Dockerfile Generator

new-dockerfile is a CLI tool and Go package automatically generates a configurable Dockerfile based on your project source code. It supports a wide range of languages and frameworks, including Next.js, Node.js, Python, Ruby, Java/Spring Boot, Go, Elixir/Phoenix, and more.

See the FlexStack Documentation page for FlexStack-specific documentation related to this tool.

Features

Supported Runtimes

Bun
Deno
Elixir
Go
Java
Next.js
Node.js
PHP
Python
Ruby
Rust
Static (HTML, CSS, JS)

Additional runtimes we'd like to support

C#/.NET
C++
Scala
Zig

Consider contributing to add support for these or any other runtimes!

Installation

cURL

curl -fsSL https://flexstack.com/install/new-dockerfile | bash

Go Package

go get github.com/flexstack/new-dockerfile

CLI Usage

new-dockerfile [options]

CLI Options

--path - Path to the project source code (default: .)
--write - Write the generated Dockerfile to the project at the specified path (default: false)
--runtime - Force a specific runtime, e.g. node (default: auto)
--quiet - Disable all logging except for errors (default: false)
--help - Show help

CLI Examples

Print the generated Dockerfile to the console:

new-dockerfile

Write a Dockerfile to the current directory:

new-dockerfile --write

Write a Dockerfile to a specific directory:

new-dockerfile > path/to/Dockerfile

Force a specific runtime:

new-dockerfile --runtime next.js

List the supported runtimes:

new-dockerfile --runtime list

Read from Config file

In the CI use case, you might need a very common step for generating a Dockerfile. You can create a config file for the CLI options. The default config file name is new-dockerfile.yaml, and it should be in the root directory of your git repository. Especially, there are multiple kinds of files, new-dockerfile might not be able to it a correct one.

runtime: go

And, the CLI option will overwrite the values from config file.

How it Works

The tool searches for common files and directories in your project to determine the runtime and framework. For example, if it finds a package.json file, it will assume the project is a Node.js project unless a next.config.js file is present, in which case it will assume the project is a Next.js project.

From there, it will read any .tool-versions or other version manager files to determine the correct version of the runtime to install. It will then make a best effort to detect any install, build, and start commands. For example, a serve, start, start:prod command in a package.json file will be used as the start command.

Runtimes are matched against in the order they appear when you run new-dockerfile --runtime list.

Read on to see runtime-specific examples and how to configure the generated Dockerfile.

Runtime Documentation

Bun

Bun is a fast JavaScript all-in-one toolkit

Detected Files

bun.lockb
bun.lock
bunfig.toml

Version Detection

.tool-versions - bun {VERSION}
.mise.toml - bun = "{VERSION}"

Runtime Image

oven/bun:${VERSION}-slim

Build Args

VERSION - The version of Bun to install (default: 1)
INSTALL_CMD - The command to install dependencies (default: bun install)
BUILD_CMD - The command to build the project (default: detected from package.json)
START_CMD - The command to start the project (default: detected from package.json)

Build Command

Detected in order of precedence:

package.json scripts: "build:prod", "build:production", "build-prod", "build-production", "build"

Start Command

Detected in order of precedence:

package.json scripts: "serve", "start:prod", "start:production", "start-prod", "start-production", "preview", "start"
package.json main/module file: bun run ${mainFile}

Deno

Deno is a secure runtime for JavaScript with native TypeScript and JSX support

Detected Files

deno.jsonc
deno.json
deno.lock
deps.ts
mod.ts

Version Detection

.tool-versions - deno {VERSION}
.mise.toml - deno = "{VERSION}"

Runtime Image

debian:stable-slim

Build Args

VERSION - The version of Deno to install (default: latest)
INSTALL_CMD - The command to install dependencies (default: detected from deno.jsonc and source code)
START_CMD - The command to start the project (default: detected from deno.jsonc and source code)

Install Command

Detected in order of precedence:

deno.jsonc tasks: "cache"
Main/module file: deno cache ["mod.ts", "src/mod.ts", "main.ts", "src/main.ts", "index.ts", "src/index.ts]"

Start Command

Detected in order of precedence:

deno.jsonc tasks: "serve", "start:prod", "start:production", "start-prod", "start-production", "preview", "start"
Main/module file: deno run ["mod.ts", "src/mod.ts", "main.ts", "src/main.ts", "index.ts", "src/index.ts]"

Elixir

Elixir is a dynamic, functional language designed for building scalable and maintainable applications.

