Wire Web Application Demo

What is this? This is a simple webserver that just serves a visitor counter and its uptime seconds. It is built using Go, Postgres, and structured using dependency injection via Google Wire.

Buy why though? Because it serves as a good example for the future, for myself and others. The DI "modules" (config, log, db, etc) are fully-fledged and feature good unit testing and environment-based setup. They are ready to be copy-pasted to other projects, or used as reference points.

Some rationale and discussion behind how/why this was put together can be found in a blog post here.

Setup and running

Building. The code is built using Go 1.12 and Go modules. All you need to do to build it is:

go build

To re-generate wire_gen.go, use:

go generate

Testing. To run the unit tests and see coverage:

go test ./... -cover

On Windows, ignore any UAC port opening warning that comes up.

Environment. The runtime is parameterized via environment variables:

• PORT - the port to serve the webserver on (optional; default=8080)
• DATABASE - the PostgreSQL connection string for its database (required)
• DEBUG - true/false toggle for debug logging (optional; default=false)

Database setup. The code bootstraps its own schema, so you just need to provide it with a database. An easy Docker-based way to do this would be:

docker run -p 5432:5432 postgres:latest
docker run --net=host -it postgres:latest psql postgres://postgres@localhost:5432
> CREATE DATABASE demo;

This would result in this connection string to be set as DATABASE (note the sslmode parameter):

postgres://postgres@localhost:5432/demo?sslmode=disable

Endpoints.

• /uptime - displays the seconds since the server got started
• /counter - increments and displays a visitor counter from the database