devcontainer-env-0.2.0 is not a library.

devcontainer-env

Bridge devcontainers and the host environment — run host commands with devcontainer service environments and automatically rewrite container service URLs to host ports.

eval "$(devcontainer-env export)"

Requirements

Rust 1.70+ (rustc, cargo)

macOS (Homebrew):

brew install rust

Nix:

nix profile install nixpkgs#rust

Installation

Cargo (Crates.io)

cargo install devcontainer-env

Nix (recommended)

Run directly without installing:

nix run github:devcontainer-env/devcontainer-env -- exec -- your-command

Or install into your profile:

nix profile install github:devcontainer-env/devcontainer-env

Usage

Export Environment Variables

eval "$(devcontainer-env export)"

To make persistent, add to your .envrc file. Then run direnv allow to enable it.

Run Commands

Execute commands with devcontainer environment variables:

devcontainer-env exec -- go test ./...

Inspect Configuration

View parsed devcontainer configuration and service port mappings:

devcontainer-env inspect

CLI Reference

Usage: devcontainer-env <COMMAND>

Commands:
  export    Export environment variables as shell statements
  exec      Execute command with devcontainer environment
  inspect   Display parsed devcontainer configuration
  help      Print help message

Options:
  -h, --help     Print help
  -V, --version  Print version

devcontainer-env export — Output environment variables from containerEnv as shell statements.

Only variables defined in the containerEnv section are exported to the host (not service configuration or service environment variables). See Configuration for an example.

$ devcontainer-env export

export EXAMPLE_API_LOG_LEVEL=DEBUG
export EXAMPLE_API_LOG_PRETTY=true
export EXAMPLE_API_DATABASE_URL=postgres://vscode@127.0.0.1:32770/example-db?sslmode=disable

devcontainer-env exec — Run a command with devcontainer environment available:

devcontainer-env exec -- <COMMAND> [ARGS...]

The -- separator is required. Everything after -- is passed to the command.

devcontainer-env inspect — Parse and display the devcontainer configuration:

$ devcontainer-env inspect

Workspace: /Users/iamralch/Projects/github.com/example-org/example-api

Containers:
  default-co-bd5e8-postgres-1
    Image: postgres:18-bookworm
    Hosts: default-co-bd5e8-postgres-1, postgres, fe6eca554c95
    Ports: 5432 → 0.0.0.0:32770, 5432 → :::32770

  default-co-bd5e8-workspace-1, main
    Image: mcr.microsoft.com/devcontainers/base:noble
    Hosts: default-co-bd5e8-workspace-1, workspace, d93fdbd4f540

Environment:
  EXAMPLE_API_LOG_LEVEL = DEBUG
  EXAMPLE_API_LOG_PRETTY = true
  EXAMPLE_API_DATABASE_URL = postgres://vscode@127.0.0.1:32770/example-db?sslmode=disable

Configuration

Configure your .devcontainer/devcontainer.json to define environment variables and services:

devcontainer.json

{
  "$schema": "https://raw.githubusercontent.com/devcontainers/spec/refs/heads/main/schemas/devContainer.base.schema.json",
  "name": "my-project",
  "service": "workspace",
  "dockerComposeFile": "docker-compose.yml",
  "workspaceFolder": "/home/vscode/workspace",
  "remoteUser": "vscode",
  "containerEnv": {
    "EXAMPLE_API_LOG_LEVEL": "DEBUG",
    "EXAMPLE_API_LOG_PRETTY": "true",
    "EXAMPLE_API_DATABASE_URL": "postgres://vscode@postgres:5432/example-db?sslmode=disable"
  }
}

docker-compose.yml

services:
  workspace:
    image: "mcr.microsoft.com/devcontainers/base:noble"
    command: sleep infinity

  postgres:
    image: postgres:18-bookworm
    restart: unless-stopped
    volumes:
      - postgres:/var/lib/postgres
    environment:
      POSTGRES_DB: my-project
      POSTGRES_USER: vscode
      POSTGRES_HOST_AUTH_METHOD: trust
    healthcheck:
      test: ["CMD-SHELL", "pg_isready"]
      interval: 1s
      timeout: 5s
      retries: 10
    ports:
      - 5432

volumes:
  postgres:

Port Mapping

Use ports: [<PORT>] syntax (not "HOST:PORT") to let Docker assign random available host ports. This prevents conflicts when running multiple devcontainers or projects simultaneously. devcontainer-env export automatically detects the Docker-assigned host port and makes it available in exported environment variables. Do not use forwardPorts in devcontainer.json — rely on docker-compose.yml port mapping instead.

devcontainer-env 0.2.0