Spring and Azure function - spring

Question

Does Spring work with Azure functions?
For example: Rest API that the code inside uses "Autowired" annotation (After running mvn azure-functions:run I've got NullPointerException on "myScriptService").
import java.util.*;
import com.microsoft.azure.serverless.functions.annotation.*;
import com.microsoft.azure.serverless.functions.*;
import com.company.ScriptService;
import org.springframework.beans.factory.annotation.Autowired;
/**
* Azure Functions with HTTP Trigger.
*/
public class Function {
#Autowired
ScriptService myScriptService;
/**
* This function listens at endpoint "/api/hello". Two ways to invoke it using "curl" command in bash:
* 1. curl -d "HTTP Body" {your host}/api/hello
* 2. curl {your host}/api/hello?name=HTTP%20Query
*/
#FunctionName("myhello")
public HttpResponseMessage<String> hello(
#HttpTrigger(name = "req",
methods = "post",
authLevel = AuthorizationLevel.ANONYMOUS) HttpRequestMessage<Optional<String>> request,
final ExecutionContext context) {
context.getLogger().info("Java HTTP trigger processed a request.");
// Parse query parameter
String query = request.getQueryParameters().get("name");
String name = request.getBody().orElse(query);
if (name == null) {
return request.createResponse(400, "Please pass a name on the query string or in the request body");
} else {
return request.createResponse(200, "Hello, " + name + ", myScriptService.isEnabled(): " + myScriptService.isEnabled());
}
}
}

Answer 1

As some asked for a solution in the comments above, I'm assuming that this problem might be of relevance for other users, too.
So I think Spring Cloud Function is the magic word here: besides some other points (see the project page for details), it aims to enable Spring Boot features (like dependency injection, what you're looking for) on serverless providers (besides Azure Functions, also AWS Lambda and Apache OpenWhisk are supported).
So you have to make some modifications to your project:
Add the spring-cloud-function-adapter-azure dependency:
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-function-adapter-azure</artifactId>
<version>2.0.1.RELEASE</version>
</dependency>
Your handler class needs some additional code:
Add the #SpringBootApplication annotation
Add the main() method known from Spring Boot applications
Make sure that Spring can find your ScriptService class e. g. by using the #ComponentScan annotation
It should look like this:
#SpringBootApplication
#ComponentScan(basePackages = { "package.of.scriptservice" })
public class Function {
#Autowired
ScriptService myScriptService;
#FunctionName("myhello")
public HttpResponseMessage<String> hello(
#HttpTrigger(name = "req", methods = "post", authLevel = AuthorizationLevel.ANONYMOUS) HttpRequestMessage<Optional<String>> request,
final ExecutionContext context) {
// Your code here
}
public static void main(String[] args) {
SpringApplication.run(DemoFunctionHandler.class, args);
}
}
You can find a full example here and here

Answer 2

It looks like that there are a lot of changes between spring cloud v1 and v2. Have a quick look at this blog post: https://spring.io/blog/2018/09/25/spring-cloud-function-2-0-and-azure-functions
If you build your project like the example, spring will create the spring boot context when the azure function is called (and you call handleRequest). But the spring context is not available before this.

Answer 3

Do you add your package to scan for spring cloud function ?
spring.cloud.function.scan.packages="yourPackage"
It is to add in your application.properties