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         <copyright>
  18                 <year>2000 - 2024</year>
  19                 <holder>Monitoring Plugins Development Team</holder>
  20         </copyright>
  21
  22 </bookinfo>
  23
  24
  25 <preface id="preface"><title>Preface</title>
  26     <para>The purpose of this guidelines is to provide a reference for
  27     the plugin developers and encourage the standardization of the
  28     different kind of plugins: C, shell, perl, python, etc.</para>
  29
  30         <para>Monitoring Plugins Development Guidelines Copyright (C) 2000-2024
  31         (Monitoring Plugins Team)</para>
  32
  33         <para>Permission is granted to make and distribute verbatim
  34         copies of this manual provided the copyright notice and this
  35         permission notice are preserved on all copies.</para>
  36
  37         <para>The plugins themselves are copyrighted by their respective
  38         authors.</para>
  39 </preface>
  40
  41 <article>
  42 <section id="DevRequirements"><title>Development platform requirements</title>
  43         <para>
  44         Monitoring Plugins are developed to the GNU standard, so any OS which is supported by GNU
  45         should run the plugins. While the requirements for compiling the Monitoring Plugins release
  46         are very basic, developing from the Git repository requires additional software to be
  47         installed. These are the minimum levels of software required:
  48
  49         <literallayout>
  50         GNU make 3.79
  51         GNU automake 1.9.2
  52         GNU autoconf 2.59
  53         GNU m4 1.4.2
  54         GNU libtool 1.5
  55         </literallayout>
  56
  57         To compile from Git, after you have cloned the repository, run:
  58         <literallayout>
  59         tools/setup
  60         ./configure
  61         make
  62         make install
  63         </literallayout>
  64         </para>
  65 </section>
  66
  67 <section id="PlugOutput"><title>Plugin Output for Nagios</title>
  68
  69                 <para>You should always print something to STDOUT that tells if the
  70                 service is working or why it is failing. Try to keep the output short -
  71                 probably less that 80 characters. Remember that you ideally would like
  72                 the entire output to appear in a pager message, which will get chopped
  73                 off after a certain length.</para>
  74
  75                 <para>As Nagios does not capture stderr output, you should only output to
  76                 STDOUT and not print to STDERR.</para>
  77
  78                 <section><title>Print only one line of text</title>
  79                 <para>Starting with version 3, Nagios will process plugins' multiline
  80                 output, which should be formatted as:</para>
  81                 <literallayout>
  82                 SERVICE STATUS: First line of output | First part of performance data
  83                 Any number of subsequent lines of output, but note that buffers
  84                 may have a limited size | Second part of performance data, which
  85                 may have continuation lines, too
  86                 </literallayout>
  87                 <para>Note, however, that the default configs still do not include
  88                 the output's continuation lines into the notifications sent when
  89                 Nagios notifies contacts about potential problems.
  90                 Thus, keep your output short and to the point.</para>
  91
  92                 <para>Output should be in the format:</para>
  93                 <literallayout>
  94                 SERVICE STATUS: Information text
  95                 </literallayout>
  96                 <para>However, note that this is not a requirement of the API, so you cannot depend on this
  97                 being an accurate reflection of the status of the service - the status should always
  98                 be determined by the return code.</para>
  99                 </section>
 100
 101                 <section><title>Verbose output</title>
 102                 <para>Use the -v flag for verbose output. You should allow multiple
 103                 -v options for additional verbosity, up to a maximum of 3. The standard
 104                 type of output should be:</para>
 105
 106                 <table id="verboselevels"><title>Verbose output levels</title>
 107                         <tgroup cols="2">
 108                                 <thead>
 109                                         <row>
 110                                                 <entry><para>Verbosity level</para></entry>
 111                                                 <entry><para>Type of output</para></entry>
 112                                         </row>
 113                                 </thead>
 114                                 <tbody>
 115                                         <row>
 116                                                 <entry align="center"><para>0</para></entry>
 117                                                 <entry><para>Single line, minimal output. Summary</para></entry>
 118                                         </row>
 119                                         <row>
 120                                                 <entry align="center"><para>1</para></entry>
 121                                                 <entry><para>Single line, additional information (eg list processes that fail)</para></entry>
 122                                         </row>
 123                                         <row>
 124                                                 <entry align="center"><para>2</para></entry>
 125                                                 <entry><para>Multi line, configuration debug output (eg ps command used)</para></entry>
 126                                         </row>
 127                                         <row>
