Docker-Env CLI Tool

Docker-Env is a command-line interface (CLI) tool designed to simplify the process of injecting environment variables into Dockerfiles from .env files. It streamlines the development and deployment workflow by automating the tedious task of manually updating environment variables in Docker configurations.

Features

• Easy Integration: Seamlessly integrates with existing Docker and Go projects.
• Automatic Environment Variable Injection: Automatically updates your Dockerfile with environment variables from a specified .env file.
• Cross-Platform Compatibility: Builds available for Linux, Windows, and macOS.

Installation Methods

Install using Go CLI:

Prerequisites

• Go 1.22.4 or later

Installation

Run the following go install command to install and keep this cli-tool in `$GOPATH/bin'.

go install github.com/SRV332003/envdaemon

Install and Build from source

Prerequisites

• Go 1.22.4 or later
• Docker

Installation

Clone the repository and navigate to the project directory:

git clone https://github.com/SRV332003/envdaemon.git
cd envdaemon

Build the project using the provided Makefile:

make build

This will compile the Docker-Env CLI tool and place the executable in your $GOPATH/bin.

Usage

To inject environment variables into your Dockerfile, first place a # {{ENV} placeholder in your Dockerfile where you want the environment variables to be injected. Then, run the following command:

envdaemon <path-to-envfile> <path-to-Dockerfile>

Example

Given a .env file with the following content:

AUTH_SECRET=your_secret
AUTH_EXPIRES_IN=1d
MAIL_HOST=smtp.mailtrap.io
MAIL_PORT=2525
MAIL_USER=your_user
MAIL_PASS=your_pass

And a Dockerfile with placeholder # {{ENV}} for environment variables:

FROM golang:1.22.4 AS builder

ARG VERSION=dev
WORKDIR /app

# {{ENV}}
COPY . .
RUN go mod download
RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -ldflags "-X main.version=${VERSION}" -o main .
CMD ["./main"]

These have the following directory structure:

.
├── .env
├── Dockerfile
└── README.MD

Running the following command will inject the environment variables from the .env file into the Dockerfile:

envdaemon .env Dockerfile

The updated Dockerfile will look like this:

FROM golang:1.22.4 AS builder

ARG VERSION=dev
WORKDIR /app

# {{ENV}}
ENV AUTH_SECRET {AUTH_SECRET}
ENV AUTH_EXPIRES_IN {AUTH_EXPIRES_IN}
ENV MAIL_HOST {MAIL_HOST}
ENV MAIL_PORT {MAIL_PORT}
ENV MAIL_USER {MAIL_USER}
ENV MAIL_PASS {MAIL_PASS}
# {{END ENV}}

COPY . .
RUN go mod download
RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -ldflags "-X main.version=${VERSION}" -o main .
CMD ["./main"]

Contributing

Contributions are welcome! Please feel free to submit a pull request or open an issue for any bugs or feature requests.

License

This project is licensed under the MIT License. See the LICENSE file for more information.