SHARD.YML(5) File Formats SHARD.YML(5)

shard.yml - metadata for projects managed by shards(1)

The file shard.yml is a YAML file with metadata about a project managed by shards, known as a shard. It must contain at least name and version attributes plus optional additional attributes.

Both libraries and applications will benefit from shard.yml.

The metadata for libraries are expected to have more information (e.g., list of authors, description, license) than applications that may only have a name, version and dependencies.

The file must be named shard.yml and be a valid YAML file with UTF-8 encoding. It must not contain duplicate attributes in any mapping. It should use an indent of 2 spaces. It should not use advanced YAML features, only simple mappings, sequences and strings (Failsafe Schema).

name

The name of the project (string, required).
•It must be unique.
•It must be 50 characters or less.
•It should be lowercase (a-z).
•It should not contain crystal.
•It may contain digits (0-9) but not start with one.
•It may contain underscores or dashes but not start/end with one.
•It must not have consecutive underscores or dashes.

Examples: minitest, mysql2, battery-horse.

version

The version number of the project (string, required).
•It must contain digits.
•It may contain dots and dashes but not consecutive ones.
•It may contain a letter to make it a 'prerelease'.

Examples: 1.2.3, 2.0.0.1, 1.0.0.alpha 2.0.0-rc1 or 2016.09.

While Shards doesn’t enforce it, following a rational versioning scheme like Semantic Versioning http://semver.org/ or Calendar Versioning http://calver.org/ is highly recommended.

authors

A list of authors, along with their contact email (optional) (sequence of string).
•Each author must have a name.
•Each author may have an email address, within angle bracket (< and >) chars.

Example:

authors:
- Ary
- Julien Portalier <julien@example.org>

crystal

A restriction to indicate which are the supported crystal versions. This will usually express a lower and upper-bound constraints (string, recommended)

When resolving dependencies, this information is not used. After dependencies have been determined shards checks all of them are expected to work with the current crystal version. If not, a warning appears for the offending dependencies. The resolved versions are installed and can be used at your own risk.

The valid values are mostly the same as for dependencies.version:

•A version number prefixed by an operator: <, <=, >, >=, != or ~>.
•Just "*" if any version will do (this is the default if unspecified).
•Multiple requirements can be separated by commas.

There is a special legacy behavior (its use is discouraged) when just a version number is used as the value: it works exactly the same as a >= check: x.y.z is interpreted as ">= x.y.z"

You are welcome to also specify the upper bound to be lower than the next (future) major Crystal version, because there’s no guarantee that it won’t break your library.

Example:

crystal: ">= 0.35, < 2.0"

dependencies

A list of required dependencies (mapping).

Each dependency begins with the name of the dependency as a key (string) then a list of attributes (mapping) that depend on the resolver type.

Example:

dependencies:
  minitest:
    github: ysbaddaden/minitest.cr
    version: 0.1.0

development_dependencies

A list of dependencies required to work on the project, but not necessary to build and run the project (mapping).

They will be installed for the main project or library itself. When the library is installed as a dependency for another project the development dependencies will never be installed.

Development dependencies follow the same scheme as dependencies.

Example:

development_dependencies:
  minitest:
    github: ysbaddaden/minitest.cr
    version: ~> 0.1.3

description

A single line description of the project (string, recommended).

documentation

The URL to a website providing the project’s documentation for online browsing (string).

executables

A list of executables to be installed (sequence).

The executables can be of any type or language (e.g., shell, binary, ruby), must exist in the bin folder of the Shard, and have the executable bit set (on POSIX platforms). When installed as a dependency for another project the executables will be copied to the bin folder of that project.

Executables are always installed last, after the postinstall script is run, so libraries can build the executables when they are installed by Shards. Installation can be disabled by passing the flag --skip-executables.

Example:

executables:
- micrate
- icr

homepage

The URL of the project’s homepage (string).

libraries

A list of shared libraries the shard tries to link to (mapping).

This field is purely informational. It serves as a canonical way to discover non Crystal dependencies in shards, both for tools as well as humans.

A shard must only list libraries it directly links to, it must not include libraries that are only referenced by dependencies. It must include all libraries it directly links to, regardless of a dependency doing it too.

It should map from the soname without any extension, path or version, for example libsqlite3 for /usr/lib/libsqlite3.so.0.8.6, to a version constraint.

The version constraint has the following format:

•It may be a version number.
•It may be "*" if any version will do.
•The version number may be prefixed by an operator: <, <=, >, >=, != or ~>.
libraries:
  libQt5Gui: "*"
  libQt5Help: "~> 5.7"
  libQtBus: ">= 4.8"

license


An OSI license http://opensource.org/ name or an URL to a license file (string, recommended).

repository

The URL of the project’s canonical repository (string, recommended).

The URL should be compatible with typical VCS tools without modifications. http/https is preferred over VCS schemes like git. It is recommended that this URL is publicly available.

Copies of a shard (such as mirrors, development forks etc.) should point to the same canonical repository address, even if hosted at different locations.

Example:

repository: "https://github.com/crystal-lang/shards"

scripts

Script hooks to run. Only postinstall is supported.

