multirepo

Multirepo example

In this example, we will walk through a simple multirepo setup that can be used with Earthly. The entire code of this exercise is available in the

• This directory
• This referenced project of HTML static files
• This referenced project of JS files

In this example, let's assume that we have a web application where HTML files are held in one repository and JS file are held in another. The complete application is a combination of both.

As such, each repository might have its self-contained Earthfile, specific to the programming language and setup of the repository. A third, main, repository might want to tie everything together in a complete web application.

Run

To run this build execute

earthly +docker

in this directory, or, without cloning the Earthly repo, run this anywhere

earthly github.com/earthly/earthly/examples/multirepo:main+docker

Then, run the resulting container:

docker run --rm -p 127.0.0.1:8080:8080 earthly/examples:multirepo

and load http://127.0.0.1:8080 in your browser.

Explanation

Notice how the build is able to reference other repositories and copy artifacts from specific build targets. For example, the line

COPY github.com/earthly/earthly-example-multirepo-static+html/* ./

references the html target of the repository github.com/earthly/earthly-example-multirepo-static and copies all its artifacts in the current build environment. Earthly takes care of cloning that repository, executing its build for the html target and extracting the artifacts to be used here.

This command is also cache-aware. If the HEAD of the repository points to a different Git hash, Earthly knows to re-clone and build the repository again, using as much cache as relevant, depending on which files have changed.

You can also specify a specific tag or branch of the remote repository, to help keep builds consistent and avoid surprising changes. For that, you can use the syntax

COPY github.com/earthly/earthly-example-multirepo-static:v0.1.1+html/* ./

where v0.1.1 is a tag or branch specifier.

Compare

Compare this example with the example presented in monorepo.