Crystal / Google Cloud Function Dynamic Memory Allocation Test

This repo demonstrates that statically compiled crystal binaries that perform dynamic memory allocations do not crash when running in Google Cloud Functions.

Usage

1. clone the repo
2. make sure that docker is installed, perform the steps needed to make docker runnable without sudo https://docs.docker.com/install/linux/linux-postinstall/#manage-docker-as-a-non-root-user, and ensure that the docker daemon is running (you can verify this with docker info)
3. sign up for a trial Google Cloud Platform account (or have an existing account)
4. install the gcloud cli tool https://cloud.google.com/sdk/gcloud/ and log in to your account using gcloud init
5. in the repo, run ./build_deploy. The crystal alpine linux docker image will be used to compile a static binary of the src/dynamic_memory_test.cr crystal file. Then this binary will be deployed as a google cloud function called crystal-dynamic-memory-test.
6. Wait about a minute for the function to initialize. There seems to be a ~1-2 minute cool down time during which requests to the cloud function will error out.
7. curl the http trigger for the cloud function url (displayed as the value of httpTrigger in step 7). If everything works correctly, you should get output like this:

$ curl https://us-central1-project-id.cloudfunctions.net/crystal-dynamic-memory-test
dynamic memory test starting...
creating 400 MB of random Int32s...
dynamic memory test completed without crashing

That's it!