build_runner 0.7.1 build_runner: ^0.7.1 copied to clipboard
Tools to write binaries that run builders.
build_runner #
Standalone generator and watcher for Dart using package:build
.
The build_runner
package provides a concrete way of generating files using
Dart code, outside of tools like pub
. Unlike pub serve/build
, files are
always generated directly on disk, and rebuilds are incremental - inspired by
tools such as Bazel.
Installation #
This package is intended to support development of Dart projects with
package:build
. In general, put it under dev_dependencies, in your
pubspec.yaml
.
dev_dependencies:
build_runner:
Usage #
When the packages providing Builder
s are configured with a build.yaml
file
they are designed to be consumed using an generated build script. Most builders
should need little or no configuration, see the documentation provided with the
Builder to decide whether the build needs to be customized. If it does you may
also provide a build.yaml
with the configuration. See the
package:build_config
README for more information on this file.
Run pub run build_runner serve
to start up a development server. To have web
code compiled with DDC add a dev_dependency
on build_web_compilers
.
Inputs #
Valid inputs follow the general dart package rules. You can read any files under
the top level lib
folder any package dependency, and you can read all files
from the current package.
In general it is best to be as specific as possible with your InputSet
s,
because all matching files will be checked against a Builder
's
buildExtensions
- see outputs for more
information.
Outputs #
- You may output files anywhere in the current package.
NOTE: When a
BuilderApplication
specifieshideOutput: true
it may output under thelib
folder of any package you depend on.
- Builders are not allowed to overwrite existing files, only create new ones.
- Outputs from previous builds will not be treated as inputs to later ones.
- You may use a previous
BuilderApplications
's outputs as an input to a later action.
Source control #
This package creates a top level .dart_tool
folder in your package, which
should not be submitted to your source control repository. You can see our own
.gitignore
as an
example.
# Files generated by dart tools
.dart_tool
When it comes to generated files it is generally best to not submit them to
source control, but a specific Builder
may provide a recommendation otherwise.
It should be noted that if you do submit generated files to your repo then when
you change branches or merge in changes you may get a warning on your next build
about declared outputs that already exist. This will be followed up with a
prompt to delete those files. You can type l
to list the files, and then type
y
to delete them if everything looks correct. If you think something is wrong
you can type n
to abandon the build without taking any action.
Publishing packages #
In general generated files should be published with your package, but this
may not always be the case. Some Builder
s may provide a recommendation for
this as well.
Legacy Usage #
If the generated script does not do everything you need it's possible to
manually write one. With this approach every package which uses a
Builder
must have it's own script, they cannot be reused
from other packages. A package which defines a Builder
may have an
example you can reference, but a unique script must be written for the consuming
packages as well. You can reference the generated script at
.dart_tool/build/entrypoint/build.dart
for an example.
Your script should use one of the following functions defined by this library:
run
: Use the same argument parsing as the generated approach.build
: Run a single build and exit.watch
: Continuously run builds as you edit files.
Configuring #
run
, build
, and watch
have a required
argument which is a List<BuilderApplication>
. These correspond to the
BuilderDefinition
class from package:build_config
. See apply
and
applyToRoot
to create instances of this class. These will be translated into
actions by crawling through dependencies. The order of this list is important.
Each Builder may read the generated outputs of any Builder that ran on a package
earlier in the dependency graph, but for the package it is running on it may
only read the generated outputs from Builders earlier in the list of
BuilderApplication
s.
NOTE: Any time you change your build script (or any of its dependencies), the next build will be a full rebuild. This is because the system has no way of knowing how that change may have affected the outputs.
Contributing #
We welcome a diverse set of contributions, including, but not limited to:
- Filing bugs and feature requests
- Send a pull request
- Or, create something awesome using this API and share with us and others!
For the stability of the API and existing users, consider opening an issue first before implementing a large new feature or breaking an API. For smaller changes (like documentation, minor bug fixes), just send a pull request.
Testing #
All pull requests are validated against travis, and must pass. The
build_runner
package lives in a mono repository with other build
packages,
and all of the following checks must pass for each package.
Ensure code passes all our analyzer checks:
$ dartanalyzer .
Ensure all code is formatted with the latest dev-channel SDK.
$ dartfmt -w .
Run all of our unit tests:
$ pub run test