extend the time trigger sample with Retry policies

Author: tzolov

spring-cloud-function-adapters/spring-cloud-function-adapter-azure/src/main/java/org/springframework/cloud/function/adapter/azure/FunctionInvoker.java

@@ -65,9 +65,11 @@
  * @param <O> result type
  * @author Oleg Zhurakousky
  * @author Chris Bono
+ * @author Christian Tzolov
+ *
  * @since 3.2
  *
- * @deprecated since 4.0.0 in favor of dependency injection model implemented by {@link AzureFunctionInstanceInjector}.
+ * @deprecated since 4.0.0 in favor of the dependency injection implementation {@link AzureFunctionInstanceInjector}.
  * Follow the official documentation for further information.
  */
 @Deprecated

spring-cloud-function-adapters/spring-cloud-function-adapter-azure/src/main/java/org/springframework/cloud/function/adapter/azure/HttpFunctionInvoker.java

@@ -30,7 +30,7 @@
  *
  * @since 3.2
  *
- * @deprecated since 4.0.0 in favor of dependency injection model implemented by {@link AzureFunctionInstanceInjector}.
+ * @deprecated since 4.0.0 in favor of the dependency injection implementation {@link AzureFunctionInstanceInjector}.
  * Follow the official documentation for further information.
  */
 @Deprecated

spring-cloud-function-samples/function-sample-azure-time-trigger/README.adoc

@@ -31,6 +31,9 @@ In result the the `uppercase` Spring Cloud Function is called and uppercase the
 [2022-10-11T08:53:00.011Z] Execution Context Log - TimeInfo: {"Schedule":{"AdjustForDST":true},"ScheduleStatus":{"Last":"2022-10-11T10:52:00.003967+02:00","Next":"2022-10-11T10:53:00+02:00","LastUpdated":"2022-10-11T10:52:00.003967+02:00"},"IsPastDue":false}
 ```
 
+The `executeExpRetry` handler demonstrates how to handle errors using the https://learn.microsoft.com/en-us/azure/azure-functions/functions-bindings-error-pages?tabs=exponential-backoff%2Cin-process&pivots=programming-language-java#retry-policies[Retry policies].
+Sample emulates 3 errors on the first 3 executions and then continues as expected.
+
 === Running on Azure
 
 Make sure you are logged in your Azure account.

spring-cloud-function-samples/function-sample-azure-time-trigger/src/main/java/com/example/azure/di/timetriggerdemo/UppercaseHandler.java

@@ -16,9 +16,12 @@
 
 package com.example.azure.di.timetriggerdemo;
 
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Consumer;
 
 import com.microsoft.azure.functions.ExecutionContext;
+import com.microsoft.azure.functions.annotation.ExponentialBackoffRetry;
+import com.microsoft.azure.functions.annotation.FixedDelayRetry;
 import com.microsoft.azure.functions.annotation.FunctionName;
 import com.microsoft.azure.functions.annotation.TimerTrigger;
 
@@ -32,10 +35,13 @@ public class UppercaseHandler {
 
     public static String EXECUTION_CONTEXT = "executionContext";
 
+    private static AtomicInteger count = new AtomicInteger();
+
     @Autowired
     private Consumer<Message<String>> uppercase;
 
     @FunctionName("uppercase")
+    @FixedDelayRetry(maxRetryCount = 4, delayInterval = "00:00:10")
     public void execute(@TimerTrigger(name = "keepAliveTrigger", schedule = "0 */1 * * * *") String timerInfo,
             ExecutionContext context) {
 
@@ -46,4 +52,24 @@ public void execute(@TimerTrigger(name = "keepAliveTrigger", schedule = "0 */1 *
 
         this.uppercase.accept(message);
     }
+
+    @FunctionName("uppercaseExpRetry")
+    @ExponentialBackoffRetry(maxRetryCount = 4, maximumInterval = "00:15:00", minimumInterval = "00:00:03")
+    public void executeExpRetry(@TimerTrigger(name = "keepAliveTrigger", schedule = "*/10 * * * * *") String timerInfo,
+            ExecutionContext context) {
+
+        if (count.incrementAndGet() < 3) {
+            context.getLogger().info("EMULATE ERROR# " + count.get());
+            throw new IllegalStateException("Emulated ERROR# " + count.get());
+        }
+
+        context.getLogger().info("ERRORLESS EXECUTION");
+
+        Message<String> message = MessageBuilder
+                .withPayload(timerInfo)
+                .setHeader(EXECUTION_CONTEXT, context)
+                .build();
+
+        this.uppercase.accept(message);
+    }
 }