ScienceLogic Policy/Rule API

Rules are the individual parts of a device policy.## Regular ExpressionsA regular expression specifies a set of strings as a pattern, rather than a list. For example, the pattern`C(o|as?)t` matches the strings Cot, Cat, and Cast, but not Coast. Skylar Compliance uses Perl-flavour RegularExpressions.Most characters can be used in a regular expression; however, some characters, called metacharacters, have specialmeanings:* `()` denote grouping: `(a|b)b` matches `ab` and `bb`* `|` denotes an alternative (see above)* `^` matches the beginning of a line* `$` matches the end of a line* `.` matches any character* `+` denotes one or more occurrences of the previous character: `a+b` matches `ab`, `aab`, `abb`, but not `b`* `*` denotes zero or more occurrences of the previous character: `a*b` matches `b`, `ab`, `aab`, `aaab`* `?` denotes zero or one occurrences of the previous character: `a?b` matches `b` and `ab`, but not `aab` or `aaab`Character classes are matches for sets of possible characters, rather than just a single character. For instance:* `[bcr]at` matches `bat`, `cat` and `rat`* `-` can be used as a range operator in a character class, so `[a-g]` matches any character from `a` to `g`There are some useful abbreviations for common character classes, in particular:* `\d` matches a digit* `\s` matches whitespace (a space or a tab)* `\w` matches a word character (alphanumeric or a _)For instance, `\d\d:\d\d:\d\d` would match a time in a hh:mm:ss format.For more information and examples of regular expressions, please see[this reference guide](http://www.regularexpressions.info/reference.html).## Lua FunctionsRules can be defined as Lua functions.Available functions for compliance rules are:* `nextline()` returns the next line of text* `getline(n)` returns the given line of text* `numlines()` returns the number of lines* `addmessage(m)` allows you to replace a series of variables in the remediation text. For instance, `addmessage("Hello")` with a remediation text of `$1` "World!" would produce the output `Hello World!`.The next `addmessage` call would replace `$2`, and so on.### ExampleThis function checks that the number of lines containing "configure" matches the lines containing "port":```luanum1 = 0num2 = 0line, next = nextline()while next do if line:match("configure") then num1 = num1+1 end if line:match("port") then num2 = num2+1 end line, next = nextlineendif num1 > num2 then addmessage("more")else if num2 < num1 then addmessage("less") endreturn num1 == num2```Remediation Text: `Config contains $1 configures than ports.`## RemediationRemediation is an action to be performed when a compliance rule is not met, generally intended to rectify theviolation. The following remediation types can be configured:* `Manual`: in this case, the remediation text will simply be appended to the notification email, signifying that the recipient should take the appropriate action.* `Command`: this will execute one of the stored Actions on the device (see Controlling a device).* `Automatic`: this setting will treat the text specified in the textbox as a command and execute it on the device.If the rule match type is **Regex**, the remediation can make use of the **Capture** feature, whereby parts ofthe pattern in brackets can be captured and then referred to in the remediation text (as `$1`, `$2`, etc.).For example, a rule may state that a configuration must not contain the regex:```set telnet (\d+\.\d+\.\d+\.\d+)```where the part in brackets is a match for an IP address. If this rule is violated, the configuration can beremedied using the phrase:```unset telnet $1```In this case, the brackets in the rule will capture the IP address, and fill it in when the command is performed, expanding to```unset telnet 1.2.3.4```if that was the matched IP address.