Detected Files

mix.exs

Version Detection

.tool-versions - elixir {VERSION}
.tool-versions - erlang {VERSION}
.elixir-version - {VERSION}
.erlang-version - {VERSION}
.mise.toml - erlang = "{VERSION}"

Runtime Image

debian:stable-slim

Build Args

VERSION - The version of Elixir to install (default: 1.12)
OTP_VERSION - The version of Erlang to install (default: 26.2.5)
BIN_NAME - The name of the release binary (default: detected via app name in mix.exs)

Start Command

/app/bin/{BIN_NAME} start

Go

Go is an open-source programming language that makes it easy to build simple, reliable, and efficient software.

Detected Files

go.mod
main.go

Version Detection

.tool-versions - golang {VERSION}
.mise.toml - go = "{VERSION}"
go.mod - go {VERSION}

Runtime Image

debian:stable-slim

Build Args

VERSION - The version of Go to install (default: 1.17)
TARGETOS - The target OS for the build (default: linux)
TARGETARCH - The target architecture for the build (default: amd64)
CGO_ENABLED - Enable CGO for the build (default: 0)
GOPROXY - The Go module proxy to use (default: direct)
PACKAGE - The package to compile e.g. ./cmd/http (default: detected via cmd directory or main.go)

Package Detection

Find the directory in cmd with a .go file
main.go file in the root directory

Install Command

if [ -f go.mod ]; then go mod download; fi

Build Command

CGO_ENABLED=${CGO_ENABLED} GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build -trimpath -ldflags="-s -w" -o /go/bin/app "${PACKAGE}"

Start Command

["/app/app"]

Java

Java is a class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible.

Detected Files

pom.{xml,atom,clj,groovy,rb,scala,yml,yaml}

Version Detection

JDK version:

.tool-versions - java {VERSION} Maven version:
.tool-versions - maven {VERSION}

Runtime Image

eclipse-temurin:${VERSION}-jdk

Build Args

VERSION - The version of the JDK to install (default: 17)
MAVEN_VERSION - The version of Maven to install (default: 3)
JAVA_OPTS - The Java options to pass to the JVM (default: -Xmx512m -Xms256m)
BUILD_CMD - The command to build the project (default: best guess via source code)
START_CMD - The command to start the project (default: detected via source code)

Install Command

If Maven: mvn install

Build Command

If Maven: mvn -DoutputFile=target/mvn-dependency-list.log -B -DskipTests clean dependency:list install

Start Command

Default: java $JAVA_OPTS -jar target/*jar
If Spring Boot: java -Dserver.port=${PORT} $JAVA_OPTS -jar target/*jar

Next.js

Next.js is a React framework that enables functionality such as server-side rendering and generating static websites.

Detected Files

next.config.{js,mjs,cjs,ts,mts}
next-env.d.ts
.next/

Version Detection

.tool-versions - nodejs {VERSION}
.nvmrc - v{VERSION}
.node-version - v{VERSION}
.mise.toml - node = "{VERSION}"
package.json - "engines": {"node": "{VERSION}"}

Runtime Image

node:${VERSION}-slim

Build Args

VERSION - The version of Node.js to install (default: lts)

Install Command

if [ -f yarn.lock ]; then yarn --frozen-lockfile; \
elif [ -f package-lock.json ]; then npm ci; \
elif [ -f bun.lockb ]; then npm i -g bun && bun install; \
elif [ -f pnpm-lock.yaml ]; then corepack enable pnpm && pnpm i --frozen-lockfile; \
else echo "Lockfile not found." && exit 1; \
fi

Build Command

if [ -f yarn.lock ]; then yarn run build; \
elif [ -f package-lock.json ]; then npm run build; \
elif [ -f bun.lockb ]; then npm i -g bun && bun run build; \
elif [ -f pnpm-lock.yaml ]; then corepack enable pnpm && pnpm run build; \
else echo "Lockfile not found." && exit 1; \
fi

Start Command

If "output" :"standalone" in next.config.js: HOSTNAME="0.0.0.0" node server.js
Otherwise ["node_modules/.bin/next", "start", "-H", "0.0.0.0"]

Node.js

Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine.

