Cannot use the project's .env in my devcontainer docker-compose.yml?

[bgloss]

I don't get the environment variables from my project's .env file into the docker-compose.ymlsetup with a pretty default project layout.

My project layout is as follows:

.devcontainer/
     devcontainer.json
     docker-compose.yml
     Dockerfile
.env

I want to have in docker-compose.yml a section to create a Postgres container with setting up the environment one by one: POSTGRES_USER, POSTGRES_PASSWORD, and POSTGRES_DB and fill them with variables from the project's .env file. The relevant section in docker-compose.yml is:

  postgres:
    image: postgres:latest
    environment:
      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
      POSTGRES_USER: ${POSTGRES_USER}
      POSTGRES_DB: ${POSTGRES_DB}

I do NOT want to have a copy of my .env file in the .devcontainer/ folder, as it is the case in some of the DevContainer templates. This would work, as in this case docker compose loads it by default. I don't want this organization, as the .env file is also needed by the project's code and expected in the project root.

I also don't want to expose the whole .env-file to my container, which I could do with the env_file option in the docker compose service description.

When building a container myself (just docker, no docker compose), I can add in devcontainer.json the option runArgs next to the option build giving the env-file information to docker: --env-file ../.env However, this is not possible when using a docker-compose setup in vscode and DevContainers with "dockerComposeFile": "docker-compose.yml".

https://containers.dev/implementors/json_reference/

At the command line docker compose --env-file ../.env up does the trick.

So, my questions:

• Am I missing something?
• Is this a missing feature in devcontainer.json?

[bamurtaugh]

Thanks for open this discussion. I've cross-posted this in our dev container community Slack channel to get some more perspectives. And if you'd like to join our community Slack, we'd love to have you join! https://github.com/orgs/devcontainers/discussions/3

[samruddhikhandale]

Hi 👋

Can you add the following to your docker-compose.yml and see if it helps? Thanks!

env_file:
      - ../.env

[samruddhikhandale]

If you are using the postgres Template, then you can add it on this line here

[bgloss]

This is not the solution. I explained in my post that it is not about providing the content of the .env-file into the postgres container, but to have the .env settings available in the docker-compose file. But ... thanks

[chrmarti]

There is a feature request for the Dev Containers extension to support --env-file: microsoft/vscode-remote-release#4885. An implementation for this would also cover GitHub Codespaces.

[nelsonsilva94]

Is there a solution for this problem?

I am getting issues to use a .env file in devcontainer

[jusito]

A workaround which will helps in some cases:

Layout from git root:
.env
compose.yml
init/ (devcontainer folder)
init/compose.yml

.devcontainer.json:

{
   "dockerComposeFile": [
        "compose.yml", // <- .env is used from this location
        "init/compose.yml"
    ]
   "service": "dev",
   ...

init/compose.yml just required to not include the other, not defining project name, and redefine volumes / networks as external:
E.g. init/compose.yml:

# This file is assumed to be consumed for devcontainer, not manually!
# npx @devcontainers/cli up --workspace-folder . (from git root)

networks:
  default:
    name: "fox_default"
    external: true

volumes:
  init-shared:
    name: "fox_init-shared"
    external: true

services:
  dev:
    ...