doc/developer-guidelines.sgml

   1 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook V4.1//EN" >
   2 <book>
   3   <title>Monitoring Plugins Development Guidelines</title>
   4
   5   <bookinfo>
   6     <authorgroup>
   7       <author>
   8         <affiliation>
   9           <orgname>Monitoring Plugins Development Team</orgname>
  10         </affiliation>
  11       </author>
  12     </authorgroup>
  13
  14     <pubdate>2013</pubdate>
  15     <title>Monitoring Plugins 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>Monitoring 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 standardization of the
  35     different kind of plugins: C, shell, perl, python, etc.</para>
  36
  37         <para>Monitoring Plugins Development Guidelines Copyright (C) 2000-2013
  38         (Monitoring 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         Monitoring 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 Monitoring 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><para>The --help or --version output should also result in Unknown state.
 204                                                 </para></entry>
 205                                         </row>
 206                                 </tbody>
 207                         </tgroup>
 208                 </table>
 209
 210
 211                 </section>
 212
 213                 <section id="thresholdformat"><title>Threshold and ranges</title>
 214                 <para>A range is defined as a start and end point (inclusive) on a numeric scale (possibly
 215                 negative or positive infinity).
 216                 </para>
 217                 <para>A threshold is a range with an alert level (either warning or critical). Use the
 218                 set_thresholds(thresholds *, char *, char *) function to set the thresholds.
 219                 </para>
 220                 <para>The theory is that the plugin will do some sort of check which returns
 221                 back a numerical value, or metric, which is then compared to the warning and
 222                 critical thresholds. Use the get_status(double, thresholds *) function to
 223                 compare the value against the thresholds.</para>
 224                 <para>This is the generalised format for ranges:</para>
 225
 226                 <literallayout>
 227                 [@]start:end
 228                 </literallayout>
 229
 230                 <para>Notes:</para>
 231                 <orderedlist>
 232                 <listitem><para>start &le; end</para>
 233                         </listitem>
 234                 <listitem><para>start and ":" is not required if start=0</para>
 235                         </listitem>
 236                 <listitem><para>if range is of format "start:" and end is not specified,
 237                         assume end is infinity</para>
 238                         </listitem>
 239                 <listitem><para>to specify negative infinity, use "~"</para>
 240                         </listitem>
 241                 <listitem><para>alert is raised if metric is outside start and end range
 242                         (inclusive of endpoints)</para>
 243                         </listitem>
 244                 <listitem><para>if range starts with "@", then alert if inside this range
 245                         (inclusive of endpoints)</para>
 246                         </listitem>
 247                 </orderedlist>
 248
 249                 <para>Note: Not all plugins are coded to expect ranges in this format yet.
 250                 There will be some work in providing multiple metrics.</para>
 251
 252                 <table id="ExampleRanges"><title>Example ranges</title>
 253                         <tgroup cols="2">
 254                                 <thead>
 255                                         <row>
 256                                                 <entry><para>Range definition</para></entry>
 257                                                 <entry><para>Generate an alert if x...</para></entry>
 258                                         </row>
 259                                 </thead>
 260                                 <tbody>
 261                                         <row>
 262                                                 <entry>10</entry>
 263                                                 <entry>&lt; 0 or &gt; 10, (outside the range of {0 .. 10})</entry>
 264                                         </row>
 265                                         <row>
 266                                                 <entry>10:</entry>
 267                                                 <entry>&lt; 10, (outside {10 .. &infin;})</entry>
 268                                         </row>
 269                                         <row>
 270                                                 <entry>~:10</entry>
 271                                                 <entry>&gt; 10, (outside the range of {-&infin; .. 10})</entry>
 272                                         </row>
 273                                         <row>
 274                                                 <entry>10:20</entry>
 275                                                 <entry>&lt; 10 or &gt; 20, (outside the range of {10 .. 20})</entry>
 276                                         </row>
 277                                         <row>
 278                                                 <entry>@10:20</entry>
 279                                                 <entry>&ge; 10 and &le; 20, (inside the range of {10 .. 20})</entry>
 280                                         </row>
 281                                 </tbody>
 282                         </tgroup>
 283                 </table>
 284                 <table id="CommandLineExamples"><title>Command line examples</title>
 285                         <tgroup cols="2">
 286                                 <thead>
 287                                         <row>
 288                                                 <entry><para>Command line</para></entry>
 289                                                 <entry><para>Meaning</para></entry>
 290                                         </row>
 291                                 </thead>
 292                                 <tbody>
 293                                         <row>
 294                                                 <entry>check_stuff -w10 -c20</entry>
 295                                                 <entry>Critical if "stuff" is over 20, else warn if over 10 (will be critical if "stuff" is less than 0)</entry>
