Go Distributed System

An example of a system based in events, using an orchestrator to handle with order validation.

Sumary

• Architecture
• Setup
• Running The Engine
• Stop All
• Documentation Endpoint
• Create Order
• Get Order
• Get Orders From User
• Running tests
• Roadmap

Architecture

I've already used many architectures in my professional life, and I noticed that all of them have pros and cons (others have more pros than cons).

A curious fact is that I love to search for the most advanced technologies being used in the big techs and apply them in my personal/professional codes. I read an article which the writer had the same perception I had, joining the cons of the most used architectures in the industry (Clean, Hexagonal, DDD, Onion, etc.).

If you like to follow new good tendencies, here is the awesome article was written by Heberto Graça that represents this project.

Bellow we have a simple architecture diagram from this project.

Rest Diagram

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Event Driven Diagram

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Full Diagram

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Setup

This project has a Makefile, that implements some docker-compose receipts.

To setup project, and start a postgres and mongodb databases, the kafka cluster, and a simple user-api used to validate some orders example, open a console in the project's root, and type:

• make setup

To follow the logs inside pods, use:

• make setup-logs

To Stop containers created by command setup, type:

• make setup-down

Running the Engine

To running the engines, it's easy, just type:

• make server

To follow the logs containers created, type:

• make server-logs

To stop containers from server, type:

• make server-down

Stop all

To stop and drop all container, just type:

• make down

It'll stop and remove all containers created for this project.

Documentation Endpoint

• [GET] /swagger/index.html

Create Order Example

You can use postman, where the collection with the request, is saved in the folder /docs/postman/Go-Service.postman_collection.json, or open a terminal, and use the examples bellow:

---

Create order using curl

curl --location --request POST '0.0.0.0:8000/api/orders' \
--form 'value="1000.00"' \
--form 'user_id="uuuu-aaaa-bbbb"' \
--form 'installment="1"' \
--form 'method="credit_card"'

Returns

{
    "id": "order-id-created",
    "value": "1000",
    "user_id": "uuuu-aaaa-bbbb",
    "installment": 1,
    "status": "PROCESSING",
    "method": "credit_card"
}

Create invalid order

With user_id invalid:

• Just put invalid in the user_id form
  • Example: --form 'user_id="uuuu-aaaa-bbbb-invalid"'

With Balance exceeding limit from user

• Just put some value bigger than 10000.00 in value form
  • Example: --form 'value="25500.00"'

---

Get order status from order using curl

curl --location --request GET '0.0.0.0:8000/api/order/<order-id>'

Returns

{
    "id": "order-id",
    "value": "1000",
    "user_id": "user-id",
    "installment": 1,
    "status": "CANCELED" | "PROCESSING" | "ACCEPTED",
    "method": "credit_card"
}

Get orders from user

curl --location --request GET '0.0.0.0:8000/api/orders/<user_id>?offset=0&limit=100'

Returns

{
    "offset": 0,
    "limit": 100,
    "total": 2,
    "orders": [
        {
            "id": "cd0124e6-1d74-4b63-993d-0e56bae28d2a",
            "value": "1000",
            "user_id": "user_id",
            "installment": 1,
            "status": "APPROVED",
            "method": "credit_card"
        },
        {
            "id": "53381fa4-42f7-4149-858d-8a919b3584ec",
            "value": "2000",
            "user_id": "user_id",
            "installment": 1,
            "status": "APPROVED",
            "method": "debit_card"
        }
    ]
}

Running Tests

Test End to End

There are some BDD tests included in this project, written in python using the lib Behave.

To run test e2e, just type this in a terminal (setup and engine must be up):

• make test-e2e

Ps.: To know more about BDD, please read this topic -> https://en.wikipedia.org/wiki/Behavior-driven_development

Roadmap

• API
• EDA Structure
• Orchestrator
• Event Log Source
• Feature Toggles
• API's Fallbacks
• Unit Tests
• Integration Tests
• E2E Tests
• Example of CI/CD in github actions
• Write Documentation