Add Python devcontainer with Node & PostgreSQL

This is the [out of the box VS Code devcontainer that bundles Python,
Node and PostgreSQL][1].  The only amendment was to apply [the bug fix
for a bug with the docker compose volume][2], that prevented the
container from starting.

[1]: https://github.com/microsoft/vscode-dev-containers/tree/main/containers/python-3-postgres
[2]: microsoft/vscode-remote-release#5388 (comment)

.devcontainer/Dockerfile

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+# [Choice] Python version (use -bullseye variants on local arm64/Apple Silicon): 3, 3.10, 3.9, 3.8, 3.7, 3.6, 3-bullseye, 3.10-bullseye, 3.9-bullseye, 3.8-bullseye, 3.7-bullseye, 3.6-bullseye, 3-buster, 3.10-buster, 3.9-buster, 3.8-buster, 3.7-buster, 3.6-buster
+ARG VARIANT=3-bullseye
+FROM mcr.microsoft.com/vscode/devcontainers/python:0-${VARIANT}
+
+ENV PYTHONUNBUFFERED 1
+
+# [Choice] Node.js version: none, lts/*, 16, 14, 12, 10
+ARG NODE_VERSION="none"
+RUN if [ "${NODE_VERSION}" != "none" ]; then su vscode -c "umask 0002 && . /usr/local/share/nvm/nvm.sh && nvm install ${NODE_VERSION} 2>&1"; fi
+
+# [Optional] If your requirements rarely change, uncomment this section to add them to the image.
+# COPY requirements.txt /tmp/pip-tmp/
+# RUN pip3 --disable-pip-version-check --no-cache-dir install -r /tmp/pip-tmp/requirements.txt \
+#    && rm -rf /tmp/pip-tmp
+
+# [Optional] Uncomment this section to install additional OS packages.
+# RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
+#     && apt-get -y install --no-install-recommends <your-package-list-here>
+

.devcontainer/devcontainer.json

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+// For format details, see https://aka.ms/devcontainer.json. For config options, see the README at:
+// https://github.com/microsoft/vscode-dev-containers/tree/v0.245.2/containers/python-3-postgres
+// Update the VARIANT arg in docker-compose.yml to pick a Python version
+{
+	"name": "Python 3 & PostgreSQL",
+	"dockerComposeFile": "docker-compose.yml",
+	"service": "app",
+	"workspaceFolder": "/workspaces/${localWorkspaceFolderBasename}",
+
+	// Configure tool-specific properties.
+	"customizations": {
+		// Configure properties specific to VS Code.
+		"vscode": {
+			// Set *default* container specific settings.json values on container create.
+			"settings": { 
+				"python.defaultInterpreterPath": "/usr/local/bin/python",
+				"python.linting.enabled": true,
+				"python.linting.pylintEnabled": true,
+				"python.formatting.autopep8Path": "/usr/local/py-utils/bin/autopep8",
+				"python.formatting.blackPath": "/usr/local/py-utils/bin/black",
+				"python.formatting.yapfPath": "/usr/local/py-utils/bin/yapf",
+				"python.linting.banditPath": "/usr/local/py-utils/bin/bandit",
+				"python.linting.flake8Path": "/usr/local/py-utils/bin/flake8",
+				"python.linting.mypyPath": "/usr/local/py-utils/bin/mypy",
+				"python.linting.pycodestylePath": "/usr/local/py-utils/bin/pycodestyle",
+				"python.linting.pydocstylePath": "/usr/local/py-utils/bin/pydocstyle",
+				"python.linting.pylintPath": "/usr/local/py-utils/bin/pylint",
+				"python.testing.pytestPath": "/usr/local/py-utils/bin/pytest"
+			},
+
+			// Add the IDs of extensions you want installed when the container is created.
+			"extensions": [
+				"ms-python.python",
+				"ms-python.vscode-pylance"
+			]
+		}
+	},
+
+	// Use 'forwardPorts' to make a list of ports inside the container available locally.
+	// This can be used to network with other containers or the host.
+	// "forwardPorts": [5000, 5432],
+
+	// Use 'postCreateCommand' to run commands after the container is created.
+	// "postCreateCommand": "pip install --user -r requirements.txt",
+
+	// Comment out to connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
+	"remoteUser": "vscode"
+}

.devcontainer/docker-compose.yml

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+version: '3.8'
+
+services:
+  app:
+    build:
+      context: ..
+      dockerfile: .devcontainer/Dockerfile
+      args:
+        # Update 'VARIANT' to pick a version of Python: 3, 3.10, 3.9, 3.8, 3.7, 3.6
+        # Append -bullseye or -buster to pin to an OS version.
+        # Use -bullseye variants on local arm64/Apple Silicon.
+        VARIANT: 3-bullseye
+        # Optional Node.js version to install
+        NODE_VERSION: "lts/*"
+
+    volumes:
+      - ../..:/workspaces:cached 
+
+    # Overrides default command so things don't shut down after the process ends.
+    command: sleep infinity
+
+    # Runs app on the same network as the database container, allows "forwardPorts" in devcontainer.json function.
+    network_mode: service:db
+
+    # Uncomment the next line to use a non-root user for all processes.
+    # user: vscode
+
+    # Use "forwardPorts" in **devcontainer.json** to forward an app port locally.
+    # (Adding the "ports" property to this file will not forward from a Codespace.)
+
+  db:
+    image: postgres:latest
+    restart: unless-stopped
+    volumes:
+      - postgres-data:/var/lib/postgresql/data
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_DB: postgres
+      POSTGRES_PASSWORD: postgres
+
+    # Add "forwardPorts": ["5432"] to **devcontainer.json** to forward PostgreSQL locally.
+    # (Adding the "ports" property to this file will not forward from a Codespace.)
+
+volumes:
+  postgres-data: