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https://github.com/scalameta/sbt-native-image

Plugin to generate native-image binaries with sbt
https://github.com/scalameta/sbt-native-image

github-actions graalvm graalvm-native-image native-image sbt scala

Last synced: 6 days ago
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Plugin to generate native-image binaries with sbt

Host: GitHub
URL: https://github.com/scalameta/sbt-native-image
Owner: scalameta
Created: 2020-08-29T10:04:58.000Z (over 4 years ago)
Default Branch: main
Last Pushed: 2024-04-20T20:47:43.000Z (8 months ago)
Last Synced: 2024-12-12T20:27:54.948Z (13 days ago)
Topics: github-actions, graalvm, graalvm-native-image, native-image, sbt, scala
Language: Scala
Homepage:
Size: 109 KB
Stars: 252
Watchers: 6
Forks: 22
Open Issues: 27
Metadata Files:
- Readme: readme.md

Awesome Lists containing this project

README

# Generate native-image binaries with sbt

This plugin makes it easy to generate native-image binaries with sbt. Key
features:

- automatic GraalVM native-image installation powered by
[Coursier](https://get-coursier.io/), no need to start sbt with a custom
`$JAVA_HOME` or spin up Docker. See
[One-click install for Scala](https://scala-lang.org/2020/06/29/one-click-install.html)
for more details.
- automatic support for Scala 2.12.12+ and 2.13.3+, no need to deal with issues
like [scala/bug#11634](https://github.com/scala/bug/issues/11634).
- works with Scala 3 (Dotty)
- get a notification when the binary is ready to use.
- works on macOS, Windows and Linux.
- works with Java 8 and Java 11.

**Overview:**

- [Getting started](#getting-started)
- [Configuration](#configuration)
- [Generate native-image from GitHub Actions](#generate-native-image-from-github-actions)
- [Comparison with sbt-native-packager](#comparison-with-sbt-native-packager)

## Getting started

First, add the sbt plugin to your build in `project/plugins.sbt`.

[![](https://index.scala-lang.org/scalameta/sbt-native-image/latest.svg?color=blue)](https://github.com/scalameta/sbt-native-image/releases)

```scala
// project/plugins.sbt
addSbtPlugin("org.scalameta" % "sbt-native-image" % "0.3.2")
```

Next, enable the plugin to your native-image application in `build.sbt` and
configure the main class.

```diff
// build.sbt
lazy val myNativeImageProject = project
+ .enablePlugins(NativeImagePlugin)
.settings(
// ...
+ Compile / mainClass := Some("com.my.MainClass")
)
```

Additionally, if your app uses reflection or JNI, you may need to run `nativeImageRunAgent` command to capture runtime information. For more details, see [`nativeImageRunAgent`](#nativeimagerunagent) section.

Finally, run the `nativeImage` task to generate the binary.

```sh
$ sbt
> myNativeImageProject/nativeImage
...
[info] Native image ready!
[info] /path/to/your/binary
```

Optionally, use `nativeImageRun` to execute the generated binary and manually
test that it works as expected.

```sh
> myNativeImageProject/nativeImageRun argument1 argument 2
# output from your native-image binary
```

## Configuration

sbt-native-image provides several settings, tasks and input tasks to customize
native-image generation and to automate your native-image workflows.

- [`nativeImage`](#nativeimage): generate a native image
- [`nativeImageOptions`](#nativeimageoptions): customize native image generation
- [`nativeImageRun`](#nativeimagerun): execute the generated native image
- [`nativeImageCopy`](#nativeimagecopy): generate a native image and copy the
binary
- [`nativeImageVersion`](#nativeimageversion): the GraalVM version to use for
native-image
- [`nativeImageJvm`](#nativeimagejvm): the GraalVM JVM version to use for
native-image
- [`nativeImageJvmIndex`](#nativeimagejvmindex): the index to use for resolving
the JVM version
- [`nativeImageCommand`](#nativeimagecommand): the command to launch
`native-image`
- [`nativeImageReady`](#nativeimageready): callback hook when native-image is
ready
- [`nativeImageCoursier`](#nativeimagecoursier): the path to a `coursier` binary
- [`nativeImageOutput`](#nativeimageoutput): the path to the generated
native-image binary
- [`nativeImageInstalled`](#nativeimageinstalled): whether GraalVM is manually
installed or should be downloaded with coursier
- [`nativeImageGraalHome`](#nativeimagegraalhome): path to GraalVM home
directory
- [`nativeImageRunAgent`](#nativeimagerunagent): run application, tracking all
usages of dynamic features of an execution with
[`native-image-agent`][assisted-configuration-of-native-image-builds]
- [`nativeImageAgentOutputDir`](#nativeimageagentoutputdir): directory where
`native-image-agent` should put generated configurations
- [`nativeImageAgentMerge`](#nativeimageagentmerge): whether
`native-image-agent` should merge generated configurations

