A tool for managing Dart projects with multiple packages, inspired by Lerna.
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About
Splitting up large code bases into separate independently versioned packages is
extremely useful for code sharing. However, making changes across many
repositories is messy and difficult to track, and testing across repositories
gets complicated really fast.
To solve these (and many other) problems, some projects will organize their code
bases into multi-package repositories (sometimes called
monorepos)
Melos is a tool that optimizes the workflow around managing multi-package
repositories with git and Pub.
Migrate to Melos 7.x.x
Since the pub workspaces feature has
been released, Melos has been updated to rely on that, instead of creating
pubspec_overrides.yaml files and thus some migration is needed.
The main difference for migration is that the melos.yaml file no longer
exists, only the root pubspec.yaml file.
To migrate to Melos 7.x.x a few steps are needed:
- Start with running
melos clean to remove all the pubspec_overrides.yaml
entries and then continue with moving all your content.
- Add
resolution: workspace to all of your packages' pubspec.yaml files.
- Add a list of all your packages to the root
pubspec.yaml file, under the
workspace key.
- Move all the content from your
melos.yaml file to the root pubspec.yaml
file, under the melos key. (Note that the packages list is no longer
needed as it is replaced with the workspace list.)
[!NOTE]
The workspace list doesn't support globs yet, so you have to list all your
packages manually. Give a thumbs up here
so that the team can prioritize this feature.
[!NOTE]
Root packages migration: If your existing project uses the repository
root as a package, you can enable useRootAsPackage: true in the melos
configuration to maintain this behavior, or restructure your project to
move the main application to a subdirectory. See the
Configuration Overview
for details.
After the migration, your root pubspec.yaml file would now look something
like this:
name: my_workspace
publish_to: none
environment:
sdk: ^3.9.0
workspace:
- packages/helper
- packages/client_package
- packages/server_package
dev_dependencies:
melos: ^7.0.0-dev.9
melos:
# All of the content of your previous melos.yaml file
# (Except for the packages and name)
And this is what the pubspec.yaml file of a package would look like:
name: my_package
environment:
sdk: ^3.9.0
resolution: workspace
[!NOTE]
You have to use Dart SDK 3.6.0 or newer to use pub workspaces.
Github Action
If you're planning on using Melos in your GitHub Actions workflows, you can use
the Melos Action
to run Melos commands, this action also supports automatic versioning and
publishing directly from your workflows.
What does a Melos workspace look like?
A default file structure looks something like this:
my-melos-repo/
pubspec.yaml
packages/
package-1/
pubspec.yaml
package-2/
pubspec.yaml
The location of your packages needs be configured via the workspace
section in your root pubspec.yaml file, see the
pub workspaces documentation for more
information.
What can Melos do?
- 🔗 Link local packages in your workspace together without adding dependency
overrides (achieved by pub workspaces).
- 📦 Automatically version, create changelogs and publish your packages using
Conventional Commits.
- 📜 Pre-define advanced custom scripts for your workspace in your root
pubspec.yaml configuration to use via melos run [scriptName]. Anyone
contributing to your workspace can just run melos run to be prompted to
select a script from a list with descriptions of each script.
- Scripts can even
prompt to select a package
to run against with pre-defined filters.
- ⚡ Execute commands across your packages easily with
melos exec -- <command here> with additional concurrency and fail-fast
options.
- Environment variables
containing various information about the current package and the workspace
are available in each execution.
- Can be combined with all package filters.
- 🎯 Many advanced package filtering options allowing you to target specific
packages or groups of packages in your workspace.
--no-private
- Exclude private packages (
publish_to: none).
--[no-]published
- Filter packages where the current local package version exists on pub.dev.
Or "-no-published" to filter packages that have not had their current
version published yet.
--[no-]nullsafety
- Filter packages where the current local version uses a "nullsafety"
prerelease preid. Or "-no-nullsafety" to filter packages where their
current version does not have a "nullsafety" preid.
--[no-]flutter
- Filter packages where the package depends on the Flutter SDK. Or
"-no-flutter" to filter packages that do not depend on the Flutter SDK.
--scope=<glob>
- Include only packages with names matching the given glob.
--ignore=<glob>
- Exclude packages with names matching the given glob.
