1 # Language Reference <a id="language-reference"></a>
3 ## Object Definition <a id="object-definition"></a>
5 Icinga 2 features an object-based configuration format. You can define new
6 objects using the `object` keyword:
8 object Host "host1.example.org" {
11 address = "192.168.0.1"
15 In general you need to write each statement on a new line. Expressions started
16 with `{`, `(` and `[` extend until the matching closing character and can be broken
17 up into multiple lines.
19 Alternatively you can write multiple statements on a single line by separating
20 them with a semicolon:
22 object Host "host1.example.org" {
23 display_name = "host1"
25 address = "192.168.0.1"; address6 = "::1"
28 Each object is uniquely identified by its type (`Host`) and name
29 (`host1.example.org`). Some types have composite names, e.g. the
30 `Service` type which uses the `host_name` attribute and the name
31 you specified to generate its object name.
33 Exclamation marks (!) are not permitted in object names.
35 Objects can contain a comma-separated list of property
36 declarations. Instead of commas semicolons may also be used.
37 The following data types are available for property values:
39 All objects have at least the following attributes:
41 Attribute | Description
42 ---------------------|-----------------------------
43 name | The name of the object. This attribute can be modified in the object definition to override the name specified with the `object` directive.
44 type | The type of the object.
46 ## Expressions <a id="expressions"></a>
48 The following expressions can be used on the right-hand side of assignments.
50 ### Numeric Literals <a id="numeric-literals"></a>
52 A floating-point number.
58 ### Duration Literals <a id="duration-literals"></a>
60 Similar to floating-point numbers except for the fact that they support
61 suffixes to help with specifying time durations.
67 Supported suffixes include ms (milliseconds), s (seconds), m (minutes),
68 h (hours) and d (days).
70 Duration literals are converted to seconds by the config parser and
71 are treated like numeric literals.
73 ### String Literals <a id="string-literals"></a>
81 #### String Literals Escape Sequences <a id="string-literals-escape-sequences"></a>
83 Certain characters need to be escaped. The following escape sequences
86 Character | Escape sequence
87 --------------------------|------------------------------------
91 <CARRIAGE-RETURN> | \\r
92 <LINE-FEED> | \\n
94 <FORM-FEED> | \\f
96 In addition to these pre-defined escape sequences you can specify
97 arbitrary ASCII characters using the backslash character (\\) followed
98 by an ASCII character in octal encoding.
100 ### Multi-line String Literals <a id="multiline-string-literals"></a>
102 Strings spanning multiple lines can be specified by enclosing them in
112 Unlike in ordinary strings special characters do not have to be escaped
113 in multi-line string literals.
115 ### Boolean Literals <a id="boolean-literals"></a>
117 The keywords `true` and `false` are used to denote truth values.
119 ### Null Value <a id="null-value"></a>
121 The `null` keyword can be used to specify an empty value.
123 ### Dictionary <a id="dictionary"></a>
125 An unordered list of key-value pairs. Keys must be unique and are
126 compared in a case-sensitive manner.
128 Individual key-value pairs must either be comma-separated or on separate lines.
129 The comma after the last key-value pair is optional.
134 address = "192.168.0.1"
