fitims/detyra

Decisions made

The Wallet App will hold its users on a map data structure. The key for the map will be user's email address.

In real-life scenarios a user would have more than one wallet, but to simplify the example I choose to have only one wallet per user.

A very good data store for the users and wallets would be a key/value data store (like Redis, BadgerDB, etc.) or even a graph database (Dgraph, Neo, etc.) but to simplify the example I decided to mock the key/value data store (in_memory package that is inside repo package).

To keep the app performant, I would use pipeline concurrency pattern, so for every transaction I would publish a transaction in a channel, and would have another goroutine that listens to the transaction channel and save the transaction in database concurrently.

Setting up and executing the code

Running the app

To run a test code, execute the following command:

go run main.go

Running unit tests

To run unit tests for the wallet, go to the wallet folder by using the command:

cd ./wallet

thne run unit test by using the command:

go test -v

To run unit tests for the store, go to the store folder by using the command:

cd ./store

thne run unit test by using the command:

go test -v

Areas to be improved

• More unit tests and better test coverage
• Make the application concurrent
• If there is a large number of users, split the users into shards and run a separate instance for each shard
• Use a distributed key/value store to store users and wallets
• Use a blob storage to store transactions
• Setup a monitoring and alerting