iamsmkr / prime-grpc-scala-akka

Project to demonstrate implementation of gRPC services in Scala using Akka gRPC.

prime-grpc-scala-akka

Head to Wiki for detailed design docs.

Install Dependencies

1. Install SBT

   On linux/windows based systems, you can use SDKMAN software development kit manager for convenient installation and usage of multiple versions.

2. Install Docker

   Follow docker installation guide here.

3. Install Minikube/Kubectl

   Use following convenience script to install both minikube and kubectl.

   $ ./deploy/scripts/setup-minikube-for-linux.sh

Build

1. Publish Protobuf Sources

Protobuf files are maintained in a separate sbt project to avoid maintaining them in both client and server.

$ cd prime-protobuf
$ sbt +publishLocal

Note: The project can be cross-compiled to multiple Scala versions. Should you choose to compile it into a Scala version of your choice, don't forget to update build.sbt with desired Scala version.

2. Publish Docker Images

$ sbt prime-generator/docker:publishLocal
$ sbt prime-proxy/docker:publishLocal

Note: Make sure to point local docker daemon to minikube internal docker registry to make the docker images available inside minikube cluster. Use following command.

$ eval $(minikube -p minikube docker-env)

Deploy

$ kubectl apply -f deploy/k8s/prime-generator.yml
$ kubectl apply -f deploy/k8s/prime-proxy.yml

Test

1. Unit Tests

$ sbt prime-generator/test
$ sbt prime-proxy/test
$ sbt test

2. Integration Tests

The end-to-end integration tests are available under prime-proxy/src/it.

$ sbt it:test

Note: While running end to end integration tests make sure to export minikube ip address as environment variable PRIME_PROXY_INTERFACE as shown below:

$ export PRIME_PROXY_INTERFACE=$(minikube ip)

Usage

The prime number generator service is available over following REST APIs.

1. Comma-Separated Stream

The following API returns a stream of comma-separated prime numbers up until a given number.

$ curl $(minikube ip)/prime/23

Note: This is achieved by making use of source streaming support in akka http. See docs. The implementation makes use of custom CsvEntityStreamingSupport.

2. Comma-Separated Seq

The following API returns a string of comma-separated list of prime numbers up until a given number.

$ curl $(minikube ip)/prime/23/seq

Note: There is a hard-limit of 10000 prime numbers is set to avoid OOM.

3. Newline-Separated Stream

The following API returns a stream of prime numbers up until a given number separated by new line.

$ curl $(minikube ip)/prime/23/csv-stream

Note: This is achieved by making use of source streaming support in akka http. See docs. The implementation makes use of default CsvEntityStreamingSupport.

4. SeverSentEvents

An alternative API returns prime numbers as SSE events. There is no hard limit set for this API.

$ curl $(minikube ip)/prime/23/sse