The Plutus Application Framework

Table of Contents

• Documentation
  • User documentation
  • Talks
  • Specifications and design
• Branching, Versioning and Releases
  • Dependency update
  • Version ranges
• Working with the project
  • How to submit an issue
  • How to develop and contribute to the project
  • How to depend on the project from another Haskell project
  • How to build the project’s artifacts
• Nix
  • How to set up the IOHK binary caches
  • Which attributes to use to build different artifacts
• Licensing

The Plutus Application Framework, part of the Plutus Platform, is a framework for developing distributed applications using the Cardano blockchain. For more information about the projects, see the User documentation.

This repository contains:

• Plutus Platform

  • Libraries which implement the Plutus Application Framework, a framework for writing applications that work with Cardano.

  • A selection of end-to-end usecases written with the Plutus Application Framework

Important

The rest of this README is focussed on people who want to develop or contribute to the Framework. For people who want to use the Framework, please consult the User documentation.

Important

DO NOT IGNORE THIS If you want to use Nix with this project, make sure to set up the IOHK binary cache. If you do not do this, you will end up building GHC, which takes several hours. If you find yourself building GHC, STOP and fix the cache.

Documentation

User documentation

The main documentation is located here.

The generated Haskell API documentation (haddocks) are here: https://playground.plutus.iohkdev.io/doc/haddock.

Talks

• Functional Smart Contracts on Cardano

• The Plutus Platform

Specifications and design

• Plutus Technical Report (draft)

Branching, Versioning and Releases

There are two protected development branches in plutus-apps: main and next-node. We adopt the PVP versioning scheme. Check out Branching Policy and Release Process to learn more.

Dependency update

The dependency update policy is dependent on the protected branch.

For cardano-node, we define major-version-bound the range of versions which are compatible with a specific era. For example, for the Alonzo era, that would be >= 1.29 && < 1.35. For the Vasil era, that would be >= 1.35 && < 1.36.

Independently of the protected branch:

• It should always use the same first-major-version of plutus as the one used by the plutus dependency of cardano-node

• It should always be safe to upgrade to a new second-major-version of plutus: at worst this will lead to some code breakage.

• It should, unless specified otherwise, use the same version for transitive dependencies (cardano-ledger, ouroboros-network, etc.) with cardano-node

• It should pin the major version of cardano-node for all packages

• It should pin the first and second-major version of plutus for all packages

main branch:

• It should not update cardano-node to a new major-version. In other words, it should use a cardano-node version which is compatible with the current Cardano mainnet

• It should use a cardano-wallet version which is compatible with the current cardano-node version

next-node branch:

• It may update the cardano-node to a new major-version. In other words, it may use a cardano-node version which is incompatible with the current Cardano mainnet

• It may use a cardano-wallet version which is incompatible with the current cardano-node version

Version ranges

Packages which depend on plutus-apps packages should use version ranges to control which version of those packages they build against.

• Packages in plutus-apps which are used downstream should pin the major-version of each other (e.g. plutus-pab-1.0.1 should depend on plutus-contract ^>= 1.0).

• Downstream packages should pin at least the first-major-version of plutus-apps packages.

  • Upgrading to a new second-major-version should always be safe for working on the current mainnet, with at most code breakage (following the PVP). Users may of course want to pin this version as well to avoid such breakage.

• Downstream packages pulling in plutus-apps packages via source-repository-package stanzas should always take tagged commits.

Working with the project

How to submit an issue

Issues can be filed in the GitHub Issue tracker.

However, note that this is pre-release software, so we will not usually be providing support.

How to develop and contribute to the project

See CONTRIBUTING, which describes our processes in more detail including development environments; and ARCHITECTURE, which describes the structure of the repository.

How to depend on the project from another Haskell project

None of our libraries are on Hackage, unfortunately (many of our dependencies aren’t either). So for the time being, you need to:

1. Add plutus-apps as a source-repository-package to your cabal.project.

2. Copy the source-repository-package stanzas from our cabal.project to yours.

3. Copy additional stanzas from our cabal.project as you need, e.g. you may need some of the allow-newer stanzas.

The plutus-starter project provides an example.

How to build the project’s artifacts

This section contains information about how to build the project’s artifacts for independent usage. For development work see How to develop and contribute to the project for more information.

Prerequisites

The Haskell libraries in the Plutus Platform are built with cabal and Nix. The other artifacts (docs etc.) are also most easily built with Nix.

Nix

Install Nix (recommended). following the instructions on the Nix website.

Make sure you have read and understood the cache warning. DO NOT IGNORE THIS.

See Nix for further advice on using Nix.

Non-Nix

You can build some of the Haskell packages without Nix, but this is not recommended and we don’t guarantee that these prerequisites are sufficient. For instance, you would have to build and install this fork of libsodium from source. If you use Nix, these tools are provided for you via shell.nix, and you do not need to install them yourself.

• If you want to build our Haskell packages with cabal, then install it.

• If you want to build our Haskell packages with stack, then install it.

How to build the Haskell packages and other artifacts with Nix

Run nix build -f default.nix plutus-apps.haskell.packages.plutus-pab.components.library from the root to build the Plutus PAB library.

See Which attributes to use to build different artifacts to find out what other attributes you can build.

How to build the Haskell packages with cabal

The Haskell packages can be built directly with cabal. We do this during development (see How to develop and contribute to the project). The best way is to do this is inside a nix-shell.

Note	For fresh development setups, you also need to run cabal update.

Run cabal build plutus-pab from the root to build the Plutus PAB library.

See the cabal project file to see the other packages that you can build with cabal.

Nix

How to set up the IOHK binary caches

Adding the IOHK binary cache to your Nix configuration will speed up builds a lot, since many things will have been built already by our CI.

If you find you are building packages that are not defined in this repository, or if the build seems to take a very long time then you may not have this set up properly.

To set up the cache:

1. On non-NixOS, edit /etc/nix/nix.conf and add the following lines:

   substituters = https://cache.iog.io https://cache.nixos.org/
   trusted-public-keys = hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
   extra-experimental-features = nix-command flakes

   Note	If you don’t have an /etc/nix/nix.conf or don’t want to edit it, you may add the nix.conf lines to ~/.config/nix/nix.conf instead. You must be a trusted user to do this.

2. On NixOS, set the following NixOS options:

   nix = {
     binaryCaches          = [ "https://cache.iog.io" ];
     binaryCachePublicKeys = [ "hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ=" ];
   };

Which attributes to use to build different artifacts

default.nix defines a package set with attributes for all the artifacts you can build from this repository. These can be built using nix build. For example:

nix build -f default.nix docs.site

Example attributes

• Project packages: defined inside plutus-apps.haskell.packages

  • e.g. plutus-apps.haskell.packages.plutus-pab.components.library

There are other attributes defined in default.nix.

Licensing

You are free to copy, modify, and distribute the Plutus Platform with under the terms of the Apache 2.0 license. See the LICENSE and NOTICE files for details.