feat: java lease support

java-runtime/ftl-runtime/deployment/src/main/java/xyz/block/ftl/deployment/FtlProcessor.java

@@ -66,6 +66,7 @@
 import xyz.block.ftl.Cron;
 import xyz.block.ftl.Export;
 import xyz.block.ftl.GeneratedRef;
+import xyz.block.ftl.LeaseClient;
 import xyz.block.ftl.Retry;
 import xyz.block.ftl.Secret;
 import xyz.block.ftl.Subscription;
@@ -120,6 +121,7 @@ class FtlProcessor {
     public static final DotName CONFIG = DotName.createSimple(Config.class);
     public static final DotName OFFSET_DATE_TIME = DotName.createSimple(OffsetDateTime.class.getName());
     public static final DotName GENERATED_REF = DotName.createSimple(GeneratedRef.class);
+    public static final DotName LEASE_CLIENT = DotName.createSimple(LeaseClient.class);
 
     @BuildStep
     ModuleNameBuildItem moduleName(ApplicationInfoBuildItem applicationInfoBuildItem) {
@@ -187,12 +189,12 @@ public ParameterExtractor handleCustomParameter(org.jboss.jandex.Type type,
                         return new VerbRegistry.ConfigSupplier(name, paramType);
                     } else if (topics.getTopics().containsKey(type.name())) {
                         var topic = topics.getTopics().get(type.name());
-                        Class<?> paramType = loadClass(type);
                         return recorder.topicParamExtractor(topic.generatedProducer());
                     } else if (verbClients.getVerbClients().containsKey(type.name())) {
                         var client = verbClients.getVerbClients().get(type.name());
-                        Class<?> paramType = loadClass(type);
                         return recorder.verbParamExtractor(client.generatedClient());
+                    } else if (LEASE_CLIENT.equals(type.name())) {
+                        return recorder.leaseClientExtractor();
                     }
                     return null;
                 } catch (ClassNotFoundException e) {
@@ -451,6 +453,9 @@ private void handleVerbMethod(ExtractionContext context, MethodInfo method, Stri
                     parameterTypes.add(paramType);
                     paramMappers.add(context.recorder().verbClientSupplier(client.generatedClient()));
                     callsMetadata.addCalls(Ref.newBuilder().setName(client.name()).setModule(client.module()).build());
+                } else if (LEASE_CLIENT.equals(param.type().name())) {
+                    parameterTypes.add(LeaseClient.class);
+                    paramMappers.add(context.recorder().leaseClientSupplier());
                 } else if (bodyType != BodyType.DISALLOWED && bodyParamType == null) {
                     bodyParamType = param.type();
                     Class<?> paramType = loadClass(param.type());

java-runtime/ftl-runtime/runtime/src/main/java/xyz/block/ftl/LeaseClient.java

@@ -0,0 +1,11 @@
+package xyz.block.ftl;
+
+import java.time.Duration;
+
+/**
+ * Client that can be used to acquire a FTL lease. If the lease cannot be acquired a {@link LeaseFailedException} is thrown.
+ */
+public interface LeaseClient {
+
+    void acquireLease(Duration duration, String... keys) throws LeaseFailedException;
+}

java-runtime/ftl-runtime/runtime/src/main/java/xyz/block/ftl/LeaseFailedException.java

@@ -0,0 +1,26 @@
+package xyz.block.ftl;
+
+/**
+ * Checked exception that is thrown when a lease cannot be acquired
+ */
+public class LeaseFailedException extends Exception {
+
+    public LeaseFailedException() {
+    }
+
+    public LeaseFailedException(String message) {
+        super(message);
+    }
+
+    public LeaseFailedException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public LeaseFailedException(Throwable cause) {
+        super(cause);
+    }
+
+    public LeaseFailedException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
+        super(message, cause, enableSuppression, writableStackTrace);
+    }
+}

java-runtime/ftl-runtime/runtime/src/main/java/xyz/block/ftl/runtime/FTLController.java

@@ -1,8 +1,12 @@
 package xyz.block.ftl.runtime;
 
 import java.net.URI;
+import java.time.Duration;
+import java.util.Arrays;
+import java.util.Deque;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
+import java.util.concurrent.LinkedBlockingDeque;
 
 import jakarta.inject.Singleton;
 
@@ -14,6 +18,10 @@
 import io.grpc.ManagedChannelBuilder;
 import io.grpc.stub.StreamObserver;
 import io.quarkus.runtime.Startup;
+import xyz.block.ftl.LeaseClient;
+import xyz.block.ftl.LeaseFailedException;
+import xyz.block.ftl.v1.AcquireLeaseRequest;
+import xyz.block.ftl.v1.AcquireLeaseResponse;
 import xyz.block.ftl.v1.CallRequest;
 import xyz.block.ftl.v1.CallResponse;
 import xyz.block.ftl.v1.ModuleContextRequest;
@@ -25,9 +33,11 @@
 