 296                                         </row>
 297                                         <row>
 298                                                 <entry>check_stuff -w~:10 -c~:20</entry>
 299                                                 <entry>Same as above. Negative "stuff" is OK</entry>
 300                                         </row>
 301                                         <row>
 302                                                 <entry>check_stuff -w10: -c20</entry>
 303                                                 <entry>Critical if "stuff" is over 20, else warn if "stuff" is below 10 (will be critical if "stuff" is less than 0)</entry>
 304                                         </row>
 305                                         <row>
 306                                                 <entry>check_stuff -c1:</entry>
 307                                                 <entry>Critical if "stuff" is less than 1</entry>
 308                                         </row>
 309                                         <row>
 310                                                 <entry>check_stuff -w~:0 -c10</entry>
 311                                                 <entry>Critical if "stuff" is above 10; Warn if "stuff" is above zero (will be critical if "stuff" is less than 0)</entry>
 312                                         </row>
 313                                         <row>
 314                                                 <entry>check_stuff -c5:6</entry>
 315                                                 <entry>Critical if "stuff" is less than 5 or more than 6</entry>
 316                                         </row>
 317                                         <row>
 318                                                 <entry>check_stuff -c@10:20</entry>
 319                                                 <entry>OK if stuff is less than 10 or higher than 20, otherwise critical </entry>
 320                                         </row>
 321                                 </tbody>
 322                         </tgroup>
 323                 </table>
 324                 </section>
 325
 326                 <section><title>Performance data</title>
 327                 <para>Nagios 3 and newer will concatenate the parts following a "|" in a) the first
 328                 line output by the plugin, and b) in the second to last line, into a string it
 329                 passes to whatever performance data processing it has configured. (Note that it
 330                 currently does not insert additional whitespace between both, so the plugin needs
 331                 to provide some to prevent the last pair of a) and the first of b) getting run
 332                 together.) Please refer to the Nagios documentation for information on how to
 333                 configure such processing. However, it is the responsibility of the plugin writer
 334                 to ensure the performance data is in a "Nagios Plugins" format.
 335                 This is the expected format:</para>
 336
 337                 <literallayout>
 338                 'label'=value[UOM];[warn];[crit];[min];[max]
 339                 </literallayout>
 340
 341                 <para>Notes:</para>
 342                 <orderedlist>
 343                 <listitem><para>space separated list of label/value pairs</para>
 344                         </listitem>
 345                 <listitem><para>label can contain any characters except the equals sign or single quote (')</para>
 346                         </listitem>
 347                 <listitem><para>the single quotes for the label are optional. Required if
 348                         spaces are in the label</para>
 349                         </listitem>
 350                 <listitem><para>label length is arbitrary, but ideally the first 19 characters
 351                         are unique (due to a limitation in RRD). Be aware of a limitation in the
 352                         amount of data that NRPE returns to Nagios</para>
 353                         </listitem>
 354                 <listitem><para>to specify a quote character, use two single quotes</para>
 355                         </listitem>
 356                 <listitem><para>warn, crit, min or max may be null (for example, if the threshold is
 357                         not defined or min and max do not apply). Trailing unfilled semicolons can be
 358                         dropped</para>
 359                         </listitem>
 360                 <listitem><para>min and max are not required if UOM=%</para>
 361                         </listitem>
 362                 <listitem><para>value, min and max in class [-0-9.]. Must all be the
 363                         same UOM. value may be a literal "U" instead, this would indicate that the
 364                         actual value couldn't be determined</para>
 365                         </listitem>
 366                 <listitem><para>warn and crit are in the range format (see
 367                         <xref linkend="thresholdformat">). Must be the same UOM</para>
 368                         </listitem>
 369                 <listitem><para>UOM (unit of measurement) is one of:</para>
 370                         <orderedlist>
 371                         <listitem><para>no unit specified - assume a number (int or float)
 372                                 of things (eg, users, processes, load averages)</para>
 373                                 </listitem>
 374                         <listitem><para>s - seconds (also us, ms)</para></listitem>
 375                         <listitem><para>% - percentage</para></listitem>
 376                         <listitem><para>B - bytes (also KB, MB, TB)</para></listitem>
 377                         <listitem><para>c - a continuous counter (such as bytes
 378                                 transmitted on an interface)</para></listitem>
 379                         </orderedlist>
 380                         </listitem>
 381                 </orderedlist>
 382
 383                 <para>It is up to third party programs to convert the Monitoring Plugins
 384                 performance data into graphs.</para>
 385                 </section>
 386
 387         <section><title>Translations</title>
 388         <para>If possible, use translation tools for all output to respect the user's language
 389                 settings. See <xref linkend="translationsdevelopers"> for guidelines
 390                 for the core plugins.
