This application is an excercise in generating ECDSA keys and a bit of Docker.

Submission Requirements

Provide the JSON output returned from your application using an input value of your email address

Here is the output of the application when using my email address as the input value:

{
  "message": "rexposadas@gmail.com",
  "signature": "MEUCIQDRUk924mRy74HXTFsNoxnQ2eSyklKQww5O3wAyICuyIwIgWvBxEKHutL7DX2MPktfNzpN+7NC/yP8MuPTmEtE+QBA=",
  "pubkey": "-----BEGIN PUBLIC KEY-----\nMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEoyekebw/acI6//bLc/clzMWJYzha\ndVtwKm5yHz6M6XhVepZdBSPPmKt+QVMAK7L6eZ6qgyngdDKba2LkP5wK8g==\n-----END PUBLIC KEY-----\n"
}

Running the application

After you have cloned this repository, you can do the following to run it:

Using go build

go build && ./codechallenge rexposadas@gmail.com

If you have jq installed, you can do the following for a prettier format.

➜ go build && ./codechallenge rexposadas@gmail.com | jq '.'
{
  "message": "rexposadas@gmail.com",
  "signature": "MEQCIEPhR7qSl+WPNgYuHQqd9DG56IN4eXiVVwSQzr3wtxy7AiAQDk0xdaxjVSy+cc1dJxBtpemzDDohdhZ5tu3PWitwWg==",
  "pubkey": "-----BEGIN PUBLIC KEY-----\nMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEcm6UU3W8TGK6IWHb+POnSpFf2VmP\n1Y2vJ52miaNTTuiMi1jlZ+tXDn4XiTQ9+SDcEjOGvBdC/eo8SzECZLuzXQ==\n-----END PUBLIC KEY-----\n"
}

Using Docker

docker build . -t codechal
docker run codechal "your@email.com"

Testing the application

Without Docker

Use the built in test command go test ./...

Using Docker in a CI/CD pipeline

I don't have much experience integrating Docker to CI/CD. One way I would attempt this is to create a test.sh file which calls go test. Then, the Docker container will accept an environment flag which, if toggled on, would run test.sh inside the Docker container.

I can see running a similar command to the one below during the deployment process:

docker run -e test=true codechal

Design decisions I made

1. In the requirements it stated "Subsequent invocations of your application should read from the same files". I assumed that this was a requirement only for the non-dockerized running of the application. Subsequent calls of this applicationg using the following format:

go build && ./codechallenge rexposadas@gmail.com

will use the files created.

Docker container's lifecycle was limited to a single run of the application. Hence, after the application has written the file inside the container and returned, the container dies and the files go with it. If this was a requirement for running the application in Docker as well, I would have done one or more of the following:

    a. Use a [volume](https://docs.docker.com/storage/volumes/) in order to hold the files. 
    b. Create a webservice so that this will be a long running application.  Generating the keys will be an API call in this case. 

2. Some key generation tools default storing the new keys in the user's home directory. I opted to generate them in the same directory the application was ran. I didn't want to write them in the user's home directory since the testers of this application will probably not want me doing that in their machines.

3. I wrote most of the key generation code in the lib directory. I couldn't think of a better name and didn't bother changing it, given the time constraints.