separate metrics of @ApplyFaultTolerance for each method

api/src/main/java/io/smallrye/faulttolerance/api/ApplyFaultTolerance.java

@@ -13,7 +13,7 @@
 
 /**
  * A special interceptor binding annotation to apply preconfigured fault tolerance.
- * If {@code @ApplyFaultTolerance("<identifier>")} is present on a business method,
+ * If {@code @ApplyFaultTolerance("<identifier>")} is present on a business method,
  * then a bean of type {@link FaultTolerance} with qualifier
  * {@link io.smallrye.common.annotation.Identifier @Identifier("&lt;identifier>")}
  * must exist. Such bean serves as a preconfigured set of fault tolerance strategies
@@ -42,8 +42,8 @@
  * <p>
  * A single preconfigured fault tolerance can even be applied to multiple methods with different
  * return types, as long as the constraint on method asynchrony described above is obeyed. In such
- * case, it is customary to declare the fault tolerance instance as {@code FaultTolerance&lt;Object>}
- * for synchronous methods, {@code FaultTolerance&lt;CompletionStage&lt;Object>>} for asynchronous
+ * case, it is customary to declare the fault tolerance instance as {@code FaultTolerance<Object>}
+ * for synchronous methods, {@code FaultTolerance<CompletionStage<Object>>} for asynchronous
  * methods that return {@code CompletionStage}, and so on. Note that this effectively precludes
  * defining a useful fallback, because fallback can only be defined when the value type is known.
  */

doc/modules/ROOT/pages/reference/reusable.adoc

@@ -50,3 +50,13 @@ Likewise, it is possible to do this for xref:reference/asynchronous.adoc#async-t
 Note that you can't define a synchronous `FaultTolerance<T>` object and apply it to any asynchronous method.
 Similarly, you can't define an asynchronous `FaultTolerance<CompletionStage<T>>` and apply it to a synchronous method or an asynchronous method with different asynchronous type.
 This limitation will be lifted in the future.
+
+== Metrics
+
+Methods annotated `@ApplyFaultTolerance` gather metrics similarly to methods annotated with {microprofile-fault-tolerance} annotations.
+That is, each method gets its own metrics, with the `method` tag being `<fully qualified class name>.<method name>`.
+
+At the same time, state is still shared.
+All methods annotated `@ApplyFaultTolerance` share the same bulkhead, circuit breaker and/or rate limit.
+
+If the `FaultTolerance` object used for `@ApplyFaultTolerance` is also used xref:reference/programmatic-api.adoc[programmatically], that usage is coalesced in metrics under the description as the `method` tag.

implementation/core/src/main/java/io/smallrye/faulttolerance/core/apiimpl/FaultToleranceImpl.java

@@ -37,9 +37,11 @@
 import io.smallrye.faulttolerance.core.invocation.AsyncSupportRegistry;
 import io.smallrye.faulttolerance.core.invocation.Invoker;
 import io.smallrye.faulttolerance.core.invocation.StrategyInvoker;
-import io.smallrye.faulttolerance.core.metrics.CompletionStageMetricsCollector;
+import io.smallrye.faulttolerance.core.metrics.DelegatingCompletionStageMetricsCollector;
+import io.smallrye.faulttolerance.core.metrics.DelegatingMetricsCollector;
 import io.smallrye.faulttolerance.core.metrics.MeteredOperation;
-import io.smallrye.faulttolerance.core.metrics.MetricsCollector;
+import io.smallrye.faulttolerance.core.metrics.MeteredOperationName;
+import io.smallrye.faulttolerance.core.metrics.MetricsProvider;
 import io.smallrye.faulttolerance.core.rate.limit.CompletionStageRateLimit;
 import io.smallrye.faulttolerance.core.rate.limit.RateLimit;
 import io.smallrye.faulttolerance.core.retry.BackOff;
@@ -103,22 +105,32 @@ public final class FaultToleranceImpl<V, S, T> implements FaultTolerance<T> {
         this.hasFallback = hasFallback;
     }
 
