Tool for managing go source code
An import path (see go-importpath(1)) denotes a package stored in the local file system. Certain import paths also describe how to obtain the source code for the package using a revision control system.
A few common code hosting sites have special syntax:
BitBucket (Mercurial)
import "bitbucket.org/user/project" import "bitbucket.org/user/project/sub/directory"
GitHub (Git)
import "github.com/user/project" import "github.com/user/project/sub/directory"
Google Code Project Hosting (Git, Mercurial, Subversion)
import "code.google.com/p/project" import "code.google.com/p/project/sub/directory"
import "code.google.com/p/project.subrepository" import "code.google.com/p/project.subrepository/sub/directory"
Launchpad (Bazaar)
import "launchpad.net/project" import "launchpad.net/project/series" import "launchpad.net/project/series/sub/directory"
import "launchpad.net/~user/project/branch" import "launchpad.net/~user/project/branch/sub/directory"
For code hosted on other servers, import paths may either be qualified with the version control type, or the go tool can dynamically fetch the import path over https/http and discover where the code resides from a <meta> tag in the HTML.
To declare the code location, an import path of the form
repository.vcs/path
specifies the given repository, with or without the .vcs suffix, using the named version control system, and then the path inside that repository. The supported version control systems are:
Bazaar
.bzr
Git
.git
Mercurial
.hg
Subversion
.svn
For example,
import "example.org/user/foo.hg"
denotes the root directory of the Mercurial repository at example.org/user/foo or foo.hg, and
import "example.org/repo.git/foo/bar"
denotes the foo/bar directory of the Git repository at example.com/repo or repo.git.
When a version control system supports multiple protocols, each is tried in turn when downloading. For example, a Git download tries git://, then https://, then http://.
If the import path is not a known code hosting site and also lacks a version control qualifier, the go tool attempts to fetch the import over https/http and looks for a <meta> tag in the document's HTML <head>.
The meta tag has the form:
<meta name="go-import" content="import-prefix vcs repo-root">
The import-prefix is the import path corresponding to the repository root. It must be a prefix or an exact match of the package being fetched with "go get". If it's not an exact match, another http request is made at the prefix to verify the <meta> tags match.
The vcs is one of "git", "hg", "svn", etc,
The repo-root is the root of the version control system containing a scheme and not containing a .vcs qualifier.
For example,
import "example.org/pkg/foo"
will result in the following request(s):
https://example.org/pkg/foo?go-get=1 (preferred) http://example.org/pkg/foo?go-get=1 (fallback)
If that page contains the meta tag
<meta name="go-import" content="example.org git https://code.org/r/p/exproj">
the go tool will verify that https://example.org/?go-get=1 contains the same meta tag and then git clone https://code.org/r/p/exproj into GOPATH/src/example.org.
New downloaded packages are written to the first directory listed in the GOPATH environment variable (see go-path(1)).
The go command attempts to download the version of the package appropriate for the Go release being used. See go-install(1) for more.
This manual page was written by Michael Stapelberg <[email protected]>, for the Debian project (and may be used by others).