Streamline and refactor the azure and the azure-web adapters.

- Add SCF/Azure Gradle sample and docs.
- Move the function-azure-di-samples into standalone projects.
 - Apply the name convetion and project structure for the SCF adaptes.
   E.g.  function-sample-azure-XXX projects under the spring-cloud-function-samples root.
 - Remove the redudant samples.
 - Improve the samples docs and the Adapter generic docs.
- Streamline docs.
- Add azure web adapter sample and README.
- Add Spring Azure Functions banner for azure and azure web adapters.
- azure-web adapter fixes:
  - Fix issues in serverles-web ProxyHttpServletResponse implementation.
  - Remove the custom FunctionClassUtils utils in favor of scf-context/util/FunctionClassUtils.
- Remove redundant files.
- Add FunctionInvoker deprecation annotations.
- Extend the time trigger sample with Retry policies example.

spring-cloud-function-samples/function-sample-azure-http-trigger/src/main/java/com/example/azure/di/httptriggerdemo/HttpTriggerDemoApplication.java

@@ -0,0 +1,47 @@
+/*
+ * 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();
+	}
+
+	@Bean
+	public Function<String, String> reverse() {
+		return payload -> new StringBuilder(payload).reverse().toString();
+	}
+
+	public static void main(String[] args) {
+		SpringApplication.run(HttpTriggerDemoApplication.class, args);
+	}
+
+}

spring-cloud-function-samples/function-sample-azure-http-trigger/src/main/java/com/example/azure/di/httptriggerdemo/MyAzureFunction.java

@@ -0,0 +1,74 @@
+/*
+ * 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.cloud.function.context.FunctionCatalog;
+import org.springframework.stereotype.Component;
+
+@Component
+public class MyAzureFunction {
+
+    /**
+     * Plain Spring bean (not Spring Cloud Functions!)
+     */
+    @Autowired
+    private Function<String, String> echo;
+
+    /**
+     * Plain Spring bean (not Spring Cloud Functions!)
+     */
+    @Autowired
+    private Function<String, String> uppercase;
+
+    /**
+     * The FunctionCatalog leverages the Spring Cloud Function framework.
+     */
+    @Autowired
+    private FunctionCatalog functionCatalog;
+
+    @FunctionName("bean")
+    public String plainBeans(
+            @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());
+    }
+
+    @FunctionName("scf")
+    public String springCloudFunction(
+            @HttpTrigger(name = "req", methods = { HttpMethod.GET,
+                    HttpMethod.POST }, authLevel = AuthorizationLevel.ANONYMOUS) HttpRequestMessage<Optional<String>> request,
+            ExecutionContext context) {
+
+        // Use SCF composition. Composed functions are not just spring beans but SCF such.
+        Function composed = this.functionCatalog.lookup("echo|reverse|uppercase");
+
+        return (String) composed.apply(request.getBody().get());
+    }
+}

spring-cloud-function-samples/function-sample-azure-http-trigger/src/main/resources/application.properties

@@ -0,0 +1 @@
+

spring-cloud-function-samples/function-sample-azure-http-trigger/src/main/resources/host.json

@@ -0,0 +1,7 @@
+{
+    "version": "2.0",
+    "extensionBundle": {
+        "id": "Microsoft.Azure.Functions.ExtensionBundle",
+        "version": "[3.*, 4.0.0)"
+    }
+}

spring-cloud-function-samples/function-sample-azure-http-trigger/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() {
+	}
+
+}