icinga2/doc/21-library-reference.md

# <a id="library-reference"></a> Library Reference

## <a id="global-functions"></a> Global functions

Function                        | Description
--------------------------------|-----------------------
regex(pattern, text)            | Returns true if the regex pattern matches the text, false otherwise.
match(pattern, text)            | Returns true if the wildcard pattern matches the text, false otherwise.
len(value)                      | Returns the length of the value, i.e. the number of elements for an array or dictionary, or the length of the string in bytes.
union(array, array, ...)        | Returns an array containing all unique elements from the specified arrays.
intersection(array, array, ...) | Returns an array containing all unique elements which are common to all specified arrays.
keys(dict)                      | Returns an array containing the dictionary's keys.
string(value)                   | Converts the value to a string.
number(value)                   | Converts the value to a number.
bool(value)                     | Converts the value to a bool.
random()                        | Returns a random value between 0 and RAND_MAX (as defined in stdlib.h).
log(value)                      | Writes a message to the log. Non-string values are converted to a JSON string.
log(severity, facility, value)  | Writes a message to the log. `severity` can be one of `LogDebug`, `LogNotice`, `LogInformation`, `LogWarning`, and `LogCritical`. Non-string values are converted to a JSON string.
typeof(value)                   | Returns the type object for a value.
get_time()                      | Returns the current UNIX timestamp.
parse_performance_data(pd)      | Parses a performance data string and returns an array describing the values.
dirname(path)                   | Returns the directory portion of the specified path.
basename(path)                  | Returns the filename portion of the specified path.
escape\_shell\_arg(text)        | Escapes a string for use as a single shell argument.
escape\_shell\_cmd(text)        | Escapes shell meta characters in a string.
exit(integer)                   | Terminates the application.

## <a id="object-accessor-functions"></a> Object Accessor Functions

These functions can be used to retrieve a reference to another object by name.

### <a id="objref-get_check_command"></a> get_check_command

Signature:

    function get_check_command(name);

Returns the CheckCommand object with the specified name, or `null` if no such CheckCommand object exists.

### <a id="objref-get_event_command"></a> get_event_command

Signature:

    function get_event_command(name);

Returns the EventCommand object with the specified name, or `null` if no such EventCommand object exists.

### <a id="objref-get_notification_command"></a> get_notification_command

Signature:

    function get_notification_command(name);

Returns the NotificationCommand object with the specified name, or `null` if no such NotificationCommand object exists.

### <a id="objref-get_host"></a> get_host

Signature:

    function get_host(host_name);

Returns the Host object with the specified name, or `null` if no such Host object exists.


### <a id="objref-get_service"></a> get_service

Signature:

    function get_service(host_name, service_name);

Returns the Service object with the specified name, or `null` if no such Service object exists.


### <a id="objref-get_user"></a> get_user

Signature:

    function get_user(name);

Returns the User object with the specified name, or `null` if no such User object exists.

### <a id="objref-get_host_group"></a> get_host_group

Signature:

    function get_host_group(name);

Returns the HostGroup object with the specified name, or `null` if no such HostGroup object exists.


### <a id="objref-get_service_group"></a> get_service_group

Signature:

    function get_service_group(name);

Returns the ServiceGroup object with the specified name, or `null` if no such ServiceGroup object exists.

### <a id="objref-get_user_group"></a> get_user_group

Signature:

    function get_user_group(name);

Returns the UserGroup object with the specified name, or `null` if no such UserGroup object exists.


### <a id="objref-get_time_period"></a> get_time_period

Signature:

    function get_time_period(name);

Returns the TimePeriod object with the specified name, or `null` if no such TimePeriod object exists.


### <a id="objref-get_object"></a> get_object

Signature:

    function get_object(type, name);

Returns the object with the specified type and name, or `null` if no such object exists. `type` must refer
to a type object.


### <a id="objref-get_objects"></a> get_objects

Signature:

    function get_objects(type);

Returns an array of objects whose type matches the specified type. `type` must refer
to a type object.


## <a id="math-object"></a> Math object

The global `Math` object can be used to access a number of mathematical constants
and functions.

### <a id="math-e"></a> Math.E

Euler's constant.

### <a id="math-ln2"></a> Math.LN2

Natural logarithm of 2.

### <a id="math-ln10"></a> Math.LN10

Natural logarithm of 10.

### <a id="math-log2e"></a> Math.LOG2E

Base 2 logarithm of E.

### <a id="math-pi"></a> Math.PI

The mathematical constant Pi.

### <a id="math-sqrt1_2"></a> Math.SQRT1_2

Square root of 1/2.

### <a id="math-sqrt2"></a> Math.SQRT2

Square root of 2.

### <a id="math-abs"></a> Math.abs

Signature:

    function abs(x);

Returns the absolute value of `x`.