 128                                                 <entry align="center"><para>3</para></entry>
 129                                                 <entry><para>Lots of detail for plugin problem diagnosis</para></entry>
 130                                         </row>
 131                                 </tbody>
 132                         </tgroup>
 133                 </table>
 134                 </section>
 135
 136                 <section><title>Screen Output</title>
 137                 <para>The plugin should print the diagnostic and just the
 138                 usage part of the help message.  A well written plugin would
 139                 then have --help as a way to get the verbose help.</para>
 140
 141                 <para>Code and output should try to respect the 80x25 size of a
 142                 crt (remember when fixing stuff in the server room!)</para>
 143                 </section>
 144
 145                 <section><title>Plugin Return Codes</title>
 146                 <para>The return codes below are based on the POSIX spec of returning
 147                 a positive value.  Netsaint prior to v0.0.7 supported non-POSIX
 148                 compliant return code of "-1" for unknown. Nagios supports POSIX return
 149                 codes by default.</para>
 150
 151                 <para>Note: Some plugins will on occasion print on STDOUT that an error
 152                 occurred and error code is 138 or 255 or some such number.  These
 153                 are usually caused by plugins using system commands and having not
 154                 enough checks to catch unexpected output.  Developers should include a
 155                 default catch-all for system command output that returns an UNKNOWN
 156                 return code.</para>
 157
 158                 <table id="ReturnCodes"><title>Plugin Return Codes</title>
 159                         <tgroup cols="3">
 160                                 <thead>
 161                                         <row>
 162                                                 <entry><para>Numeric Value</para></entry>
 163                                                 <entry><para>Service Status</para></entry>
 164                                                 <entry><para>Status Description</para></entry>
 165                                         </row>
 166                                 </thead>
 167                                 <tbody>
 168                                         <row>
 169                                                 <entry align="center"><para>0</para></entry>
 170                                                 <entry valign="middle"><para>OK</para></entry>
 171                                                 <entry><para>The plugin was able to check the service and it
 172                                                 appeared to be functioning properly</para></entry>
 173                                         </row>
 174                                         <row>
 175                                                 <entry align="center"><para>1</para></entry>
 176                                                 <entry valign="middle"><para>Warning</para></entry>
 177                                                 <entry><para>The plugin was able to check the service, but it
 178                                                 appeared to be above some "warning" threshold or did not appear
 179                                                 to be working properly</para></entry>
 180                                         </row>
 181                                         <row>
 182                                                 <entry align="center"><para>2</para></entry>
 183                                                 <entry valign="middle"><para>Critical</para></entry>
 184                                                 <entry><para>The plugin detected that either the service was not
 185                                                 running or it was above some "critical" threshold</para></entry>
 186                                         </row>
 187                                         <row>
 188                                                 <entry align="center"><para>3</para></entry>
 189                                                 <entry valign="middle"><para>Unknown</para></entry>
 190                                                 <entry><para>Invalid command line arguments were supplied to the
 191                                                 plugin or low-level failures internal to the plugin (such as unable to fork,
 192                                                 or open a tcp socket) that prevent it from performing the specified
 193                                                 operation. Higher-level errors (such as name resolution errors,
 194                                                 socket timeouts, etc) are outside of the control of plugins and should
 195                                                 generally NOT be reported as UNKNOWN states.
 196                                                 </para><para>The --help or --version output should also result in Unknown state.
 197                                                 </para></entry>
 198                                         </row>
 199                                 </tbody>
 200                         </tgroup>
 201                 </table>
 202
 203
 204                 </section>
 205
 206                 <section id="thresholdformat"><title>Threshold and ranges</title>
 207                 <para>A range is defined as a start and end point (inclusive) on a numeric scale (possibly
 208                 negative or positive infinity).
 209                 </para>
 210                 <para>A threshold is a range with an alert level (either warning or critical). Use the
 211                 set_thresholds(thresholds *, char *, char *) function to set the thresholds.
