This Dockerfile builds a self-contained version of Emscripten SDK that enables Emscripten to be used without any other installation on the host system.
It is published at https://hub.docker.com/r/emscripten/emsdk.
Simple usage of this container to compile a hello-world
# create helloworld.cpp cat << EOF > helloworld.cpp #include <iostream> int main() { std::cout << "Hello World!" << std::endl; return 0; } EOF
# compile with docker image docker run \ --rm \ -v $(pwd):/src \ -u $(id -u):$(id -g) \ emscripten/emsdk \ emcc helloworld.cpp -o helloworld.js # execute on host machine node helloworld.js
Teardown of compilation command:
part | description |
---|---|
docker run | A standard command to run a command in a container |
--rm | remove a container after execution (optimization) |
-v $(pwd):$(pwd) | Mounting current folder from the host system into mirrored path on the container TIP: This helps to investigate possible problem as we preserve exactly the same paths like in host. In such case modern editors (like Sublime, Atom, VS Code) let us to CTRL+Click on a problematic file |
-u $(id -u):$(id -g) | Run the container as a non-root user with the same UID and GID as local user. Hence all files produced by this are accessible to non-root users |
emscripten/emsdk | Get the latest tag of this container |
emcc helloworld.cpp -o helloworld.js | Execute emcc command with following arguments inside container, effectively compile our source code |
This image has following optional arguments
arg | default value | description |
---|---|---|
EMSCRIPTEN_VERSION | tot (special case, tip-of-tree) | One of released version of Emscripten. For example 2.0.0 Minimal supported version is 1.39.0 |
Building
This step will build Dockerfile as given tag on local machine
# using docker docker build \ --network host \ --build-arg=EMSCRIPTEN_VERSION=1.39.17 \ -t emscripten/emsdk:1.39.17 \ -f docker/Dockerfile \ .
# using predefined make target make version=1.39.17 build test
Tagging
In case of using docker build
command directly, given --tag
should match version of released Emscripten (you can see list of non-legacy versions by executing emsdk list
).
Pushing
This step will take local image and push to default docker registry. You need to make sure that you logged in docker cli (docker login
) and you have rights to push to that registry.
# using docker docker push emscripten/emsdk:1.39.17
# using predefined make target make version=1.39.17 push
In case of pushing the most recent version, this version should be also tagged as latest
and pushed.
# using docker cli docker tag emscripten/emsdk:1.39.17 emscripten/emsdk:latest docker push emscripten/emsdk:latest ```bash # using make make version=1.39.17 alias=latest push
If your project uses packages that this image doesn't provide you might want to:
create own Dockerfile that holds:
# Point at any base image that you find suitable to extend. FROM emscripten/emsdk:1.39.17 # Install required tools that are useful for your project i.e. ninja-build RUN apt update && apt install -y ninja-build
build it
docker build -t extended_emscripten .
test
docker run --rm extended_emscripten ninja --version # 1.10.0