Richard Scott created NIFI-15737:
------------------------------------
Summary: UpdateAttribute: Add Sequential Evaluation Mode for
Advanced Rules
Key: NIFI-15737
URL: https://issues.apache.org/jira/browse/NIFI-15737
Project: Apache NiFi
Issue Type: New Feature
Reporter: Richard Scott
h2. *Motivation*
The *UpdateAttribute* processor Advanced UI evaluates all rules against the
original set of FlowFile attributes. Attribute updates made by one rule are not
visible to subsequent rules during the same evaluation.
This limits support for {*}incremental or dependent transformations{*},
requiring:
* loopback patterns
* multiple processors
* complex Expression Language
These approaches introduce unnecessary complexity and reduce flow readability
for what is conceptually a single logical operation.
h2. *Proposed Enhancement*
Introduce an optional evaluation mode:
*Sequential Evaluation*
When enabled, Advanced rules are evaluated in configured order. If a rule’s
condition matches, its updates are applied immediately and become visible to
subsequent rules during the same FlowFile evaluation.
h2. *Example Use Case*
h3. Scenario: Aggregating a total from optional attributes
Attributes:
* {{room.rate}}
* {{room.service}}
* {{in.room.entertainment}}
* {{late.checkout}} (optional)
h3. Example
Assume the following incoming attributes:
Rule 1
Condition: always true
hotel.bill.total = 0
Rule 2
Condition: room.rate exists
hotel.bill.total = ${hotel.bill.total:plus(${room.rate})}
Rule 3
Condition: room.service exists
hotel.bill.total = ${hotel.bill.total:plus(${room.service})}
Rule 4
Condition: in.room.entertainment exists
hotel.bill.total = ${hotel.bill.total:plus(${in.room.entertainment})}
Rule 5
Condition: late.checkout exists
hotel.bill.total = ${hotel.bill.total:plus(${late.checkout})}
Evaluation result:
After Rule 1: hotel.bill.total = 0
After Rule 2: hotel.bill.total = 200
After Rule 3: hotel.bill.total = 235
After Rule 4: hotel.bill.total = 250
Rule 5 skipped because late.checkout does not exist
Final hotel.bill.total = 250
This enables a natural, incremental approach to attribute transformation within
a single processor, eliminating the need for loopback patterns and
significantly improving flow clarity and maintainability.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