 @Singleton
 @Startup
-public class FTLController {
+public class FTLController implements LeaseClient {
     private static final Logger log = Logger.getLogger(FTLController.class);
     final String moduleName;
+    private StreamObserver<AcquireLeaseRequest> leaseClient;
+    private final Deque<CompletableFuture<?>> leaseWaiters = new LinkedBlockingDeque<>();
 
     private Throwable currentError;
     private volatile ModuleContextResponse moduleContextResponse;
@@ -76,7 +86,29 @@ public FTLController(@ConfigProperty(name = "ftl.endpoint", defaultValue = "http
         var channel = channelBuilder.build();
         verbService = VerbServiceGrpc.newStub(channel);
         verbService.getModuleContext(ModuleContextRequest.newBuilder().setModule(moduleName).build(), moduleObserver);
+        synchronized (this) {
+            this.leaseClient = verbService.acquireLease(new StreamObserver<AcquireLeaseResponse>() {
+                @Override
+                public void onNext(AcquireLeaseResponse value) {
+                    leaseWaiters.pop().complete(null);
+                }
+
+                @Override
+                public void onError(Throwable t) {
+                    leaseWaiters.pop().completeExceptionally(t);
+                }
 
+                @Override
+                public void onCompleted() {
+                    synchronized (FTLController.this) {
+                        while (!leaseWaiters.isEmpty()) {
+                            leaseWaiters.pop().completeExceptionally(new RuntimeException("connection closed"));
+                        }
+                        leaseClient = verbService.acquireLease(this);
+                    }
+                }
+            });
+        }
     }
 
     public byte[] getSecret(String secretName) {
@@ -97,6 +129,7 @@ public byte[] getConfig(String secretName) {
 
     public byte[] callVerb(String name, String module, byte[] payload) {
         CompletableFuture<byte[]> cf = new CompletableFuture<>();
+
         verbService.call(CallRequest.newBuilder().setVerb(Ref.newBuilder().setModule(module).setName(name))
                 .setBody(ByteString.copyFrom(payload)).build(), new StreamObserver<>() {
 
@@ -154,6 +187,23 @@ public void onCompleted() {
         }
     }
 
+    public void acquireLease(Duration duration, String... keys) throws LeaseFailedException {
+        CompletableFuture<?> cf = new CompletableFuture<>();
+        synchronized (this) {
+            leaseWaiters.push(cf);
+            leaseClient.onNext(AcquireLeaseRequest.newBuilder().setModule(moduleName)
+                    .addAllKey(Arrays.asList(keys))
+                    .setTtl(com.google.protobuf.Duration.newBuilder()
+                            .setSeconds(duration.toSeconds()))
+                    .build());
+        }
+        try {
+            cf.get();
+        } catch (Exception e) {
+            throw new LeaseFailedException(e);
+        }
+    }
+
     private ModuleContextResponse getModuleContext() {
         var moduleContext = moduleContextResponse;
         if (moduleContext != null) {

java-runtime/ftl-runtime/runtime/src/main/java/xyz/block/ftl/runtime/FTLRecorder.java

@@ -12,6 +12,7 @@
 
 import io.quarkus.arc.Arc;
 import io.quarkus.runtime.annotations.Recorder;
+import xyz.block.ftl.LeaseClient;
 import xyz.block.ftl.v1.CallRequest;
 
 @Recorder
@@ -71,6 +72,20 @@ public Object apply(ObjectMapper mapper, CallRequest callRequest) {
         }
     }
 
+    public BiFunction<ObjectMapper, CallRequest, Object> leaseClientSupplier() {
+        return new BiFunction<ObjectMapper, CallRequest, Object>() {
+            volatile LeaseClient leaseClient;
+
+            @Override
+            public Object apply(ObjectMapper mapper, CallRequest callRequest) {
+                if (leaseClient == null) {
+                    leaseClient = Arc.container().instance(LeaseClient.class).get();
+                }
+                return leaseClient;
+            }
+        };
+    }
+
     public ParameterExtractor topicParamExtractor(String className) {
 
         try {
@@ -107,4 +122,23 @@ public Object extractParameter(ResteasyReactiveRequestContext context) {
             throw new RuntimeException(e);
         }
     }
+
+    public ParameterExtractor leaseClientExtractor() {
+        try {
+            return new ParameterExtractor() {
+
+                volatile LeaseClient leaseClient;
+
+                @Override
+                public Object extractParameter(ResteasyReactiveRequestContext context) {
+                    if (leaseClient == null) {
+                        leaseClient = Arc.container().instance(LeaseClient.class).get();
+                    }
+                    return leaseClient;
+                }
+            };
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
 }