 212                 </para>
 213                 <para>The theory is that the plugin will do some sort of check which returns
 214                 back a numerical value, or metric, which is then compared to the warning and
 215                 critical thresholds. Use the get_status(double, thresholds *) function to
 216                 compare the value against the thresholds.</para>
 217                 <para>This is the generalised format for ranges:</para>
 218
 219                 <literallayout>
 220                 [@]start:end
 221                 </literallayout>
 222
 223                 <para>Notes:</para>
 224                 <orderedlist>
 225                 <listitem><para>start &le; end</para>
 226                         </listitem>
 227                 <listitem><para>start and ":" is not required if start=0</para>
 228                         </listitem>
 229                 <listitem><para>if range is of format "start:" and end is not specified,
 230                         assume end is infinity</para>
 231                         </listitem>
 232                 <listitem><para>to specify negative infinity, use "~"</para>
 233                         </listitem>
 234                 <listitem><para>alert is raised if metric is outside start and end range
 235                         (inclusive of endpoints)</para>
 236                         </listitem>
 237                 <listitem><para>if range starts with "@", then alert if inside this range
 238                         (inclusive of endpoints)</para>
 239                         </listitem>
 240                 </orderedlist>
 241
 242                 <para>Note: Not all plugins are coded to expect ranges in this format yet.
 243                 There will be some work in providing multiple metrics.</para>
 244
 245                 <table id="ExampleRanges"><title>Example ranges</title>
 246                         <tgroup cols="2">
 247                                 <thead>
 248                                         <row>
 249                                                 <entry><para>Range definition</para></entry>
 250                                                 <entry><para>Generate an alert if x...</para></entry>
 251                                         </row>
 252                                 </thead>
 253                                 <tbody>
 254                                         <row>
 255                                                 <entry>10</entry>
 256                                                 <entry>&lt; 0 or &gt; 10, (outside the range of {0 .. 10})</entry>
 257                                         </row>
 258                                         <row>
 259                                                 <entry>10:</entry>
 260                                                 <entry>&lt; 10, (outside {10 .. &infin;})</entry>
 261                                         </row>
 262                                         <row>
 263                                                 <entry>~:10</entry>
 264                                                 <entry>&gt; 10, (outside the range of {-&infin; .. 10})</entry>
 265                                         </row>
 266                                         <row>
 267                                                 <entry>10:20</entry>
 268                                                 <entry>&lt; 10 or &gt; 20, (outside the range of {10 .. 20})</entry>
 269                                         </row>
 270                                         <row>
 271                                                 <entry>@10:20</entry>
 272                                                 <entry>&ge; 10 and &le; 20, (inside the range of {10 .. 20})</entry>
 273                                         </row>
 274                                 </tbody>
 275                         </tgroup>
 276                 </table>
 277                 <table id="CommandLineExamples"><title>Command line examples</title>
 278                         <tgroup cols="2">
 279                                 <thead>
 280                                         <row>
 281                                                 <entry><para>Command line</para></entry>
 282                                                 <entry><para>Meaning</para></entry>
 283                                         </row>
 284                                 </thead>
 285                                 <tbody>
 286                                         <row>
 287                                                 <entry>check_stuff -w10 -c20</entry>
 288                                                 <entry>Critical if "stuff" is over 20, else warn if over 10 (will be critical if "stuff" is less than 0)</entry>
 289                                         </row>
 290                                         <row>
 291                                                 <entry>check_stuff -w~:10 -c~:20</entry>
 292                                                 <entry>Same as above. Negative "stuff" is OK</entry>
 293                                         </row>
 294                                         <row>
 295                                                 <entry>check_stuff -w10: -c20</entry>
 296                                                 <entry>Critical if "stuff" is over 20, else warn if "stuff" is below 10 (will be critical if "stuff" is less than 0)</entry>
 297                                         </row>
 298                                         <row>
 299                                                 <entry>check_stuff -c1:</entry>
 300                                                 <entry>Critical if "stuff" is less than 1</entry>
 301                                         </row>
 302                                         <row>
 303                                                 <entry>check_stuff -w~:0 -c10</entry>
 304                                                 <entry>Critical if "stuff" is above 10; Warn if "stuff" is above zero (will be critical if "stuff" is less than 0)</entry>
 305                                         </row>
 306                                         <row>
 307                                                 <entry>check_stuff -c5:6</entry>
 308                                                 <entry>Critical if "stuff" is less than 5 or more than 6</entry>
 309                                         </row>
 310                                         <row>
 311                                                 <entry>check_stuff -c@10:20</entry>
 312                                                 <entry>OK if stuff is less than 10 or higher than 20, otherwise critical </entry>
 313                                         </row>
 314                                 </tbody>
 315                         </tgroup>
 316                 </table>
 317                 </section>
 318
 319                 <section><title>Performance data</title>
 320                 <para>Nagios 3 and newer will concatenate the parts following a "|" in a) the first
 321                 line output by the plugin, and b) in the second to last line, into a string it
 322                 passes to whatever performance data processing it has configured. (Note that it
 323                 currently does not insert additional whitespace between both, so the plugin needs
 324                 to provide some to prevent the last pair of a) and the first of b) getting run
 325                 together.) Please refer to the Nagios documentation for information on how to
 326                 configure such processing. However, it is the responsibility of the plugin writer
 327                 to ensure the performance data is in a "Nagios Plugins" format.
