feat: Replace deprecated Doppler recentLogs with Log Cache client

[ZPascal]

Feat: Replace deprecated Doppler recentLogs with Log Cache client

Problem

The DopplerClient.recentLogs() endpoint relies on the Loggregator Traffic Controller /apps/{id}/recentlogs HTTP endpoint, which was removed in Loggregator ≥ 107.0 (shipped with CF Deployment ≥ 24.3 and Tanzu Application Service ≥ 4.0). Calls to this endpoint on modern CF foundations fail at runtime, and the related types (LogsRequest, LogMessage from org.cloudfoundry.doppler) caused compilation errors in the integration tests.

Out of the scope

• LogCache client-based log streaming support

Fixes #1181 & #1230

---

Changes

cloudfoundry-client

• Marked DopplerClient.recentLogs() as @Deprecated with a Javadoc @deprecated note pointing to the replacement API and documenting the platform version boundary (Loggregator < 107.0 / CFD < 24.3 / TAS < 4.0).
• Added LogCacheClient.recentLogs(ReadRequest) as the new, non-deprecated entry point.

cloudfoundry-client-reactor

• Implemented ReactorLogCacheEndpoints.recentLogs() — delegates to the existing read() method.
• Wired the implementation in _ReactorLogCacheClient.

cloudfoundry-operations

• Extended Applications interface with logsRecent(ReadRequest) backed by LogCacheClient.
• Updated DefaultApplications to accept and hold a Mono<LogCacheClient> alongside the existing Mono<DopplerClient>.
• The existing logs(LogsRequest) / logs(ApplicationLogsRequest) methods are now marked @Deprecated.
• Updated _DefaultCloudFoundryOperations to expose logCacheClient as an optional builder field (mirrors the existing dopplerClient pattern; missing client yields a descriptive IllegalStateException on first use).

Integration & unit tests

• Updated AbstractOperationsTest and DefaultApplicationsTest to supply the new LogCacheClient mock.
• Renamed / split test cases to clearly distinguish Doppler (logsRecentDoppler, logsDoppler, logsNoAppDoppler) from Log Cache (logsRecentLogCache) paths; added @SuppressWarnings("deprecation") where the old API is still exercised.
• Added ApplicationsTest.logsRecent() integration test that provisions an application, fetches recent logs via LogCacheClient, and asserts that each entry carries a valid LogType (OUT or ERR).
• Updated IntegrationTestConfiguration to inject and wire LogCacheClient into DefaultCloudFoundryOperations.

Documentation (README.md)

• Added a ## Deprecations section (with a [!WARNING] callout) right after ## Versions, covering:
  • the deprecated API surface (DopplerClient.recentLogs(), RecentLogsRequest, LogMessage),
  • platform version boundaries,
  • a before/after migration code example.
• Added an inline [!NOTE] callout in the ### CloudFoundryClient, DopplerClient, UaaClient Builders section cross-linking to the new deprecation notice.

---

Migration guide

// Before (deprecated — only works on CFD < 24.3 / TAS < 4.0)
dopplerClient.recentLogs(RecentLogsRequest.builder()
    .applicationId(appId)
    .build());

// After
logCacheClient.recentLogs(ReadRequest.builder()
    .sourceId(appId)
    .build());

// Or via CloudFoundryOperations
cloudFoundryOperations.applications()
    .logsRecent(ReadRequest.builder()
        .sourceId(appId)
        .build());

---

Checklist

• Existing unit tests updated and passing
• New unit test added (logsRecentLogCache)
• New integration test added (logsRecent)
• Deprecated API annotated with @Deprecated + Javadoc @deprecated
• README.md updated with deprecation notice and migration guide
• Integration tests verified against a live CF foundation (requires CF Deployment ≥ 24.3 or TAS ≥ 4.0 for the Log Cache path)

Integrationtest results

[pivotal-david-osullivan]

Thank you for the PR!

Compilation is currently failing on the implementation missing the new recentLogs method that you added to the client

[ZPascal]

Thank you @pivotal-david-osullivan & @anthonydahanne for fixing the tests and the reactor part. I am also working on the issue again from the SAP side and I plan to set up a BBL environment to test the change in a CF environment. Let's sync on Slack how we can handle it together and we can discuss the test setup/steps.

[anthonydahanne]

Thank you @pivotal-david-osullivan & @anthonydahanne for fixing the tests and the reactor part. I am also working on the issue again from the SAP side and I plan to set up a BBL environment to test the change in a CF environment. Let's sync on Slack how we can handle it together and we can discuss the test setup/steps.

cool!
the current struggle is supporting recent , since there does not seem to be a Websocket or SSE endpoint for streaming logs; apparently the CLI polls, so we'd need to do just that.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: jorbaum / name: Joris Baum (06d11f6, 4ab560d)
• ✅ login: Lokowandtg / name: Georg Lokowandt (5ed6c07)
• ✅ login: ZPascal / name: Pascal Zimmermann (03e1eb7, 1afe7df, 61c556d, 7a4cb06, 9f76d44, b6b5205, 13aff7b, 5e0d918, 5e78e83, 78d06ab, 7e7174b, 8a8cdee, b39e647)