Frequently Used Predefined Environment Variables in Go

Go has some predefined environment variables that are frequently used and should be taken into account, as they will be useful in our projects. For example, GOOS will give us the operating system we are on.

More used

• GOROOT: – Location of the Go SDK (fixed).
• GOPATH: – Root directory of your Go workspace (customizable).
• CGO_ENABLED: – Controls Go’s integration with C code (1 to enable, 0 to disable).
• GO111MODULE: – Controls the mode of using Go modules (auto, on, off).
• GOOS: – Operating system
• GOARCH: – Architecture

Less frequently used:

• GOPROXY and GOSUMDB: Important for dependency management in restricted networks and to ensure module integrity.
• GOCACHE: Beneficial for improving compilation times in large projects.
• GOTMPDIR and GOMODCACHE: Useful in advanced development configurations.

Next, we will delve deeper into these variables.

GOROOT

The location where Go is installed is set by default unless you use a binary distribution.

You can always know the value of GOROOT with the following command:

go env GOROOT

set GOROOT=C:\path\to\your\goroot

setx GOROOT=C:\path\to\your\goroot

export GOROOT=C:\path\to\your\goroot

#add the following line
export GOROOT=C:\path\to\your\goroot

source .bashrc

GOPATH (en des-uso)

Root directory of your Go workspace, it has currently been replaced by modules, but you might still need it.

You can get the value of GOPATH with the following command:

go env GOPATH

set GOPATH=C:\path\to\your\gopath

setx GOPATH=C:\path\to\your\gopath

export GOPATH=C:\path\to\your\gopath

#add the following line
export GOPATH=C:\path\to\your\gopath

source .bashrc

CGO_ENABLED

Controls the integration of Go with C code. In other words, this variable enables the use of C code in Go.

It can have two values: 1 or 0. To use C, it must be set to 1. It is recommended to keep it set to 1 permanently (default).

go env CGO_ENABLED

set CGO_ENABLED=1

setx CGO_ENABLED=1

export CGO_ENABLED=1

# add this line to your bashrc
export CGO_ENABLED=1

source .bashrc

GO111MODULE

GO111MODULE indicates whether modules are enabled or not; if not, Go will use GOPATH. The GO111MODULE variable has three possible values: on, off, and auto.

If set to auto, it will check if a go.mod file exists; if not, it will use GOPATH.

go env GO111MODULE

set GO111MODULE=on

setx GO111MODULE=on

export GO111MODULE=on

# add this line to your bashrc
export GO111MODULE="on"

source .bashrc

GOOS and GOARCH

You can always check your architecture with GOARCH and your OS with GOOS. Obviously, this is not a value you can change.

go env GOOS
go env GOARCH

You can detect the user’s OS who is using your program with runtime.

if runtime.GOOS == "windows" {
    fmt.Println("Estas usando windows")
}

GOCACHE

The Go cache command creates outputs for reuse in future builds. By default, Go uses a sub-folder named ‘go-build’ in the system user’s cache folder (OS).

The GOCACHE variable allows us to specify another location for this data.

go env GOCACHE

GOMODCACHE

The GOMODCACHE variable specifies where the module cache will be stored; the default path is $GOPATH/pkg/mod.

go env GOMODCACHE

GOTMPDIR

If the GOTMPDIR variable is defined, temporary files will be created in that directory.

Otherwise, they will be created in the OS’s temporary files.

go env GOTMPDIR

GOSUMDB

The GOSUMDB environment variable in Go is used to specify the checksum database that the Go toolchain should use to verify the integrity of modules.

It checks the checksums of modules that are not yet listed in go.sum.

There may be occasions where the proxy and checksum cannot be reached. In this case, it is recommended to disable it using the following configuration.

go env -w GOPROXY=direct
go env -w GOSUMDB=off

You can see the path of GOSUMDB with:

go env GOSUMDB

GOPROXY

In general, this is a variable we shouldn’t change, except in some cases when necessary.

Default value: https://proxy.golang.org,direct

go env GOPROXY