 328                 This is the expected format:</para>
 329
 330                 <literallayout>
 331                 'label'=value[UOM];[warn];[crit];[min];[max]
 332                 </literallayout>
 333
 334                 <para>Notes:</para>
 335                 <orderedlist>
 336                 <listitem><para>space separated list of label/value pairs</para>
 337                         </listitem>
 338                 <listitem><para>label can contain any characters except the equals sign or single quote (')</para>
 339                         </listitem>
 340                 <listitem><para>the single quotes for the label are optional. Required if
 341                         spaces are in the label</para>
 342                         </listitem>
 343                 <listitem><para>label length is arbitrary, but ideally the first 19 characters
 344                         are unique (due to a limitation in RRD). Be aware of a limitation in the
 345                         amount of data that NRPE returns to Nagios</para>
 346                         </listitem>
 347                 <listitem><para>to specify a quote character, use two single quotes</para>
 348                         </listitem>
 349                 <listitem><para>warn, crit, min or max may be null (for example, if the threshold is
 350                         not defined or min and max do not apply). Trailing unfilled semicolons can be
 351                         dropped</para>
 352                         </listitem>
 353                 <listitem><para>min and max are not required if UOM=%</para>
 354                         </listitem>
 355                 <listitem><para>value, min and max in class [-0-9.]. Must all be the
 356                         same UOM. value may be a literal "U" instead, this would indicate that the
 357                         actual value couldn't be determined</para>
 358                         </listitem>
 359                 <listitem><para>warn and crit are in the range format (see
 360                         <xref linkend="thresholdformat">). Must be the same UOM</para>
 361                         </listitem>
 362                 <listitem><para>UOM (unit of measurement) is one of:</para>
 363                         <orderedlist>
 364                         <listitem><para>no unit specified - assume a number (int or float)
 365                                 of things (eg, users, processes, load averages)</para>
 366                                 </listitem>
 367                         <listitem><para>s - seconds (also us, ms)</para></listitem>
 368                         <listitem><para>% - percentage</para></listitem>
 369                         <listitem><para>B - bytes (also KB, MB, TB)</para></listitem>
 370                         <listitem><para>c - a continuous counter (such as bytes
 371                                 transmitted on an interface)</para></listitem>
 372                         </orderedlist>
 373                         </listitem>
 374                 </orderedlist>
 375
 376                 <para>It is up to third party programs to convert the Monitoring Plugins
 377                 performance data into graphs.</para>
 378                 </section>
 379 </section>
 380
 381 <section id="SysCmdAuxFiles"><title>System Commands and Auxiliary Files</title>
 382
 383                 <section><title>Don't execute system commands without specifying their
 384                 full path</title>
 385                 <para>Don't use exec(), popen(), etc. to execute external
 386                 commands without explicitly using the full path of the external
 387                 program.</para>
 388
 389                 <para>Doing otherwise makes the plugin vulnerable to hijacking
 390                 by a trojan horse earlier in the search path. See the main
 391                 plugin distribution for examples on how this is done.</para>
 392                 </section>
 393
 394                 <section><title>Use spopen() if external commands must be executed</title>
 395
 396             <para>If you have to execute external commands from within your
 397         plugin and you're writing it in C, use the spopen() function
 398                 that Karl DeBisschop has written.</para>
 399
 400                 <para>The code for spopen() and spclose() is included with the
 401                 core plugin distribution.</para>
 402                 </section>
 403
 404                 <section><title>Don't make temp files unless absolutely required</title>
 405
 406                 <para>If temp files are needed, make sure that the plugin will
 407                 fail cleanly if the file can't be written (e.g., too few file
 408                 handles, out of disk space, incorrect permissions, etc.) and
 409                 delete the temp file when processing is complete.</para>
 410                 </section>
 411
 412         <section><title>Don't be tricked into following symlinks</title>
 413
 414                 <para>If your plugin opens any files, take steps to ensure that
 415                 you are not following a symlink to another location on the
 416                 system.</para>
 417                 </section>
 418
 419                 <section><title>Validate all input</title>
 420
 421                 <para>use routines in utils.c or utils.pm and write more as needed</para>
 422                 </section>
 423
 424 </section>
 425
 426
 427
 428
 429 <section id="PerlPlugin"><title>Perl Plugins</title>
 430
 431                 <para>Perl plugins are coded a little more defensively than other
 432                 plugins because of embedded Perl.  When configured as such, embedded
