In this article I will describe how to set up your own Bazel repository. Using the bzlmod the new external dependency system introduced in Bazel 5+.
Also I will add a GO hello world project to show how could you add other projects to the monorepo.
Let's start
The first thing you need to do is create a new directory. I will call it bazel-intro.
Inside the bazel-intro directory create a MODULE.bazel and a BUILD file:
- MODULE.bazel: According to the official docs The MODULE.bazel file should be located at the root of the workspace directory (next to the WORKSPACE file). Unlike with the WORKSPACE file, you donβt need to specify your transitive dependencies; instead, you should only specify direct dependencies, and the MODULE.bazel files of your dependencies will be processed to discover transitive dependencies automatically. We are not going to add the WORKSPACE file.
Folder structure:
- bazel-intro
- MODULE.bazel
- BUILD
Fill MODULE.bazel file
Since we are going to use GO, we need to add this lines to our MODULE.bazel file:
bazel_dep(name = "gazelle", version = "0.37.0")
bazel_dep(name = "rules_go", version = "0.48.1")
The gazelle "dependency" enables us to use gazelle, which is a build file generator that helps us to create/update BUILDS files for every project inside our monorepo. And rules_go enables us to build GO code in bazel. You can find the more recent versions here.
According to the rules_go and gazelle docs you need to add to your MODULE.bazel file:
GO extensions
go_sdk = use_extension("@rules_go//go:extensions.bzl", "go_sdk")
# Download an SDK for the host OS & architecture as well as common remote execution platforms.
go_sdk.download(version = "1.20.3")
Gazelle
go_deps = use_extension("@gazelle//:extensions.bzl", "go_deps")
go_deps.from_file(go_mod = "//:go.mod")
use_repo(go_deps,
"com_github_gofiber_fiber_v2",
)
In the last line you may see that we add to the rule use_repo:
- com_github_gofiber_fiber_v2: I add this dependency here because we will setup a Fiber http server later (our GO project).
Important: If you need to add more dependecies you could do it here. For example:
Adding more deps example:
Lets say we want to add com_github_joho_godotenv to our project
use_repo(go_deps,
"com_github_gofiber_fiber_v2",
"com_github_joho_godotenv"
)
Filling BUILD file
Remember the build file we create at the begining? We are going to populate it with the next lines of code. In your top-level BUILD file add:
load("@gazelle//:def.bzl", "gazelle")
gazelle(name = "gazelle")
This will add gazelle.
Creating a project
Folder structure:
- bazel-intro
- services
- app
- main.go
- app
- MODULE.bazel
- BUILD
- services
Create a project is simple.
- Create a directory called services.
- Inside services folder create a folder called app.
- Inside app folder create a main.go file.
- Add the next code to your main.go file:
package main
import (
"log"
"github.com/gofiber/fiber/v2"
)
func main() {
app := fiber.New()
app.Get("/", func (c *fiber.Ctx) error {
return c.SendString("Hello, World!")
})
log.Fatal(app.Listen(":3000"))
}
Creating go.mod and go.sum
In your terminal type go mod init something
:
For example:
go mod init bazel-intro/services
and then go mod tidy
.
Let's gazelle and build :)
Run in your terminal:
bazel run //:gazelle
then
bazel build //...
and finally
bazel run services/app
And that is all! ππ
You should see the fiber http server running
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