GitHub Codespaces: Add devcontainer.json files to Livebook (#1138)

.devcontainer/Dockerfile

@@ -0,0 +1,46 @@
+# This image version needs to match what is in the root Dockerfile.
+FROM hexpm/elixir:1.13.2-erlang-24.1.7-debian-bullseye-20210902-slim
+
+ENV HOME=/home/livebook
+ENV PATH ${PATH}:${HOME}/.mix/escripts
+
+# GitHub Codespaces put you in a `/workspaces` folder no matter what.
+ENV WORKSPACE_FOLDER=/workspaces/livebook
+
+WORKDIR ${WORKSPACE_FOLDER}
+
+# Install the dependencies from the build image (which is discarded in the normal production images)
+RUN apt-get update && apt-get upgrade -y && \
+    apt-get install --no-install-recommends -y \
+        # Bash (for easier shell use)
+        bash \
+        # Runtime dependencies
+        build-essential ca-certificates libncurses5-dev inotify-tools \
+        # In case someone uses `Mix.install/2` and point to a git repo
+        git \
+        # Additional standard tools
+        curl wget \
+        # In case someone uses Torchx for Nx
+        cmake && \
+    apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false && \
+    apt-get clean -y && \
+    rm -rf /var/lib/apt/lists/*
+
+# Install hex and rebar
+RUN mix local.hex --force && mix local.rebar --force
+
+# Node/nvm setup
+ARG NODE_SCRIPT_SOURCE="https://raw.githubusercontent.com/microsoft/vscode-dev-containers/main/script-library/node-debian.sh"
+ARG NODE_SCRIPT_SHA="dev-mode"
+ARG NODE_VERSION="14"
+ENV NVM_DIR=/usr/local/share/nvm
+ENV NVM_SYMLINK_CURRENT=true
+ENV PATH=${NVM_DIR}/current/bin:${PATH}
+
+RUN curl -sSL ${NODE_SCRIPT_SOURCE} -o /tmp/node-setup.sh && \
+    /bin/bash /tmp/node-setup.sh "${NVM_DIR}" "${NODE_VERSION}" "${USERNAME}"
+
+# On Codespaces the code is automatically copied and we run the setup as a hook,
+# we still do this for the image, so the container can be tested on its own
+COPY . .
+RUN mix do dev.setup, deps.compile, compile

.devcontainer/devcontainer.json

@@ -0,0 +1,27 @@
+// For format details, see https://aka.ms/devcontainer.json.
+// Also see https://github.com/microsoft/vscode-dev-containers/tree/v0.231.6/containers/elixir-phoenix-postgres
+{
+  "name": "Livebook development environment",
+  "dockerComposeFile": "docker-compose.yml",
+  "service": "livebook_dev",
+
+  // Despite being required to set workspaceFolder, it doesn't actually do anything and you end up in /workspaces/livebook no matter what.
+  "workspaceFolder": "/workspaces/livebook",
+
+  // Codespaces will mount the source code and overwrite the build artifacts that the Dockerfile creates, so we rebuild with a lifecycle script.
+  "updateContentCommand": "mix do dev.setup, deps.compile, compile",
+
+  "extensions": ["jakebecker.elixir-ls"],
+  "forwardPorts": [4000, 4001, 8080, 8081],
+  "otherPortsAttributes": {
+    "onAutoForward": "ignore"
+  },
+  "settings": {
+    // Needed because of: https://github.com/microsoft/vscode/issues/102057#issuecomment-657728467
+    "debug.javascript.autoAttachFilter": "onlyWithFlag",
+    "debug.javascript.autoAttachSmartPattern": [
+      "!**/node_modules/**",
+      "**/$KNOWN_TOOLS$/**"
+    ]
+  },
+}

.devcontainer/docker-compose.yml

@@ -0,0 +1,19 @@
+version: "3.8"
+
+services:
+  livebook_dev:
+    container_name: livebook_dev
+    image: livebook_dev:latest
+    build:
+      context: ..
+      dockerfile: ./.devcontainer/Dockerfile
+    environment:
+      - LIVEBOOK_HOME=/data
+      - LIVEBOOK_DATA_PATH=/data
+    # Overrides default command so things don't shut down after the process ends.
+    command: sleep infinity
+    ports:
+      - "8080:8080"
+      - "8081:8081"
+      - "4000:4000"
+      - "4001:4001"

README.md

@@ -126,6 +126,15 @@ If you want to run Livebook on embedded devices, such as Raspberry Pi, BeagleBon
 check out [our Livebook firmware](https://github.com/livebook-dev/nerves_livebook) built
 with [Nerves](https://www.nerves-project.org/).
 
+### GitHub Codespaces (development)
+
+Livebook also has a `devcontainer.json` file for launching containers
+on [GitHub Codespaces](https://github.com/features/codespaces) for development
+purposes. Once booted, you can invoke `mix phx.server` in the terminal to start
+your own Livebook session.
+
+Check [the official GitHub Codespaces documentation](https://docs.github.com/en/codespaces/developing-in-codespaces/creating-a-codespace#creating-a-codespace) to learn more.
+
 ## Security considerations
 
 Livebook is built to document and execute code. Anyone with access to a Livebook instance