Environment variables

You can set environment variables in your container without altering the container image by using one of the options below.

You should verifyTerminal > Integrated: Inherit Env is checked in settings or the variables you set may not appear in the Integrated Terminal. This setting is checked by default.

Option 1: Add individual variables

Depending on what you reference indevcontainer.json:

• Dockerfile or image: Add thecontainerEnv property todevcontainer.json to set variables that should apply to the entire container orremoteEnv to set variables for VS Code and related sub-processes (terminals, tasks, debugging, etc.):

  "containerEnv": {    "MY_CONTAINER_VAR":"some-value-here",    "MY_CONTAINER_VAR2":"${localEnv:SOME_LOCAL_VAR}"},"remoteEnv": {    "PATH":"${containerEnv:PATH}:/some/other/path",    "MY_REMOTE_VARIABLE":"some-other-value-here",    "MY_REMOTE_VARIABLE2":"${localEnv:SOME_LOCAL_VAR}"}

  As this example illustrates,containerEnv can reference local variables andremoteEnv can reference both local and existing container variables.

Video: Modify PATH in a dev container

• Docker Compose: Since Docker Compose has built-in support for updating container-wide variables, onlyremoteEnv is supported indevcontainer.json:

  "remoteEnv": {    "PATH":"${containerEnv:PATH}:/some/other/path",    "MY_REMOTE_VARIABLE":"some-other-value-here",    "MY_REMOTE_VARIABLE2":"${localEnv:SOME_LOCAL_VAR}"}

  As this example illustrates,remoteEnv can reference both local and existing container variables.

  To update variables that apply to the entire container, update (orextend) yourdocker-compose.yml with the following for the appropriate service:

  version:'3'services:  your-service-name-here:    environment:      -YOUR_ENV_VAR_NAME=your-value-goes-here      -ANOTHER_VAR=another-value     # ...

If you've already built the container and connected to it, runDev Containers: Rebuild Container from the Command Palette (F1) to pick up the change. Otherwise runDev Containers: Open Folder in Container... to connect to the container.

Option 2: Use an env file

If you have a large number of environment variables that you need to set, you can use a.env file instead.

First, create an environment file somewhere in your source tree. Consider this.devcontainer/devcontainer.env file:

YOUR_ENV_VAR_NAME=your-value-goes-hereANOTHER_ENV_VAR_NAME=your-value-goes-here

Next, depending on what you reference indevcontainer.json:

• Dockerfile or image: Editdevcontainer.json and add a path to thedevcontainer.env :

  "runArgs": ["--env-file",".devcontainer/devcontainer.env"]

• Docker Compose: Editdocker-compose.yml and add a path to thedevcontainer.env file relative to the Docker Compose file:

  version:'3'services:  your-service-name-here:    env_file:devcontainer.env    # ...

docker compose will automatically pick up a file called.env in the folder containing thedocker-compose.yml, but you can also create one in another location.

If you've already built the container and connected to it, runDev Containers: Rebuild Container from the Command Palette (F1) to pick up the change. Otherwise runDev Containers: Open Folder in Container... to connect to the container.

Video: Load variables from an .env file