nextcloud-docs/dart/content.md

What is Dart?

Dart is a client-optimized language for developing fast apps on any platform. Its goal is to offer the most productive programming language for multi-platform development, paired with a flexible execution runtime platform for app frameworks. For more details, see https://dart.dev.

By utilizing Dart's support for ahead-of-time (AOT) compilation to executables, you can create very small runtime images (~10 MB).

Using this image

We recommend using small runtime images that leverage Dart's support for ahead-of-time (AOT) compilation to executables. This enables creating small runtime images (~10 MB).

Creating a Dart server app

After installing the Dart SDK, version 2.14 or later, use the dart command to create a new server app:

$ dart create -t server-shelf myserver

Running the server with Docker Desktop

If you have Docker Desktop installed, you can build and run on your machine with the docker command:

$ docker build -t dart-server .
$ docker run -it --rm -p 8080:8080 --name myserver dart-server

When finished, you can stop the container using the name you provided:

$ docker kill myserver

Image documentation

Dockerfile

The Dockerfile created by the dart tool performs two steps:

1. Using the Dart SDK in the dart:stable image, compiles your server (bin/server.dart) to an executable (server).

2. Assembles the runtime image by combining the compiled server with the Dart VM runtime and it's needed dependencies located in /runtime/.

   # Specify the Dart SDK base image version using dart:<version> (ex: dart:2.12)
   FROM dart:stable AS build
   
   # Resolve app dependencies.
   WORKDIR /app
   COPY pubspec.* ./
   RUN dart pub get
   
   # Copy app source code and AOT compile it.
   COPY . .
   # Ensure packages are still up-to-date if anything has changed
   RUN dart pub get --offline
   RUN dart compile exe bin/server.dart -o bin/server
   
   # Build minimal serving image from AOT-compiled `/server` and required system
   # libraries and configuration files stored in `/runtime/` from the build stage.
   FROM scratch
   COPY --from=build /runtime/ /
   COPY --from=build /app/bin/server /app/bin/
   
   # Start server.
   EXPOSE 8080
   CMD ["/app/bin/server"]
   

.dockerignore

Additionally it creates a recommended .dockerignore file, which enumarates files that should be omitted from the built Docker image:

.dockerignore
Dockerfile
build/
.dart_tool/
.git/
.github/
.gitignore
.packages

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Maintained with ❤️ by the Dart team.