RouteOnAttribute

Description

Routes FlowFiles based on their Attributes using the Attribute Expression Language

Tags

Attribute Expression Language, Expression Language, Regular Expression, attributes, detect, filter, find, regex, regexp, routing, search, string, text

Properties

In the list below required Properties are shown with an asterisk (*). Other properties are considered optional. The table also indicates any default values, and whether a property supports the NiFi Expression Language.

Display Name	API Name	Default Value	Allowable Values	Description
Routing Strategy *	Routing Strategy	Route to Property name	Route to Property name Route to 'matched' if all match Route to 'matched' if any matches	Specifies how to determine which relationship to use when evaluating the Expression Language

Dynamic Properties

Name	Value	Description
Relationship Name	Expression Language expression that returns a boolean value indicating whether or not the FlowFile should be routed to this Relationship	Routes FlowFiles whose attributes match the Expression Language specified in the Dynamic Property Value to the Relationship specified in the Dynamic Property Key Supports Expression Language: Yes, evaluated using FlowFile Attributes and Environment variables.

Relationships

Name	Description
unmatched	FlowFiles that do not match any user-define expression will be routed here

Reads Attributes

This processor does not read attributes.

Writes Attributes

Name	Description
RouteOnAttribute.Route	The relation to which the FlowFile was routed

State Management

This component does not store state.

Restricted

This component is not restricted.

Input Requirement

This component requires an incoming relationship.

Example Use Cases

Use Case 1

Route data to one or more relationships based on its attributes using the NiFi Expression Language.

Configuration

Set the "Routing Strategy" property to "Route to Property name".
For each route that a FlowFile might be routed to, add a new property. The name of the property should describe the route.
The value of the property is an Attribute Expression Language expression that returns a boolean value indicating whether or not a given FlowFile will be routed to the associated relationship.

For example, we might route data based on its file extension using the following properties:
- "Routing Strategy" = "Route to Property Name"
- "jpg" = "${filename:endsWith('.jpg')}"
- "png" = "${filename:endsWith('.png')}"
- "pdf" = "${filename:endsWith('.pdf')}"

The Processor will now have 3 relationships: jpg, png, and pdf. Each of these should be connected to the appropriate downstream processor.

Use Case 2

Keep data only if its attributes meet some criteria, such as its filename ends with .txt.

Configuration

Add a new property for each condition that must be satisfied in order to keep the data.
If the data should be kept in the case that any of the provided conditions is met, set the "Routing Strategy" property to "Route to 'matched' if any matches".
If all conditions must be met in order to keep the data, set the "Routing Strategy" property to "Route to 'matched' if all match".

For example, to keep files whose filename ends with .txt and have a file size of at least 1000 bytes, we will use the following properties:
- "ends_with_txt" = "${filename:endsWith('.txt')}"
- "large_enough" = "${fileSize:ge(1000)}
- "Routing Strategy" = "Route to 'matched' if all match"

Auto-terminate the 'unmatched' relationship.
Connect the 'matched' relationship to the next processor in the flow.

Use Case 3

Discard or drop a file based on attributes, such as filename.

Configuration

Add a new property for each condition that must be satisfied in order to drop the data.
If the data should be dropped in the case that any of the provided conditions is met, set the "Routing Strategy" property to "Route to 'matched' if any matches".
If all conditions must be met in order to drop the data, set the "Routing Strategy" property to "Route to 'matched' if all match".

Here are a couple of examples for configuring the properties:
Example 1 Use Case: Data should be dropped if its "uuid" attribute has an 'a' in it or ends with '0'.
Here, we will use the following properties:
- "has_a" = "${uuid:contains('a')}"
- "ends_with_0" = "${uuid:endsWith('0')}
- "Routing Strategy" = "Route to 'matched' if any matches"
Example 2 Use Case: Data should be dropped if its 'uuid' attribute has an 'a' AND it ends with a '1'.
Here, we will use the following properties:
- "has_a" = "${uuid:contains('a')}"
- "ends_with_1" = "${uuid:endsWith('1')}
- "Routing Strategy" = "Route to 'matched' if all match"

Auto-terminate the 'matched' relationship.
Connect the 'unmatched' relationship to the next processor in the flow.

Example Use Cases Involving Other Components

Multiprocessor Use Case 1

Route record-oriented data based on whether or not the record's values meet some criteria

Components Involved

• PartitionRecord
  1. Choose a RecordReader that is appropriate based on the format of the incoming data.
  2. Choose a RecordWriter that writes the data in the desired output format.
  3. Add a single additional property. The name of the property should describe the criteria to route on. The property's value should be a RecordPath that returns true if the Record meets the criteria or false otherwise. This adds a new attribute to the FlowFile whose name is equal to the property name.
  4. Connect the 'success' Relationship to RouteOnAttribute.
• RouteOnAttribute
  1. Set "Routing Strategy" to "Route to Property name"
  2. Add two additional properties. For the first one, the name of the property should describe data that matches the criteria. The value is an Expression Language expression that checks if the attribute added by the PartitionRecord processor has a value of true. For example, ${criteria:equals('true')}.
  3. The second property should have a name that describes data that does not match the criteria. The value is an Expression Language that evaluates to the opposite of the first property value. For example, ${criteria:equals('true'):not()}.
  4. Connect each of the newly created Relationships to the appropriate downstream processors.

System Resource Considerations

This component does not specify system resource considerations.

See Also