Add log cache log streaming support

README.md

@@ -17,6 +17,41 @@ The `cf-java-client` project is a Java language binding for interacting with a C
 ## Versions
 The Cloud Foundry Java Client has two active versions. The `5.x` line is compatible with Spring Boot `2.4.x - 2.6.x` just to manage its dependencies, while the `4.x` line uses Spring Boot `2.3.x`.
 
+## Deprecations
+
+### `DopplerClient.recentLogs()` — Recent Logs via Doppler
+
+> [!WARNING]
+> **Deprecated since cf-java-client `5.17.x`**
+>
+> The `DopplerClient.recentLogs()` endpoint (and the related `RecentLogsRequest` / `LogMessage` types from the `org.cloudfoundry.doppler` package) are **deprecated** and will be removed in a future release.
+>
+> This API relies on the [Loggregator][loggregator] Doppler/Traffic Controller endpoint `/apps/{id}/recentlogs`, which was removed in **Loggregator ≥ 107.0**.
+> The affected platform versions are:
+>
+> | Platform | Last version with Doppler recent-logs support |
+> | -------- | --------------------------------------------- |
+> | CF Deployment (CFD) | `< 24.3` |
+> | Tanzu Application Service (TAS) | `< 4.0` |
+>
+> **Migration:** Replace any call to `DopplerClient.recentLogs()` with [`LogCacheClient.read()`][log-cache-api] (available via `org.cloudfoundry.logcache.v1.LogCacheClient`).
+>
+> ```java
+> // Before (deprecated)
+> dopplerClient.recentLogs(RecentLogsRequest.builder()
+>     .applicationId(appId)
+>     .build());
+>
+> // After
+> logCacheClient.read(ReadRequest.builder()
+>     .sourceId(appId)
+>     .envelopeTypes(EnvelopeType.LOG)
+>     .build());
+> ```
+
+[loggregator]: https://github.com/cloudfoundry/loggregator
+[log-cache-api]: https://github.com/cloudfoundry/log-cache
+
 ## Dependencies
 Most projects will need two dependencies; the Operations API and an implementation of the Client API.  For Maven, the dependencies would be defined like this:
 
@@ -76,6 +111,9 @@ Both the `cloudfoundry-operations` and `cloudfoundry-client` projects follow a [
 
 ### `CloudFoundryClient`, `DopplerClient`, `UaaClient` Builders
 
+> [!NOTE]
+> **`DopplerClient` — partial deprecation:** The `recentLogs()` method on `DopplerClient` is deprecated and only works against Loggregator \< 107.0 (CFD \< 24.3 / TAS \< 4.0). See the [Deprecations](#deprecations) section above for the migration path to `LogCacheClient`.
+
 The lowest-level building blocks of the API are `ConnectionContext` and `TokenProvider`.  These types are intended to be shared between instances of the clients, and come with out of the box implementations.  To instantiate them, you configure them with builders:
 
 ```java

cloudfoundry-client-reactor/src/main/java/org/cloudfoundry/reactor/logcache/v1/ReactorLogCacheEndpoints.java

@@ -16,15 +16,23 @@
 
 package org.cloudfoundry.reactor.logcache.v1;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicLong;
+import org.cloudfoundry.logcache.v1.Envelope;
+import org.cloudfoundry.logcache.v1.EnvelopeType;
 import org.cloudfoundry.logcache.v1.InfoRequest;
 import org.cloudfoundry.logcache.v1.InfoResponse;
 import org.cloudfoundry.logcache.v1.MetaRequest;
 import org.cloudfoundry.logcache.v1.MetaResponse;
 import org.cloudfoundry.logcache.v1.ReadRequest;
 import org.cloudfoundry.logcache.v1.ReadResponse;
+import org.cloudfoundry.logcache.v1.TailLogsRequest;
 import org.cloudfoundry.reactor.ConnectionContext;
 import org.cloudfoundry.reactor.TokenProvider;
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
 final class ReactorLogCacheEndpoints extends AbstractLogCacheOperations {
@@ -48,4 +56,111 @@ Mono<MetaResponse> meta(MetaRequest request) {
     Mono<ReadResponse> read(ReadRequest request) {
         return get(request, ReadResponse.class, "read", request.getSourceId()).checkpoint();
     }
+
+    Mono<ReadResponse> recentLogs(ReadRequest request) {
+        return read(request);
+    }
+
+    /**
+     * Continuously polls Log Cache and emits new {@link Envelope}s as they arrive.