 433                 Perl Nagios (ePN) requires stricter use of the some of Perl's features.
 434                 This section outlines some of the steps needed to use ePN
 435                 effectively.</para>
 436
 437                 <orderedlist>
 438
 439                         <listitem><para> Do not use BEGIN and END blocks since they will be called
 440                         only once (when Nagios starts and shuts down) with Embedded Perl (ePN).  In
 441                         particular, do not use BEGIN blocks to initialize variables.</para>
 442                         </listitem>
 443
 444                         <listitem><para>To use utils.pm, you need to provide a full path to the
 445                         module in order for it to work.</para>
 446
 447           <literallayout>
 448           e.g.
 449                 use lib "/usr/local/nagios/libexec";
 450                 use utils qw(...);
 451           </literallayout>
 452                         </listitem>
 453
 454                         <listitem><para>Perl scripts should be called with "-w"</para>
 455                         </listitem>
 456
 457                         <listitem><para>All Perl plugins must compile cleanly under "use strict" - i.e. at
 458                         least explicitly package names as in "$main::x" or predeclare every
 459                         variable. </para>
 460
 461
 462                         <para>Explicitly initialize each variable in use.  Otherwise with
 463                         caching enabled, the plugin will not be recompiled each time, and
 464                         therefore Perl will not reinitialize all the variables.  All old
 465                         variable values will still be in effect.</para>
 466                         </listitem>
 467
 468                         <listitem><para>Do not use &gt;DATA&lt; handles (these simply do not compile under ePN).</para>
 469                         </listitem>
 470
 471                         <listitem><para>Do not use global variables in named subroutines. This is bad practise anyway, but with ePN the
 472                         compiler will report an error "&lt;global_var&gt; will not stay shared ..". Values used by
 473                         subroutines should be passed in the argument list.</para>
 474                         </listitem>
 475
 476                         <listitem><para>If writing to a file (perhaps recording
 477                         performance data) explicitly close close it.  The plugin never
 478                         calls <emphasis role="strong">exit</emphasis>; that is caught by
 479                         p1.pl, so output streams are never closed.</para>
 480                         </listitem>
 481
 482                         <listitem><para>As in <xref linkend="runtime"> all plugins need
 483                         to monitor their runtime, specially if they are using network
 484                         resources.  Use of the <emphasis>alarm</emphasis> is recommended
 485                         noting that some Perl modules (eg LWP) manage timers, so that an alarm
 486                         set by a plugin using such a module is overwritten by the module.
 487                         (workarounds are cunning (TM) or using the module timer)
 488                         Plugins may import a default time out ($TIMEOUT) from utils.pm.
 489                         </para>
 490                         </listitem>
 491
 492                         <listitem><para>Perl plugins should import %ERRORS from utils.pm
 493                         and then "exit $ERRORS{'OK'}" rather than "exit 0"
 494                         </para>
 495                         </listitem>
 496
 497                 </orderedlist>
 498
 499 </section>
 500
 501 <section id="runtime"><title>Runtime Timeouts</title>
 502
 503                 <para>Plugins have a very limited runtime - typically 10 sec.