-    @Override
-    public T call(Callable<T> action) throws Exception {
+    T call(Callable<T> action, MeteredOperationName meteredOperationName) throws Exception {
         if (asyncSupport == null) {
             InvocationContext<T> ctx = new InvocationContext<>(action);
+            if (meteredOperationName != null) {
+                ctx.set(MeteredOperationName.class, meteredOperationName);
+            }
             eventHandlers.register(ctx);
             return ((FaultToleranceStrategy<T>) strategy).apply(ctx);
         }
 
         Invoker<T> invoker = new CallableInvoker<>(action);
         InvocationContext<CompletionStage<V>> ctx = new InvocationContext<>(() -> asyncSupport.toCompletionStage(invoker));
+        if (meteredOperationName != null) {
+            ctx.set(MeteredOperationName.class, meteredOperationName);
+        }
         eventHandlers.register(ctx);
         Invoker<CompletionStage<V>> wrapper = new StrategyInvoker<>(null,
                 (FaultToleranceStrategy<CompletionStage<V>>) strategy, ctx);
         return asyncSupport.fromCompletionStage(wrapper);
     }
 
+    @Override
+    public T call(Callable<T> action) throws Exception {
+        return call(action, null);
+    }
+
     @Override
     public void run(Runnable action) {
         try {
@@ -259,7 +271,7 @@ private void eagerInitialization() {
             }
         }
 
-        private FaultTolerance<T> build(BuilderLazyDependencies lazyDependencies) {
+        private FaultToleranceImpl<?, ?, T> build(BuilderLazyDependencies lazyDependencies) {
             Consumer<CircuitBreakerEvents.StateTransition> cbMaintenanceEventHandler = null;
             if (circuitBreakerBuilder != null && circuitBreakerBuilder.name != null) {
                 cbMaintenanceEventHandler = eagerDependencies.cbMaintenance()
@@ -285,12 +297,13 @@ private FaultTolerance<T> build(BuilderLazyDependencies lazyDependencies) {
             return isAsync ? buildAsync(lazyDependencies, eventHandlers) : buildSync(lazyDependencies, eventHandlers);
         }
 
-        private FaultTolerance<T> buildSync(BuilderLazyDependencies lazyDependencies, EventHandlers eventHandlers) {
+        private FaultToleranceImpl<T, T, T> buildSync(BuilderLazyDependencies lazyDependencies, EventHandlers eventHandlers) {
             FaultToleranceStrategy<T> strategy = buildSyncStrategy(lazyDependencies);
-            return new FaultToleranceImpl<>(strategy, (AsyncSupport<T, T>) null, eventHandlers, fallbackBuilder != null);
+            return new FaultToleranceImpl<>(strategy, null, eventHandlers, fallbackBuilder != null);
         }
 
-        private <V> FaultTolerance<T> buildAsync(BuilderLazyDependencies lazyDependencies, EventHandlers eventHandlers) {
+        private <V> FaultToleranceImpl<V, CompletionStage<V>, T> buildAsync(BuilderLazyDependencies lazyDependencies,
+                EventHandlers eventHandlers) {
             FaultToleranceStrategy<CompletionStage<V>> strategy = buildAsyncStrategy(lazyDependencies);
             AsyncSupport<V, T> asyncSupport = AsyncSupportRegistry.get(new Class[0], asyncType);
             return new FaultToleranceImpl<>(strategy, asyncSupport, eventHandlers, fallbackBuilder != null);
@@ -354,10 +367,10 @@ private FaultToleranceStrategy<T> buildSyncStrategy(BuilderLazyDependencies lazy
                                 fallbackBuilder.whenPredicate));
             }
 