### `nativeImage`

**Type**: `TaskKey[File]`

**Description**: runs native-image and returns the resulting binary file.

**Example usage**: `sbt myProject/nativeImage`

### `nativeImageOptions`

**Type**: `TaskKey[Seq[String]]`

**Description**: custom native-image linking options. See `native-image --help`
for available options. Empty by default.

**Example usage**: `nativeImageOptions ++= List("--initialize-at-build-time")`

### `nativeImageRun`

**Type**: `InputKey[File]`

**Description**: executes the native-image binary with given arguments. This
task can only be used after `nativeImage` has completed.

**Example usage**:

- `sbt myProject/nativeImage 'myProject/nativeImageRun hello'`
- Error: `sbt clean myProject/nativeImageRun`. Crashes because native-image does
not exist.

### `nativeImageCopy`

**Type**: `InputKey[File]`

**Description**: identical to `nativeImage` except the resulting binary is
additionally copied to the provided file. This task is helpful when configuring
CI to generate the binary in a specific place.

**Example usage**:

- `sbt 'myProject/nativeImageCopy mybinary-x86_64-apple-darwin'`.
- `sbt 'myProject/nativeImageCopy mybinary-x86_64-pc-linux'`.

### `nativeImageVersion`

**Type**: `SettingKey[String]`

**Description**: the GraalVM version to use.

**Default**: 20.2.0

**Example usage**: `nativeImageVersion := "19.3.3"`

### `nativeImageJvm`

**Type**: `SettingKey[String]`

**Description**: the GraalVM JVM version to use.

**Default**: `"graalvm-java11"`. Must be one of the combinations below.

**Example usage**: `nativeImageJvm := "graalvm"`

|nativeImageJvm|nativeImageVersion|nativeImageJvmIndex|source|
|---|---|---|---|
|graalvm, graalvm-java11, graalvm-java17|1.0.0-x,19.0.0~21.1.0|cs|https://github.com/coursier/jvm-index|
|graalvm-ce-java8, graalvm-ce-java11, graalvm-ce-java16|19.3~21.1.0|jabba|https://raw.githubusercontent.com/shyiko/jabba/master/index.json|

### `nativeImageJvmIndex`

**Type**: `SettingKey[String]`

**Description**: the index to use for resolving the JVM version. By default,
uses the [Cousier JVM index](https://github.com/coursier/jvm-index).

**Default**: `"cs"`. Must be one of: `"cs"`, `"jabba"`.

**Example usage**: `nativeImageJvmIndex := "jabba"`.

### `nativeImageCommand`

**Type**: `TaskKey[Seq[String]]`

**Description**: the base command that is used to launch native-image.

**Default**: resolves the command using `nativeImageGraalHome` task.

**Example usage**: `nativeImageCommand := List("/path/to/native-image")`

### `nativeImageReady`

**Type**: `SettingKey[() => Unit]`

**Description**: a side-effecting callback that is called the native image is
ready.

**Default**: alerts the message "Native image ready!" via the `say` command-line
tool on macOS. Does nothing by default on Linux and Windows.

### `nativeImageCoursier`

**Type**: `TaskKey[File]`

**Description**: the path to a `coursier` binary.

**Default**: copies a slim bootstrap binary from sbt-native-image resources.
This setting is ignored if you customize `nativeImageCommand` to use something
else than Coursier.

### `nativeImageOutput`

**Type**: `SettingKey[File]`

**Description**: the path to the native-image binary that is generated.

**Default**: `target/native-image/NAME` where `NAME` is the name of the sbt
project. for available options.

**Example usage**: `nativeImageOutput := file("target") / "my-binary"`

### `nativeImageInstalled`

**Type**: `SettingKey[Boolean]`

**Description**: whether GraalVM is manually installed or should be downloaded
with coursier.

**Default**: checks if `NATIVE_IMAGE_INSTALLED` / `GRAALVM_INSTALLED`
environment variables or `native-image-installed` / `graalvm-installed`
properties are set to `true`.

