Add azure function-catalog support docs

Author: tzolov

docs/src/main/asciidoc/adapters/azure-intro.adoc

@@ -51,10 +51,11 @@ dependencies {
 
 NOTE: version `4.0.0+` is required. Having the adapter on the classpath activates the Azure Java Worker integration.
 
-=== Function Implementation
+[[azure.development.guidelines]]
+=== Development Guidelines
 
 Use the `@Component` (or `@Service`) annotation to turn any exiting Azure Function class (e.g. with `@FunctionName` handlers) into a Spring component.
-Then you can auto-wire the required dependencies (or the https://docs.spring.io/spring-cloud-function/docs/current/reference/html/spring-cloud-function.html#_function_catalog_and_flexible_function_signatures[FunctionCatalog] for Spring Cloud Function composition) and use those inside the Azure function handlers.
+Then you can auto-wire the required dependencies (or the <<spring-cloud-function.adoc#function.catalog,Function Catalog>> for Spring Cloud Function composition) and use those inside the Azure function handlers.
 
 [source,java]
 ----
@@ -95,7 +96,7 @@ When invoked by a trigger (such as `@HttpTrigger`), functions process that trigg
 <4> The `plainBean` method handler is mapped to an Azure function that uses of the auto-wired `uppercase` spring bean to compute the result.
 It demonstrates how to use "plain" Spring components in your Azure handlers.
 <5> The `springCloudFunction` method handler is mapped to another Azure function, that uses the auto-wired `FunctionCatalog` instance to compute the result.
-<6> Shows how to leverage the Spring Cloud Function https://docs.spring.io/spring-cloud-function/docs/current/reference/html/spring-cloud-function.html#_function_catalog_and_flexible_function_signatures[FunctionCatalog] composition API.
+<6> Shows how to leverage the Spring Cloud Function <<spring-cloud-function.adoc#function.catalog,Function Catalog>> composition API.
 
 TIP: Use the Java annotations included in the https://learn.microsoft.com/en-us/java/api/com.microsoft.azure.functions.annotation?view=azure-java-stable[com.microsoft.azure.functions.annotation.*] package to bind input and outputs to your methods.
 
@@ -126,6 +127,16 @@ public class HttpTriggerDemoApplication {
 <1> The `@SpringBootApplication` annotated class is used as a `Main-Class` as explained in <<star-class-configuration, main class configuration>>.
 <2> Functions auto-wired and used in the Azure function handlers.
 
+==== Function Catalog
+
+The Spring Cloud Function supports a range of type signatures for user-defined functions, while providing a consistent execution model.
+For this it uses the <<spring-cloud-function.adoc#function.catalog,Function Catalog>> to transform all user defined functions into a canonical representation.
+
+The Azure adapter can auto-wire any Spring component, such as the `uppercase` above.
+But those are treated as plain Java class instances, not as a canonical Spring Cloud Functions!
+
+To leverage Spring Cloud Function and have access to the canonical function representations, you need to auto-wire the `FunctionCatalog` and use it in your handler, like the `functionCatalog` instance the `springCloudFunction()` handler above.
+
 ==== Accessing Azure ExecutionContext
 
 Some time there is a need to access the target execution context provided by the Azure runtime in the form of `com.microsoft.azure.functions.ExecutionContext`.
@@ -164,6 +175,7 @@ public Function<Message<String>, String> uppercase(JsonMapper mapper) {
 ----
 <1> Retrieve the ExecutionContext instance from the header.
 
+
 [[azure.configuration]]
 === Configuration
 
@@ -510,4 +522,12 @@ WARNING: The legacy `FunctionInvoker` programming model is deprecated and will n
 
 For additional documentation and samples about the Function Integration approach follow the https://github.com/spring-cloud/spring-cloud-function/tree/main/spring-cloud-function-samples/function-sample-azure/[azure-sample] README and code.
 
+== Relevant Links
+
+- https://learn.microsoft.com/en-us/azure/developer/java/spring-framework/getting-started-with-spring-cloud-function-in-azure[Spring Cloud Function in Azure]
+- https://spring.io/blog/2023/02/24/spring-cloud-function-for-azure-function[Spring Cloud Function for Azure Function (blog)]
+- <<spring-cloud-function.adoc#,Spring Cloud Function - Reference Guide>>
+- https://learn.microsoft.com/en-us/azure/azure-functions/functions-reference-java?tabs=bash%2Cconsumption[Azure Functions Java developer guide]
+- https://learn.microsoft.com/en-us/azure/azure-functions/functions-reference?tabs=blob[Azure Functions developer guide]
+
 :sectnums!:

docs/src/main/asciidoc/spring-cloud-function.adoc

@@ -24,6 +24,7 @@ include::getting-started.adoc[]
 
 == Programming model
 
+[[function.catalog]]
 
 === Function Catalog and Flexible Function Signatures