Detected Files

yarn.lock
package-lock.json
pnpm-lock.yaml

Version Detection

.tool-versions - nodejs {VERSION}
.nvmrc - v{VERSION}
.node-version - v{VERSION}

Runtime Image

node:${VERSION}-slim

Build Args

VERSION - The version of Node.js to install (default: lts)
INSTALL_CMD - The command to install dependencies (default: detected from source code)
BUILD_CMD - The command to build the project (default: detected from source code)
START_CMD - The command to start the project (default: detected from source code)

Install Command

If Yarn: yarn --frozen-lockfile
If npm: npm ci
If pnpm: corepack enable pnpm && pnpm i --frozen-lockfile

Build Command

In order of precedence:

package.json scripts: "build:prod", "build:production", "build-prod", "build-production", "build"

Start Command

In order of precedence:

package.json scripts: "serve", "start:prod", "start:production", "start-prod", "start-production", "preview", "start"
package.json scripts search for regex matching: ^.*?\b(ts-)?node(mon)?\b.*?(index|main|server|client)\.([cm]?[tj]s)\b
package.json main/module file: node ${mainFile}

PHP

PHP is a popular general-purpose scripting language that is especially suited to web development.

Detected Files

composer.json
index.php

Version Detection

.tool-versions - php {VERSION}
composer.json - "php": "{VERSION}"

Runtime Image

php:${VERSION}-apache

Build Args

VERSION - The version of PHP to install (default: 8.3)
INSTALL_CMD - The command to install dependencies (default: detected via source code)
BUILD_CMD - The command to build the project (default: detected via source code)
START_CMD - The command to start the project (default: apache2-foreground)

Install Command

If Composer: composer update && composer install --prefer-dist --no-dev --optimize-autoloader --no-interaction
If package.json exists: composer install command + see Node.js install command

Build Command

If package.json exists: see Node.js build command

Start Command

apache2-foreground

Python

Python is a high-level, interpreted programming language that is known for its readability and simplicity.

Detected Files

requirements.txt
uv.lock
poetry.lock
Pipefile.lock
pyproject.toml
pdm.lock
main.py
app.py
application.py
app/__init__.py
filepath.Join(filepath.Base(path), "app.py")
filepath.Join(filepath.Base(path), "application.py")
filepath.Join(filepath.Base(path), "main.py")
filepath.Join(filepath.Base(path), "__init__.py")

Version Detection

.tool-versions - python {VERSION}
.python-version - {VERSION}
.mise.toml - python = "{VERSION}"
runtime.txt - python-{VERSION}

Runtime Image

python:${VERSION}-slim

Build Args

VERSION - The version of Python to install (default: 3.10)
INSTALL_CMD - The command to install dependencies (default: detected from source code)
START_CMD - The command to start the project (default: detected from source code)

Install Command

If Poetry: pip install poetry && poetry install --no-dev --no-ansi --no-root
If Pipenv: pipenv install --dev --system --deploy
If uv: pip install uv && uv sync --python-preference=only-system --no-cache --no-dev
If PDM: pip install pdm && pdm install --prod
If pyproject.toml exists: pip install --upgrade build setuptools && pip install .
If requirements.txt exists: pip install -r requirements.txt

Start Command

If Django is detected: python manage.py runserver 0.0.0.0:${PORT}
If FastAPI is detected: fastapi run [main.py, app.py, application.py, app/main.py, app/application.py, app/__init__.py] --port ${PORT}
If pyproject.toml exists: python -m ${projectName}
Otherwise: python [main.py, app.py, application.py, app/main.py, app/application.py, app/__init__.py]

Ruby

Ruby is a dynamic, open-source programming language with a focus on simplicity and productivity.

