Vessel

The original package manager for the Motoko programming language.

Getting started

Download a copy of the vessel binary from the release page or build one yourself
1. For Ubuntu in $HOME/bin RUN wget https://github.com/dfinity/vessel/releases/download/v0.7.0/vessel-linux64
  
  For macOS in /usr/local/bin RUN: wget https://github.com/dfinity/vessel/releases/download/v0.7.0/vessel-macos
2. Rename vessel-linux64 to vessel eg: RUN mv vessel-linux64 vessel
3. Change permissions, chmod +x vessel
Run vessel init in your project root.
Edit vessel.dhall to include your dependencies (potentially also edit package-set.dhall to include additional package sources)
In a dfx project: Edit dfx.json under defaults->build->packtool to say "vessel sources" like so:
```
...
"defaults": {
  "build": {
    "packtool": "vessel sources"
  }
}
...
```
Then run dfx build
In a non-dfx project: Run $(vessel bin)/moc $(vessel sources) -wasi-system-api main.mo to compile the main.mo file with the installed packages in scope and using the wasi API to let you run the generated WASM with tools like wasmtime.

How it works

Vessel is inspired by the spago package manager for PureScript. Any git repository with a src/ directory is a valid package to Vessel, which is a flexible and lightweight approach to package management, that is easily extended with more guarantees and features as our community grows. The two concepts you need to understand to work with Vessel are package sets and the manifest file.

Package sets

Vessel uses the idea of a package set to manage where it pulls dependencies from. A package set is a collection of packages at certain versions that are known to compile together. The package set also specifies the dependencies between these packages, so that Vessel can find all the transitively needed packages to build your project. There will be a community maintained package set of publicly available, open source packages. You can then base your projects package set on the public one and extend it with your private and local packages. The package set your project uses is stored in the package-set.dhall file by default.

Manifest file

Your vessel.dhall file contains the list of packages you need for your project to build. Vessel will look at this file, and figure out all the transitive packages you need using the package set file. Optionally it also contains a compiler version that Vessel uses to download the compiler binaries for you. Any change to this file requires a reload of the language service so your packages can be picked up by your editor for now.

After Vessel has installed all required packages through cloning or downloading tarballs, it puts them in a project local location (the .vessel directory).

How Tos

How do I reset all caches?

Remove the .vessel directory in your project

How do I depend on a git branch of a package?

The "version" field in the package set format refers to any git ref so you can put a branch name, a commit hash or a tag in there.

CAREFUL: Vessel has no way of invalidating "moving" references like a branch name. If you push a new commit to the branch you'll need to run vessel install --force to bypass your local cache.

How do I add a local package to my package set?

Make sure your local package is a git repository, then add an entry like so to your additions in the package-set.dhall file:

let additions = [
   { name = "mypackage"
   , repo = "file:///home/path/to/mypackage"
   , version = "v1.0.0"
   , dependencies = ["base"]
   }
]

Now you can depend on this package by adding mypackage to your vessel.dhall file.

How do I integrate Vessel into my custom build?

Running vessel sources will return flags in a format you can pass directly to the various compiler tools. Running vessel bin returns the path containing the compiler binaries. Use like so: $(vessel bin)/mo-doc.

License

Vessel is distributed under the terms of the Apache License (Version 2.0).

See LICENSE for details.