github.com/0xKiwi/rules_go@v0.24.3/go/tools/fetch_repo/main.go (about)

     1  // Command fetch_repo is similar to "go get -d" but it works even if the given
     2  // repository path is not a buildable Go package and it checks out a specific
     3  // revision rather than the latest revision.
     4  //
     5  // The difference between fetch_repo and "git clone" or {new_,}git_repository is
     6  // that fetch_repo recognizes import redirection of Go and it supports other
     7  // version control systems than git.
     8  //
     9  // These differences help us to manage external Go repositories in the manner of
    10  // Bazel.
    11  package main
    12  
    13  import (
    14  	"flag"
    15  	"fmt"
    16  	"log"
    17  
    18  	"golang.org/x/tools/go/vcs"
    19  )
    20  
    21  var (
    22  	remote     = flag.String("remote", "", "The URI of the remote repository. Must be used with the --vcs flag.")
    23  	cmd        = flag.String("vcs", "", "Version control system to use to fetch the repository. Should be one of: git,hg,svn,bzr. Must be used with the --remote flag.")
    24  	rev        = flag.String("rev", "", "target revision")
    25  	dest       = flag.String("dest", "", "destination directory")
    26  	importpath = flag.String("importpath", "", "Go importpath to the repository fetch")
    27  
    28  	// Used for overriding in tests to disable network calls.
    29  	repoRootForImportPath = vcs.RepoRootForImportPath
    30  )
    31  
    32  func getRepoRoot(remote, cmd, importpath string) (*vcs.RepoRoot, error) {
    33  	if (cmd == "") != (remote == "") {
    34  		return nil, fmt.Errorf("--remote should be used with the --vcs flag. If this is an import path, use --importpath instead.")
    35  	}
    36  
    37  	if cmd != "" && remote != "" {
    38  		v := vcs.ByCmd(cmd)
    39  		if v == nil {
    40  			return nil, fmt.Errorf("invalid VCS type: %s", cmd)
    41  		}
    42  		return &vcs.RepoRoot{
    43  			VCS:  v,
    44  			Repo: remote,
    45  			Root: importpath,
    46  		}, nil
    47  	}
    48  
    49  	// User did not give us complete information for VCS / Remote.
    50  	// Try to figure out the information from the import path.
    51  	r, err := repoRootForImportPath(importpath, true)
    52  	if err != nil {
    53  		return nil, err
    54  	}
    55  	if importpath != r.Root {
    56  		return nil, fmt.Errorf("not a root of a repository: %s", importpath)
    57  	}
    58  	return r, nil
    59  }
    60  
    61  func run() error {
    62  	r, err := getRepoRoot(*remote, *cmd, *importpath)
    63  	if err != nil {
    64  		return err
    65  	}
    66  	return r.VCS.CreateAtRev(*dest, r.Repo, *rev)
    67  }
    68  
    69  func main() {
    70  	flag.Parse()
    71  
    72  	if err := run(); err != nil {
    73  		log.Fatal(err)
    74  	}
    75  }