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https://issues.apache.org/jira/browse/NIP-25?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Pierre Villard resolved NIP-25.
-------------------------------
Resolution: Fixed
> Add Metadata-Only Parameter Listing to ParameterProvider
> --------------------------------------------------------
>
> Key: NIP-25
> URL: https://issues.apache.org/jira/browse/NIP-25
> Project: NiFi Improvement Proposal
> Issue Type: Improvement
> Reporter: Pierre Villard
> Assignee: Pierre Villard
> Priority: Major
>
> h2. Motivation
> The {{ParameterProvider}} interface currently requires implementations to
> return fully resolved parameter values whenever the framework enumerates
> available parameters. For providers backed by external secret stores such as
> AWS Secrets Manager, or Azure Key Vault, fetching every secret value may be
> expensive.
> The NiFi framework uses {{ParameterProvider.fetchParameters()}} to populate
> the secrets-picker UI presented to connector users. This UI only needs
> parameter metadata (name, group, description) and never displays secret
> values. There is currently no way for a provider to return metadata without
> also fetching values, forcing the expensive full-fetch path even when only a
> listing is needed.
> h2. Scope
> Add a single default method to the {{ParameterProvider}} interface in
> nifi-api:
> {code:java}
> default List<ParameterGroup> listParameters(ConfigurationContext context)
> throws IOException {
> return fetchParameters(context);
> } {code}
>
> The default implementation delegates to the existing
> {{fetchParameters(context)}} method, ensuring full backward compatibility.
> Providers that can separate metadata retrieval from value retrieval can
> override this method to return {{Parameter}} objects with null values and
> populated descriptors.
> No new types, interfaces, or classes are introduced in nifi-api.
> h2. Description
> The change consists of a single default method addition to
> {{{}org.apache.nifi.parameter.ParameterProvider{}}}:
> * Method: {{listParameters(ConfigurationContext context)}}
> * Returns: {{List<ParameterGroup>}} — the same return type as
> {{{}fetchParameters(){}}}, using existing {{ParameterGroup}} and
> {{Parameter}} types.
> * Contract: Returns parameter metadata (names, groups, descriptors). Values
> may be null when the provider can enumerate parameters without resolving
> their values.
> * Default behavior: Calls {{{}fetchParameters(context){}}}, so existing
> providers require no changes.
> Subsequent framework changes (outside the scope of this NIP) would update
> {{{}SecretsManager{}}}, {{{}SecretProvider{}}}, and the web layer to call
> {{listParameters()}} instead of {{fetchParameters()}} / {{getAllSecrets()}}
> when populating the secrets-picker UI. Provider implementations in the NiFi
> codebase or external repositories can then override {{listParameters()}} to
> provide an optimized metadata-only code path.
> h2. Compatibility
> This is a purely additive change with no impact on backward compatibility:
> * The method has a default implementation, so existing {{ParameterProvider}}
> implementations continue to compile and function without modification.
> * No existing method signatures, return types, or behaviors are altered.
> * No new types are introduced.
> * The change does not require a new major version of the Apache NiFi API.
> h2. Verification
> * Existing unit tests for {{ParameterProvider}} implementations continue to
> pass without modification, confirming backward compatibility.
> * A new unit test should verify that the default {{listParameters()}}
> implementation delegates to {{fetchParameters()}} and returns the same result.
> * Framework-level integration can be verified when the corresponding NiFi
> framework changes consume the new method.
> h2. Alternatives
> # New {{SecretDescriptor}} interface in nifi-api — Introduce a metadata-only
> type separate from {{{}Secret{}}}. This was considered but using existing
> {{{}ParameterGroup{}}}/{{{}Parameter{}}} types with null values achieves the
> same goal without expanding the API surface.
> # Add a {{metadataOnly}} flag to {{fetchParameters()}} — Modify the existing
> method signature or add a boolean parameter. This is not great because it
> changes the contract of an established method and is less clear than a
> distinct method name.
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