Running crystal in AWS lambda

Learning Resources
1

Hey,

I wrote a quick blog post how to run a crystal app in AWS Lambda thanks to the newly announced custom runtimes. No rocket science in there, but maybe it helps others. Despite crystal you need serverless, a node-based tool to deploy apps on AWS Lambda and optionally docker to create Linux binaries under osx.

More at https://spinscale.de/posts/2018-12-10-running-crystal-apps-in-aws-lambda/

If you have questions/suggestions, feel free to drop me a note. Once I created a properly tested version of the above, I will put it on github.

–Alex

14 Likes
2

Happy new year everyone!

I have pushed some sample code and docs, so everyone can run code on AWS Lambda using crystal.

See https://github.com/spinscale/crystal-aws-lambda

6 Likes
3

to make sure I do not let this thread die… I changed the above link so, that you can now use the repo as a library, so all you need is to write code like this

require "lambda_builder"

runtime = LambdaBuilder::Runtime.new

runtime.register_handler("httpevent",
  ->(input : JSON::Any) {
    req = LambdaBuilder::Util::LambdaHttpRequest.new(input)
    user = req.query_params.fetch("hello", "World")
    response = LambdaBuilder::Util::LambdaHttpResponse.new(200, "Hello #{user} from Crystal")
    # not super efficient, serializing to JSON string and then parsing, simplify this
    return JSON.parse response.to_json
  }
)

runtime.register_handler("scheduledevent",
  ->(input : JSON::Any) {
    runtime.logger.debug("Hello from scheduled event, input: #{input}")
    return JSON.parse "{}"
  }
)

runtime.register_handler("snsevent",
  ->(input : JSON::Any) {
    runtime.logger.info("SNSEvent input: #{input}")
    return JSON.parse "{}"
  }
)

runtime.run

Documentation is not yet awesome… the little one decided, reading her books is more important :slight_smile: so, PRs welcome of course

2 Likes
4

You should let register_handler receive a block and capture it (&handler), that you you can avoid the unnecessary and verbose JSON::Any and proc syntax everywhere. I’ll try to send you a PR later.

5

thanks a ton for your input, just refactored this, now one can run

require "lambda_builder"

runtime = LambdaBuilder::Runtime.new

runtime.register_handler("httpevent") do |input|
  req = LambdaBuilder::Util::LambdaHttpRequest.new(input)
  user = req.query_params.fetch("hello", "World")
  response = LambdaBuilder::Util::LambdaHttpResponse.new(200, "Hello #{user} from Crystal")
  # not super efficient, serializing to JSON string and then parsing, simplify this
  JSON.parse response.to_json
end

runtime.register_handler("scheduledevent") do |input|
  runtime.logger.debug("Hello from scheduled event, input: #{input}")
  JSON.parse "{}"
end

runtime.register_handler("snsevent") do |input|
  runtime.logger.info("SNSEvent input: #{input}")
  JSON.parse "{}"
end

runtime.run
1 Like
6

Hey @spinscale, have you tried faastruby.io? No need to fiddle with runtimes or any framework, just write:

def handler(event : FaaStRuby::Event) : FaaStRuby::Response
  render text: "Hello, Crystal!\n"
end

Then:
faastruby deploy-to workspace_name

Done. :slight_smile:
More info at https://faastruby.io/getting-started-crystal/

Full Disclosure: I am the creator of FaaStRuby

2 Likes
7

Interesting article.! I never knew that it is actually possible to use crystal with AWS lambda. As it is comparatively the new programming language. I also write lots of stuff regarding Amazon AWS and it sustainability with many of the programming language and the best programming language option for setting up AWS lambda server. My recent work is with Cloudways which is on Php based managed hosting platform.
However, I have found crystal as the interesting programming language and as it is a new programming language and has a vast market ahead of it. So, I will come up with an interesting article on this programming language.

3 Likes