Github user dlukyanov commented on a diff in the pull request:
https://github.com/apache/nifi/pull/1662#discussion_r148955987
--- Diff:
nifi-nar-bundles/nifi-groovyx-bundle/nifi-groovyx-processors/src/main/resources/docs/org.apache.nifi.processors.groovyx.ExecuteGroovyScript/additionalDetails.html
---
@@ -0,0 +1,202 @@
+<!DOCTYPE html>
+<html lang="en">
+<!--
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+<head>
+ <meta charset="utf-8" />
+ <title>Groovy</title>
+ <!--link rel="stylesheet" href="../../css/component-usage.css"
type="text/css" /-->
+ <link rel="stylesheet" href="/nifi-docs/css/component-usage.css"
type="text/css" />
+</head>
+
+<body>
+<h2>Summary</h2>
+<p>This is a grooviest groovy script :)</p>
+<h2>Script Bindings:</h2>
+<table>
+<tr><th>variable</th><th>type</th><th>description</th></tr>
+<tr>
+ <td>session</td>
+ <td>org.apache.nifi.processor.ProcessSession</td>
+ <td>the session that is used to get, change, and transfer input
files</td>
+</tr>
+<tr>
+ <td>context</td>
+ <td>org.apache.nifi.processor.ProcessContext</td>
+ <td>the context (almost unusefull)</td>
+</tr>
+<tr>
+ <td>log</td>
+ <td>org.apache.nifi.logging.ComponentLog</td>
+ <td>the logger for this processor instance</td>
+</tr>
+<tr>
+ <td>REL_SUCCESS</td>
+ <td>org.apache.nifi.processor.Relationship</td>
+ <td>the success relationship</td>
+</tr>
+<tr>
+ <td>REL_FAILURE</td>
+ <td>org.apache.nifi.processor.Relationship</td>
+ <td>the failure relationship</td>
+</tr>
+<tr>
+ <td>flowFile</td>
+ <td>org.apache.nifi.flowfile.FlowFile</td>
+ <td>Binded only if the property `Require flow file`=true for the
processor</td>
+</tr>
+<tr>
+ <td>CTL</td>
+ <td>java.util.HashMap</td>
+ <td>Map populated with controller services binded through `CTL.*`
processor properties</td>
+</tr>
+<tr>
+ <td>Dynamic processor properties</td>
+ <td>org.apache.nifi.components.PropertyDescriptor</td>
+ <td>All processor properties not started with `CTL.` are binded to
script variables</td>
+</tr>
+</table>
+
+<h2>CTL map</h2>
+<p>
+CTL.* objects accessible if corresponding processor property defined.<br/>
+<b>Example:</b> if you defined property <code>`CTL.cache`</code> to
DistributedMapCacheClientService, then you can access it from code
<code>CTL.cache</code><br/>
--- End diff --
Yes, this adds kind of limit. All custom properties with name beginning
with `CTL.` automatically supposed to be linked to controller services. It
means you can't define custom `CTL.*` property with plain string value. After
`CTL.`there could be any chars. On the level of groovy script the additional
predefined variable binded : `CTL` - a hashmap with substring after `CTL.` as a
key and linked controller service as a value. If you defined `CTL.aaa` and
linked it to distributed cache client service, then on level of groovy it'slike
`def CTL=[:]` and `CTL['aaa']=LINK_TO_THE_SERVICE`. So, in groovy you can
access this service `CTL.aaa.someServiceMethod(...)`
The only conflict expected when you'll try to define custom script variable
with name `CTL`. Otherwise-no conflicts.
---