138 Identifiers may not contain certain characters (e.g. space) or start
139 with certain characters (e.g. digits). If you want to use a dictionary
140 key that is not a valid identifier, you can enclose the key in double
143 ### Array <a id="array"></a>
145 An ordered list of values.
147 Individual array elements must be comma-separated.
148 The comma after the last element is optional.
154 An array may simultaneously contain values of different types, such as
157 ### Operators <a id="expression-operators"></a>
159 The following operators are supported in expressions. The operators are sorted by descending precedence.
161 Operator | Precedence | Examples (Result) | Description
162 ---------|------------|-----------------------------------------------|--------------------------------
163 () | 1 | (3 + 3) * 5 | Groups sub-expressions
164 () | 1 | Math.random() | Calls a function
165 [] | 1 | a[3] | Array subscript
166 . | 1 | a.b | Element access
167 ! | 2 | !"Hello" (false), !false (true) | Logical negation of the operand
168 ~ | 2 | ~true (false) | Bitwise negation of the operand
169 + | 2 | +3 | Unary plus
170 - | 2 | -3 | Unary minus
171 * | 3 | 5m * 10 (3000) | Multiplies two numbers
172 / | 3 | 5m / 5 (60) | Divides two numbers
173 % | 3 | 17 % 12 (5) | Remainder after division
174 + | 4 | 1 + 3 (4), "hello " + "world" ("hello world") | Adds two numbers; concatenates strings
175 - | 4 | 3 - 1 (2) | Subtracts two numbers
176 << | 5 | 4 << 8 (1024) | Left shift
177 >> | 5 | 1024 >> 4 (64) | Right shift
178 < | 6 | 3 < 5 (true) | Less than
179 > | 6 | 3 > 5 (false) | Greater than
180 <= | 6 | 3 <= 3 (true) | Less than or equal
181 >= | 6 | 3 >= 3 (true) | Greater than or equal
182 in | 7 | "foo" in [ "foo", "bar" ] (true) | Element contained in array
183 !in | 7 | "foo" !in [ "bar", "baz" ] (true) | Element not contained in array
184 == | 8 | "hello" == "hello" (true), 3 == 5 (false) | Equal to
185 != | 8 | "hello" != "world" (true), 3 != 3 (false) | Not equal to
186 & | 9 | 7 & 3 (3) | Binary AND
187 ^ | 10 | 17 ^ 12 (29) | Bitwise XOR
188 | | 11 | 2 | 3 (3) | Binary OR
189 && | 13 | true && false (false), 3 && 7 (7), 0 && 7 (0) | Logical AND
190 || | 14 | true || false (true), 0 || 7 (7)| Logical OR
191 = | 12 | a = 3 | Assignment
192 => | 15 | x => x * x (function with arg x) | Lambda, for loop
194 ### Function Calls <a id="function-calls"></a>
196 Functions can be called using the `()` operator:
198 const MyGroups = [ "test1", "test" ]
201 check_interval = len(MyGroups) * 1m
204 A list of available functions is available in the [Library Reference](18-library-reference.md#library-reference) chapter.
206 ## Assignments <a id="dictionary-operators"></a>
208 In addition to the `=` operator shown above a number of other operators
209 to manipulate attributes are supported. Here's a list of all
212 ### Operator = <a id="operator-assignment"></a>
214 Sets an attribute to the specified value.
223 In this example `a` has the value `7` after both instructions are executed.
225 ### Operator += <a id="operator-additive-assignment"></a>
227 The += operator is a shortcut. The following expression:
241 ### Operator -= <a id="operator-substractive-assignment"></a>
243 The -= operator is a shortcut. The following expression:
257 ### Operator \*= <a id="operator-multiply-assignment"></a>
259 The *= operator is a shortcut. The following expression:
273 ### Operator /= <a id="operator-dividing-assignment"></a>
275 The /= operator is a shortcut. The following expression:
289 ## Indexer <a id="indexer"></a>
291 The indexer syntax provides a convenient way to set dictionary elements.
299 Example (alternative syntax):
302 hello["key"] = "world"
305 This is equivalent to writing:
313 If the `hello` attribute does not already have a value, it is automatically initialized to an empty dictionary.
315 ## Template Imports <a id="template-imports"></a>
317 Objects can import attributes from other objects.
321 template Host "default-host" {
325 template Host "test-host" {
326 import "default-host"
331 object Host "localhost" {
334 address = "127.0.0.1"
338 The `default-host` and `test-host` objects are marked as templates
339 using the `template` keyword. Unlike ordinary objects templates are not
340 instantiated at run-time. Parent objects do not necessarily have to be
341 templates, however in general they are.
343 The `vars` dictionary for the `localhost` object contains all three
344 custom attributes and the custom attribute `colour` has the value `"blue"`.
