Part 1: A simple Earthfile

Earthfiles are always named Earthfile, regardless of their location in the codebase.
Go
JavaScript
Java
Python
Go
Here is a sample earthfile of a Go app
# Earthfile
​
FROM golang:1.15-alpine3.13
WORKDIR /go-example
​
build:
    COPY main.go .
    RUN go build -o build/go-example main.go
    SAVE ARTIFACT build/go-example /go-example AS LOCAL build/go-example
​
docker:
    COPY +build/go-example .
    ENTRYPOINT ["/go-example/go-example"]
    SAVE IMAGE go-example:latest
The code of the app might look like this
// main.go
​
package main
​
import "fmt"
​
func main() {
    fmt.Println("hello world")
}
JavaScript
Here is a sample earthfile of a JS app
# Earthfile
​
FROM node:13.10.1-alpine3.11
WORKDIR /js-example
​
build:
    # In JS, there's nothing to build in this simple form.
    # The source is also the artifact used in production.
    COPY index.js .
    SAVE ARTIFACT index.js /dist/index.js AS LOCAL ./dist/index.js
​
docker:
    COPY +build/dist dist
    ENTRYPOINT ["node", "./dist/index.js"]
    SAVE IMAGE js-example:latest
The code of the app might look like this
// index.js
​
console.log("hello world");
Java
Here is a sample earthfile of a Java app
# Earthfile
​
FROM openjdk:8-jdk-alpine
RUN apk add --update --no-cache gradle
WORKDIR /java-example
​
build:
    COPY build.gradle ./
    COPY src src
    RUN gradle build
    RUN gradle install
    SAVE ARTIFACT build/install/java-example/bin /bin AS LOCAL build/bin
    SAVE ARTIFACT build/install/java-example/lib /lib AS LOCAL build/lib
​
docker:
    COPY +build/bin bin
    COPY +build/lib lib
    ENTRYPOINT ["/java-example/bin/java-example"]
    SAVE IMAGE java-example:latest
The code of the app might look like this
// src/main/java/hello/HelloWorld.java
​
package hello;
​
public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("hello world");
    }
}
Python
Here is a sample earthfile of a Python app
# Earthfile
​
FROM python:3
WORKDIR /code
​
build:
     # In Python, there's nothing to build.
    COPY src src
    SAVE ARTIFACT src /src
​
docker:
    COPY +build/src src
    ENTRYPOINT ["python3", "./src/hello.py"]
    SAVE IMAGE python-example:latest
The code of the app might look like this
// src/hello.py
​
print("hello world")
You will notice that the recipes look very much like Dockerfiles. This is an intentional design decision. Existing Dockerfiles can be ported to earthfiles by copy-pasting them over and then tweaking them slightly. Compared to Dockerfile syntax, some commands are new (like SAVE ARTIFACT), others have additional semantics (like COPY +target/some-artifact) and other semantics have been removed (like FROM ... AS ... and COPY --from).
You might notice the command COPY +build/... ..., which has an unfamiliar form. This is a special type of COPY, which can be used to pass artifacts from one target to another. In this case, the target build (referenced as +build) produces an artifact, which has been declared with SAVE ARTIFACT, and the target docker copies that artifact in its build environment.
With Earthly you have the ability to pass such artifacts or images between targets within the same Earthfile, but also across different Earthfiles across directories or even across repositories. To read more about this, see the target, artifact and image referencing guide.
Target and artifact reference syntax
Continue tutorial
👉 Part 2: Executing a build​
🎓 Learn the basics
Part 2: Executing a build
Last updated 1 week ago