go-bestflight

In order to be efficient when looking for the best routes for the registered connections, Bestflight use the Dijkstra's Shortest Path algorithm.

Build

If you have go >= 1.13, you can build the application using the command go mod download and then go build -o bestflight cmd/bestflight/main.go .

Or you can run the pre built file bestflight in this repo with ./bestflight sourcefile.csv 5000.

Usage

go-bestflight has two interface that can be used: one cli to get the best routes via command line and an HTTP API for both get the best routes and register new routes.

An source file with pre-registered routes can be passed by argument. Its content must contain the following format:

GRU,BRC,10
BRC,SCL,5
GRU,CDG,75
GRU,SCL,20
GRU,ORL,56
ORL,CDG,5
SCL,ORL,20

When running the app, simply pass the file path as the first argument followed by the port the HTTP web server will use to run. Example:

./bestflight routes.csv 5000

The file will be created if it does not exists. An input will be asked:

please enter the route:

Enter the desired boarding and destination in the format: GRU-CDG

An output will be given in the format: best route: SCL - GRU - BRC > $25

API

The API has only two endpoint, one to register new routes and another to get the best route between two airports.

Register new routes

Method: POST

Endpoint: /route

Contet-Type: json

Body Parameters:

• boarding: string containing an airport with the format "GRU". Case insensitive.
• destination: string containing an airport with the format "GRU". Case insensitive.
• cost: integer with minum value of 0 and maximum of 1000000

Example:

{
	"boarding": "SCL",
	"destination": "GRU",
	"cost": 15
}

Status Codes:

• 201: if successfully created
• 200: if the route already exists
• 400: malformed route

Response Body: same content sent.

Get the best route between two airports

Method: GET

Endpoint: /route

Query Parameters:

• board: string containing an airport with the format "GRU". Case insensitive.
• dest: string containing an airport with the format "GRU". Case insensitive.

Example:

/routes?board=SCL&dest=BRC

Status Codes:

• 200: if successfully found
• 204: searched, but not found
• 400: malformed route

Response body:

• route: string containing the route in a readable way. Example: SCL - GRU - BRC
• cost: integer with the value fot taking the route.

Example:

{
    "route": "SCL - GRU - BRC",
    "cost": 25
}

Docker

The application can also be executed in a container if you have docker. Follow the steps:

• Create a file called input.csv into the project root.
• Build the image: docker build -t bestflight .
• Run a container with an interactive tty: docker container run --name bestflight -it -p 5000:5000 bestflight sh
• Run the command: ./bestflight input.csv 5000

Application structure

The application structure is loosely based on the model Ports and Adapters. In real world usage, the best way of taking advantage of this strcture is by making have use of interfaces, but since this is a small project, I didn't feel the need for it.

The package structure is divided in three main components:

• application: where different instances and interfaces of the application can be managed, such as this one with a cli and http interfaces. Also responsible for the appplication boostratp and configuration.
• domain: contains all the entities, custom errors and services used for the business logic.
• resources: any external resource used by the services in the domain, for example. Components like repositories as whole (file, dbs, etc), gateways (http clients) and others.

Although this project does not use databases or cache services, what would be the ideal in a real world production environment, there are three resources in this project that simulates them on memory. They are all under resources: cache, file anddatabase.

The cache resource simulates the use of a Redis-like service where we could use as a routes structure-ready-for-search, so we could have an alternative option to the slow IO operations on databases.

The database is to simulate persistent and more reliable data.

And finally the file resource to manage the input/source file used when running the application.