User manager

This small project implements a CRUD system for user management.

All options are reachable with the classical verbs (PUT, GET, DELETE, POST) at /users and /users/{id}

The get support different list options:

• include.firstname to filter by firstname
• include.country to filter by country
• include.lastname to filter by lastname
• page.number (page number, 1 is the first page)
• page.rows (#rows per page)

All calls are 100% async with rabbitMq in the middle. Moreover, all calls, but the list user is fire and forget returning an 202 instead of a 200. The flow of a request is the following for PUT, DELETE and POST:

"user-manager" -> "rabbit-mq (processor queue)" -> "processor" -> "mysql"

The flow of a request is the following for GET:

"user-manager" -> "rabbit-mq (processor queue)" -> "processor" -> "mysql" -> "processor" -> "rabbit-mq (callback queue)" -> "user-manager"

The service could be scaled adding more user-managers or processors.

On the top of that each time a resource is modified in the db a new message is sent in a notification queue

Note that created_at and updated_at are missing. It would have been "just more of the same" since it was already a lot of code I decided there was not a real need to add that.

Note tests should grow in number, due to time constrains I avoided completely to write tests for some packages

Note config is hardcoded for time constrain

Usage with dockerCompose

make run to run the whole solution

If you do not want to use the UI you can connect directly to the endpoint with curl or any other tool:

curl -X POST "http://[::]:35307/users" -H "accept: application/json" -H "Content-Type: application/json" -d "{ \"first_name\": \"paolo\", \"last_name\": \"gallina\", \"nickName\": \"gallocedrone\", \"password\": \"supersecurepassword\", \"email\": \"paologallina@gmail.com\", \"country\": \"Italy\", \"id\": \"f478e0c4-bc9c-11ec-8422-0242ac120002\"}"
curl -X GET "http://[::]:35307/users?include.firstname=paolo&page.number=1&page.rows=3" -H "accept: application/json"
curl -X GET "http://[::]:35307/users?include.firstname=notExisting" -H "accept: application/json"
curl -X PUT "http://[::]:35307/users/f478e0c4-bc9c-11ec-8422-0242ac120002" -H "accept: application/json" -H "Content-Type: application/json" -d "{ \"first_name\": \"paolo\", \"last_name\": \"gallina\", \"nickName\": \"gallocedrone\", \"password\": \"supersecurepassword\", \"email\": \"paologallina@gmail.com\", \"country\": \"Italy\", \"id\": \"f478e0c4-bc9c-11ec-8422-0242ac120002\"}"
curl -X DELETE "http://[::]:35307/users/f478e0c4-bc9c-11ec-8422-0242ac120002" -H "accept: application/json"

Run tests

make e2e-test to run the whole e2e suite with server, rabbitmq, processor and mysql

make integration-test to run integration tests against rabbit mq

make test to run unit tests

Access RabbitMQ console

Navigate to http://localhost:15672/ and inset guest and guest as user and passwords

Improvements needed performance/monitoring

• each request should have an ID assigned and logs should include it in the formatted message
• Metrics could be added as middleware with statistics
• User could receive a more useful error message in the body
• Most options should be configurable, currently it is not possible
• Currently, there is one channel per operation it is a big overhead, and we should have a pool of channels or just one per consumer with golang channels in front of them (they are not thread safe)