Completable result code throwable (#6348)

Author: jack-berg

docs/apidiffs/current_vs_latest/opentelemetry-sdk-common.txt

@@ -1,2 +1,7 @@
 Comparing source compatibility of opentelemetry-sdk-common-1.41.0-SNAPSHOT.jar against opentelemetry-sdk-common-1.40.0.jar
-No changes.
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.sdk.common.CompletableResultCode  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.sdk.common.CompletableResultCode failExceptionally(java.lang.Throwable)
+	+++  NEW METHOD: PUBLIC(+) java.lang.Throwable getFailureThrowable()
+		+++  NEW ANNOTATION: javax.annotation.Nullable
+	+++  NEW METHOD: PUBLIC(+) STATIC(+) io.opentelemetry.sdk.common.CompletableResultCode ofExceptionalFailure(java.lang.Throwable)

sdk/common/src/main/java/io/opentelemetry/sdk/common/CompletableResultCode.java

@@ -13,6 +13,7 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
 import javax.annotation.Nullable;
 
 /**
@@ -33,9 +34,19 @@ public static CompletableResultCode ofFailure() {
     return FAILURE;
   }
 
+  /**
+   * Returns a {@link CompletableResultCode} that has been {@link #failExceptionally(Throwable)
+   * failed exceptionally}.
+   */
+  public static CompletableResultCode ofExceptionalFailure(Throwable throwable) {
+    return new CompletableResultCode().failExceptionally(throwable);
+  }
+
   /**
    * Returns a {@link CompletableResultCode} that completes after all the provided {@link
-   * CompletableResultCode}s complete. If any of the results fail, the result will be failed.
+   * CompletableResultCode}s complete. If any of the results fail, the result will be failed. If any
+   * {@link #failExceptionally(Throwable) failed exceptionally}, the result will be failed
+   * exceptionally with the first {@link Throwable} from {@code codes}.
    */
   public static CompletableResultCode ofAll(Collection<CompletableResultCode> codes) {
     if (codes.isEmpty()) {
@@ -44,15 +55,20 @@ public static CompletableResultCode ofAll(Collection<CompletableResultCode> code
     CompletableResultCode result = new CompletableResultCode();
     AtomicInteger pending = new AtomicInteger(codes.size());
     AtomicBoolean failed = new AtomicBoolean();
+    AtomicReference<Throwable> throwableRef = new AtomicReference<>();
     for (CompletableResultCode code : codes) {
       code.whenComplete(
           () -> {
             if (!code.isSuccess()) {
               failed.set(true);
+              Throwable codeThrowable = code.getFailureThrowable();
+              if (codeThrowable != null) {
+                throwableRef.compareAndSet(null, codeThrowable);
+              }
             }
             if (pending.decrementAndGet() == 0) {
               if (failed.get()) {
-                result.fail();
+                result.failInternal(throwableRef.get());
               } else {
                 result.succeed();
               }
@@ -71,6 +87,10 @@ public CompletableResultCode() {}
   @GuardedBy("lock")
   private Boolean succeeded = null;
 
+  @Nullable
+  @GuardedBy("lock")
+  private Throwable throwable = null;
+
   @GuardedBy("lock")
   private final List<Runnable> completionActions = new ArrayList<>();
 
@@ -89,11 +109,27 @@ public CompletableResultCode succeed() {
     return this;
   }
 
-  /** Complete this {@link CompletableResultCode} unsuccessfully if it is not already completed. */
+  /**
+   * Complete this {@link CompletableResultCode} unsuccessfully if it is not already completed,
+   * setting the {@link #getFailureThrowable() failure throwable} to {@code null}.
+   */
   public CompletableResultCode fail() {
+    return failInternal(null);
+  }
+
+  /**
+   * Completes this {@link CompletableResultCode} unsuccessfully if it is not already completed,
+   * setting the {@link #getFailureThrowable() failure throwable} to {@code throwable}.
+   */
+  public CompletableResultCode failExceptionally(Throwable throwable) {
+    return failInternal(throwable);
+  }
+
+  private CompletableResultCode failInternal(@Nullable Throwable throwable) {
     synchronized (lock) {
       if (succeeded == null) {
         succeeded = false;
+        this.throwable = throwable;
         for (Runnable action : completionActions) {
           action.run();
         }
@@ -104,7 +140,7 @@ public CompletableResultCode fail() {
 
   /**
    * Obtain the current state of completion. Generally call once completion is achieved via the
-   * thenRun method.
+   * {@link #whenComplete(Runnable)} method.
    *
    * @return the current state of completion
    */
@@ -114,6 +150,21 @@ public boolean isSuccess() {
     }
   }
 
+  /**
+   * Returns {@link Throwable} if this {@link CompletableResultCode} was {@link
+   * #failExceptionally(Throwable) failed exceptionally}. Generally call once completion is achieved
+   * via the {@link #whenComplete(Runnable)} method.
+   *
+   * @return the throwable if failed exceptionally, or null if: {@link #fail() failed without
+   *     exception}, {@link #succeed() succeeded}, or not complete.
+   */
+  @Nullable
+  public Throwable getFailureThrowable() {
+    synchronized (lock) {
+      return throwable;
+    }
+  }
+
   /**
    * Perform an action on completion. Actions are guaranteed to be called only once.
    *

sdk/common/src/test/java/io/opentelemetry/sdk/common/CompletableResultCodeTest.java

@@ -21,12 +21,32 @@ class CompletableResultCodeTest {
 
   @Test
   void ofSuccess() {
-    assertThat(CompletableResultCode.ofSuccess().isSuccess()).isTrue();
+    assertThat(CompletableResultCode.ofSuccess())
+        .satisfies(
+            code -> {
+              assertThat(code.isSuccess()).isTrue();
+              assertThat(code.getFailureThrowable()).isNull();
+            });
   }
 
   @Test
   void ofFailure() {
-    assertThat(CompletableResultCode.ofFailure().isSuccess()).isFalse();
+    assertThat(CompletableResultCode.ofFailure())
+        .satisfies(
+            code -> {
+              assertThat(code.isSuccess()).isFalse();
+              assertThat(code.getFailureThrowable()).isNull();
+            });
+  }
+
+  @Test
+  void ofExceptionalFailure() {
+    assertThat(CompletableResultCode.ofExceptionalFailure(new Exception("error")))
+        .satisfies(
+            code -> {
+              assertThat(code.isSuccess()).isFalse();
+              assertThat(code.getFailureThrowable()).hasMessage("error");
+            });
   }
 
   @Test
@@ -149,6 +169,24 @@ void ofAllWithFailure() {
         .isFalse();
   }
 
+  @Test
+  void ofAllWithExceptionalFailure() {
+    assertThat(
+            CompletableResultCode.ofAll(
+                Arrays.asList(
+                    CompletableResultCode.ofSuccess(),
+                    CompletableResultCode.ofFailure(),
+                    CompletableResultCode.ofExceptionalFailure(new Exception("error1")),
+                    CompletableResultCode.ofExceptionalFailure(new Exception("error2")),
+                    CompletableResultCode.ofSuccess())))
+        .satisfies(
+            code -> {
+              assertThat(code.isSuccess()).isFalse();
+              // failure throwable is set to first throwable seen in the collection
+              assertThat(code.getFailureThrowable()).hasMessage("error1");
+            });
+  }
+
   @Test
   void join() {
     CompletableResultCode result = new CompletableResultCode();