Callbacks Handler

This simple service was created to handle the callbacks from APIs. These callbacks are bombarded to the service, stored in Redis and then updated in a blocking manner in the MySQL db.

Dependencies

• "github.com/etowett/returns/common" - contains all the common methods used in "github.com/etowett/returns/mylib
• "github.com/garyburd/redigo/redis" - Golang client for redis
• "github.com/go-sql-driver/mysql" - Golang driver for MySQL
• github.com/joho/godotenv - Golang loader for environment variables from .env

Most of the other dependencies are found in the import statements

Getting Started

Description

• main.go is the main file that is run for execution i.e. go run main.go
• The common folder contains the common methods re-used throughout the project.
• The config folder houses configuration for use if you want to run this application as a service with systemd
• mylib contains the structs, interfaces and functions that handle the receiving of callbacks, parsing into required data structures and processing into the final step.

Setting up

• Ensure you've setup Golang and your $GO_PATH (if not, please Google 😏 )
• Do go get github.com/etowett/returns. This will clone a copy of this repo into your /path/to/golang/projects/src/github.com/etowett

.env and environment variables

Rename the env.sample file into .env and fill out the required variables

Redis

Redis should be running locally. github.com/etowett/returns/common/utils.go has the following function to initialize a Redis pool.

    // RedisPool returns a redis pool
    func RedisPool() *redis.Pool {
        return &redis.Pool{
            MaxIdle:   80,
            MaxActive: 12000, // max number of connections
            Dial: func() (redis.Conn, error) {
                c, err := redis.Dial("tcp", ":6379")
                if err != nil {
                    panic(err.Error())
                }
                return c, err
            },
        }
    }

The connection is pretty normal

MySQL

There are 2 scenarios for connection in MySQL. We use a remote DB so our connection looks like this in github.com/etowett/returns/main.go:

    common.DbCon, err = sql.Open("mysql", os.Getenv("DB_USER")+":"+os.Getenv("DB_PASS")+"@tcp("+os.Getenv("DB_HOST")+":3306)/"+os.Getenv("DB_NAME")+"?charset=utf8")
	if err != nil {
		panic(err.Error())
	}
	defer common.DbCon.Close()

If your DB is in your local server, it would be something like this:

common.DbCon, err = sql.Open("mysql", os.Getenv("DB_USER")+":"+os.Getenv("DB_PASS")+os.Getenv("DB_NAME")+"?charset=utf8")
if err != nil {
    panic(err.Error())
}
defer common.DbCon.Close()

Just remove the tcp part.

Logging

• Create a folder for the log file as specified in your LOG_DIR variable in .env
• Open a terminal and tail -f /path/to/logs/returns.log

Ensure that this folder has the proper permissions to allow writing into it's files

Building and installing

• Run go build to build the app
• Run go install. Check the /path/to/golang/projects/bin folder and you should find a returns executable.
• Run ./returns on one terminal.
• Open another terminal and run the python requests simulator file client.py i.e. ./client.py

You should see outputs of Dlrs received and logs on the tailed logs terminal.

TODOs

• Dockerize the app so that it runs in it's own container
• Handle callbacks for inboxes
• Handle callbacks for opt-out

Contributing

Contributions are welcome. PRs will be accepted if they've followed atleast the minimum standards.

Issues

Reach out to:

• Eutychus Towett
• Martin Musale