--diff=<ref>
- Only include packages that have been changed since the specified
ref,
e.g. a commit sha or git tag.
--dir-exists=<dirRelativeToPackageRoot>
- Include only packages where a specific directory exists inside the
package.
--file-exists=<fileRelativeToPackageRoot>
- Include only packages where a specific file exists in the package.
--depends-on=<dependantPackageName>
- Include only packages that depend on a specific package.
--no-depends-on=<noDependantPackageName>
- Include only packages that don't depend on a specific package.
--include-dependencies
- Expands the filtered list of packages to include those packages'
transitive dependencies (ignoring filters).
--include-dependents
- Expands the filtered list of packages to include those packages'
transitive dependents (ignoring filters).
- ♨️ Advanced support for IntelliJ IDEs with automatic creation of
run configurations for workspace defined scripts and more
on workspace bootstrap.
- Integration with VS Code through an extension.
Getting Started
Go to the
Getting Started
page of the documentation to start
using Melos.
Who is using Melos?
The following projects are using Melos:
- firebase/flutterfire
- Flame-Engine/Flame
- fluttercommunity/plus_plugins
- GetStream/stream-chat-flutter
- canonical/ubuntu-desktop-provision
- ubuntu/app-center
- 4itworks/opensource_qwkin_dart
- gql-dart/ferry
- cbl-dart/cbl-dart
- ema987/paddinger
- flutter-stripe/flutter_stripe
- danvick/flutter_form_builder
- kmartins/groveman
- flutternetwork/WiFiFlutter
- iapicca/yak_packages
- atsign-foundation/at_app
- sub6resources/flutter_html
- ferraridamiano/ConverterNOW
- rrifafauzikomara/youtube_video
- mobxjs/mobx.dart
- NetGlade/auto_mappr
- myConsciousness/atproto.dart
- GrowERP Flutter ERP
- mrverdant13/coverde
- ThexXTURBOXx/flutter_web_auth_2
- woltapp/wolt_modal_sheet
- cfug/dio
- simolus3/drift
- Lyokone/flutterlocation
- FlutterGen/flutter_gen
- jhomlala/alice
- powersync/powersync.dart
- rodydavis/signals.dart
- foss42/apidash
- ReactiveX/rxdart
- StacDev/stac
- Jaspr
- starknet.dart
- flyerhq/flutter_chat_ui
- maplibre/flutter-maplibre-gl
- Khuwn-Soulutions/supabase_codegen
- G1Joshi/Booking-App
Submit a PR if you'd like to add your project to the list. Update the
README.md
and the docs.
You can also add a README badge to your projects README to
let others know about Melos 💙.
Documentation
Documentation is available at
https://melos.invertase.dev.
Migrations
When migrating between major versions of Melos, please read the
migration guide.
Commands
Full commands list and args can be viewed by running melos --help.
> melos --help
A CLI tool for managing Dart & Flutter projects with multiple packages.
Usage: melos <command> [arguments]
Global options:
-h, --help Print this usage information.
--verbose Enable verbose logging.
--sdk-path Path to the Dart/Flutter SDK that should be used. This command line option has
precedence over the `sdkPath` option in the root `pubspec.yaml` configuration
file and the `MELOS_SDK_PATH` environment variable. To use the system-wide SDK,
provide the special value "auto".
Available commands:
bootstrap Initialize the workspace, link local packages together and install remaining package
dependencies. Supports all package filtering options.
clean Clean this workspace and all packages. This deletes the temporary pub & ide files such
as ".packages" & ".flutter-plugins". Supports all package filtering options.
exec Execute an arbitrary command in each package. Supports all package filtering options.
format Idiomatically format Dart source code.
list List local packages in various output formats. Supports all package filtering options.
publish Publish any unpublished packages or package versions in your repository to pub.dev. Dry
run is on by default.
run Run a script by name defined in the workspace pubspec.yaml config file.
version Automatically version and generate changelogs based on the Conventional Commits
specification. Supports all package filtering options.
Run "melos help <command>" for more information about a command.
How to Contribute
To start making contributions please refer to
CONTRIBUTING.md.
Lerna
This project is heavily inspired by Lerna.
README Badge
Using Melos? Add a README badge to show it off:
[](https://github.com/invertase/melos)
License
Built and maintained with 💛 by Invertase.
