Account-service

A RESTful service to demonstrate money transfer between accounts

Dependencies

OpenJDK 8+
sbt 1.2.x+

Try out the service without cloning the repo!

$ cat << EOF > application.conf
account_service {
  server {
    host = "0.0.0.0"
    port = 8080
  }
}
EOF

$ docker run -v $(pwd)/application.conf:/apps/account-service/application.conf -p 8080:8080 -ti varadharajan/account-service:latest

You should be able to access the API at http://localhost:8080 (For example: http://localhost:8080/v1/accounts). Pressing RETURN key would stop the container.

Here are some API calls:

# Create two accounts
$ curl -H "Content-Type: application/json" -X POST -d '{"name":"varadharajan"}' http://localhost:8080/v1/accounts
$ curl -H "Content-Type: application/json" -X POST -d '{"name":"srinath"}' http://localhost:8080/v1/accounts
# From the above responses, we can get the account ID of those users

# Get all users in the system
$ curl http://localhost:8080/v1/accounts

# Get details of an account
$ curl http://localhost:8080/v1/accounts/<account-UUID>

# Fund transfer to accounts
$ curl -X PUT "http://localhost:8080/v1/accounts/<account-UUID>/deposit?amount=100"
$ curl -X PUT "http://localhost:8080/v1/accounts/<account-UUID>/withdraw?amount=100"

# Transfer money from one account to another
$ curl -H "Content-Type: application/json" -X POST -d '{"from":"<account-UUID>","to": "<account-UUID>","amount": 50}' http://localhost:8080/v1/accounts/transfer

Local Development

The project supports sbt + JDK style of development, provided compatible version of dependencies

$ sbt test # To run the tests
$ sbt assembly # To build the fat jar. Artifact will be @ $PROJECT_DIR/target/

Docker can be used to build an executeable artifact

$ docker build -t account-service:dev .

$ cat << EOF > application.conf
account_service {
  server {
    host = "0.0.0.0"
    port = 8080
  }
}
EOF

$ docker run -v $(pwd)/application.conf:/apps/account-service/application.conf -p 8080:8080 -ti account-service:dev

CI / CD

The project has been configured to use Travis CI as the CI service. On every commit / PR merge to master branch, we build the docker container, run tests inside it, and then push the newly built container to Dockerhub. Please note that, this DockerHub repository will be deleted after receiving coding assignment feedback.
Checkout the builds @ https://travis-ci.com/varadharajan/account-service/
Checkout the Dockerhub repo @ https://hub.docker.com/r/varadharajan/account-service/tags

Considerations

We make use of Software Transactional Memory using Scala STM as the underlying concurrency control mechanism for in-memory datastructures.
The service is implemented in a completely non-blocking, asynchronous fashion using Futures and Akka HTTP (Server + Client).
The codebase is roughly split into the below segments:

Model.scala : Contains the core domain models and API Request + Response SerDe utils.
Repository.scala : Persistence layer for core models. Its straightforward in this case because of in-memory datastructures and the use of STM, however we need to revist them a bit if we want to add persistence.
Service.scala : Contains the API mashup layer taking to rest of classes. Also contains the Routers defining the routes for the interfaces.

varadharajan / account-service