 504                 As a result, it is very important for plugins to maintain internal
 505                 code to exit if runtime exceeds a threshold. </para>
 506
 507                 <para>All plugins should timeout gracefully, not just networking
 508                 plugins. For instance, df may lock if you have automounted
 509                 drives and your network fails - but on first glance, who'd think
 510                 df could lock up like that.  Plus, it should just be more error
 511                 resistant to be able to time out rather than consume
 512                 resources.</para>
 513
 514                 <section><title>Use DEFAULT_SOCKET_TIMEOUT</title>
 515
 516                 <para>All network plugins should use DEFAULT_SOCKET_TIMEOUT to timeout</para>
 517
 518                 </section>
 519
 520
 521                 <section><title>Add alarms to network plugins</title>
 522
 523                 <para>If you write a plugin which communicates with another
 524                 networked host, you should make sure to set an alarm() in your
 525                 code that prevents the plugin from hanging due to abnormal
 526                 socket closures, etc. Nagios takes steps to protect itself
 527                 against unruly plugins that timeout, but any plugins you create
 528                 should be well behaved on their own.</para>
 529
 530                 </section>
 531
 532
 533
 534 </section>
 535
 536 <section id="PlugOptions"><title>Plugin Options</title>
 537
 538                 <para>A well written plugin should have --help as a way to get
 539                 verbose help. Code and output should try to respect the 80x25 size of a
 540                 crt (remember when fixing stuff in the server room!)</para>
 541
 542                 <section><title>Option Processing</title>
 543
 544                 <para>For plugins written in C, we recommend the C standard
 545                 getopt library for short options. Getopt_long is always available.
 546                 </para>
 547
 548                 <para>For plugins written in Perl, we recommend Getopt::Long module.</para>
 549
 550                 <para>Positional arguments are strongly discouraged.</para>
 551
 552                 <para>There are a few reserved options that should not be used
 553                 for other purposes:</para>
 554
 555                 <literallayout>
 556           -V version (--version)
 557           -h help (--help)
 558           -t timeout (--timeout)
 559           -w warning threshold (--warning)
 560           -c critical threshold (--critical)
 561           -H hostname (--hostname)
 562           -v verbose (--verbose)
 563                 </literallayout>
 564
 565                 <para>In addition to the reserved options above, some other standard options are:</para>
 566
 567                 <literallayout>
 568           -C SNMP community (--community)
 569           -a authentication password (--authentication)
 570           -l login name (--logname)
 571           -p port or password (--port or --passwd/--password)monitors operational
 572           -u url or username (--url or --username)
 573                 </literallayout>
 574
 575                 <para>Look at check_pgsql and check_procs to see how I currently
 576                 think this can work.  Standard options are:</para>
 577
 578
 579                 <para>The option -V or --version should be present in all
 580                 plugins. For C plugins it should result in a call to print_revision, a
 581                 function in utils.c which takes two character arguments, the
 582                 command name and the plugin revision.</para>
 583
 584                 <para>The -? option, or any other unparsable set of options,
 585                 should print out a short usage statement. Character width should
 586                 be 80 and less and no more that 23 lines should be printed (it
 587                 should display cleanly on a dumb terminal in a server
 588                 room).</para>
 589
 590                 <para>The option -h or --help should be present in all plugins.
 591                 In C plugins, it should result in a call to print_help (or
 592                 equivalent).  The function print_help should call print_revision,
 593                 then print_usage, then should provide detailed
 594                 help. Help text should fit on an 80-character width display, but
 595                 may run as many lines as needed.</para>
 596
 597                 <para>The option -v or --verbose should be present in all plugins.
