[NIFI-2974] Allow for per-instance configuration values to override defaults for component properties

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.0.0
• Component/s: Extensions
• Labels: configuration customization variable
• Assignee: Unassigned
• Reporter: Andy LoPresto
• Created: 01/Nov/16 04:15
• Updated: 18/May/17 03:17

Description

A nice feature would be to allow per-user or per-instance configuration values that could override default values for components (processors, controller services, reporting tasks).

For example, in every GenerateFlowFile processor I add to a flow, I generally want to change the Run Schedule from 0 secs to 1 sec to stop from flooding the flow. In every LogAttribute, I want to log the payload, so I change that value to true. As this issue originally stated, an SSLStandardContextService often needs to be created with the default keystore/truststore paths or with the /Library/Java/JavaVirtualMachines/jdk<version>.jdk/Contents/Home/jre/lib/security/cacerts path.

However, I do not believe these values are standard across the install base of the application, so I cannot change them in the source code to impact all users. I think being able to populate the Variable Registry with these values using the FQDN of the component class and property would be an important feature.

Example variable registry file (side note – another good reason to enforce property descriptors having a .name() without spaces and a human-formatted .displayName()):

org.apache.nifi.processors.standard.LogAttribute.Log\u0020Payload=true
org.apache.nifi.processors.standard.GenerateFlowFile.generate-ff-custom-text=This is a plaintext message.
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