 391         </para>
 392         </section>
 393 </section>
 394
 395 <section id="SysCmdAuxFiles"><title>System Commands and Auxiliary Files</title>
 396
 397                 <section><title>Don't execute system commands without specifying their
 398                 full path</title>
 399                 <para>Don't use exec(), popen(), etc. to execute external
 400                 commands without explicitly using the full path of the external
 401                 program.</para>
 402
 403                 <para>Doing otherwise makes the plugin vulnerable to hijacking
 404                 by a trojan horse earlier in the search path. See the main
 405                 plugin distribution for examples on how this is done.</para>
 406                 </section>
 407
 408                 <section><title>Use spopen() if external commands must be executed</title>
 409
 410             <para>If you have to execute external commands from within your
 411         plugin and you're writing it in C, use the spopen() function
 412                 that Karl DeBisschop has written.</para>
 413
 414                 <para>The code for spopen() and spclose() is included with the
 415                 core plugin distribution.</para>
 416                 </section>
 417
 418                 <section><title>Don't make temp files unless absolutely required</title>
 419
 420                 <para>If temp files are needed, make sure that the plugin will
 421                 fail cleanly if the file can't be written (e.g., too few file
 422                 handles, out of disk space, incorrect permissions, etc.) and
 423                 delete the temp file when processing is complete.</para>
 424                 </section>
 425
 426         <section><title>Don't be tricked into following symlinks</title>
 427
 428                 <para>If your plugin opens any files, take steps to ensure that
 429                 you are not following a symlink to another location on the
 430                 system.</para>
 431                 </section>
 432
 433                 <section><title>Validate all input</title>
 434
 435                 <para>use routines in utils.c or utils.pm and write more as needed</para>
 436                 </section>
 437
 438 </section>
 439
 440
 441
 442
 443 <section id="PerlPlugin"><title>Perl Plugins</title>
 444
 445                 <para>Perl plugins are coded a little more defensively than other
 446                 plugins because of embedded Perl.  When configured as such, embedded
 447                 Perl Nagios (ePN) requires stricter use of the some of Perl's features.
 448                 This section outlines some of the steps needed to use ePN
 449                 effectively.</para>
 450
 451                 <orderedlist>
 452
 453                         <listitem><para> Do not use BEGIN and END blocks since they will be called
 454                         only once (when Nagios starts and shuts down) with Embedded Perl (ePN).  In
 455                         particular, do not use BEGIN blocks to initialize variables.</para>
 456                         </listitem>
 457
 458                         <listitem><para>To use utils.pm, you need to provide a full path to the
 459                         module in order for it to work.</para>
 460
 461           <literallayout>
 462           e.g.
 463                 use lib "/usr/local/nagios/libexec";
 464                 use utils qw(...);
 465           </literallayout>
 466                         </listitem>
 467
 468                         <listitem><para>Perl scripts should be called with "-w"</para>
 469                         </listitem>
 470
 471                         <listitem><para>All Perl plugins must compile cleanly under "use strict" - i.e. at
 472                         least explicitly package names as in "$main::x" or predeclare every
 473                         variable. </para>
 474
 475
 476                         <para>Explicitly initialize each variable in use.  Otherwise with
 477                         caching enabled, the plugin will not be recompiled each time, and
 478                         therefore Perl will not reinitialize all the variables.  All old
 479                         variable values will still be in effect.</para>
 480                         </listitem>
 481
 482                         <listitem><para>Do not use &gt;DATA&lt; handles (these simply do not compile under ePN).</para>
 483                         </listitem>
 484
 485                         <listitem><para>Do not use global variables in named subroutines. This is bad practise anyway, but with ePN the
 486                         compiler will report an error "&lt;global_var&gt; will not stay shared ..". Values used by
 487                         subroutines should be passed in the argument list.</para>
 488                         </listitem>
 489
 490                         <listitem><para>If writing to a file (perhaps recording
 491                         performance data) explicitly close close it.  The plugin never
 492                         calls <emphasis role="strong">exit</emphasis>; that is caught by
 493                         p1.pl, so output streams are never closed.</para>
 494                         </listitem>
 495
 496                         <listitem><para>As in <xref linkend="runtime"> all plugins need
 497                         to monitor their runtime, specially if they are using network
 498                         resources.  Use of the <emphasis>alarm</emphasis> is recommended
 499                         noting that some Perl modules (eg LWP) manage timers, so that an alarm
 500                         set by a plugin using such a module is overwritten by the module.