 598                 The user should be allowed to specify -v multiple times to increase
 599                 the verbosity level, as described in <xref linkend="verboselevels">.</para>
 600
 601                 <para>The exit code for version information or help should be UNKNOWN
 602                 (3).</para>
 603     </section>
 604
 605     <section>
 606       <title>Plugins with more than one type of threshold, or with
 607       threshold ranges</title>
 608
 609       <para>Old style was to do things like -ct for critical time and
 610       -cv for critical value. That goes out the window with POSIX
 611       getopt. The allowable alternatives are:</para>
 612
 613       <orderedlist>
 614         <listitem>
 615           <para>long options like -critical-time (or -ct and -cv, I
 616           suppose).</para>
 617         </listitem>
 618
 619         <listitem>
 620           <para>repeated options like `check_load -w 10 -w 6 -w 4 -c
 621           16 -c 10 -c 10`</para>
 622         </listitem>
 623
 624         <listitem>
 625           <para>for brevity, the above can be expressed as `check_load
 626           -w 10,6,4 -c 16,10,10`</para>
 627         </listitem>
 628
 629         <listitem>
 630           <para>ranges are expressed with colons as in `check_procs -C
 631           httpd -w 1:20 -c 1:30` which will warn above 20 instances,
 632           and critical at 0 and above 30</para>
 633         </listitem>
 634
 635         <listitem>
 636           <para>lists are expressed with commas, so Jacob's check_nmap
 637           uses constructs like '-p 1000,1010,1050:1060,2000'</para>
 638         </listitem>
 639
 640         <listitem>
 641           <para>If possible when writing lists, use tokens to make the
 642           list easy to remember and non-order dependent - so
 643           check_disk uses '-c 10000,10%' so that it is clear which is
 644           the percentage and which is the KB values (note that due to
 645           my own lack of foresight, that used to be '-c 10000:10%' but
 646           such constructs should all be changed for consistency,
 647           though providing reverse compatibility is fairly
 648           easy).</para>
 649         </listitem>
 650
 651       </orderedlist>
 652
 653       <para>As always, comments are welcome - making this consistent
 654       without a host of long options was quite a hassle, and I would
 655       suspect that there are flaws in this strategy.
 656       </para>
 657     </section>
 658 </section>
 659
 660 <section id="Testcases"><title>Test cases</title>
 661 <para>
 662 Tests are the best way of knowing if the plugins work as expected. Please
 663 create and update test cases where possible.
 664 </para>
 665
 666 <para>
 667 To run a test, from the top level directory, run "make test". This will run
 668 all the current tests and report an overall success rate.
 669 </para>
 670
 671 <section><title>Test cases for plugins</title>
 672 <para>These use perl's Test::More. To do a one time test, run "cd plugins && perl t/check_disk.t".
 673 </para>
 674
 675 <para>There will sometimes be failures seen in this output which are known failures that
 676 need to be fixed. As long as the return code is 0, it will be reported as "test pass".
 677 (If you have a fix so that the specific test passes, that will be gratefully received!)
 678 </para>
 679
 680 <para>
 681 If you want a summary test, run: "cd plugins && prove t/check_disk.t".
 682 This runs the test in a summary format.
 683 </para>
 684
 685 <para>
 686 For a good and amusing tutorial on using Test::More, see this
 687 <ulink url="http://search.cpan.org/dist/Test-Simple/lib/Test/Tutorial.pod">
 688 link</ulink>
 689 </para>
 690
 691 </section>
 692
 693 <section><title>Testing the C library functions</title>
 694 <para>
 695 We use <ulink url="http://jc.ngo.org.uk/trac-bin/trac.cgi/wiki/LibTap">the libtap library</ulink>, which gives
 696 perl's TAP
 697 (Test Anything Protocol) output. This is used by the FreeBSD team for their regression testing.
 698 </para>
 699
 700 <para>
 701 To run tests using the libtap library, download the latest tar ball and extract.
 702 There is a problem with tap-1.01 where
 703 <ulink url="http://jc.ngo.org.uk/trac-bin/trac.cgi/ticket/25">pthread support doesn't appear to work</ulink>
 704 properly on non-FreeBSD systems. Install with 'CPPFLAGS="-UHAVE_LIBPTHREAD" ./configure && make && make check && make install'.
 705 </para>
 706
 707 <para>
 708 When you run Monitoring Plugins' configure, it will look for the tap library and will automatically
 709 setup the tests. Run "make test" to run all the tests.
 710 </para>
 711 </section>
 712
 713 </section>
 714 <section id="CodingGuidelines"><title>Coding guidelines</title>
 715         <para>See <ulink url="http://www.gnu.org/prep/standards_toc.html">GNU
 716         Coding standards</ulink> for general guidelines.
 717         Some parts of the guidelines (namely and explicitly the coding style)
 718         are not seen as best practice by us.</para>
 719         <section><title>C coding</title>
 720
 721         <para>You should use the type "bool" and its values
 722         "true" and "false" instead of the "int" type for booleans.