-            if (lazyDependencies.metricsProvider().isEnabled()) {
-                MeteredOperation meteredOperation = buildMeteredOperation();
-                result = new MetricsCollector<>(result, lazyDependencies.metricsProvider().create(meteredOperation),
-                        meteredOperation);
+            MetricsProvider metricsProvider = lazyDependencies.metricsProvider();
+            if (metricsProvider.isEnabled()) {
+                MeteredOperation defaultOperation = buildMeteredOperation();
+                result = new DelegatingMetricsCollector<>(result, metricsProvider, defaultOperation);
             }
 
             return result;
@@ -436,10 +449,10 @@ private <V> FaultToleranceStrategy<CompletionStage<V>> buildAsyncStrategy(Builde
                                 fallbackBuilder.whenPredicate));
             }
 
-            if (lazyDependencies.metricsProvider().isEnabled()) {
-                MeteredOperation meteredOperation = buildMeteredOperation();
-                result = new CompletionStageMetricsCollector<>(result,
-                        lazyDependencies.metricsProvider().create(meteredOperation), meteredOperation);
+            MetricsProvider metricsProvider = lazyDependencies.metricsProvider();
+            if (metricsProvider.isEnabled()) {
+                MeteredOperation defaultOperation = buildMeteredOperation();
+                result = new DelegatingCompletionStageMetricsCollector<>(result, metricsProvider, defaultOperation);
             }
 
             // thread offload is always enabled

implementation/core/src/main/java/io/smallrye/faulttolerance/core/apiimpl/LazyFaultTolerance.java

@@ -5,16 +5,17 @@
 import java.util.function.Supplier;
 
 import io.smallrye.faulttolerance.api.FaultTolerance;
+import io.smallrye.faulttolerance.core.metrics.MeteredOperationName;
 
 public final class LazyFaultTolerance<T> implements FaultTolerance<T> {
-    private final Supplier<FaultTolerance<T>> builder;
+    private final Supplier<FaultToleranceImpl<?, ?, T>> builder;
     private final Class<?> asyncType;
 
     private final ReentrantLock lock = new ReentrantLock();
 
-    private volatile FaultTolerance<T> instance;
+    private volatile FaultToleranceImpl<?, ?, T> instance;
 
-    LazyFaultTolerance(Supplier<FaultTolerance<T>> builder, Class<?> asyncType) {
+    LazyFaultTolerance(Supplier<FaultToleranceImpl<?, ?, T>> builder, Class<?> asyncType) {
         this.builder = builder;
         this.asyncType = asyncType;
     }
@@ -23,6 +24,10 @@ public Class<?> internalGetAsyncType() {
         return asyncType;
     }
 
+    public T call(Callable<T> action, MeteredOperationName meteredOperationName) throws Exception {
+        return instance().call(action, meteredOperationName);
+    }
+
     @Override
     public T call(Callable<T> action) throws Exception {
         return instance().call(action);
@@ -50,8 +55,8 @@ public <U> FaultTolerance<U> castAsync(Class<?> asyncType) {
         return instance().castAsync(asyncType);
     }
 
-    private FaultTolerance<T> instance() {
-        FaultTolerance<T> instance = this.instance;
+    private FaultToleranceImpl<?, ?, T> instance() {
+        FaultToleranceImpl<?, ?, T> instance = this.instance;
         if (instance == null) {
             lock.lock();
             try {

implementation/core/src/main/java/io/smallrye/faulttolerance/core/metrics/DelegatingCompletionStageMetricsCollector.java

