GH-968 Support Azure Functions DI hook

- Extend spring-cloud-function-adapter-azure with AzureFunctionInstanceInjector registered through the  META-INF/services/com.microsoft.azure.functions.spi.inject.FunctionInstanceInjector
 - Add DI demos for HttpTrigger and TimeTrigger functions.

 Resolves #968
 Resolves #969
Add FunctionInvoker backward compatibiity

document the time trigger DI sample

Add generic instructions to implement Azure Function with the help of the DI hook

Add generic instructions to implement Azure Function with the help of the DI hook

Minor

Fix injector backward compatibility and add blob demo

disable the azure di samples maven module builds

spring-cloud-function-samples/function-azure-di-samples/azure-httptrigger-demo/src/main/java/com/example/azure/di/httptriggerdemo/HttpTriggerDemoApplication.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2021-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.azure.di.httptriggerdemo;
+
+import java.util.function.Function;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+
+@SpringBootApplication
+public class HttpTriggerDemoApplication {
+
+	@Bean
+	public Function<String, String> echo() {
+		return payload -> payload;
+	}
+
+	@Bean
+	public Function<String, String> uppercase() {
+		return payload -> payload.toUpperCase();
+	}
+
+	public static void main(String[] args) {
+		SpringApplication.run(HttpTriggerDemoApplication.class, args);
+	}
+
+}

spring-cloud-function-samples/function-azure-di-samples/azure-httptrigger-demo/src/main/java/com/example/azure/di/httptriggerdemo/MyAzureFunction.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2021-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.azure.di.httptriggerdemo;
+
+import java.util.Optional;
+import java.util.function.Function;
+
+import com.microsoft.azure.functions.ExecutionContext;
+import com.microsoft.azure.functions.HttpMethod;
+import com.microsoft.azure.functions.HttpRequestMessage;
+import com.microsoft.azure.functions.annotation.AuthorizationLevel;
+import com.microsoft.azure.functions.annotation.FunctionName;
+import com.microsoft.azure.functions.annotation.HttpTrigger;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+@Component
+public class MyAzureFunction {
+
+    @Autowired
+    private Function<String, String> echo;
+
+    @Autowired
+    private Function<String, String> uppercase;
+
+    @FunctionName("ditest")
+    public String execute(
+            @HttpTrigger(name = "req", methods = { HttpMethod.GET,
+                    HttpMethod.POST }, authLevel = AuthorizationLevel.ANONYMOUS) HttpRequestMessage<Optional<String>> request,
+            ExecutionContext context) {
+
+        return echo.andThen(uppercase).apply(request.getBody().get());
+    }
+}

spring-cloud-function-samples/function-azure-di-samples/azure-httptrigger-demo/src/main/resources/application.properties

@@ -0,0 +1 @@
+

spring-cloud-function-samples/function-azure-di-samples/azure-httptrigger-demo/src/main/resources/host.json

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+{
+    "version": "2.0",
+    "extensionBundle": {
+        "id": "Microsoft.Azure.Functions.ExtensionBundle",
+        "version": "[3.*, 4.0.0)"
+    }
+}

spring-cloud-function-samples/function-azure-di-samples/azure-httptrigger-demo/src/test/java/com/example/azure/di/httptriggerdemo/HttptriggerDemoApplicationTests.java

@@ -0,0 +1,13 @@
+package com.example.azure.di.httptriggerdemo;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class HttptriggerDemoApplicationTests {
+
+	@Test
+	void contextLoads() {
+	}
+
+}