 723         </para>
 724         </section>
 725
 726         <section><title>Crediting sources</title>
 727         <para>If you have copied a routine from another source, make sure the license
 728         from your source allows this. Add a comment referencing the ACKNOWLEDGEMENTS
 729         file, where you can put more detail about the source.</para>
 730         <para>For contributed code, do not add any named credits in the source code
 731         - contributors should be added into the THANKS.in file instead.
 732         </para>
 733         </section>
 734
 735         <section><title>Commit Messages</title>
 736         <para>If the change is due to a contribution, please quote the contributor's name
 737         and, if applicable, add the GitHub Issue Tracker number. Don't forget to
 738   update the THANKS.in file.</para>
 739         <para>If you have a change that is useful for noting in the next release, please
 740         update the NEWS file.</para>
 741         <para>All commits will be written to a ChangeLog at release time.
 742         </para>
 743         </section>
 744 </section>
 745
 746 <section id="SubmittingChanges"><title>Submission of new plugins and patches</title>
 747
 748         <section id="Patches"><title>Patches</title>
 749         <para>If you have a bug patch, please supply a unified or context diff against the
 750         version you are using. For new features, please supply a diff against
 751         the Git "master" branch.</para>
 752
 753         <para>Patches should be submitted via
 754         <ulink url="https://github.com/monitoring-plugins/monitoring-plugins/pulls">GitHub's
 755         Pull requests for Monitoring Plugins</ulink>
 756         </para>
 757
 758         <para>Submission of a patch implies that the submmitter acknowledges that they
 759         are the author of the code (or have permission from the author to release the code)
 760         and agree that the code can be released under the GPL. The copyright for the changes will
 761         then revert to the Monitoring Plugins Development Team - this is required so that any copyright
 762         infringements can be investigated quickly without contacting a huge list of copyright holders.
 763         Credit will always be given for any patches through a THANKS file in the distribution.</para>
 764         </section>
 765
 766
 767         <section id="Contributedplugins"><title>Contributed plugins</title>
 768         <para>Plugins that have been contributed to the project and
 769         distributed with the Monitoring Plugins files are held in the contrib/ directory and are not installed
 770         by default. These plugins are not officially supported by the team.
 771         The current policy is that these plugins should be owned and maintained by the original
 772         contributor, preferably hosted on <ulink url="https://exchange.icinga.com/">Icinga Exchange</ulink>.
 773         </para>
 774         <para>If patches or bugs are raised to an contributed plugin, we will start communications with the
 775         original contributor, but seek to remove the plugin from our distribution.
 776         </para>
 777         <para>The aim is to distribute only code that the Monitoring Plugins team are responsible for.
 778         </para>
 779         </section>
 780
 781         <section id="Newplugins"><title>New plugins</title>
 782         <para>If you would like others to use your plugins, please add it to
 783         the official 3rd party plugin repository,
 784         <ulink url="https://exchange.icinga.com/">Icinga Exchange</ulink>.
 785         </para>
 786
 787         <para>We are not accepting requests for inclusion of plugins into
 788         our distribution at the moment, but when we do, these are the minimum
 789         requirements:
 790         </para>
 791
 792       <orderedlist>
 793         <listitem>
 794           <para>Include copyright and license information in all files. Copyright must be solely
 795                 granted to the Monitoring Plugins Development Team</para>
 796         </listitem>
 797         <listitem>
 798           <para>The standard command options are supported (--help, --version,
 799           --timeout, --warning, --critical)</para>
 800         </listitem>
 801         <listitem>
 802           <para>It is determined to be not redundant (for instance, we would not
 803                 add a new version of check_disk just because someone had provide
 804                 a plugin that had perf checking - we would incorporate the features
 805                 into an existing plugin)</para>
 806         </listitem>
 807         <listitem>
 808           <para>One of the developers has had the time to audit the code and declare
 809                 it ready for core</para>
 810         </listitem>
 811         <listitem>
 812           <para>It should also follow code format guidelines, and use functions from
 813 utils (perl or c or sh) rather than using its own</para>
 814         </listitem>
 815         <listitem>
 816           <para>Includes patches to configure.in if required (via the EXTRAS list if
 817           it will only work on some platforms)</para>
 818         </listitem>
 819         <listitem>
 820           <para>If possible, please submit a test harness. Documentation on sample
 821           tests coming soon</para>
 822         </listitem>
 823       </orderedlist>
 824
 825         </section>
 826
 827 </section>
 828 </article>
 829
 830 </book>