+     *
+     * <p>Mirrors the Go {@code logcache.Walk()} / {@code cf tail --follow} semantics:
+     * <ol>
+     *   <li>Start the cursor at {@code startTime} (defaults to now&nbsp;&minus;&nbsp;5&nbsp;s in
+     *       nanoseconds).</li>
+     *   <li>Issue {@code GET /api/v1/read/{sourceId}?start_time=cursor}.</li>
+     *   <li>Emit every returned envelope in ascending timestamp order and advance
+     *       the cursor to {@code lastTimestamp + 1}.</li>
+     *   <li>When the batch is empty, wait {@code pollInterval} before the next poll.</li>
+     *   <li>Repeat forever – the caller cancels the subscription to stop.</li>
+     * </ol>
+     * Fully non-blocking: no {@code Thread.sleep}.
+     */
+    Flux<Envelope> logsTail(TailLogsRequest request) {
+        long defaultStartNanos = (System.currentTimeMillis() - 5_000L) * 1_000_000L;
+        AtomicLong cursor =
+                new AtomicLong(
+                        request.getStartTime() != null
+                                ? request.getStartTime()
+                                : defaultStartNanos);
+
+        List<EnvelopeType> envelopeTypes =
+                request.getEnvelopeTypes() != null
+                        ? request.getEnvelopeTypes()
+                        : Collections.emptyList();
+        String nameFilter = request.getNameFilter();
+
+        /*
+         * Strategy (mirrors Go's logcache.Walk):
+         *  – Mono.defer builds a fresh ReadRequest from the mutable cursor on every repetition.
+         *  – The Mono returns either the sorted batch (non-empty) or an empty list.
+         *  – flatMapMany turns each batch into a stream of individual Envelope items.
+         *  – repeat() subscribes again after each completion.
+         *  – When the batch was empty we insert a delay via Mono.delay before the next
+         *    repetition so we do not hammer the server. We signal "empty" by returning
+         *    a sentinel Mono<Boolean> (false = was empty, true = had data) and use
+         *    repeatWhen to conditionally delay.
+         */
+        return Flux.defer(
+                        () -> {
+                            // Build the read request from the current cursor position.
+                            ReadRequest.Builder builder =
+                                    ReadRequest.builder()
+                                            .sourceId(request.getSourceId())
+                                            .startTime(cursor.get());
+                            if (!envelopeTypes.isEmpty()) {
+                                builder.envelopeTypes(envelopeTypes);
+                            }
+                            if (nameFilter != null && !nameFilter.isEmpty()) {
+                                builder.nameFilter(nameFilter);
+                            }
+
+                            return read(builder.build())
+                                    .onErrorReturn(ReadResponse.builder().build())
+                                    .flatMapMany(
+                                            resp -> {
+                                                List<Envelope> raw =
+                                                        resp.getEnvelopes() != null
+                                                                ? resp.getEnvelopes().getBatch()
+                                                                : Collections.emptyList();
+
+                                                if (raw.isEmpty()) {
+                                                    // Signal "no data" so repeatWhen can insert the
+                                                    // back-off delay.
+                                                    return Flux.empty();
+                                                }
+
+                                                // Sort ascending by timestamp and advance the
+                                                // cursor.
+                                                List<Envelope> sorted = new ArrayList<>(raw);
+                                                sorted.sort(
+                                                        (a, b) ->
+                                                                Long.compare(
+                                                                        a.getTimestamp() != null
+                                                                                ? a.getTimestamp()
+                                                                                : 0L,
+                                                                        b.getTimestamp() != null
+                                                                                ? b.getTimestamp()
+                                                                                : 0L));
+
+                                                Envelope last = sorted.get(sorted.size() - 1);
+                                                cursor.set(
+                                                        (last.getTimestamp() != null
+                                                                        ? last.getTimestamp()
+                                                                        : cursor.get())
+                                                                + 1);
+
+                                                return Flux.fromIterable(sorted);
+                                            });
+                        })
+                // repeatWhen receives a Flux<Long> where each element is the count of items
+                // emitted in the previous cycle (0 = empty batch → insert delay).
