Update devcontainer.json

.devcontainer/devcontainer.json

@@ -1,9 +1,30 @@
+// Source: https://github.com/NixOS/nix/issues/6680#issuecomment-1577781769
 {
-  "image":"mcr.microsoft.com/devcontainers/base:alpine",
+  "image": "mcr.microsoft.com/devcontainers/base:alpine",
   "features": {
     "ghcr.io/devcontainers/features/nix:1": {
       "multiUser": true,
-      "version": "latest"
+      "version": "latest",
+      // Needed for flakes & nix-direnv:
+      "extraNixConfig": "experimental-features = nix-command flakes,keep-outputs = true,keep-derivations = true"
+    }
+  },
+  "onCreateCommand": {
+    // Set up global gitignore for direnv.
+    // "init-git": "mkdir -p ~/.config/git && printf '.direnv/\\n.envrc\\n' > ~/.config/git/ignore && git config --global core.excludesfile ~/.config/git/ignore",
+    // Install, set up and allow direnv in workspace.
+    "install-direnv": "nix profile install nixpkgs#direnv nixpkgs#nix-direnv && mkdir -p ~/.config/direnv && echo 'source $HOME/.nix-profile/share/nix-direnv/direnvrc' >> ~/.config/direnv/direnvrc && cp .envrc.recommended .envrc && direnv allow && echo 'eval \"$(direnv hook bash)\"' >> ~/.bashrc",
+    // Run `print-dev-env` to build `devShells.${system}.default`.
+    "build-dev-env": "nix print-dev-env"
+  },
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        // Inject direnv variables into VS Code terminals and tasks:
+        "mkhl.direnv",
+        // Support for `.nix` files:
+        "jnoortheen.nix-ide"
+      ]
     }
   }
 }