### <a id="math-acos"></a> Math.acos

Signature:

    function acos(x);

Returns the arccosine of `x`.

### <a id="math-asin"></a> Math.asin

Signature:

    function asin(x);

Returns the arcsine of `x`.

### <a id="math-atan"></a> Math.atan

Signature:

    function atan(x);

Returns the arctangent of `x`.

### <a id="math-atan2"></a> Math.atan2

Signature:

    function atan2(y, x);

Returns the arctangent of the quotient of `y` and `x`.

### <a id="math-ceil"></a> Math.ceil

Signature:

    function ceil(x);

Returns the smallest integer value not less than `x`.

### <a id="math-cos"></a> Math.cos

Signature:

    function cos(x);

Returns the cosine of `x`.

### <a id="math-exp"></a> Math.exp

Signature:

    function exp(x);

Returns E raised to the `x`th power.

### <a id="math-floor"></a> Math.floor

Signature:

    function floor(x);

Returns the largest integer value not greater than `x`.

### <a id="math-isinf"></a> Math.isinf

Signature:

    function isinf(x);

Returns whether `x` is infinite.

### <a id="math-isnan"></a> Math.isnan

Signature:

    function isnan(x);

Returns whether `x` is NaN (not-a-number).

### <a id="math-log"></a> Math.log

Signature:

    function log(x);

Returns the natural logarithm of `x`.

### <a id="math-max"></a> Math.max

Signature:

    function max(...);

Returns the largest argument. A variable number of arguments can be specified.
If no arguments are given -Infinity is returned.

### <a id="math-min"></a> Math.min

Signature:

    function min(...);

Returns the smallest argument. A variable number of arguments can be specified.
If no arguments are given +Infinity is returned.

### <a id="math-pow"></a> Math.pow

Signature:

    function pow(x, y);

Returns `x` raised to the `y`th power.

### <a id="math-random"></a> Math.random

Signature:

    function random();

Returns a pseudo-random number between 0 and 1.

### <a id="math-round"></a> Math.round

Signature:

    function round(x);

Returns `x` rounded to the nearest integer value.

### <a id="math-sign"></a> Math.sign

Signature:

    function sign(x);

Returns -1 if `x` is negative, 1 if `x` is positive
and 0 if `x` is 0.

### <a id="math-sin"></a> Math.sin

Signature:

    function sin(x);

Returns the sine of `x`.

### <a id="math-sqrt"></a> Math.sqrt

Signature:

    function sqrt(x);

Returns the square root of `x`.

### <a id="math-tan"></a> Math.tan

Signature:

    function tan(x);

Returns the tangent of `x`.

## <a id="json-object"></a> Json object

The global `Json` object can be used to encode and decode JSON.

### <a id="json-encode"></a> Json.encode

Signature:

    function encode(x);

Encodes an arbitrary value into JSON.

### <a id="json-decode"></a> Json.decode

Signature:

    function decode(x);

Decodes a JSON string.

## <a id="number-type"></a> Number type

### <a id="number-to_string"></a> Number#to_string

Signature:

    function to_string();

The `to_string` method returns a string representation of the number.

Example:

    var example = 7
	example.to_string() /* Returns "7" */

## <a id="boolean-type"></a> Boolean type

### <a id="boolean-to_string"></a> Boolean#to_string

Signature:

    function to_string();

The `to_string` method returns a string representation of the boolean value.

Example:

    var example = true
	example.to_string() /* Returns "true" */

## <a id="string-type"></a> String type

### <a id="string-find"></a> String#find

Signature:

    function find(str, start);

Returns the zero-based index at which the string `str` was found in the string. If the string
was not found -1 is returned. `start` specifies the zero-based index at which `find` should
start looking for the string (defaults to 0 when not specified).

Example:

    "Hello World".find("World") /* Returns 6 */

### <a id="string-contains"></a> String#contains

Signature:

    function contains(str);

Returns `true` if the string `str` was found in the string. If the string
was not found `false` is returned. Use [find](21-library-reference.md#string-find)
for getting the index instead.

Example:

    "Hello World".contains("World") /* Returns true */

### <a id="string-len"></a> String#len

Signature

    function len();

Returns the length of the string in bytes. Note that depending on the encoding type of the string
this is not necessarily the number of characters.

Example:

    "Hello World".len() /* Returns 11 */

### <a id="string-lower"></a> String#lower

Signature:

    function lower();

Returns a copy of the string with all of its characters converted to lower-case.

Example:

    "Hello World".lower() /* Returns "hello world" */

### <a id="string-upper"></a> String#upper

Signature:

    function upper();

Returns a copy of the string with all of its characters converted to upper-case.