346 Parent objects are resolved in the order they're specified using the
349 Default templates which are automatically imported into all object definitions
350 can be specified using the `default` keyword:
352 template CheckCommand "plugin-check-command" default {
356 Default templates are imported before any other user-specified statement in an
357 object definition is evaluated.
359 If there are multiple default templates the order in which they are imported
362 ## Constants <a id="constants"></a>
364 Global constants can be set using the `const` keyword:
366 const VarName = "some value"
368 Once defined a constant can be accessed from any file. Constants cannot be changed
373 > Best practice is to manage constants in the [constants.conf](04-configuring-icinga-2.md#constants-conf) file.
375 ### Icinga 2 Specific Constants <a id="icinga-constants"></a>
377 Icinga 2 provides a number of special global constants. Some of them can be overridden using the `--define` command line parameter:
379 Variable |Description
380 --------------------|-------------------
381 PrefixDir |**Read-only.** Contains the installation prefix that was specified with cmake -DCMAKE_INSTALL_PREFIX. Defaults to "/usr/local".
382 SysconfDir |**Read-only.** Contains the path of the sysconf directory. Defaults to PrefixDir + "/etc".
383 ZonesDir |**Read-only.** Contains the path of the zones.d directory. Defaults to SysconfDir + "/zones.d".
384 LocalStateDir |**Read-only.** Contains the path of the local state directory. Defaults to PrefixDir + "/var".
385 RunDir |**Read-only.** Contains the path of the run directory. Defaults to LocalStateDir + "/run".
386 PkgDataDir |**Read-only.** Contains the path of the package data directory. Defaults to PrefixDir + "/share/icinga2".
387 StatePath |**Read-write.** Contains the path of the Icinga 2 state file. Defaults to LocalStateDir + "/lib/icinga2/icinga2.state".
388 ObjectsPath |**Read-write.** Contains the path of the Icinga 2 objects file. Defaults to LocalStateDir + "/cache/icinga2/icinga2.debug".
389 PidPath |**Read-write.** Contains the path of the Icinga 2 PID file. Defaults to RunDir + "/icinga2/icinga2.pid".
390 Vars |**Read-write.** Contains a dictionary with global custom attributes. Not set by default.
391 NodeName |**Read-write.** Contains the cluster node name. Set to the local hostname by default.
392 RunAsUser |**Read-write.** Defines the user the Icinga 2 daemon is running as. Set in the Icinga 2 sysconfig.
393 RunAsGroup |**Read-write.** Defines the group the Icinga 2 daemon is running as. Set in the Icinga 2 sysconfig.
394 PlatformName |**Read-only.** The name of the operating system, e.g. "Ubuntu".
395 PlatformVersion |**Read-only.** The version of the operating system, e.g. "14.04.3 LTS".
396 PlatformKernel |**Read-only.** The name of the operating system kernel, e.g. "Linux".
397 PlatformKernelVersion|**Read-only.** The version of the operating system kernel, e.g. "3.13.0-63-generic".
398 BuildCompilerName |**Read-only.** The name of the compiler Icinga was built with, e.g. "Clang".
399 BuildCompilerVersion|**Read-only.** The version of the compiler Icinga was built with, e.g. "7.3.0.7030031".
400 BuildHostName |**Read-only.** The name of the host Icinga was built on, e.g. "acheron".
401 ApplicationVersion |**Read-only.** The application version, e.g. "2.9.0".
402 MaxConcurrentChecks |**Read-write**. The number of max checks run simultaneously. Defaults to 512.
403 Environment |**Read-write**. The name of the Icinga environment. Included in the SNI host name when making outbound connections. Defaults to "production".
406 Advanced runtime constants. Please only use them if advised by support or developers.
408 Variable | Description
409 ---------------------------|-------------------
410 EventEngine |**Read-write.** The name of the socket event engine, can be `poll` or `epoll`. The epoll interface is only supported on Linux.