@@ -0,0 +1,34 @@
+package io.smallrye.faulttolerance.core.metrics;
+
+import java.util.concurrent.CompletionStage;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+import io.smallrye.faulttolerance.core.FaultToleranceStrategy;
+import io.smallrye.faulttolerance.core.InvocationContext;
+
+public class DelegatingCompletionStageMetricsCollector<V> implements FaultToleranceStrategy<CompletionStage<V>> {
+    private final FaultToleranceStrategy<CompletionStage<V>> delegate;
+    private final MetricsProvider provider;
+    private final MeteredOperation originalOperation;
+
+    private final ConcurrentMap<MeteredOperation, CompletionStageMetricsCollector<V>> cache = new ConcurrentHashMap<>();
+
+    public DelegatingCompletionStageMetricsCollector(FaultToleranceStrategy<CompletionStage<V>> delegate,
+            MetricsProvider provider, MeteredOperation originalOperation) {
+        this.delegate = delegate;
+        this.provider = provider;
+        this.originalOperation = originalOperation;
+    }
+
+    @Override
+    public CompletionStage<V> apply(InvocationContext<CompletionStage<V>> ctx) throws Exception {
+        MeteredOperationName name = ctx.get(MeteredOperationName.class);
+        MeteredOperation operation = name != null
+                ? new DelegatingMeteredOperation(originalOperation, name.get())
+                : originalOperation;
+        CompletionStageMetricsCollector<V> delegate = cache.computeIfAbsent(operation,
+                ignored -> new CompletionStageMetricsCollector<>(this.delegate, provider.create(operation), operation));
+        return delegate.apply(ctx);
+    }
+}

implementation/core/src/main/java/io/smallrye/faulttolerance/core/metrics/DelegatingMeteredOperation.java

@@ -0,0 +1,56 @@
+package io.smallrye.faulttolerance.core.metrics;
+
+final class DelegatingMeteredOperation implements MeteredOperation {
+    private final MeteredOperation operation;
+    private final String name;
+
+    DelegatingMeteredOperation(MeteredOperation operation, String name) {
+        this.operation = operation;
+        this.name = name;
+    }
+
+    @Override
+    public boolean isAsynchronous() {
+        return operation.isAsynchronous();
+    }
+
+    @Override
+    public boolean hasBulkhead() {
+        return operation.hasBulkhead();
+    }
+
+    @Override
+    public boolean hasCircuitBreaker() {
+        return operation.hasCircuitBreaker();
+    }
+
+    @Override
+    public boolean hasFallback() {
+        return operation.hasFallback();
+    }
+
+    @Override
+    public boolean hasRateLimit() {
+        return operation.hasRateLimit();
+    }
+
+    @Override
+    public boolean hasRetry() {
+        return operation.hasRetry();
+    }
+
+    @Override
+    public boolean hasTimeout() {
+        return operation.hasTimeout();
+    }
+
+    @Override
+    public String name() {
+        return name;
+    }
+
+    @Override
+    public Object cacheKey() {
+        return name;
+    }
+}

implementation/core/src/main/java/io/smallrye/faulttolerance/core/metrics/DelegatingMetricsCollector.java

@@ -0,0 +1,33 @@
+package io.smallrye.faulttolerance.core.metrics;
+
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+import io.smallrye.faulttolerance.core.FaultToleranceStrategy;
+import io.smallrye.faulttolerance.core.InvocationContext;
+
+public class DelegatingMetricsCollector<V> implements FaultToleranceStrategy<V> {
+    private final FaultToleranceStrategy<V> delegate;
+    private final MetricsProvider provider;
+    private final MeteredOperation originalOperation;
+
+    private final ConcurrentMap<MeteredOperation, MetricsCollector<V>> cache = new ConcurrentHashMap<>();
+
+    public DelegatingMetricsCollector(FaultToleranceStrategy<V> delegate, MetricsProvider provider,
+            MeteredOperation originalOperation) {
+        this.delegate = delegate;
+        this.provider = provider;
+        this.originalOperation = originalOperation;
+    }
+
+    @Override
+    public V apply(InvocationContext<V> ctx) throws Exception {
+        MeteredOperationName name = ctx.get(MeteredOperationName.class);
+        MeteredOperation operation = name != null
+                ? new DelegatingMeteredOperation(originalOperation, name.get())
+                : originalOperation;
+        MetricsCollector<V> delegate = cache.computeIfAbsent(operation,
+                ignored -> new MetricsCollector<>(this.delegate, provider.create(operation), operation));
+        return delegate.apply(ctx);
+    }
+}

implementation/core/src/main/java/io/smallrye/faulttolerance/core/metrics/MeteredOperationName.java