Detected Files

Gemfile
Gemfile.lock
config.ru
Rakefile
config/environment.rb

Version Detection

.tool-versions - ruby {VERSION}
.ruby-version - {VERSION}
.mise.toml - ruby = "{VERSION}"
Gemfile - ruby '{VERSION}'

Runtime Image

ruby:${VERSION}-slim

Build Args

VERSION - The version of Ruby to install (default: 3.0)
INSTALL_CMD - The command to install dependencies (default: detected from source code)
BUILD_CMD - The command to build the project (default: detected from source code)
START_CMD - The command to start the project (default: detected from source code)

Install Command

bundle install
If package.json exists: bundle install && [package manager install command]

Build Command

If Rails: bundle exec rake assets:precompile

Start Command

If Rails: bundle exec rails server -b 0.0.0.0 -p ${PORT}
If config.ru exists: bundle exec rackup config.ru -p ${PORT}
If config/environment.rb exists: bundle exec rails server -b
If Rakefile exists: bundle exec rake

Rust

Rust is a systems programming language that is known for its speed, memory safety, and parallelism.

Detected Files

Cargo.toml

Runtime Image

debian:stable-slim

Build Args

TARGETOS - The target OS for the build (default: linux)
TARGETARCH - The target architecture for the build (default: amd64)
BIN_NAME - The name of the release binary (default: detected via Cargo.toml)

Build Command

if [ "${TARGETARCH}" = "amd64" ]; then rustup target add x86_64-unknown-linux-gnu; else rustup target add aarch64-unknown-linux-gnu; fi
if [ "${TARGETARCH}" = "amd64" ]; then cargo zigbuild --release --target x86_64-unknown-linux-gnu; else cargo zigbuild --release --target aarch64-unknown-linux-gnu; fi

Start Command

Determined by the binary name in the Cargo.toml file

["/app/app"]

Static (HTML, CSS, JS)

Static Web Server is a cross-platform, high-performance & asynchronous web server for static files serving. It is nearly as fast as Nginx and Lighttpd, but is easily configurable with environment variables.

Detected Files

public/
static/
dist/
index.html

Runtime Image

joseluisq/static-web-server:${VERSION}-debian

Build Args

VERSION - The version of the static web server to install (default: 2)
SERVER_ROOT - The root directory of the server (default: detected from source code)

Used By

FlexStack - A platform that simplifies the deployment of containerized applications to AWS. FlexStack uses this tool to automatically detect the runtime and framework used by your project, so you can just bring your code and deploy it with confidence.
Your project here - If you're using this tool in your project, let us know! We'd love to feature you here.

Contributing

Read the CONTRIBUTING.md guide to learn how to contribute to this project.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Name		Name	Last commit message	Last commit date
Latest commit History 48 Commits
.github		.github
cmd/new-dockerfile		cmd/new-dockerfile
node		node
runtime		runtime
testdata		testdata
.gitignore		.gitignore
.goreleaser.yaml		.goreleaser.yaml
.tool-versions		.tool-versions
CODE_OF_CONDUCT.md		CODE_OF_CONDUCT.md
CONTRIBUTING.md		CONTRIBUTING.md
Dockerfile		Dockerfile
LICENSE		LICENSE
README.md		README.md
go.mod		go.mod
go.sum		go.sum
main.go		main.go

Uh oh!

License

Uh oh!

flexstack/new-dockerfile

Folders and files

Latest commit

History

Repository files navigation

Dockerfile Generator

Features

Supported Runtimes

Additional runtimes we'd like to support

Installation

cURL

Go Package

CLI Usage

CLI Options

CLI Examples

Read from Config file

How it Works

Runtime Documentation

Bun

Detected Files

Version Detection

Runtime Image

Build Args

Build Command

Start Command

Deno

Detected Files

Version Detection

Runtime Image

Build Args

Install Command

Start Command

Elixir

Detected Files

Version Detection

Runtime Image

Build Args

Start Command

Go

Detected Files

Version Detection

Runtime Image

Build Args

Package Detection

Install Command

Build Command

Start Command

Java

Detected Files

Version Detection

Runtime Image

Build Args

Install Command

Build Command

Start Command

Next.js

Detected Files

Version Detection

Runtime Image

Build Args

Install Command

Build Command

Start Command

Node.js

Detected Files

Version Detection

Runtime Image

Build Args

Install Command

Build Command

Start Command

PHP

Detected Files

Version Detection

Runtime Image

Build Args

Install Command

Packages