411 AttachDebugger |**Read-write.** Whether to attach a debugger when Icinga 2 crashes. Defaults to `false`.
412 ICINGA2\_RLIMIT\_FILES |**Read-write.** Defines the resource limit for RLIMIT_NOFILE that should be set at start-up. Value cannot be set lower than the default `16 * 1024`. 0 disables the setting. Set in Icinga 2 sysconfig.
413 ICINGA2\_RLIMIT\_PROCESSES |**Read-write.** Defines the resource limit for RLIMIT_NPROC that should be set at start-up. Value cannot be set lower than the default `16 * 1024`. 0 disables the setting. Set in Icinga 2 sysconfig.
414 ICINGA2\_RLIMIT\_STACK |**Read-write.** Defines the resource limit for RLIMIT_STACK that should be set at start-up. Value cannot be set lower than the default `256 * 1024`. 0 disables the setting. Set in Icinga 2 sysconfig.
416 ## Apply <a id="apply"></a>
418 The `apply` keyword can be used to create new objects which are associated with
419 another group of objects.
421 apply Service "ping" to Host {
422 import "generic-service"
424 check_command = "ping4"
426 assign where host.name == "localhost"
429 In this example the `assign where` condition is a boolean expression which is
430 evaluated for all objects of type `Host` and a new service with name "ping"
431 is created for each matching host. [Expression operators](17-language-reference.md#expression-operators)
432 may be used in `assign where` conditions.
434 The `to` keyword and the target type may be omitted if there is only one target
435 type, e.g. for the `Service` type.
437 Depending on the object type used in the `apply` expression additional local
438 variables may be available for use in the `where` condition:
440 Source Type | Target Type | Variables
441 ------------------|-------------|--------------
442 Service | Host | host
443 Dependency | Host | host
444 Dependency | Service | host, service
445 Notification | Host | host
446 Notification | Service | host, service
447 ScheduledDowntime | Host | host
448 ScheduledDowntime | Service | host, service
450 Any valid config attribute can be accessed using the `host` and `service`
451 variables. For example, `host.address` would return the value of the host's
452 "address" attribute -- or null if that attribute isn't set.
454 More usage examples are documented in the [monitoring basics](03-monitoring-basics.md#using-apply-expressions)
457 ## Apply For <a id="apply-for"></a>
459 [Apply](17-language-reference.md#apply) rules can be extended with the
460 [for loop](17-language-reference.md#for-loops) keyword.
462 apply Service "prefix-" for (key => value in host.vars.dictionary) to Host {
463 import "generic-service"
465 check_command = "ping4"
466 vars.host_value = value
470 Any valid config attribute can be accessed using the `host` and `service`
471 variables. The attribute must be of the Array or Dictionary type. In this example
472 `host.vars.dictionary` is of the Dictionary type which needs a key-value-pair
475 In this example all generated service object names consist of `prefix-` and
476 the value of the `key` iterator. The prefix string can be omitted if not required.
478 The `key` and `value` variables can be used for object attribute assignment, e.g. for
479 setting the `check_command` attribute or custom attributes as command parameters.
481 `apply for` rules are first evaluated against all objects matching the `for loop` list
482 and afterwards the `assign where` and `ignore where` conditions are evaluated.
484 It is not necessary to check attributes referenced in the `for loop` expression
485 for their existance using an additional `assign where` condition.
487 More usage examples are documented in the [monitoring basics](03-monitoring-basics.md#using-apply-for)
490 ## Group Assign <a id="group-assign"></a>
492 Group objects can be assigned to specific member objects using the `assign where`
493 and `ignore where` conditions.
495 object HostGroup "linux-servers" {
496 display_name = "Linux Servers"
498 assign where host.vars.os == "Linux"
501 In this example the `assign where` condition is a boolean expression which is evaluated
502 for all objects of the type `Host`. Each matching host is added as member to the host group
503 with the name "linux-servers". Membership exclusion can be controlled using the `ignore where`
504 condition. [Expression operators](17-language-reference.md#expression-operators) may be used in `assign where` and
505 `ignore where` conditions.
