santi81 / hangman-api

Hangman API Microservice

1.1 Redis/Cache

Scala Cache was used as a facade for cache implementations - Work in Progress

Fundamental approach would be to be able to abstract based on config to use in memory cache or other cache implementations or plugin your own implementation:

• Redis
• Google Guava
• Memcached
• Ehcache
• Caffeine
• cache2k
• OHC

1.2 Http Rest Server

To build a request and response Http Rest Server, Finagle-Finch was used:

• https://twitter.github.io/finagle/
• https://finagle.github.io/finch/

The EndPoints available on the server: Support Swagger API Definition 

| Method | EndPoint | Example Parameter|
| ------ | ------ | ------ |
| POST | /createGame | {} |
| GET | /retrieveGame/<gameID> | *not required* |
| POST | /submitGuess | {"game_id": "1608240105","guess" : "P"} 

1.3 Concurrency Control

ScalaSTM was used to store the data in memory and control of the concurrency.

• https://nbronson.github.io/scala-stm/

2 Requirements

2.1 Create Docker Image

$ docker build -t <image-tag> . 

Start docker with the image to do the tests:

$ docker pull redis
$ docker run redis
$ docker run -p 9905:9905 <image-tag>

$ Docker will run the unit tests and then start the server. Wait until the server loads the message:

*** Stating HTTP Server **** Host: 0.0.0.0 Port: 9905

Note: See more command curl information in item 3.3, to run the integrated tests, see item 3.4. More information on removing and stopping the docker image see item 4.

2.2 Local SBT and Java

To build the project on the machine it is necessary to have the programs installed:

• JDK-1.8.0 - Java Development Kit
• SBT-1.2.8 - The interactive build tool

Note: The programs above are with the version used to develop this solution.

3 Installation

3.1 Install Redis

$ brew install redis
$ redis-server /usr/local/etc/redis.conf
$ redis-cli ping
If it replies “PONG”, then it’s good to go!

3.2 Install JDK

For JDK installation:

$ tar -xvzf jdk-8u212-linux-x64.tar.gz
$ sudo mv jdk-8xxx /opt/jdk1.8.0
$ export JAVA_HOME=/opt/jdk1.8.0
$ export PATH=/opt/jdk1.8.0/bin:${PATH}

3.3 Install SBT

For SBT installation:

$ wget https://piccolo.link/sbt-1.2.8.tgz
$ tar xfv sbt-1.2.8.tgz
$ sudo mv sbt /opt/sbt
$ export PATH=/opt/sbt/bin:${PATH}

3.4 Building and Testing Application

To build the application just run:

$ git clone https://github.com/santi81/hangman-api.git
$ sbt compile; sbt test; sbt run

You can also run unit tests like this:

$ sbt clean coverage test coverageReport

When you receive the message on the terminal after the sbt run:

*** Stating HTTP Server **** Host: 0.0.0.0 Port: 9905

On another terminal run the command:

3.5 More Test Commands

Creating a new game manually via curl:

$ curl -i -H "Content-Type: application/json" -X POST -d '{}' http://127.0.0.1:9905/createGame

The answer should be:

{"game_id": 1608240105}

Retrieve the game details:

$ curl -i -H "Content-Type: application/json" -X GET  http://127.0.0.1:9905/retrieveGame/1608240105

The answer should be:

{ "game_id": "1608240105", "guesses": { "num_guesses_left": 10, "num_total_guesses": 10, "num_guesses_used": 0 }, "status": { "total_chars": 8, "word": [ " ", " ", " ", " ", " ", " ", " ", " " ], "wrong_guesses": [ " ", " ", " ", " ", " ", " ", " ", " ", " ", " " ], "game_over": false } }

Make a guess:

$ curl -i -H "Content-Type: application/json" -X POST -d '{"game_id":"1608240105", "guess":"C"}' http://127.0.0.1:9905/submitGuess

The answer should be:

{ "game_id": "1608240105", "guesses": { "num_guesses_left": 10, "num_total_guesses": 10, "num_guesses_used": 0 }, "status": { "total_chars": 8, "word": [ " ", " ", " ", " ", " ", " ", " ", "C" ], "wrong_guesses": [ " ", " ", " ", " ", " ", " ", " ", " ", " ", " " ], "game_over": false } }

If necessary, you can change the host and port configuration of the server. This can be checked at: src/main/resources/application.conf

3.6 Integration Test

A small HTTP client server was created to do the integrated test. To run the server it is necessary to compile the code via SBT and it is necessary that the server is running via local compilation or in the docker.

In the project root directory run:

$ sbt "test:runMain backend.api.integration.HttpClientSuiteTest"

4 Docker commands

Stop the docker image:

$ docker container ls
$ docker stop <CONTAINER-ID>

Remove the docker image:

$ docker images
$ docker rmi -f <IMAGE-ID>