@@ -0,0 +1,13 @@
+package io.smallrye.faulttolerance.core.metrics;
+
+public final class MeteredOperationName {
+    private final String name;
+
+    public MeteredOperationName(String name) {
+        this.name = name;
+    }
+
+    public String get() {
+        return name;
+    }
+}

implementation/fault-tolerance/src/main/java/io/smallrye/faulttolerance/FaultToleranceInterceptor.java

@@ -78,6 +78,7 @@
 import io.smallrye.faulttolerance.core.invocation.StrategyInvoker;
 import io.smallrye.faulttolerance.core.metrics.CompletionStageMetricsCollector;
 import io.smallrye.faulttolerance.core.metrics.MeteredOperation;
+import io.smallrye.faulttolerance.core.metrics.MeteredOperationName;
 import io.smallrye.faulttolerance.core.metrics.MetricsCollector;
 import io.smallrye.faulttolerance.core.metrics.MetricsProvider;
 import io.smallrye.faulttolerance.core.rate.limit.CompletionStageRateLimit;
@@ -210,14 +211,16 @@ private Object preconfiguredFlow(FaultToleranceOperation operation, InvocationCo
             throw new FaultToleranceException("Configured fault tolerance '" + identifier
                     + "' is not created by the FaultTolerance API, this is not supported");
         }
+        LazyFaultTolerance<Object> lazyFaultTolerance = (LazyFaultTolerance<Object>) faultTolerance;
 
-        Class<?> asyncType = ((LazyFaultTolerance<?>) faultTolerance).internalGetAsyncType();
+        Class<?> asyncType = lazyFaultTolerance.internalGetAsyncType();
+        MeteredOperationName meteredOperationName = new MeteredOperationName(operation.getName());
 
         AsyncSupport<?, ?> forOperation = AsyncSupportRegistry.get(operation.getParameterTypes(), operation.getReturnType());
         AsyncSupport<?, ?> fromConfigured = asyncType == null ? null : AsyncSupportRegistry.get(new Class[0], asyncType);
 
         if (forOperation == null && fromConfigured == null) {
-            return faultTolerance.call(interceptionContext::proceed);
+            return lazyFaultTolerance.call(interceptionContext::proceed, meteredOperationName);
         } else if (forOperation == null) {
             throw new FaultToleranceException("Configured fault tolerance '" + identifier
                     + "' expects the operation to " + fromConfigured.mustDescription()
@@ -231,7 +234,7 @@ private Object preconfiguredFlow(FaultToleranceOperation operation, InvocationCo
                     + "' expects the operation to " + fromConfigured.mustDescription()
                     + ", but it " + forOperation.doesDescription() + ": " + operation);
         } else {
-            return faultTolerance.call(interceptionContext::proceed);
+            return lazyFaultTolerance.call(interceptionContext::proceed, meteredOperationName);
         }
     }
 

testsuite/basic/src/test/java/io/smallrye/faulttolerance/reuse/async/completionstage/metrics/MyFaultTolerance.java

@@ -0,0 +1,21 @@
+package io.smallrye.faulttolerance.reuse.async.completionstage.metrics;
+
+import static java.util.concurrent.CompletableFuture.completedFuture;
+
+import java.util.concurrent.CompletionStage;
+
+import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.enterprise.inject.Produces;
+
+import io.smallrye.common.annotation.Identifier;
+import io.smallrye.faulttolerance.api.FaultTolerance;
+
+@ApplicationScoped
+public class MyFaultTolerance {
+    @Produces
+    @Identifier("my-fault-tolerance")
+    public static final FaultTolerance<CompletionStage<String>> FT = FaultTolerance.<String> createAsync()
+            .withRetry().maxRetries(2).done()
+            .withFallback().handler(() -> completedFuture("fallback")).done()
+            .build();
+}