Package management

Any programming language that aims to make collaboration easier needs a way to distribute (and consume) its reusable modules. LIGO provides first-class support for such distributable units (i.e. packages).

Packages

Reusable modules that developers intend to share with others can be distributed as packages by placing a ligo.json (a manifest file) next to their Ligo modules.

$ ls

ligo.json

set.mligo

list.mligo

Any directory (recursively) containing .mligo files can be turned into a package by simply placing a manifest file, ligo.json over there.

LIGO registry

The LIGO registry is used to host LIGO packages. The LIGO registry contains the contracts/libraries along with their metadata. The packages which reside on the LIGO registry can be installed using the ligo install command.

Consuming

To fetch (download) & maintain different versions of external libraries we need a package manager. LIGO libraries can be published to the LIGO registry as well as npm. Using ligo install command we can fetch these ligo libraries.

Note: Earlier versions of LIGO used esy as the backend for package management. This is not so anymore, and installing esy is not necessary.

Workflow

We will need the LIGO compiler to compile smart contracts, to get the LIGO compiler follow these instructions.

Next, we will use a simple dependency @ligo/math-lib published on the LIGO registry. To download & install the library, run,

$ ligo install @ligo/math-lib

Now we can write a smart contract which will use the @ligo/mathlib library.

#import "@ligo/mathlib/rational/rational.mligo" "Rational"

...

Note: When using LIGO packages via #import/#include

If only the name of the package is provided, it will be resolved to the main file of the package.

If you want to import a specific file from the package, the syntax is of the form

#import "<pkg name>/<file in package>" "Module"

#include "pkg name>/<file in package>"

and we write some tests for our smart contract in main.test.mligo

#include "main.jsligo"

const test = (() => {

let storage = Test.compile_value(list([1, 2, 3]));

let [addr, _, _] = Test.originate_from_file("./main.jsligo",

"main", (list([]) as list<string>), storage, 0tez);

let taddr : typed_address<parameter, storage> = Test.cast_address(addr);

let contr : contract<parameter> = Test.to_contract(taddr);

Test.transfer_to_contract_exn(contr, Reverse(), 1mutez);

assert (Test.get_storage(taddr) == list([3, 2, 1]))

})();

To compile the contract to Michelson run the command

$ ligo compile contract main.jsligo

This will find the dependencies installed on the local machine, and compile the main.mligo file.

To test the contract using LIGO's testing framework run the command

$ ligo run test main.test.jsligo

If you working with an existing LIGO project, to install the dependencies, at the root of the project just run

$ ligo install

Specifying package versions

To use package, it is necessary to specify the exact version of the package. Semver ranges are currently not supported. This will, however, change soon.

Upgrading the version of a LIGO package

During the lifecycle of a project, if you wish to upgrade the version of a LIGO package, Just update the package version to the desired one in the ligo.json. e.g.

{

...

"dependencies": {

"ligo-foo": "1.0.6",

- "@ligo/bigarray": "1.0.0",

+ "@ligo/bigarray": "1.0.1",

"ligo-test_2": "1.0.0",

"ligo_test_1": "1.0.0"

}

}

and run the command

$ ligo install

This will fetch the updated version of the LIGO package, and the compiler will use the updated version of the package.

Using a LIGO package via REPL

If you wish to try out a LIGO package in the REPL environment, Install the LIGO package by following the steps above, and then fire up the LIGO REPL using the following command

$ ~/projects/ligo/_build/install/default/bin/ligo repl jsligo

Welcome to LIGO's interpreter!

Included directives:

#use "file_path";;

#import "file_path" "module_name";;

In [1]: #import "@ligo/bigarray/lib/bigarray.mligo" "BA";;

Out [1]: Done.

In [2]: BA.concat (list([1, 2, 3]))(list([4, 5, 6]));;

Out [2]: CONS(1 , CONS(2 , CONS(3 , CONS(4 , CONS(5 , CONS(6 , LIST_EMPTY()))))))

In [3]:

Packaging

Packages are code units that can be shared with other developers. Therefore, authors must provide useful metadata, both for other programmers in the community as well as the LIGO toolchain, to understand the package's contents, its version, and other useful information.

Adding package metadata (LIGO manifest)

This is an important step, as it will help the tools and your users/collaborators, provide vital information about your package.

For LIGO packages, authors must provide a manifest file (ligo.json).

The structure of a LIGO manifest is as follows,

Required fields

• name : Name of the package.

• version : Version of the package (Should be a valid sem-ver).

• main : The main file of the package, Ideally this file should export all the functionality that the package provides.

• author : Author of the package.

• license : A valid SPDX license identifier.

• repository : The place where the LIGO code is hosted (remote repository), The repository field follows a structure same as npm.

• bugs : The url to your project's issue tracker and/or the email address to which issues should be reported. The bugs fields follows a structure same as npm.

• type : The type field can be one of library or contract, If the field is ommited default value of type is library

• storage_fn : In the case when type is contract, the name of the function which provides initial storage needs to be provided.

• storage_arg : In the case when type is contract, an expression that is a parameter to the storage_fn needs to be provided.

