Withoutings

Demo application for talking with Withings API. It is written in Go with few dependencies, and uses PostgreSQL as a database. The code is organized using DDD-ish / Clean Architecture-ish principles, based on the book and articles by https://threedots.tech/.

Features

Currently available features

• Lets users log in with Withings OAuth and stores their access token in the database.
• Lets users subscribe to notifications from Withings.
• Stores received notifications in the database.
• Downloads available data relevant to the received notifications and stores it in the database.

Planned features

• Forward received notifications and their payloads to webhooks, IFTTT, Dropbox, Google Drive, etc.
• Download historical data, not just data corresponding to notifications.

Technologies used

Withoutings uses a pragmatic stack that is simple to maintain and deploy:

• Go
• PostgreSQL
• Server-side rendering with Go's html/template
• No JavaScript so far. But might add HTMX.

...and not used

• Redis (unlogged tables are good enough)
• ORM (sqlc is superior)
• Dedicated queue/pubsub (Postgres all the way!)

Installation and setup

The application serves a website and runs services that talk with the Withings API. Therefore it must have a public URL that can receive webhooks sent by the Withings Notification service.

Set up a Withings Developer account

Go to the Withings Developer Dashboard. Create a new application.

Define environment variables

See env.example.sh. Make a copy of it named env.dev.sh and fill in the values.

source env.sh && go run cmd/main.go

The webhook secret must be added in the registered callback path in the Withings Developer Dashboard. See env.example.sh.

Development

Forward remote port to local port

To receive webhooks in your development environment, you can forward a remote port to your local port.

Withings calls https://withings.mywebsite.com/auth/callback which is forwarded to port 3628 on the server (e.g. using Caddy or nginx), which is again forwarded to port 3628 in your development environment.

Using SSH

# Using SSH
ssh -R 3628:127.0.0.1:3628 -N -f [email protected]

Using Caddy and Tailscale

Set up Tailscale on your development machine and the server. Then add the following to your Caddyfile:

withings-dev.example.com {
        reverse_proxy /* <dev-machine-name>:3628 {
        }
}

The server must also listen on the Tailscale interface. Configure that in env.dev.sh.

export WOT_LISTEN_ADDR='<dev-machine-tailscale-ip>:3628';

Migrations

Migrations are managed using golang-migrate. The library is embedded in the build, so you can run migrations using withoutings migrate.

Create migration

Append a new migration file in the migration directory.

Run all necessary migrations

source env.sh && withoutings migrate

Revert migration

Manually revert by executing the down SQL from the migration file. Remember to also decrement the migration version in the schema_migrations table.

SQL queries

Go code is generated from SQL queries using sqlc. The schema is inferred using the migration files.

Install sqlc

brew install sqlc
# or
go install github.com/kyleconroy/sqlc/cmd/sqlc@latest

Mock generation

Mocks are generated using mockery.

Install mockery

brew install mockery

Generate mocks

For now, you have to generate mocks using go generate.