Marcin Świerczyński's blog

Alexa Skill with Quarkus Native

posted 27 Mar 2023 in ProgrammingJavaQuarkusQuarkus Native

Airly Alexa Skill

Some time ago I wrote a skill for Alexa fetching current air pollution data from Airly - the air pollution service popular in Poland.

The skill is very simple - one says “Alexa, open air quality” and it replies something like “Great air here today! The Common Air Quality Index is 12”.

I wrote it in Java - event it’s not the best choice for AWS Lambda - because why not? :)

The code is available at https://github.com/MarcinSwierczynski/alexa-airly

The performance

I implemented the above with standard approach - using Java Corretto and Alexa Skills Kit SDK for Java.

It wasn’t a surprise, but the Lambda calls duration were pretty long, especially because of cold start.

As you can see, it took 8-9 s for a single call.

Quarkus to the rescue?

I decided to use Quarkus to improve the situation.

The code is at https://github.com/MarcinSwierczynski/alexa-airly-quarkus

The important parts are:

• QuarkusDelegateStreamLambda is needed even it does nothing
• it is referred in application.properties as quarkus.lambda.handler=alexa
• slf4j should be excluded from ask-sdk artifact
• Quarkus needs to be initialized e.g. in a static block in a subclass of SkillStreamHandler

It worked well with the calls duration ~12 s for a cold start and ~4 s later on.

Better, but so good given the nature of the air pollution skill - you usually use it a few times a day.

Quarkus Native

So, the natural remedy was Quarkus Native.

The code is at https://github.com/MarcinSwierczynski/alexa-airly-quarkus-native

The important parts are:

• io.quarkiverse.amazonalexa:quarkus-amazon-alexa dependency
• QuarkusDelegateStreamLambda now does JSON/bytes conversion
• it is referred in application.properties as quarkus.lambda.handler=alexa
• slf4j should still be excluded from ask-sdk artifact
• Quarkus does not need to be initialized in a subclass of SkillStreamHandler

The calls are around 800 ms, so an order of magnitude less then whit standard approach!

Conclusion

Quarkus Native seems to be a great alternative for writing Lambdas. Especially if you have Java competences in your team and don’t want to introduce Go/Python.