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GoTV

GoTV is an abbreviation of Go Toolchain Version. It is a tool used to manage and use multiple coexisting installations of official Go toolchain versions harmoniously and conveniently.

Project page: https://github.com/go101/gotv

Please follow @Go100and1 to get the latest news of GoTV (and all kinds of Go details/facts/tips/...).

Installation

Run

go install go101.org/gotv@latest

to install GoTV.

A 1.17+ toolchain version is needed to finish the installation. The toolchain version may be uninstalled after pinning a suitable toolchain version (see below).

Usage

Run gotv without any arguments to show help messages.

Most gotv commands are in the following format:

gotv ToolchainVersion [go-arguments...]

During running the first such a command, the Go git repository will be cloned (which needs several minutes to finish).

ToolchainVersion might be

Examples:

$ gotv 1.17. version
[Run]: $HOME/.cache/gotv/tag_go1.17.13/bin/go version
go version go1.17.13 linux/amd64

$ gotv 1.18.3 version
[Run]: $HOME/.cache/gotv/tag_go1.18.3/bin/go version
go version go1.18.3 linux/amd64

$ cat search.go
package main

import "fmt"

func demoFilter(n int) bool {
	return n & 1 == 0;
}

// Search values and return them without perverting order.
func search(start, end int)(r []int) {
	var count = 0
	for i, index := start, 0; i <= end; i++ {
		if demoFilter(i) {
			count++
			defer func(value int) {
				r[index] = value
				index++
			}(i)
		}
	}

	r = make([]int, count) // only allocate once
	return
}

func main() {
	fmt.Println(search(0, 9))
}

$ gotv 1.21. run search.go
[Run]: $HOME/.cache/gotv/tag_go1.21.7/bin/go run search.go
[8 6 4 2 0]
$ gotv 1.22. run search.go
[Run]: $HOME/.cache/gotv/tag_go1.22.1/bin/go run search.go
[0 0 0 0 0]

(The example code comes from this blog article. More uses of GoTV are demonstrated here.)

All gotv specific commands:

# sync the local Go git repository with remote
gotv fetch-versions

# list all versions seen locally
gotv list-versions

# build and cache some toolchain versions
gotv cache-version ToolchainVersion [ToolchainVersion ...]

# uncache some toolchain versions to save disk space
gotv uncache-version ToolchainVersion [ToolchainVersion ...]

# pin a specified toolchain version at a stable path
gotv pin-version ToolchainVersion

# unpin the current pinned toolchain version
gotv unpin-version

# set the default toolchain version (since v0.2.1)
gotv default-version ToolchainVersion

# check the default toolchain version (since v0.2.1)
gotv default-version

Pin a toolchain version

We can use the gotv pin-version command to pin a specific toolchain version to a stable path. After adding the stable path to the PATH environment veriable, we can use the official go command directly. And after doing these, the toolchain versions installed through ways other than GoTV may be safely uninstalled.

It is recommended to pin a 1.17+ version for bootstrap purpose now. The following example shows how to pin Go toolchain version 1.17.13:

$ gotv pin-version 1.17.
[Run]: cp -r $HOME/.cache/gotv/tag_go1.17.13 $HOME/.cache/gotv/pinned-toolchain

Please put the following shown pinned toolchain path in
your PATH environment variable to use go commands directly:

	/home/username/.cache/gotv/pinned-toolchain/bin

After the prompted path is added to the PATH environment variable, open a new terminal window:

$ go version
go version go1.17.13 linux/amd64

The command gotv pin-version .! will upgrade the pinned toolchain to the latest release version (which may be a beta or rc version).

Set a bootstrap toolchain version

To build a toolchain verision, another already built toolchain version is needed to be used in the building process. The other toolchain version is called the bootstrap version.

Some facts:

Currently, GoTV uses the toolchain set in the PATH environment variable as the bootstrap version by default. If GOROOT_BOOTSTRAP environment variable is set, then its value will be used.


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