Optional fields:

• description : A brief description of the package.
• readme : Some readme text, if this field is omitted the contents of README.md or README will be used in its place.
• dependencies : A object (key-value pairs) of dependencies of the package where key is a package_name and the value is a package_version
• dev_dependencies : A object (key-value pairs) of dev_dependencies of the package where key is a package_name and value is a package_version

Sample LIGO manifest (ligo.json) with some of the above information:

{

"name": "math-lib",

"version": "1.0.3",

"description": "A math library for LIGO with support for Float & Rational numbers",

"main": "lib.mligo",

"repository": {

"type": "git",

"url": "git+https://github.com/ligolang/math-lib-cameligo.git"

},

"author": "ligoLANG <https://ligolang.org/>",

"license": "MIT",

"bugs": {

"url": "https://github.com/ligolang/math-lib-cameligo/issues"

},

"dependencies": {

"math-lib-core": "^1.0.1",

"math-lib-float": "^1.0.2",

"math-lib-rational": "^1.0.1"

}

}

Ignore some files or directories while packaging using .ligoignore

You can specify some files or directories which you want to keep out of the LIGO package (keys, deployment scripts, etc.) in a .ligoignore file. .ligoignore file is similar to a .gitignore file (you can specify glob patterns of files or directories you would like to ignore)

Creating and publishing packages to the LIGO registry

We are going the write a simple package ligo-list-helpers library that is similar to the bigarray package we used earlier.

/* LIGO library for working with lists */

export const concat = <T>(xs : list<T>, ys : list<T>) : list<T> => {

let f = ([x, ys] : [T, list<T>]) : list<T> => list([x, ...ys]);

return List.fold_right(f, xs, ys)

}

export const reverse = <T>(xs : list<T>) : list<T> => {

let f = ([ys, x] : [list<T>, T]) : list<T> => list([x, ...ys]);

return List.fold_left(f, (list([]) as list<T>), xs)

}

and some tests for the library

#include "list.jsligo"

const test_concat = (() => {

let xs = list([1, 2, 3]);

let ys = list([4, 5, 6]);

let zs = concat(xs, ys);

assert (zs == list([1, 2, 3, 4, 5, 6]))

})();

const test_reverse = (() => {

let xs = list([1, 2, 3]);

assert (reverse(xs) == list([3, 2, 1]))

})();

To run the tests run the command

$ ligo run test list.test.jsligo

Logging in

Before publishing, the registry server needs to authenticate the user to avoid abuse. To login,

$ ligo login

If you're a new user,

$ ligo add-user

This would create a .ligorc in the home directory.

Note: By default, LIGO creates the rc file (.ligorc) in the home directory.

Publishing

LIGO packages can be published to a central repository at packages.ligolang.org with the ligo publish command.

$ ligo publish

==> Reading manifest... Done

==> Validating manifest file... Done

==> Finding project root... Done

==> Packing tarball... Done

publishing: ligo-list-helpers@1.0.0

=== Tarball Details ===

name: ligo-list-helpers

version: 1.0.0

filename: ligo-list-helpers-1.0.0.tgz

package size: 895 B

unpacked size: 1.1 kB

shasum: 37737db2f58b572f560bd2c45b38e6d01277395d

integrity: sha512-a904c5af793e6[...]fc0efee74cfbb26

total files: 6

==> Checking auth token... Done

==> Uploading package... Done

Package successfully published

Note: while publishing a package If just want to see what LIGO publish would do, you can use the --dry-run flag

$ ligo publish --dry-run

Quick CLI options reference

--cache-path

By default dependencies are installed in the .ligo directory at the root of the project, If you wish to change the path where dependencies are installed use the --cache-path option to specify the path e.g.

$ ligo install --cache-path PATH

--project-root

LIGO will try to infer the root directory of the project so that it can find the dependencies installed on your local machine, If you wish to specify the root directory manually you can do so using the --project-root option e.g.

$ ligo compile contract main.jsligo --project-root PATH

--ligorc-path

LIGO creates a .ligorc file to store auth tokens for the user for a specific registry, This auth token is useful when publishing a package.

By default LIGO creates the .ligorc in the home directory, If you wish to override this you can do so using the --ligorc-path e.g.

# Loging in

$ ligo login --ligorc-path ./.ligorc

# Publishing

$ ligo publish --ligorc-path ./.ligorc

Note: Using ligo login users can log into multiple registries e.g. LIGO registry, and the LIGO beta registry, A new entry will be created in the .ligorc for storing auth token of each registry.

--dry-run

While using ligo publish if you don't want to make changes to the LIGO registry, you can use the --dry-run flag. e.g.

$ ligo publish --dry-run

This will only display the report on the command line what it would have done in the case of ligo publish.

Unpublishing Packages

Packages can be published in two ways,

1. Completely delete the entry
2. Only unpublish a specific version

unpublish is that subcommand, grouped under registry subcommand, removes a package or a specific version of it from the registry

Summary

[--package-name Name] . of the package on which publish/unpublish is

executed

[--package-version Version]

. of the package on which publish/unpublish is

executed

To unpublish a package, run ligo registry unpublish --package-name <name> --package-version <version> from anywhere on the CLI (not necessarily from within a project)

Examples,

ligo registry unpublish --package-name foo --package-version 1.0.0

If --package-version is skipped, the entire package is unpublished.

Notes

1. Are packages written in different syntaxes interoperable?

Yes, any syntax can be used in packages. Furthermore, one can consume a package written in one syntax from another.

2. What happens if there are entry points declared in a LIGO package?

If you need to use the entry points defined within a package, the best approach is likely to alias them:

#import "package_name/increment.mligo" "Increment"

[@entry] let add = Increment.add

In this case, only add entry point from the package will be used by the compiler. By adding an alias for Increment.sub, it is possible to also include that entry point in the final contract.