Support updated env file format

[mrmachine]

• VSCode Version:

  Version: 1.55.0 (Universal)
  Commit: c185983a683d14c396952dd432459097bc7f757f
  Date: 2021-03-30T16:01:05.981Z
  Electron: 11.3.0
  Chrome: 87.0.4280.141
  Node.js: 12.18.3
  V8: 8.7.220.31-electron.0
  OS: Darwin arm64 20.3.0
  

• Local OS Version: macOS Big Sur 11.2.3 (20D91)

• Remote OS Version: Ubuntu 20.04 LTS

• Remote Extension/Connection Type: Docker

Steps to Reproduce:

1. Create a .env file in the project root with export COMPOSE_PROJECT_NAME='foo' inside.

2. Choose Remote-Containers: Rebuild and Reopen in Container

3. Watch the log. It will include a line like this:

   [1437 ms] Start: Run: docker-compose --project-name BASE_DIR_NAME -f /Users/me/path/to/BASE_DIR_NAME/docker-compose.yml -f /Users/me/path/to/BASE_DIR_NAME/.devcontainer/docker-compose.devcontainer.yml up -d --build
   

Does this issue occur when you try this locally?: N/A
Does this issue occur when you try this locally and all extensions are disabled?: N/A

NOTE: COMPOSE_PROJECT_NAME=foo inside the .env file DOES work. VS Code will then execute docker-compose --project-name foo ... But export FOO='BAR' has been supported by Docker Compose since version 1.26, and allows the .env file to include inline comments and be more compatible and portable (e.g. can be sourced by bash).

[chrmarti]

Does Docker Compose support this updated format? I don't see 'export' mentioned in the documentation: https://docs.docker.com/compose/env-file/#syntax-rules

[mrmachine]

Yes it does, since docker/compose#7150 which was included in 1.26.0

See: https://github.com/docker/compose/releases/tag/1.26.0

Added python-dotenv to delegate .env file processing.