Example:

    "Hello World".upper() /* Returns "HELLO WORLD" */

### <a id="string-replace"></a> String#replace

Signature:

    function replace(search, replacement);

Returns a copy of the string with all occurences of the string specified in `search` replaced
with the string specified in `replacement`.

### <a id="string-split"></a> String#split

Signature:

    function split(delimiters);

Splits a string into individual parts and returns them as an array. The `delimiters` argument
specifies the characters which should be used as delimiters between parts.

Example:

    "x-7,y".split("-,") /* Returns [ "x", "7", "y" ] */

### <a id="string-substr"></a> String#substr

Signature:

    function substr(start, len);

Returns a part of a string. The `start` argument specifies the zero-based index at which the part begins.
The optional `len` argument specifies the length of the part ("until the end of the string" if omitted).

Example:

    "Hello World".substr(6) /* Returns "World" */

### <a id="string-to_string"></a> String#to_string

Signature:

    function to_string();

Returns a copy of the string.

### <a id="string-reverse"></a> String#reverse

Signature:

    function reverse();

Returns a copy of the string in reverse order.

## <a id="array-type"></a> Array type

### <a id="array-add"></a> Array#add

Signature:

    function add(value);

Adds a new value after the last element in the array.

### <a id="array-clear"></a> Array#clear

Signature:

    function clear();

Removes all elements from the array.

### <a id="array-shallow-clone"></a> Array#shallow_clone

    function shallow_clone();

Returns a copy of the array. Note that for elements which are reference values (e.g. objects such
as arrays and dictionaries) only the references are copied.

### <a id="array-contains"></a> Array#contains

Signature:

    function contains(value);

Returns true if the array contains the specified value, false otherwise.

### <a id="array-len"></a> Array#len

Signature:

    function len();

Returns the number of elements contained in the array.

### <a id="array-remove"></a> Array#remove

Signature:

    function remove(index);

Removes the element at the specified zero-based index.

### <a id="array-set"></a> Array#set

Signature:

    function set(index, value);

Sets the element at the zero-based index to the specified value. The `index` must refer to an element
which already exists in the array.

### <a id="array-get"></a> Array#get

Signature:

    function get(index);

Retrieves the element at the specified zero-based index.

### <a id="array-sort"></a> Array#sort

Signature:

    function sort(less_cmp);

Returns a copy of the array where all items are sorted. The items are
compared using the `<` (less-than) operator. A custom comparator function
can be specified with the `less_cmp` argument.

### <a id="array-join"></a> Array#join

Signature:

    function join(separator);

Joins all elements of the array using the specified separator.

### <a id="array-reverse"></a> Array#reverse

Signature:

    function reverse();

Returns a new array with all elements of the current array in reverse order.

### <a id="dictionary-shallow-clone"></a> Dictionary#shallow_clone

Signature:

    function shallow_clone();

Returns a copy of the dictionary. Note that for elements which are reference values (e.g. objects such
as arrays and dictionaries) only the references are copied.

### <a id="dictionary-contains"></a> Dictionary#contains

Signature:

    function contains(key);

Returns true if a dictionary item with the specified `key` exists, false otherwise.

### <a id="dictionary-len"></a> Dictionary#len

Signature:

    function len();

Returns the number of items contained in the dictionary.

### <a id="dictionary-remove"></a> Dictionary#remove

Signature:

    function remove(key);

Removes the item with the specified `key`. Trying to remove an item which does not exist
is a no-op.

### <a id="dictionary-set"></a> Dictionary#set

Signature:

    function set(key, value);

Creates or updates an item with the specified `key` and `value`.

### <a id="dictionary-get"></a> Dictionary#get

Signature:

    function get(key);

Retrieves the value for the specified `key`. Returns `null` if they `key` does not exist
in the dictionary.

### <a id="dictionary-keys"></a> Dictionary#keys

Signature:

    function keys();

Returns a list of keys for all items that are currently in the dictionary.

## <a id="scriptfunction-type"></a> Function type

### <a id="scriptfunction-call"></a> Function#call

Signature:

    function call(thisArg, ...);

Invokes the function using an alternative `this` scope. The `thisArg` argument specifies the `this`
scope for the function. All other arguments are passed directly to the function.

Example:

    function set_x(val) {
	  this.x = val
	}
	
	dict = {}
	
	set_x.call(dict, 7) /* Invokes set_x using `dict` as `this` */

### <a id="scriptfunction-callv"></a> Function#callv

Signature:

    function callv(thisArg, args);

Invokes the function using an alternative `this` scope. The `thisArg` argument specifies the `this`
scope for the function. The items in the `args` array are passed to the function as individual arguments.

Example:

    function set_x(val) {
	  this.x = val
	}
	
	var dict = {}

	var args = [ 7 ]

	set_x.callv(dict, args) /* Invokes set_x using `dict` as `this` */