+                .repeatWhen(
+                        companion ->
+                                companion.flatMap(
+                                        count ->
+                                                count == 0
+                                                        ? Mono.delay(request.getPollInterval())
+                                                        : Mono.just(count)));
+    }
 }

cloudfoundry-client-reactor/src/main/java/org/cloudfoundry/reactor/logcache/v1/_ReactorLogCacheClient.java

@@ -16,16 +16,19 @@
 
 package org.cloudfoundry.reactor.logcache.v1;
 
+import org.cloudfoundry.logcache.v1.Envelope;
 import org.cloudfoundry.logcache.v1.InfoRequest;
 import org.cloudfoundry.logcache.v1.InfoResponse;
 import org.cloudfoundry.logcache.v1.LogCacheClient;
 import org.cloudfoundry.logcache.v1.MetaRequest;
 import org.cloudfoundry.logcache.v1.MetaResponse;
 import org.cloudfoundry.logcache.v1.ReadRequest;
 import org.cloudfoundry.logcache.v1.ReadResponse;
+import org.cloudfoundry.logcache.v1.TailLogsRequest;
 import org.cloudfoundry.reactor.ConnectionContext;
 import org.cloudfoundry.reactor.TokenProvider;
 import org.immutables.value.Value;
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
 import java.net.URI;
@@ -53,6 +56,16 @@ public Mono<ReadResponse> read(ReadRequest request) {
         return getReactorLogCacheEndpoints().read(request);
     }
 
+    @Override
+    public Mono<ReadResponse> recentLogs(ReadRequest request) {
+        return getReactorLogCacheEndpoints().recentLogs(request);
+    }
+
+    @Override
+    public Flux<Envelope> logsTail(TailLogsRequest request) {
+        return getReactorLogCacheEndpoints().logsTail(request);
+    }
+
     /**
      * The connection context
      */

cloudfoundry-client/src/main/java/org/cloudfoundry/doppler/DopplerClient.java

@@ -42,9 +42,15 @@ public interface DopplerClient {
     /**
      * Makes the <a href="https://github.com/cloudfoundry/loggregator/tree/develop/src/trafficcontroller#endpoints">Recent Logs</a> request
      *
+     * @deprecated Use {@link org.cloudfoundry.logcache.v1.LogCacheClient#recentLogs(org.cloudfoundry.logcache.v1.ReadRequest)} instead.
+     * Only works with {@code Loggregator < 107.0}, shipped in {@code CFD < 24.3} and {@code TAS < 4.0}.
      * @param request the Recent Logs request
-     * @return the events from the recent logs
+     * @return a flux of events from the recent logs
+     * @see <a href="https://github.com/cloudfoundry/loggregator">Loggregator</a>
+     * @see <a href="https://github.com/cloudfoundry/log-cache">Log Cache</a>
+     * @see org.cloudfoundry.logcache.v1.LogCacheClient#recentLogs(org.cloudfoundry.logcache.v1.ReadRequest)
      */
+    @Deprecated
     Flux<Envelope> recentLogs(RecentLogsRequest request);
 
     /**

cloudfoundry-client/src/main/java/org/cloudfoundry/logcache/v1/LogCacheClient.java

@@ -16,6 +16,7 @@
 
 package org.cloudfoundry.logcache.v1;
 
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
 /**
@@ -46,4 +47,25 @@ public interface LogCacheClient {
      * @return the read response
      */
     Mono<ReadResponse> read(ReadRequest request);
+
+    /**
+     * Makes the Log Cache RecentLogs /api/v1/read request
+     *
+     * @param request the Recent Logs request
+     * @return the events from the recent logs
+     */
+    Mono<ReadResponse> recentLogs(ReadRequest request);
+
+    /**
+     * Continuously polls the Log Cache /api/v1/read endpoint and streams new {@link Envelope}s
+     * as they appear. This is the Java equivalent of the Go {@code logcache.Walk()} API and
+     * {@code cf tail --follow}.