### `nativeImageGraalHome`

**Type**: `TaskKey[Path]`

**Description**: path to GraalVM home directory.

**Default**: if `nativeImageInstalled` is `true`, then tries to read the path
from environment variables 1) `GRAAL_HOME`, 2) `GRAALVM_HOME` or 3) `JAVA_HOME`
(in given order). Otherwise, automatically installs GraalVM via
[Coursier](https://get-coursier.io/). Customize this setting if you prefer to
not to use environment variables.

**Example usage**:
`nativeImageGraalHome := file("/path/to/graalvm/base/directory").toPath`

### `nativeImageRunAgent`

**Type**: `InputKey[Unit]`

**Description**: run application, tracking all usages of dynamic features of an
execution with
[`native-image-agent`][assisted-configuration-of-native-image-builds].

You may need to run this command if your app or any dependency uses reflection or JNI.

**Example usage**:

First, add the reflection configuration to the native image options

```diff
// build.sbt

lazy val myNativeProject = project
.settings(
+ nativeImageOptions += s"-H:ReflectionConfigurationFiles=${target.value / "native-image-configs" / "reflect-config.json"}",
+ nativeImageOptions += s"-H:ConfigurationFileDirectories=${target.value / "native-image-configs" }",
+ nativeImageOptions +="-H:+JNI"
)
.enablePlugins(NativeImagePlugin)
```

Then, make sure to generate the reflection configuration with
`nativeImageRunAgent` before running `nativeImage`.

```sh
# Step 0: Start sbt shell.
$ sbt
# Step 1: Run application on the JVM with native-image agent.
> myProject/nativeImageRunAgent " arg1 arg2"
# Step 2: Create native-image binary with assisted configuration.
> myProject/nativeImage
# Step 3: Run native-image that was generated with assisted configuration.
> myProject/nativeImageRun arg1 arg2
```

### `nativeImageAgentOutputDir`

**Type**: `SettingKey[File]`

**Description**: directory where `native-image-agent` should put generated
configurations.

**Default**: `baseDirectory.value / "native-image-configs"`

**Example usage**:
`nativeImageAgentOutputDir := baseDirectory.value / "native-image-agent" / "out"`

### `nativeImageAgentMerge`

**Type**: `SettingKey[Boolean]`

**Description**: whether `native-image-agent` should merge generated
configurations.

**Default**: `false`

**Example usage**: `nativeImageAgentMerge := true`

## Generate native-image from GitHub Actions

The easiest way to distribute native-image binaries for Linux and macOS is to
build the binaries in CI with GitHub Actions.

1. Copy the `native.yml` file from this repo into the `.github/workflows/`
directory in your project.

mkdir -p .github/workflows && \
curl -L https://raw.githubusercontent.com/scalameta/sbt-native-image/master/.github/workflows/native.yml > .github/workflows/native.yml

2. Edit the file to replace "example" with the name of your binary.
3. Commit your changes.
4. Push your commit to GitHub and see the binary get uploaded as an artifact to
the CI job.
5. Create a GitHub release and see the binary get uploaded as assets to the
release page.

## Comparison with sbt-native-packager

The sbt-native-packager plugin provides similar support to generate native-image
binaries. Check out their documentation at
https://sbt-native-packager.readthedocs.io/en/stable/formats/graalvm-native-image.html

The key differences between sbt-native-packager and sbt-native-image are:

- sbt-native-image automatically installs GraalVM native-image by default. You
don't need to configure a docker image or manually install a correct GraalVM
JDK before starting sbt.
- sbt-native-image automatically works out-of-the-box with Scala 2.12.12+ and
2.13.3+. You don't need custom settings to work around issues like like
[scala/bug#11634](https://github.com/scala/bug/issues/11634).
- sbt-native-image displays live progress output from the `native-image` while
it's generating the binary. For some reason, sbt-native-packager only displays
output from native-image after the process completes (see issue
[#1345](https://github.com/sbt/sbt-native-packager/issues/1345)).
- sbt-native-packager has Docker support, which is helpful if you need more
fine-grained control over the linking environment. There are no plans to add
Docker support in sbt-native-image.

[assisted-configuration-of-native-image-builds]:
https://www.graalvm.org/reference-manual/native-image/BuildConfiguration/#assisted-configuration-of-native-image-builds