 501                         (workarounds are cunning (TM) or using the module timer)
 502                         Plugins may import a default time out ($TIMEOUT) from utils.pm.
 503                         </para>
 504                         </listitem>
 505
 506                         <listitem><para>Perl plugins should import %ERRORS from utils.pm
 507                         and then "exit $ERRORS{'OK'}" rather than "exit 0"
 508                         </para>
 509                         </listitem>
 510
 511                 </orderedlist>
 512
 513 </section>
 514
 515 <section id="runtime"><title>Runtime Timeouts</title>
 516
 517                 <para>Plugins have a very limited runtime - typically 10 sec.
 518                 As a result, it is very important for plugins to maintain internal
 519                 code to exit if runtime exceeds a threshold. </para>
 520
 521                 <para>All plugins should timeout gracefully, not just networking
 522                 plugins. For instance, df may lock if you have automounted
 523                 drives and your network fails - but on first glance, who'd think
 524                 df could lock up like that.  Plus, it should just be more error
 525                 resistant to be able to time out rather than consume
 526                 resources.</para>
 527
 528                 <section><title>Use DEFAULT_SOCKET_TIMEOUT</title>
 529
 530                 <para>All network plugins should use DEFAULT_SOCKET_TIMEOUT to timeout</para>
 531
 532                 </section>
 533
 534
 535                 <section><title>Add alarms to network plugins</title>
 536
 537                 <para>If you write a plugin which communicates with another
 538                 networked host, you should make sure to set an alarm() in your
 539                 code that prevents the plugin from hanging due to abnormal
 540                 socket closures, etc. Nagios takes steps to protect itself
 541                 against unruly plugins that timeout, but any plugins you create
 542                 should be well behaved on their own.</para>
 543
 544                 </section>
 545
 546
 547
 548 </section>
 549
 550 <section id="PlugOptions"><title>Plugin Options</title>
 551
 552                 <para>A well written plugin should have --help as a way to get
 553                 verbose help. Code and output should try to respect the 80x25 size of a
 554                 crt (remember when fixing stuff in the server room!)</para>
 555
 556                 <section><title>Option Processing</title>
 557
 558                 <para>For plugins written in C, we recommend the C standard
 559                 getopt library for short options. Getopt_long is always available.
 560                 </para>
 561
 562                 <para>For plugins written in Perl, we recommend Getopt::Long module.</para>
 563
 564                 <para>Positional arguments are strongly discouraged.</para>
 565
 566                 <para>There are a few reserved options that should not be used
 567                 for other purposes:</para>
 568
 569                 <literallayout>
 570           -V version (--version)
 571           -h help (--help)
 572           -t timeout (--timeout)
 573           -w warning threshold (--warning)
 574           -c critical threshold (--critical)
 575           -H hostname (--hostname)
 576           -v verbose (--verbose)
 577                 </literallayout>
 578
 579                 <para>In addition to the reserved options above, some other standard options are:</para>
 580
 581                 <literallayout>
 582           -C SNMP community (--community)
 583           -a authentication password (--authentication)
 584           -l login name (--logname)
 585           -p port or password (--port or --passwd/--password)monitors operational
 586           -u url or username (--url or --username)
 587                 </literallayout>
 588
 589                 <para>Look at check_pgsql and check_procs to see how I currently
 590                 think this can work.  Standard options are:</para>
 591
 592
 593                 <para>The option -V or --version should be present in all
 594                 plugins. For C plugins it should result in a call to print_revision, a
 595                 function in utils.c which takes two character arguments, the
 596                 command name and the plugin revision.</para>
 597
 598                 <para>The -? option, or any other unparsable set of options,
 599                 should print out a short usage statement. Character width should
 600                 be 80 and less and no more that 23 lines should be printed (it
 601                 should display cleanly on a dumb terminal in a server
 602                 room).</para>
 603
 604                 <para>The option -h or --help should be present in all plugins.
