Bin Directory

• It will contain our compiled application binaries

cmd/api

• it will contain the application specific code for our greenlight api application
• This will include the code for running the server, reading and writing HTTP requests, and managing authentication

internal

• it will contain various ancillary packages used by our API.
• It will contain the code for interacting with our database, doing data validation, sending emails and so on. Basically, any code which isn’t application-specific and can potentially be reused will live in here.
• Our Go code under cmd/api will import the packages in the internal directory (but never the other way around).

migrations

• this directory will contain the SQL migration files for our database.

remote

• this directory will contain the configuration files and setup scripts for our production server.

go.mod

• this file will declare our project dependencies, versions and module path.

Makefile

• this file will contain recipes for automating common administrative tasks — like auditing our Go code, building binaries, and executing database migrations.