Support external extension

Author: trungleduc

README.md

@@ -37,6 +37,7 @@ npm start
 ```bash
  python -m http.server 3344 -d jupyterlite/_output
 ```
+
 - Build JupyterLite and watch for code changes:
 
 ```bash
@@ -49,3 +50,14 @@ npm start:watch
 npm run clean # Clean build assets
 npm run start:bash # Open a bash shell in the container
 ```
+
+### Customize jupyterlite build
+
+- All files located in `./jupyterlite` will be copied to the build directory in the container. So you can add your config file (`jupyter_lite_config.py|json`,...) to this directory.
+
+- To add local JupyterLite extensions to the build, update `.env` file with path to your extensions and key prefixed by `JUPYTERLITE_EXTERNAL`
+
+```bash
+#.env file
+JUPYTERLITE_EXTERNAL_MY_CUSTOM_EXTENSION=../demo/my-custom-ext
+```

script/build.sh

@@ -30,9 +30,18 @@ emmake make -j4
 emmake make install
 popd
 
+echo "############## INSTALL EXTENSIONS ##############"
+for subdir in /home/$MAMBA_USER/extensions/*; do
+    if [ -d "$subdir" ]; then
+        echo "Running pip install -e $subdir"
+        pip install -e "$subdir" -v --no-build-isolation
+    fi
+done
+
 echo "############## BUILDING JUPYTERLITE ##############"
 cd /home/$MAMBA_USER/xeus
+rm -fr tsconfig.tsbuildinfo
 python -m pip install -e . -v --no-build-isolation
 cd $LITE_DIR
-rm -fr *
+rm -fr _output .jupyterlite.doit.db
 jupyter lite build --XeusAddon.prefix=$PREFIX --XeusAddon.mounts=$PREFIX/lib/python3.11/site-packages/pyjs:/lib/python3.11/site-packages/pyjs

script/cmd.js

@@ -58,10 +58,7 @@ function clean() {
 
 function start(mode) {
   const outDir = `${ROOT}/jupyterlite`;
-  if (mode !== "bash") {
-    if (fs.existsSync(outDir)) {
-      fs.rmSync(outDir, { recursive: true, force: true });
-    }
+  if (!fs.existsSync(path.join(outDir))) {
     fs.mkdirSync(outDir);
   }
   let cmd = "";
@@ -79,9 +76,17 @@ function start(mode) {
   const xeusPythonMount = `${XEUS_PYTHON_PATH}:${CONTAINER_ROOT}/xeus-python`;
   const empackMount = `${EMPACK_PATH}:${CONTAINER_ROOT}/empack`;
   const cacheMount = `${STORAGE_VOLUME}:/opt/conda/opt/emsdk`;
-  
-  const mount = `-v ${jupyterliteMount} -v ${pyjsMount} -v ${xeusMount} -v ${xeusPythonMount} -v ${empackMount} -v ${cacheMount}`;
-  
+
+  let mount = `-v ${jupyterliteMount} -v ${pyjsMount} -v ${xeusMount} -v ${xeusPythonMount} -v ${empackMount} -v ${cacheMount}`;
+  Object.entries(process.env).forEach(([key, val]) => {
+    if (key.startsWith("JUPYTERLITE_EXTERNAL_")) {
+      const mountString = ` -v ${path.resolve(
+        val
+      )}:${CONTAINER_ROOT}/extensions/${key}`;
+      mount += mountString;
+    }
+  });
+
   execSync(
     `docker run --name xeus-stack-container --rm -it ${mount} xeus-stack:latest ${cmd}`,
     {