RULE

### Prerequisite

Parsing Rules requires **View/Edit** RBAC permissions for **Data Management** (under **Configurations** → **Data Management**), which are the same permissions required for Dataset Management, Data Model Rules, and Event Forwarding.

Rules are very similar to functions in modern programming languages. They are essentially pieces of Cortex Query Language (XQL) syntax, tagged with a name - alias, for easier code reuse and avoiding code duplications. A `RULE` is an add-on to the Parsing Rule syntax and is optional to configure.

`RULE` syntax is derived from XQL with a few modifications, as explained in the [Parsing Rules file structure and syntax]().

### Note

For more information on the XQL syntax, see [Get started with XQL](../../../../reference-and-developer-docs/cortex-agentix-xql/get-started-with-xql).

A few more points to keep in mind when writing `RULE` sections.

* Rules are defined by `[rule:ruleName]` as depicted in the following example:

 ```programlisting
 [rule:filter_issues]
 filter raw_log not contains "issue";
 ```
* Rules are invoked by using a `call` keyword as depicted in the following example:

 ```programlisting
 [rule:filter_issues]
 filter raw_log not contains "issue"; 
 [rule:use_another_rule]
 filter severity="LOW" | call filter_issues | fields - raw_log;
 ```

 This is equivalent to writing:

 ```programlisting
 [rule:use_another_rule]
 filter severity="LOW" | filter raw_log not contains "issue" | fields - raw_log;
 ```
* Rule names are not case-sensitive. They can be written in any user-desired casing, such as UPPER\_SNAKE, lower\_snake, camelCase, and CamelCase). For example, `MY_RULE=My_Rule=my_rule`.
* Rule names must be unique across the entire file. This means you cannot have the same rule name defined more than once in the same file.
* Since section order is unimportant, you do not have to declare a `rule` before using it. You can have the `rule` definition section written below other sections that use this rule.
* You can add a single tag or list of tags to the ingested data as part of the ingestion flow that you can easily query. You can add tags using both the `INGEST` and `RULE` sections.

 Adding a single tag:

 ```programlisting
 [INGEST:vendor="Check Point", product="Anti Malware", target_dataset="malware_test", no_hit= drop , ingestnull = true ]
 alter xx = call new_tag_rule; 
 ```

 ```programlisting
 [RULE:new_tag_rule]
 tag add "test";
 ```

 Adding a list of tags:

 ```programlisting
 [INGEST:vendor="Check Point", product="Anti Malware", target_dataset="malware_test", no_hit= drop , ingestnull = true ]
 alter xx = call new_tag_rule; 
 ```

 ```programlisting
 [RULE:new_tag_rule]
 tag add "test1", "test2", "test3";
 ```

 <div data-gb-custom-block data-tag="hint" data-style="info" class="hint hint-info"><h3>Note</h3><p>You can also add tags using only the <code>INGEST</code> section. For more information, see <a href="ingest">INGEST</a>.</p></div>