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What Is the Go Workspace Mode
Yuki Ito (@mrno110)
Go 1.18 Release Party
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Merpay / Mercoin
Architect
Mercari
Microservices Platform CI/CD
Yuki Ito
@mrno110
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Disclaimer
$ go version
go version go1.18rc1 linux/amd64
As of this writing...
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Agenda
ɾBackground
ɾWorkspace Mode
ɾUse cases
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Background
ɾgithub.com/110y/gwdemo1
ɾgithub.com/110y/gwdemo2
ɾgithub.com/110y/gwdemo3
Let's assume we develop 3 modules
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Background
gwdemo3
gwdemo2
gwdemo1
Let's assume we develop 3 modules
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Background
gwdemo3
package gwdemo3
import "fmt"
func Hello(s string) string {
return fmt.Sprintf("Hello, %s!", s)
}
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Background
gwdemo1 gwdemo2
package main
import (
"fmt"
"github.com/110y/gwdemo3"
)
func main() {
fmt.Println(gwdemo3.Hello("Workspace"))
}
package main
import (
"fmt"
"github.com/110y/gwdemo3"
)
func main() {
fmt.Println(gwdemo3.Hello("Generics"))
}
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Background
When we add a new feature to gwdemo3...
package gwdemo3
import "fmt"
func Hello(s string) string {
return fmt.Sprintf("Hello, %s!", s)
}
func Bye(s string) string {
return fmt.Sprintf("Bye, %s!", s)
}
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Background
And want to use it on gwdemo1 and gwdemo2 locally...
package main
import (
"fmt"
"github.com/110y/gwdemo3"
)
func main() {
fmt.Println(gwdemo3.Hello("Workspace"))
fmt.Println(gwdemo3.Bye("Workspace"))
}
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Background
We have to add a replace directive to the go.mod
fi
le
module github.com/110y/gwdemo1
go 1.18
require github.com/110y/gwdemo3 v0.0.0-20220218011518-502c64a9beed
replace github.com/110y/gwdemo3 => ../gwdemo3
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Background
Problem
ɾHave to add replace directive to each module's go.mod
fi
le.
ɾHave to remove replace directive before submitting the code.
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Background
But working with the replace directive can
often be awkward: each module
developer might have working versions at
di
ff
erent location on disk, so having the
directive in a
fi
le that needs to be
distributed with the module isn't a good
fi
t for all use cases.
https://go.googlesource.com/proposal/+/master/design/45713-workspace.md
Proposal: Multi-Module Workspaces in cmd/go
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Agenda
ɾBackground
ɾWorkspace Mode
ɾUse cases
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Workspace Mode
gwdemo3
gwdemo2
gwdemo1
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Workspace Mode
Workspace
gwdemo3
gwdemo2
gwdemo1
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Workspace Mode
$ mkdir gwdemo-workspace
$ cd gwdemo-workspace
$ git clone https://github.com/110y/gwdemo1.git
$ git clone https://github.com/110y/gwdemo2.git
$ git clone https://github.com/110y/gwdemo3.git
Workspace
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Workspace Mode
Workspace
$ go work init ./gwdemo1 ./gwdemo2 ./gwdemo3
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Workspace Mode
go work init creates go.work
fi
le
go 1.18
use (
./gwdemo1
./gwdemo2
./gwdemo3
)
go.work
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Workspace Mode
$ tree .
.
├── go.work
├── gwdemo1
│ ├── go.mod
│ ├── go.sum
│ └── main.go
├── gwdemo2
│ ├── go.mod
│ ├── go.sum
│ └── main.go
└── gwdemo3
├── go.mod
└── gwdemo3.go
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Workspace Mode
$ cd gwdemo1
$ go env GOWORK
/path/to/gwdemo-workspace/go.work
Workspace
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Workspace Mode
$ go help work
...
To determine whether the go command is operating
in workspace mode, use the "go env GOWORK"
command. This will specify the workspace file
being used.
...
Workspace
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Workspace Mode
package gwdemo3
import "fmt"
func Hello(s string) string {
return fmt.Sprintf("Hello, %s!", s)
}
func Bye(s string) string {
return fmt.Sprintf("Bye, %s!", s)
}
gwdemo3
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Workspace Mode
package main
import (
"fmt"
"github.com/110y/gwdemo3"
)
func main() {
fmt.Println(gwdemo3.Hello("Workspace"))
fmt.Println(gwdemo3.Bye("Workspace"))
}
gwdemo1
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Workspace Mode
$ cd gwdemo1
$ go env GOWORK
/path/to/gwdemo-workspace/go.work
$ go run .
Hello, Workspace!
Bye, Workspace!
Workspace
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Problem
✅ Have to add replace directive to each module's go.mod
fi
le.
✅ Have to remove replace directive before submitting the code.
Workspace Mode
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Workspace Mode
$ cd gwdemo1
$ go env GOWORK
/path/to/gwdemo-workspace/go.work
$ GOWORK=off go run .
# github.com/110y/gwdemo1
./main.go:12:22: undefined: gwdemo3.Bye
Check the actual behavior with GOWORK=o
f
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Workspace Mode
-work
fi
le
fl
ag...?
https://go-review.googlesource.com/c/go/+/385995/
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Agenda
ɾBackground
ɾWorkspace Mode
ɾUse cases
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Use cases
Microservice Chassis Pattern
https://microservices.io/patterns/microservice-chassis.html
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Use cases
chassis
application
template
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Use cases
chassis
application
template
Workspace
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Use cases
Multi Modules Monorepo
├── cmd
│ ├── app1
│ │ ├── go.mod
│ │ └── main.go
│ ├── app2
│ │ ├── go.mod
│ │ └── main.go
│ └── app3
│ ├── go.mod
│ └── main.go
├── go.work
└── pkg
├── echo
│ ├── echo.go
│ └── go.mod
└── hello
├── go.mod
└── hello.go
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Workspace Mode
Workspace
gwdemo3
gwdemo2
gwdemo1