This is a simple web app written in Haskell which allows users to manage and improve ("dial in") their espresso shots.
It uses the Snap framework for the backend, Persistent/Esqueleto for persistence, Servant for the API definitions and Reflex for the frontend. Building and deployment to AWS is done using Nix.
Use nix-shell -A shells.ghc dialin.nix to enter a nix-shell sandbox that provides you with cabal and all the required dependencies. Then, use cabal new-build backend to build the backend or cabal new-build frontend to build the GHC version of the frontend. This also allows for incremental builds and faster development cycles.
To build the frontend using GHCJS for deployment, use nix-build dialin.nix -o frontend-ghcjs-result -A ghcjs.frontend.
Nix is set up to deploy the app to an EC2 instance on AWS. It expects the file ~/.ec2-keys to contain a valid EC2 key pair matching the access key ID in dialin-ec2.nix.
To create a deployment, use nixops create ./dialin-configuration.nix ./dialin-ec2.nix -d dialin. nixops deploy -d dialin will then deploy the app to the instance. Note that the initial deployment will take a relatively long time, while subsequent deployments are fairly quick. To update the deployment without starting from scratch, simply use nixops modify ./dialin-configuration.nix ./dialin-ec2.nix -d dialin.
