Asset Rules

Asset rules create assets based on stream properties (such as ID, Name, Description, and stream metadata). Asset rules are executed on streams in the following ways:

• On-demand execution – an asset rule is defined and created and it is applied to all existing applicable streams
• Unattended execution – all asset rules are run whenever a stream is created, updated, or deleted.

The asset rules API allows you to programmatically create, read, update, and delete asset rules.

Example Asset Rule

{
   "Id":"sampleID",
   "Name":"sampleName",
   "Description":"sampleDescription",
   "AutomationId":"sampleAutomationID",
   "Expressions":[
      {
         "Field":"Id",
         "Specifications":[
            {
               "Type":"Group",
               "Name":"streamId"
            }
         ]
      },
      {
         "Field":"Name",
         "Specifications":[
            {
               "Type":"Group",
               "Name":"location",
               "StrictValueMappings":true,
               "ValueMappings":{
                  "SL":"San leandro",
                  "AUS":"Austin"
               }
            },
            {
               "Type":"Delimiter",
               "Value":"."
            },
            {
               "Type":"Literal",
               "Value":"test"
            }
         ]
      }
   ],
   "Outputs":[
      {
         "Field":"Asset",
         "Value":{
            "Id":"{location} asset",
            "Name":"{location} asset",
            "Description":"this is an asset generated by an asset rule",
            "Metadata":[
               {
                  "Id":"Location",
                  "Name":"Location",
                  "Description":"the location of the asset",
                  "SdsTypeCode":"18",
                  "Value":"{location}"
               }
            ],
            "StreamReferences":[
               {
                  "Id":"Rule Stream",
                  "Description":"a stream reference to the input stream that caused the rule to generate this asset",
                  "StreamId":"{streamId}"
               }
            ]
         }
      }
   ]
}

Rule Properties

Expressions

Rule expressions define which streams a rule applies to and what information is extracted from the stream. For a rule to apply to a stream, all of the rule's expressions must match. Expressions have the following properties:

• Fields – strings that determine which stream property to look at for specifications
• Specifications – objects that define specifications of a segment in a pattern. Refer to [Specification Types][xref:AssetRules#specification-types] and [Specification Objects][xref:AssetRules#specification-objects] for a description.

Fields

The following fields are supported:

The Metadata and Type fields are objects rather than values, so [Json Path Syntax][xref:AssetRules#JSON Paths] is required. The extracted value must be a single value, rather than an object or array. For Metadata, the syntax should always extract the value of a single key in the Metadata collection. For more information on available properties for a stream type, see [Types][xref:sdsTypes].

Specification Types

Specification Objects

JSON Paths

JSON paths can be used in the Expression Field to retrieve stream metadata and stream type properties. The following are examples of JSON paths. Note: RegEx in JSON path is not supported in the Field specification.

Retrieve the value of the metadata key 'location' for the stream:

{
   "Field": "Metadata['location']",
   "Specifications": [
      {
         "Type": "Group",
         "Name": "value"
      }
   ]
}

Retrieve the unit of measure of the 'Value' property from the stream type:

{
   "Field": "Type.Properties[?(@.Id == 'Value')].Uom",
   "Specifications": [
      {
         "Type": "Group",
         "Name": "valueUom"
      }
   ]
}

Outputs

Only asset outputs are supported.

Asset output objects