507 Source Type | Variables
508 ------------------|--------------
510 ServiceGroup | host, service
514 ## Boolean Values <a id="boolean-values"></a>
516 The `assign where`, `ignore where`, `if` and `while` statements, the `!` operator as
517 well as the `bool()` function convert their arguments to a boolean value based on the
520 Description | Example Value | Boolean Value
521 ---------------------|-------------------|--------------
522 Empty value | null | false
524 Non-zero integer | -23945 | true
525 Empty string | "" | false
526 Non-empty string | "Hello" | true
527 Empty array | [] | false
528 Non-empty array | [ "Hello" ] | true
529 Empty dictionary | {} | false
530 Non-empty dictionary | { key = "value" } | true
532 For a list of supported expression operators for `assign where` and `ignore where`
533 statements, see [expression operators](17-language-reference.md#expression-operators).
535 ## Comments <a id="comments"></a>
537 The Icinga 2 configuration format supports C/C++-style and shell-style comments.
544 object Host "localhost" {
545 check_interval = 30 // this is also a comment.
546 retry_interval = 15 # yet another comment
549 ## Includes <a id="includes"></a>
551 Other configuration files can be included using the `include` directive.
552 Paths must be relative to the configuration file that contains the
557 include "some/other/file.conf"
558 include "conf.d/*.conf"
560 Wildcard includes are not recursive.
562 Icinga also supports include search paths similar to how they work in a
567 Note the use of angle brackets instead of double quotes. This causes the
568 config compiler to search the include search paths for the specified
569 file. By default $PREFIX/share/icinga2/include is included in the list of search
570 paths. Additional include search paths can be added using
571 [command-line options](11-cli-commands.md#config-include-path).
573 Wildcards are not permitted when using angle brackets.
575 ## Recursive Includes <a id="recursive-includes"></a>
577 The `include_recursive` directive can be used to recursively include all
578 files in a directory which match a certain pattern.
582 include_recursive "conf.d", "*.conf"
583 include_recursive "templates"
585 The first parameter specifies the directory from which files should be
586 recursively included.
588 The file names need to match the pattern given in the second parameter.
589 When no pattern is specified the default pattern "*.conf" is used.
591 ## Zone Includes <a id="zone-includes"></a>
593 The `include_zones` recursively includes all subdirectories for the
596 In addition to that it sets the `zone` attribute for all objects created
597 in these subdirectories to the name of the subdirectory.
601 include_zones "etc", "zones.d", "*.conf"
602 include_zones "puppet", "puppet-zones"
604 The first parameter specifies a tag name for this directive. Each `include_zones`
605 invocation should use a unique tag name. When copying the zones' configuration
606 files Icinga uses the tag name as the name for the destination directory in
607 `/var/lib/icinga2/api/config`.
609 The second parameter specifies the directory which contains the subdirectories.
611 The file names need to match the pattern given in the third parameter.
612 When no pattern is specified the default pattern "*.conf" is used.
614 ## Library directive <a id="library"></a>
616 The `library` directive was used to manually load additional
617 libraries. Starting with version 2.9 it is no longer necessary to explicitly load
618 libraries and this directive has no effect.
620 ## Functions <a id="functions"></a>
622 Functions can be defined using the `function` keyword.
626 function multiply(a, b) {
630 When encountering the `return` keyword further execution of the function is terminated and
631 the specified value is supplied to the caller of the function:
635 In this example the `multiply` function we declared earlier is invoked with two arguments (3 and 5).
636 The function computes the product of those arguments and makes the result available to the
639 When no value is supplied for the `return` statement the function returns `null`.
641 Functions which do not have a `return` statement have their return value set to the value of the
642 last expression which was performed by the function. For example, we could have also written our
643 `multiply` function like this:
645 function multiply(a, b) {
649 Anonymous functions can be created by omitting the name in the function definition. The
650 resulting function object can be used like any other value:
652 var fn = function() { 3 }
656 ## Lambda Expressions <a id="lambdas"></a>
658 Functions can also be declared using the alternative lambda syntax.
664 Multiple statements can be used by putting the function body into braces:
671 Just like with ordinary functions the return value is the value of the last statement.
673 For lambdas which take exactly one argument the braces around the arguments can be omitted:
677 ## Abbreviated Lambda Syntax <a id="nullary-lambdas"></a>
679 Lambdas which take no arguments can also be written using the abbreviated lambda syntax.
685 This creates a new function which returns the value 3.
687 ## Variable Scopes <a id="variable-scopes"></a>
689 When setting a variable Icinga checks the following scopes in this order whether the variable
690 already exists there:
696 The local scope contains variables which only exist during the invocation of the current function,
697 object or apply statement. Local variables can be declared using the `var` keyword:
699 function multiply(a, b) {
704 Each time the `multiply` function is invoked a new `temp` variable is used which is in no way
705 related to previous invocations of the function.
707 When setting a variable which has not previously been declared as local using the `var` keyword
708 the `this` scope is used.
710 The `this` scope refers to the current object which the function or object/apply statement
713 object Host "localhost" {
717 In this example the `this` scope refers to the "localhost" object. The `check_interval` attribute
718 is set for this particular host.
720 You can explicitly access the `this` scope using the `this` keyword:
722 object Host "localhost" {
723 var check_interval = 5m
725 /* This explicitly specifies that the attribute should be set
726 * for the host, if we had omitted `this.` the (poorly named)
727 * local variable `check_interval` would have been modified instead.
729 this.check_interval = 1m
732 Similarly the keywords `locals` and `globals` are available to access the local and global scope.
734 Functions also have a `this` scope. However unlike for object/apply statements the `this` scope for
735 a function is set to whichever object was used to invoke the function. Here's an example:
740 function init(word) {
745 /* Let's invoke the init() function */
748 We're using `hm.init` to invoke the function which causes the value of `hm` to become the `this`
749 scope for this function call.
751 ## Closures <a id="closures"></a>
753 By default `function`s, `object`s and `apply` rules do not have access to variables declared
754 outside of their scope (except for global variables).
756 In order to access variables which are defined in the outer scope the `use` keyword can be used:
758 function MakeHelloFunction(name) {
759 return function() use(name) {
760 log("Hello, " + name)
764 In this case a new variable `name` is created inside the inner function's scope which has the
765 value of the `name` function argument.
767 Alternatively a different value for the inner variable can be specified:
769 function MakeHelloFunction(name) {
770 return function() use (greeting = "Hello, " + name) {
775 ## Conditional Statements <a id="conditional-statements"></a>
777 Sometimes it can be desirable to only evaluate statements when certain conditions are met. The if/else
778 construct can be used to accomplish this.
792 An if/else construct can also be used in place of any other value. The value of an if/else statement
793 is the value of the last statement which was evaluated for the branch which was taken:
796 log("Taking the 'true' branch")
799 log("Taking the 'false' branch")
803 This example prints the log message "Taking the 'true' branch" and the `a` variable is set to 21 (7 * 3).
805 The value of an if/else construct is null if the condition evaluates to false and no else branch is given.
807 ## While Loops <a id="while-loops"></a>
809 The `while` statement checks a condition and executes the loop body when the condition evaluates to `true`.
810 This is repeated until the condition is no longer true.
821 The `continue` and `break` keywords can be used to control how the loop is executed: The `continue` keyword
822 skips over the remaining expressions for the loop body and begins the next loop evaluation. The `break` keyword
823 breaks out of the loop.
825 ## For Loops <a id="for-loops"></a>
827 The `for` statement can be used to iterate over arrays and dictionaries.
831 var list = [ "a", "b", "c" ]
837 The loop body is evaluated once for each item in the array. The variable `item` is declared as a local
838 variable just as if the `var` keyword had been used.
840 Iterating over dictionaries can be accomplished in a similar manner:
842 var dict = { a = 3, b = 7 }
844 for (key => value in dict) {
845 log("Key: " + key + ", Value: " + value)
848 The `continue` and `break` keywords can be used to control how the loop is executed: The `continue` keyword
849 skips over the remaining expressions for the loop body and begins the next loop evaluation. The `break` keyword
850 breaks out of the loop.
