MINIFICPP-2765 Move GCP Extension to stable C API

[martinzink]

Depends on but can be independenly reviewed because that PR is implementation detail for the GCP refactor

• MINIFICPP-2764 Controller Service CPP API #2152

---

Thank you for submitting a contribution to Apache NiFi - MiNiFi C++.

In order to streamline the review of the contribution we ask you
to ensure the following steps have been taken:

For all changes:

• Is there a JIRA ticket associated with this PR? Is it referenced
  in the commit message?

• Does your PR title start with MINIFICPP-XXXX where XXXX is the JIRA number you are trying to resolve? Pay particular attention to the hyphen "-" character.

• Has your PR been rebased against the latest commit within the target branch (typically main)?

• Is your initial contribution a single, squashed commit?

For code changes:

• If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under ASF 2.0?
• If applicable, have you updated the LICENSE file?
• If applicable, have you updated the NOTICE file?

For documentation related changes:

• Have you ensured that format looks appropriate for the output in which it is rendered?

Note:

Please ensure that once the PR is submitted, you check GitHub Actions CI results for build issues and submit an update to your PR as soon as possible.

[Copilot]

Pull request overview

Migrates the GCP extension from the legacy MiNiFi C++ extension model to the stable C API extension model, updating processors, controller services, and tests accordingly.

Changes:

• Ported GCP processors and the credentials controller service to the stable C API (api::core::*) lifecycle (onScheduleImpl / onTriggerImpl / enableImpl).
• Replaced REGISTER_RESOURCE registration with a new ExtensionInitializer.cpp using MinifiInitExtension registration calls.
• Updated GCP extension unit tests to use C API test utilities and adjusted test linking.

Reviewed changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
extensions/gcp/tests/PutGCSObjectTests.cpp	Updates processor tests to use C API processor/controller-service wrappers and shared mock client injection.
extensions/gcp/tests/ListGCSBucketTests.cpp	Updates list-bucket tests to C API controller service creation and processor property setting.
extensions/gcp/tests/GCPCredentialsControllerServiceTests.cpp	Adjusts controller service tests for C API controller service wrapper access and property setting.
extensions/gcp/tests/FetchGCSObjectTests.cpp	Refactors fetch tests to C API processor creation and property accessors.
extensions/gcp/tests/DeleteGCSObjectTests.cpp	Refactors delete tests to C API processor creation and property accessors.
extensions/gcp/tests/CMakeLists.txt	Switches test linking to libminifi-c-unittest for the C API test harness.
extensions/gcp/processors/PutGCSObject.h	Moves processor to C API lifecycle overrides and updates includes/annotations.
extensions/gcp/processors/PutGCSObject.cpp	Implements onScheduleImpl / onTriggerImpl and uses API property parsing and session attribute APIs.
extensions/gcp/processors/ListGCSBucket.h	Moves processor to C API lifecycle overrides and updates includes/annotations.
extensions/gcp/processors/ListGCSBucket.cpp	Implements onScheduleImpl / onTriggerImpl and uses API property parsing and session attribute APIs.
extensions/gcp/processors/GCSProcessor.h	Migrates base processor to api::core::ProcessorImpl and updates scheduling/credentials retrieval APIs.
extensions/gcp/processors/GCSProcessor.cpp	Implements onScheduleImpl and updates controller service parsing to API utilities.
extensions/gcp/processors/FetchGCSObject.h	Moves processor to C API lifecycle overrides and updates includes/annotations.
extensions/gcp/processors/FetchGCSObject.cpp	Implements onScheduleImpl / onTriggerImpl and uses API property parsing and session attribute APIs.
extensions/gcp/processors/DeleteGCSObject.h	Moves processor to C API lifecycle overrides and updates includes/annotations.
extensions/gcp/processors/DeleteGCSObject.cpp	Implements onTriggerImpl and uses API property parsing and session attribute APIs.
extensions/gcp/controllerservices/GCPCredentialsControllerService.h	Migrates controller service to api::core::ControllerServiceImpl and introduces enableImpl.
extensions/gcp/controllerservices/GCPCredentialsControllerService.cpp	Implements credentials loading via controller service context and adds file-content helper.
extensions/gcp/GCPAttributes.h	Switches metadata attribute setting to use api::core::ProcessSession::setAttribute.
extensions/gcp/ExtensionInitializer.cpp	Adds stable C API extension entry point and registers processors/controller service.
extensions/gcp/CMakeLists.txt	Registers the extension via register_c_api_extension and links extension lib accordingly.

Comments suppressed due to low confidence (1)

extensions/gcp/controllerservices/GCPCredentialsControllerService.cpp:1

• enableImpl() always returns MINIFI_STATUS_SUCCESS, even when the credentials location is invalid or credential creation fails (credentials_ stays null). This can leave the controller service enabled in a broken state and shifts the failure downstream. Return a non-success status (and ideally stop enabling) when credentials_location is missing/invalid or when credentials_ could not be created.

/**

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.