Automatically activate venv

.devcontainer/devcontainer.json

@@ -1,13 +1,23 @@
 // For format details, see https://aka.ms/devcontainer.json
 {
 	"name": "pallets/flask",
+	"image": "mcr.microsoft.com/vscode/devcontainers/python:3",
 
-	// Features to add to the devcontainer
-	"features": {
-		"ghcr.io/devcontainers/features/python:1": {}
+	// 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": "/workspaces/flask/.venv/bin/python",
+				"python.linting.enabled": true,
+				"python.linting.pylintEnabled": true
+
+			}
+		}
 	},
 
-	// Displays a custom welcome message
+	// Displays a custom welcome message.
 	"onCreateCommand": "sudo cp .devcontainer/welcome-message.txt /usr/local/etc/vscode-dev-containers/first-run-notice.txt",
 
 	// Runs the initial setup commands after the container is created.

.devcontainer/welcome-message.txt

@@ -3,5 +3,5 @@
 🛠️  Your environment is setup with all the required dependencies and your fork has been added as a remote.
 
 🚀  To start coding, wait for the "postCreateCommand" to finish setting things up, then:
-    - run `. .venv/bin/activate` to activate your virtualenv
+    - make sure the virtualenv is activated by running `. .venv/bin/activate`
     - run `git checkout -b your-branch-name origin/{main-or-latest-release}` to start working on a new feature or bug fix

CONTRIBUTING.rst

@@ -83,6 +83,16 @@ a `devcontainer`_ that installs required dependencies for you.
     finish running.
 -   Checkout a new branch and `start coding`_.
 
+Note that if you reconnect to an existing codespace, you may need to
+open a new terminal or run one of the following commands to activate
+your python virtualenv:
+
+- Linux/macOS
+
+    .. code-block:: text
+
+        $ . .venv/bin/activate
+
 .. _GitHub Codespaces: https://docs.github.com/en/codespaces
 .. _devcontainer: https://docs.github.com/en/codespaces/setting-up-your-project-for-codespaces/adding-a-dev-container-configuration/introduction-to-dev-containers