 605                 In C plugins, it should result in a call to print_help (or
 606                 equivalent).  The function print_help should call print_revision,
 607                 then print_usage, then should provide detailed
 608                 help. Help text should fit on an 80-character width display, but
 609                 may run as many lines as needed.</para>
 610
 611                 <para>The option -v or --verbose should be present in all plugins.
 612                 The user should be allowed to specify -v multiple times to increase
 613                 the verbosity level, as described in <xref linkend="verboselevels">.</para>
 614
 615                 <para>The exit code for version information or help should be UNKNOWN
 616                 (3).</para>
 617     </section>
 618
 619     <section>
 620       <title>Plugins with more than one type of threshold, or with
 621       threshold ranges</title>
 622
 623       <para>Old style was to do things like -ct for critical time and
 624       -cv for critical value. That goes out the window with POSIX
 625       getopt. The allowable alternatives are:</para>
 626
 627       <orderedlist>
 628         <listitem>
 629           <para>long options like -critical-time (or -ct and -cv, I
 630           suppose).</para>
 631         </listitem>
 632
 633         <listitem>
 634           <para>repeated options like `check_load -w 10 -w 6 -w 4 -c
 635           16 -c 10 -c 10`</para>
 636         </listitem>
 637
 638         <listitem>
 639           <para>for brevity, the above can be expressed as `check_load
 640           -w 10,6,4 -c 16,10,10`</para>
 641         </listitem>
 642
 643         <listitem>
 644           <para>ranges are expressed with colons as in `check_procs -C
 645           httpd -w 1:20 -c 1:30` which will warn above 20 instances,
 646           and critical at 0 and above 30</para>
 647         </listitem>
 648
 649         <listitem>
 650           <para>lists are expressed with commas, so Jacob's check_nmap
 651           uses constructs like '-p 1000,1010,1050:1060,2000'</para>
 652         </listitem>
 653
 654         <listitem>
 655           <para>If possible when writing lists, use tokens to make the
 656           list easy to remember and non-order dependent - so
 657           check_disk uses '-c 10000,10%' so that it is clear which is
 658           the percentage and which is the KB values (note that due to
 659           my own lack of foresight, that used to be '-c 10000:10%' but
 660           such constructs should all be changed for consistency,
 661           though providing reverse compatibility is fairly
 662           easy).</para>
 663         </listitem>
 664
 665       </orderedlist>
 666
 667       <para>As always, comments are welcome - making this consistent
 668       without a host of long options was quite a hassle, and I would
 669       suspect that there are flaws in this strategy.
 670       </para>
 671     </section>
 672 </section>
 673
 674 <section id="Testcases"><title>Test cases</title>
 675 <para>
 676 Tests are the best way of knowing if the plugins work as expected. Please
 677 create and update test cases where possible.
 678 </para>
 679
 680 <para>
 681 To run a test, from the top level directory, run "make test". This will run
 682 all the current tests and report an overall success rate.
 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 sometimes 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/dist/Test-Simple/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 Monitoring 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 the type "bool" and its values
 737         "true" and "false" instead of the "int" type for booleans.
 738         </para>
 739         </section>
 740
 741         <section><title>Crediting sources</title>
 742         <para>If you have copied a routine from another source, make sure the licence
 743         from your source allows this. Add a comment referencing the ACKNOWLEDGEMENTS
 744         file, where you can put more detail about the source.</para>
 745         <para>For contributed code, do not add any named credits in the source code
 746         - contributors should be added into the THANKS.in file instead.
 747         </para>
 748         </section>
 749
 750         <section><title>Commit Messages</title>
 751         <para>If the change is due to a contribution, please quote the contributor's name
 752         and, if applicable, add the GitHub Issue Tracker number. Don't forget to
 753   update the THANKS.in file.</para>
 754         <para>If you have a change that is useful for noting in the next release, please
 755         update the NEWS file.</para>
 756         <para>All commits will be written to a ChangeLog at release time.
 757         </para>
 758         </section>
 759
 760         <section id="translationsdevelopers"><title>Translations for developers</title>
 761         <para>To make the job easier for translators, please follow these guidelines:</para>
 762         <orderedlist>
 763           <listitem><para>
 764             Before creating new strings, check the po/monitoring-plugins.pot file to
 765             see if a similar string
 766             already exists
 767           </para></listitem>
 768           <listitem><para>
 769             For help texts, break into individual options so that these can be reused
 770             between plugins
 771           </para></listitem>
 772           <listitem><para>Try to avoid linefeeds unless you are working on a block of text</para></listitem>
 773           <listitem><para>Short help is not translated</para></listitem>
 774           <listitem><para>Long help has options in English language, but text translated</para></listitem>
 775           <listitem><para>"Copyright" kept in English</para></listitem>
 776           <listitem><para>Copyright holder names kept in original text</para></listitem>
 777           <listitem><para>Debugging output does not need to be translated</para></listitem>
 778         </orderedlist>
 779         </section>
 780
 781         <section><title>Translations for translators</title>
 782         <para>To create an up to date list of translatable strings, run: tools/gen_locale.sh</para>
 783         </section>
 784
 785 </section>
 786
 787 <section id="SubmittingChanges"><title>Submission of new plugins and patches</title>
 788
 789         <section id="Patches"><title>Patches</title>
 790         <para>If you have a bug patch, please supply a unified or context diff against the
 791         version you are using. For new features, please supply a diff against
 792         the Git "master" branch.</para>
 793
 794         <para>Patches should be submitted via
 795         <ulink url="https://github.com/monitoring-plugins/monitoring-plugins/pulls">GitHub's
 796         Pull requests for Monitoring Plugins</ulink>
 797         </para>
 798
 799         <para>Submission of a patch implies that the submmitter acknowledges that they
 800         are the author of the code (or have permission from the author to release the code)
 801         and agree that the code can be released under the GPL. The copyright for the changes will
 802         then revert to the Monitoring Plugins Development Team - this is required so that any copyright
 803         infringements can be investigated quickly without contacting a huge list of copyright holders.
 804         Credit will always be given for any patches through a THANKS file in the distribution.</para>
 805         </section>
 806
 807
 808         <section id="Contributedplugins"><title>Contributed plugins</title>
 809         <para>Plugins that have been contributed to the project and
 810         distributed with the Monitoring Plugins files are held in the contrib/ directory and are not installed
 811         by default. These plugins are not officially supported by the team.
 812         The current policy is that these plugins should be owned and maintained by the original
 813         contributor, preferably hosted on <ulink url="https://exchange.icinga.com/">Icinga Exchange</ulink>.
 814         </para>
 815         <para>If patches or bugs are raised to an contributed plugin, we will start communications with the
 816         original contributor, but seek to remove the plugin from our distribution.
 817         </para>
 818         <para>The aim is to distribute only code that the Monitoring Plugins team are responsible for.
 819         </para>
 820         </section>
 821
 822         <section id="Newplugins"><title>New plugins</title>
 823         <para>If you would like others to use your plugins, please add it to
 824         the official 3rd party plugin repository,
 825         <ulink url="https://exchange.icinga.com/">Icinga Exchange</ulink>.
 826         </para>
 827
 828         <para>We are not accepting requests for inclusion of plugins into
 829         our distribution at the moment, but when we do, these are the minimum
 830         requirements:
 831         </para>
 832
 833       <orderedlist>
 834         <listitem>
 835           <para>Include copyright and license information in all files. Copyright must be solely
 836                 granted to the Monitoring Plugins Development Team</para>
 837         </listitem>
 838         <listitem>
 839           <para>The standard command options are supported (--help, --version,
 840           --timeout, --warning, --critical)</para>
 841         </listitem>
 842         <listitem>
 843           <para>It is determined to be not redundant (for instance, we would not
 844                 add a new version of check_disk just because someone had provide
 845                 a plugin that had perf checking - we would incorporate the features
 846                 into an existing plugin)</para>
 847         </listitem>
 848         <listitem>
 849           <para>One of the developers has had the time to audit the code and declare
 850                 it ready for core</para>
 851         </listitem>
 852         <listitem>
 853           <para>It should also follow code format guidelines, and use functions from
 854 utils (perl or c or sh) rather than using its own</para>
 855         </listitem>
 856         <listitem>
 857           <para>Includes patches to configure.in if required (via the EXTRAS list if
 858           it will only work on some platforms)</para>
 859         </listitem>
 860         <listitem>
 861           <para>If possible, please submit a test harness. Documentation on sample
 862           tests coming soon</para>
 863         </listitem>
 864       </orderedlist>
 865
 866         </section>
 867
 868 </section>
 869 </article>
 870
 871 </book>