+     * <p>
+     * The returned {@link Flux} will never complete on its own – unsubscribe (or cancel) it to
+     * stop streaming.
+     *
+     * @param request the tail request (source id, optional filters, poll interval)
+     * @return an infinite stream of envelopes
+     */
+    Flux<Envelope> logsTail(TailLogsRequest request);
 }

cloudfoundry-client/src/main/java/org/cloudfoundry/logcache/v1/_TailLogsRequest.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2013-2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.cloudfoundry.logcache.v1;
+
+import org.cloudfoundry.Nullable;
+import org.immutables.value.Value;
+
+import java.time.Duration;
+import java.util.List;
+
+/**
+ * The request options for the Log Cache tail (streaming follow) operation.
+ * This continuously polls the Log Cache /api/v1/read endpoint, emitting new envelopes
+ * as they appear – equivalent to {@code cf tail --follow} or the Go {@code logcache.Walk()} API.
+ */
+@Value.Immutable
+abstract class _TailLogsRequest {
+
+    /**
+     * The source id (application guid or service guid) to stream logs for.
+     */
+    abstract String getSourceId();
+
+    /**
+     * Optional start time (UNIX nanoseconds).  Defaults to "now – 5 seconds" when not set.
+     */
+    @Nullable
+    abstract Long getStartTime();
+
+    /**
+     * Optional envelope type filter.
+     */
+    @Nullable
+    abstract List<EnvelopeType> getEnvelopeTypes();
+
+    /**
+     * Optional regex name filter (requires Log Cache ≥ 2.1.0).
+     */
+    @Nullable
+    abstract String getNameFilter();
+
+    /**
+     * How long to wait between successive polls when no new envelopes are available.
+     * Defaults to 250 ms (matching the Go client's {@code AlwaysRetryBackoff}).
+     */
+    @Value.Default
+    Duration getPollInterval() {
+        return Duration.ofMillis(250);
+    }
+}
+

cloudfoundry-operations/src/main/java/org/cloudfoundry/operations/_DefaultCloudFoundryOperations.java

@@ -23,6 +23,7 @@
 import org.cloudfoundry.client.v3.spaces.ListSpacesRequest;
 import org.cloudfoundry.client.v3.spaces.SpaceResource;
 import org.cloudfoundry.doppler.DopplerClient;
+import org.cloudfoundry.logcache.v1.LogCacheClient;
 import org.cloudfoundry.networking.NetworkingClient;
 import org.cloudfoundry.operations.advanced.Advanced;
 import org.cloudfoundry.operations.advanced.DefaultAdvanced;
@@ -79,7 +80,7 @@ public Advanced advanced() {
     @Override
     @Value.Derived
     public Applications applications() {
-        return new DefaultApplications(getCloudFoundryClientPublisher(), getDopplerClientPublisher(), getSpaceId());
+        return new DefaultApplications(getCloudFoundryClientPublisher(), getDopplerClientPublisher(), getLogCacheClientPublisher(), getSpaceId());
     }
 
     @Override
@@ -197,6 +198,19 @@ Mono<DopplerClient> getDopplerClientPublisher() {
             .orElse(Mono.error(new IllegalStateException("DopplerClient must be set")));
     }
 
+    /**
+     * The {@link LogCacheClient} to use for operations functionality
+     */
+    @Nullable
+    abstract LogCacheClient getLogCacheClient();
+
+    @Value.Derived
+    Mono<LogCacheClient> getLogCacheClientPublisher() {
+        return Optional.ofNullable(getLogCacheClient())
+            .map(Mono::just)
+            .orElse(Mono.error(new IllegalStateException("LogCacheClient must be set")));
+    }
+
     /**
      * The {@link NetworkingClient} to use for operations functionality
      */