feat: expectation pattern support

Signed-off-by: Attila Mészáros <a_meszaros@apple.com>

Author: csviri

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/expectation/Expectation.java

@@ -0,0 +1,32 @@
+package io.javaoperatorsdk.operator.processing.expectation;
+
+import java.util.function.BiPredicate;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.javaoperatorsdk.operator.api.reconciler.Context;
+
+public interface Expectation<P extends HasMetadata> {
+
+  String UNNAMED = "unnamed";
+
+  boolean isFulfilled(P primary, Context<P> context);
+
+  default String name() {
+    return UNNAMED;
+  }
+
+  static <P extends HasMetadata> Expectation<P> createExpectation(
+      String name, BiPredicate<P, Context<P>> predicate) {
+    return new Expectation<>() {
+      @Override
+      public String name() {
+        return name;
+      }
+
+      @Override
+      public boolean isFulfilled(P primary, Context<P> context) {
+        return predicate.test(primary, context);
+      }
+    };
+  }
+}

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/expectation/ExpectationManager.java

@@ -0,0 +1,59 @@
+package io.javaoperatorsdk.operator.processing.expectation;
+
+import java.time.Duration;
+import java.time.LocalDateTime;
+import java.util.Optional;
+import java.util.concurrent.ConcurrentHashMap;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+import io.javaoperatorsdk.operator.api.reconciler.Context;
+import io.javaoperatorsdk.operator.processing.event.ResourceID;
+
+public class ExpectationManager<P extends HasMetadata> {
+
+  private final ConcurrentHashMap<ResourceID, RegisteredExpectation<P>> registeredExpectations =
+      new ConcurrentHashMap<>();
+
+  public void setExpectation(P primary, Expectation<P> expectation, Duration timeout) {
+    registeredExpectations.put(
+        ResourceID.fromResource(primary),
+        new RegisteredExpectation<>(LocalDateTime.now(), timeout, expectation));
+  }
+
+  /**
+   * Checks if provided expectation is fulfilled. Return the expectation result. If the result of
+   * expectation is fulfilled or timeout, the expectation is automatically removed;
+   */
+  public Optional<ExpectationResult<P>> checkOnExpectation(P primary, Context<P> context) {
+    var resourceID = ResourceID.fromResource(primary);
+    var regExp = registeredExpectations.get(ResourceID.fromResource(primary));
+    if (regExp == null) {
+      return Optional.empty();
+    }
+    if (regExp.expectation().isFulfilled(primary, context)) {
+      registeredExpectations.remove(resourceID);
+      return Optional.of(
+          new ExpectationResult<>(regExp.expectation(), ExpectationStatus.FULFILLED));
+    } else if (regExp.isTimedOut()) {
+      registeredExpectations.remove(resourceID);
+      return Optional.of(
+          new ExpectationResult<>(regExp.expectation(), ExpectationStatus.TIMED_OUT));
+    } else {
+      return Optional.of(
+          new ExpectationResult<>(regExp.expectation(), ExpectationStatus.NOT_FULFILLED));
+    }
+  }
+
+  public boolean isExpectationPresent(P primary) {
+    return registeredExpectations.containsKey(ResourceID.fromResource(primary));
+  }
+
+  public Optional<Expectation<P>> getExpectation(P primary) {
+    var regExp = registeredExpectations.get(ResourceID.fromResource(primary));
+    return Optional.ofNullable(regExp).map(RegisteredExpectation::expectation);
+  }
+
+  public void cleanup(P primary) {
+    registeredExpectations.remove(ResourceID.fromResource(primary));
+  }
+}

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/expectation/ExpectationResult.java

@@ -0,0 +1,15 @@
+package io.javaoperatorsdk.operator.processing.expectation;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+
+public record ExpectationResult<P extends HasMetadata>(
+    Expectation<P> expectation, ExpectationStatus status) {
+
+  public boolean isFulfilled() {
+    return status == ExpectationStatus.FULFILLED;
+  }
+
+  public boolean isTimedOut() {
+    return status == ExpectationStatus.TIMED_OUT;
+  }
+}

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/expectation/ExpectationStatus.java

@@ -0,0 +1,7 @@
+package io.javaoperatorsdk.operator.processing.expectation;
+
+public enum ExpectationStatus {
+  FULFILLED,
+  NOT_FULFILLED,
+  TIMED_OUT
+}

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/expectation/RegisteredExpectation.java

@@ -0,0 +1,14 @@
+package io.javaoperatorsdk.operator.processing.expectation;
+
+import java.time.Duration;
+import java.time.LocalDateTime;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+
+record RegisteredExpectation<P extends HasMetadata>(
+    LocalDateTime registeredAt, Duration timeout, Expectation<P> expectation) {
+
+  public boolean isTimedOut() {
+    return LocalDateTime.now().isAfter(registeredAt.plus(timeout));
+  }
+}