Add Option to ignore certain folder

[DanielHabenicht]

Proposed Feature

It would be great to ignore certain folders from being mounted to the container, by adding an option like this:

// devcontainer.json
"workspaceFolderIgnore": [
    "path/to/folder/node_modules"
]

Reasons

1. A Dev-Dockerfile with the RUN npm install command specified creates a node_modules folder which might be OS-specific (for example if node-sass gets installed). This folder gets overridden by the folder mount done by the vs-code-remote plugin. That causes consecutive steps (like npm run start) to fail.

   By ignoring this folder from mounting the images node_modules folder gets preserved and everything works as expected.

2. Other tools might also create such folders (e.g. golang).

3. A user not familiar with docker wants to ignore specific files.

Current Workaround

(From #560 (comment))

"runArgs": [
  "--mount",
    "type=volume,target=/workspace/node_modules"
  ],
  "workspaceFolder": "/workspace",

[bjoernhommel]

Any progress on this?

[jlarmstrongiv]

The workaround works just fine, but I updated it to:

    mounts: [
      "type=volume,target=${containerWorkspaceFolder}/node_modules",
    ],

Also, npm ci no longer deletes the node_modules folder