Shards may run scripts automatically after certain actions. The scripts themselves are mere shell commands.

postinstall

The postinstall hook of a dependency will be run whenever that dependency is installed or upgraded in a project that requires it. This may be used to compile a C library, to build tools to help working on the project, or anything else.

The script will be run from the dependency’s installation directory, for example lib/foo for a Shard named foo.

Example:

scripts:
  postinstall: cd src/libfoo && make

targets

A list of targets to build (mapping).

Each target begins with the name of the target as a key (string), then a list of attributes (mapping). The target name is the built binary name, created in the bin folder of the project.

Example:

targets:
  server:
    main: src/server/cli.cr
  worker:
    main: src/worker.cr

The above example will build bin/server from src/server/cli.cr and bin/worker from src/worker.cr.

main

A path to the source file to compile (string).

Each dependency needs at least one attribute that defines the resolver for this dependency. Those can be path, git, github, gitlab, bitbucket.

path

A local path (string).

The library will be installed as a symlink to the local path. The version attribute isn’t required but will be used if present to validate the dependency.

git

A Git repository URL (string).

The URL may be any protocol https://git-scm.com/docs/git-clone#_git_urls supported by Git, which includes SSH, GIT and HTTPS.

The Git repository will be cloned, the list of versions (and associated shard.yml) will be extracted from Git tags (e.g., v1.2.3).

One of the other attributes (version, tag, branch or commit) is required. When missing, Shards will install the HEAD refs.

Example: git: git://git.example.org/crystal-library.git

github

GitHub repository URL as user/repo (string)

Extends the git resolver, and acts exactly like it.

Example: github: ysbaddaden/minitest.cr

gitlab

GitLab repository URL as user/repo (string).

Extends the git resolver, and acts exactly like it.

Only matches dependencies hosted on gitlab.com. For personal GitLab installations, you must use the generic git resolver.

Example: gitlab: thelonlyghost/minitest.cr

bitbucket

Bitbucket repository URL as user/repo (string).

Extends the git resolver, and acts exactly like it.

Example: bitbucket: tom/library

hg

A Mercurial repository URL (string).

The URL may be any protocol https://www.mercurial-scm.org/repo/hg/help/clone supported by Mercurial, which includes SSH and HTTPS.

The Mercurial repository will be cloned, the list of versions (and associated shard.yml) will be extracted from Mercurial tags (e.g., v1.2.3).

One of the other attributes (version, tag, branch, bookmark or commit) is required. When missing, Shards will install the @ bookmark or tip.

Example: hg: https://hg.example.org/crystal-library

fossil

A Fossil https://www.fossil-scm.org repository URL (string).

The URL may be any protocol https://fossil-scm.org/home/help/clone supported by Fossil, which includes SSH and HTTPS.

The Fossil repository will be cloned, the list of versions (and associated shard.yml) will be extracted from Fossil tags (e.g., v1.2.3).

One of the other attributes (version, tag, branch, or commit) is required. When missing, Shards will install trunk.

Example: fossil: https://fossil.example.org/crystal-library

version

A version requirement (string).
•It may be an explicit version number.
•It may be "*" wildcard if any version will do (this is the default). Shards will then install the latest tagged version (or HEAD if no tagged version available).
•The version number may be prefixed by an operator: <, <=, >, >=, != or ~>.
•Multiple requirements can be separated by commas.

Examples: 1.2.3, >= 1.0.0, >= 1.0.0, < 2.0 or ~> 2.0.

Most of the version operators, like >= 1.0.0, are self-explanatory, but the ~> operator has a special meaning. It specifies a minimum version, but allows the last digit specified to go up, excluding the major release number:

•~> 0.3.5 is identical to >= 0.3.5 and < 0.4.0.
•~> 2.0.3 is identical to >= 2.0.3 and < 2.1.
•~> 2.1 is identical to >= 2.1 and < 3.0.
•~> 0.3 is identical to >= 0.3 and < 1.0.
•~> 1 is identical to >= 1.0 and < 2.0.

Note

Even though 2.1.0-dev is strictly before 2.1.0, a version constraint like ~> 2.0.3
would not install it since only the .3 can change but the 2.0 part is fixed.

branch

Install the specified branch of a git dependency, or the named branch of a mercurial or fossil dependency (string).

commit

Install the specified commit of a git, mercurial, or fossil dependency (string).

tag

Install the specified tag of a git, mercurial, or fossil dependency (string).

bookmark

Install the specified bookmark of a mercurial dependency (string).

Here is an example shard.yml for a library named shards at version 1.2.3 with some dependencies:

name: shards
version: 1.2.3
crystal: '>= 0.35.0'
authors:
- Julien Portalier <julien@example.com>
license: MIT
description: |
  Dependency manager for the Crystal Language
dependencies:
  openssl:
    github: datanoise/openssl.cr
    branch: master
development_dependencies:
  minitest:
    git: https://github.com/ysbaddaden/minitest.cr.git
    version: "~> 0.1.0"
libraries:
  libgit2: ~> 0.24
scripts:
  postinstall: make ext
targets:
  shards:
    main: src/shards.cr

Written by Julien Portalier and the Crystal project.

shards(1)

2024-03-28 shards 0.18.0