852 ## Constructors <a id="constructor"></a>
854 In order to create a new value of a specific type constructor calls may be used.
858 var pd = PerfdataValue()
862 You can also try to convert an existing value to another type by specifying it as an argument for the constructor call.
866 var s = String(3) /* Sets s to "3". */
868 ## Throwing Exceptions <a id="throw"></a>
870 Built-in commands may throw exceptions to signal errors such as invalid arguments. User scripts can throw exceptions
871 using the `throw` keyword.
875 throw "An error occurred."
877 ## Handling Exceptions <a id="try-except"></a>
879 Exceptions can be handled using the `try` and `except` keywords. When an exception occurs while executing code in the
880 `try` clause no further statements in the `try` clause are evaluated and the `except` clause is executed instead.
887 log("This statement won't get executed.")
889 log("An error occurred in the try clause.")
892 ## Breakpoints <a id="breakpoints"></a>
894 The `debugger` keyword can be used to insert a breakpoint. It may be used at any place where an assignment would also be a valid expression.
896 By default breakpoints have no effect unless Icinga is started with the `--script-debugger` command-line option. When the script debugger is enabled Icinga stops execution of the script when it encounters a breakpoint and spawns a console which lets the user inspect the current state of the execution environment.
898 ## Types <a id="types"></a>
900 All values have a static type. The `typeof` function can be used to determine the type of a value:
902 typeof(3) /* Returns an object which represents the type for numbers */
904 The following built-in types are available:
906 Type | Examples | Description
907 -----------|-------------------|------------------------
908 Number | 3.7 | A numerical value.
909 Boolean | true, false | A boolean value.
910 String | "hello" | A string.
911 Array | [ "a", "b" ] | An array.
912 Dictionary | { a = 3 } | A dictionary.
914 Depending on which libraries are loaded additional types may become available. The `icinga`
915 library implements a whole bunch of other [object types](09-object-types.md#object-types),
916 e.g. Host, Service, CheckCommand, etc.
918 Each type has an associated type object which describes the type's semantics. These
919 type objects are made available using global variables which match the type's name:
921 /* This logs 'true' */
922 log(typeof(3) == Number)
924 The type object's `prototype` property can be used to find out which methods a certain type
927 /* This returns: ["contains","find","len","lower","replace","reverse","split","substr","to_string","trim","upper"] */
928 keys(String.prototype)
930 Additional documentation on type methods is available in the
931 [library reference](18-library-reference.md#library-reference).
933 ## Location Information <a id="location-information"></a>
935 The location of the currently executing script can be obtained using the
936 `current_filename` and `current_line` keywords.
940 log("Hello from '" + current_filename + "' in line " + current_line)
942 ## Reserved Keywords <a id="reserved-keywords"></a>
944 These keywords are reserved and must not be used as constants or custom attributes.
984 You can escape reserved keywords using the `@` character. The following example
985 tries to set `vars.include` which references a reserved keyword and generates
988 [2014-09-15 17:24:00 +0200] critical/config: Location:
989 /etc/icinga2/conf.d/hosts/localhost.conf(13): vars.sla = "24x7"
990 /etc/icinga2/conf.d/hosts/localhost.conf(14):
991 /etc/icinga2/conf.d/hosts/localhost.conf(15): vars.include = "some cmdb export field"
993 /etc/icinga2/conf.d/hosts/localhost.conf(16): }
994 /etc/icinga2/conf.d/hosts/localhost.conf(17):
996 Config error: in /etc/icinga2/conf.d/hosts/localhost.conf: 15:8-15:14: syntax error, unexpected include (T_INCLUDE), expecting T_IDENTIFIER
997 [2014-09-15 17:24:00 +0200] critical/config: 1 errors, 0 warnings.
999 You can escape the `include` keyword by prefixing it with an additional `@` character:
1001 object Host "localhost" {
1002 import "generic-host"
1004 address = "127.0.0.1"
1010 vars.@include = "some cmdb export field"