go 模块安装 go 工具

Question

I'm using go modules as dependency management, and I'm having problem to install something like this:

go get -u github.com/go-critic/go-critic/...

the result from above was:

go: cannot find main module; see 'go help modules'

Answer 1

Several of the other answers here have grown stale at this point.

There are at least two cases to consider:

Case 1

You want to install a tool, but you don't want to modify your current go.mod to track that tool as a dependency.

In short, with Go 1.12 or 1.13, the simplest solution is to cd to a directory without a go.mod , such as:

$ cd /tmp
$ go get github.com/some/tool@v1.0.1

Alternatively, gobin is a module-aware command to install or run binaries that provides additional flexibility, including the ability to install without altering your current module's go.mod

See this related answer for more details, including a solution for Go 1.11, as well as the likely new option in Go 1.14 for getting a tool without it updating your go.mod .

Case 2

On the other hand, if you want to explicitly track a tool as a versioned dependency in your go.mod , then see the "How can I track tool dependencies for a module?" FAQ on the modules wiki.

In short, you create a tools.go file in a separate package, and set a // +build tools build tag, such as:

// +build tools

package tools

import (
    _ "golang.org/x/tools/cmd/stringer"
)

The import statements allow the go command to precisely record the version information for your tools in your module's go.mod , while the // +build tools build constraint prevents your normal builds from actually importing your tools.

Answer 2

Edit: The original answer herein referred specifically to the state of the tooling in Go 1.11. Since the release of Go 1.12, this is no longer accurate. Please see this answer , and the ones it links to, for details of handling this situation in Go 1.12 and later.

If the GO111MODULE var is set to on , you have to be inside an initialized go module directory tree in order to use go get , even if you're trying to get a tool rather than a new dependency . This is a known and heavily debated issue:

https://github.com/golang/go/issues/27643

https://github.com/golang/go/issues/24250

https://github.com/golang/go/issues/25922

The solution, short term, is to run GO111MODULE=off go get <tool> . This explicitly disables the module support, even if you're in a module package currently, and forces it to only utilize your GOPATH.

Long-term, figuring out what the best solution is to support tool install via go get (or another command, like go install with a flag) is an ongoing area of discussion with little in the way of established consensus as of yet. However, there's a PR open for Go 1.12 that, if accepted, will allow go get to simply work while outside a module, even with GO111MODULE=on set.

Answer 3

With Go 1.12 (February 2019), GO111MODULE=on go get will work.
(From issue 24250 )

Modules

When GO111MODULE is set to on , the go command now supports module-aware operations outside of a module directory, provided that those operations do not need to resolve import paths relative to the current directory or explicitly edit the go.mod file.
Commands such as go get , go list , and go mod download behave as if in a module with initially-empty requirements.
In this mode, go env GOMOD reports the system's null device ( /dev/null or NUL ).

Answer 4

I faced the same issue and resolved it by the below command.

$ go env -w GO111MODULE=auto

Answer 5

试试这个命令GO111MODULE=on go get -u github.com/go-critic/go-critic/...

Answer 6

Just had the same issue on go1.11.2. Tried to set GO111MODULE=on , but this couldn't fix it.

My solution:

1. Upgrade to use go 1.12.5: https://golang.org/doc/install?download=go1.12.5.linux-amd64.tar.gz

   This can resolve go: cannot find main module; see 'go help modules' go: cannot find main module; see 'go help modules' issue.

2. Then I got another issue go: cannot use path@version syntax in GOPATH mode ,

   which can be resolved setting env GO111MODULE=on

Answer 7

I had the same problem and it was "almost" solved directly. At first it did not work. This was because the module was already initialized and I had run the "go get..." command before I had set GO111MODULE=on.

To get it working I removed "go.mod" reinitialized the mod by running "go mod init ..." and re run the necessary "go get ...." commands.