE" values to keep the code uniformly.</para>
 742         </section>
 743
 744         <section><title>Crediting sources</title>
 745         <para>If you have copied a routine from another source, make sure the licence
 746         from your source allows this. Add a comment referencing the ACKNOWLEDGEMENTS
 747         file, where you can put more detail about the source.</para>
 748         <para>For contributed code, do not add any named credits in the source code
 749         - contributors should be added into the THANKS.in file instead.
 750         </para>
 751         </section>
 752
 753         <section><title>CVS comments</title>
 754         <para>If the change is due to a contribution, please quote the contributor's name
 755         and, if applicable, add the SourceForge Tracker number. Don't forget to
 756 update the THANKS.in file.</para>
 757         <para>If you have a change that is useful for noting in the next release, please
 758         update the NEWS file.</para>
 759         <para>All CVS commit comments will be written to a ChangeLog at release time.
 760         </para>
 761         </section>
 762
 763         <section id="translationsdevelopers"><title>Translations for developers</title>
 764         <para>To make the job easier for translators, please follow these guidelines:</para>
 765         <orderedlist>
 766           <listitem><para>
 767             Before creating new strings, check the po/nagios-plugins.pot file to
 768             see if a similar string
 769             already exists
 770           </para></listitem>
 771           <listitem><para>
 772             For help texts, break into individual options so that these can be reused
 773             between plugins
 774           </para></listitem>
 775           <listitem><para>Try to avoid linefeeds unless you are working on a block of text</para></listitem>
 776           <listitem><para>Short help is not translated</para></listitem>
 777           <listitem><para>Long help has options in English language, but text translated</para></listitem>
 778           <listitem><para>"Copyright" kept in English</para></listitem>
 779           <listitem><para>Copyright holder names kept in original text</para></listitem>
 780           <listitem><para>Debugging output does not need to be translated</para></listitem>
 781         </orderedlist>
 782         </section>
 783
 784         <section><title>Translations for translators</title>
 785         <para>To create an up to date list of translatable strings, run: tools/gen_locale.sh</para>
 786         </section>
 787
 788 </section>
 789
 790 <section id="SubmittingChanges"><title>Submission of new plugins and patches</title>
 791
 792         <section id="Patches"><title>Patches</title>
 793         <para>If you have a bug patch, please supply a unified or context diff against the
 794         version you are using. For new features, please supply a diff against
 795         the CVS HEAD version.</para>
 796
 797         <para>Patches should be submitted via
 798         <ulink url="http://sourceforge.net/tracker/?group_id=29880&amp;atid=397599">SourceForge's
 799         tracker system for Nagiosplug patches</ulink>
 800         and be announced to the nagiosplug-devel mailing list.</para>
 801
 802         <para>Submission of a patch implies that the submmitter acknowledges that they
 803         are the author of the code (or have permission from the author to release the code)
 804         and agree that the code can be released under the GPL. The copyright for the changes will
 805         then revert to the Nagios Plugin Development Team - this is required so that any copyright
 806         infringements can be investigated quickly without contacting a huge list of copyright holders.
 807         Credit will always be given for any patches through a THANKS file in the distribution.</para>
 808         </section>
 809
 810
 811         <section id="Contributedplugins"><title>Contributed plugins</title>
 812         <para>Plugins that have been contributed to the project and
 813         distributed with the Nagios Plugin files are held in the contrib/ directory and are not installed
 814         by default. These plugins are not officially supported by the team.
 815         The current policy is that these plugins should be owned and maintained by the original
 816         contributor, preferably hosted on <ulink url="http://www.nagiosexchange.org">NagiosExchange</ulink>.
 817         </para>
 818         <para>If patches or bugs are raised to an contributed plugin, we will start communications with the
 819         original contributor, but seek to remove the plugin from our distribution.
 820         </para>
 821         <para>The aim is to distribute only code that the Nagios Plugin team are responsible for.
 822         </para>
 823         </section>
 824
 825         <section id="Newplugins"><title>New plugins</title>
 826         <para>If you would like others to use your plugins, please add it to
 827         the official 3rd party plugin repository,
 828         <ulink url="http://www.nagiosexchange.org">NagiosExchange</ulink>.
 829         </para>
 830
 831         <para>We are not accepting requests for inclusion of plugins into
 832         our distribution at the moment, but when we do, these are the minimum
 833         requirements:
 834         </para>
 835
 836       <orderedlist>
 837         <listitem>
 838           <para>Include copyright and license information in all files. Copyright must be solely
 839                 granted to the Nagios Plugin Development Team</para>
 840         </listitem>
 841         <listitem>
 842           <para>The standard command options are supported (--help, --version,
 843           --timeout, --warning, --critical)</para>
 844         </listitem>
 845         <listitem>
 846           <para>It is determined to be not redundant (for instance, we would not
 847                 add a new version of check_disk just because someone had provide
 848                 a plugin that had perf checking - we would incorporate the features
 849                 into an exisiting plugin)</para>
 850         </listitem>
 851         <listitem>
 852           <para>One of the developers has had the time to audit the code and declare
 853                 it ready for core</para>
 854         </listitem>
 855         <listitem>
 856           <para>It should also follow code format guidelines, and use functions from
 857 utils (perl or c or sh) rather than using its own</para>
 858         </listitem>
 859         <listitem>
 860           <para>Includes patches to configure.in if required (via the EXTRAS list if
 861           it will only work on some platforms)</para>
 862         </listitem>
 863         <listitem>
 864           <para>If possible, please submit a test harness. Documentation on sample
 865           tests coming soon</para>
 866         </listitem>
 867       </orderedlist>
 868
 869         </section>
 870
 871 </section>
 872 </article>
 873
 874 </book>