lib/git: new package that wrap common git commands and parse git config

List of current git commands that are wrapped,

- Setting HEAD to specific revision: "git checkout <revision>"
- Cloning repository: "git clone <remoteURL>"
- Fetch all changes from remote: "git fetch --all"
- Get tag on revision: "git describe --tags --exact-match <revision>"
- Get latest commit: "git rev-parse --short <ref>"
- Get latest tag
- Get latest version (combination of get latest commit and tag)
- Log revisions: "git --no-pager log --oneline"

1 files changed, 364 insertions, 0 deletions

diff --git a/lib/git/git.go b/lib/git/git.go
new file mode 100644
index 00000000..9e8af25d
--- /dev/null
+++ b/lib/git/git.go
@@ -0,0 +1,364 @@
+// Copyright 2018, Shulhan <ms@kilabit.info>. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package git provide a wrapper for git comman line interface.
+package git
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+
+	"github.com/shuLhan/share/lib/ini"
+)
+
+const (
+	_defRemoteName = "origin"
+	_defRef        = "origin/master"
+	_defBranch     = "master"
+)
+
+var (
+	_debug  int
+	_stdout = os.Stdout
+	_stderr = os.Stderr
+)
+
+//
+// CheckoutRevision will set the HEAD to specific revision on specific branch.
+// Any untracked files and directories will be removed before checking out
+// existing branch or creating new branch.
+// If ref is empty, it will use default reference "origin/master".
+// If branch is empty, it will use default branch "master".
+// If revision is empty, it will do nothing.
+//
+func CheckoutRevision(repoDir, ref, branch, revision string) error {
+	if len(revision) == 0 {
+		return nil
+	}
+
+	cmd := exec.Command("git")
+	cmd.Args = append(cmd.Args, "clean", "-qdff")
+	cmd.Dir = repoDir
+	cmd.Stdout = _stdout
+	cmd.Stderr = _stderr
+	if _debug >= 1 {
+		fmt.Printf("= CheckoutRevision %s %s\n", cmd.Dir, cmd.Args)
+	}
+	err := cmd.Run()
+	if err != nil {
+		err = fmt.Errorf("CheckoutRevision: %s", err)
+		return err
+	}
+
+	err = FetchAll(repoDir)
+	if err != nil {
+		err = fmt.Errorf("CheckoutRevision: %s", err)
+		return err
+	}
+
+	cmd = exec.Command("git")
+	cmd.Dir = repoDir
+	cmd.Stdout = _stdout
+	cmd.Stderr = _stderr
+
+	if len(ref) == 0 {
+		ref = _defRef
+	}
+	cmd.Args = append(cmd.Args, "checkout", "--quiet", "--track", ref)
+
+	if len(branch) == 0 {
+		branch = _defBranch
+	}
+	cmd.Args = append(cmd.Args, "-B", branch)
+
+	if _debug >= 1 {
+		fmt.Printf("= CheckoutRevision %s %s\n", cmd.Dir, cmd.Args)
+	}
+	err = cmd.Run()
+	if err != nil {
+		err = fmt.Errorf("CheckoutRevision: %s", err)
+		return err
+	}
+
+	cmd = exec.Command("git")
+	cmd.Dir = repoDir
+	cmd.Stdout = _stdout
+	cmd.Stderr = _stderr
+
+	cmd.Args = append(cmd.Args, "reset", "--quiet", "--hard", revision)
+	if _debug >= 1 {
+		fmt.Printf("= CheckoutRevision %s %s\n", cmd.Dir, cmd.Args)
+	}
+	err = cmd.Run()
+	if err != nil {
+		err = fmt.Errorf("CheckoutRevision: %s", err)
+	}
+
+	return err
+}
+
+//
+// Clone the repository into destination directory.
+//
+// If destination directory is not empty it will return an error.
+//
+func Clone(remoteURL, dest string) (err error) {
+	err = os.MkdirAll(dest, 0700)
+	if err != nil {
+		err = fmt.Errorf("Clone: %s", err)
+		return
+	}
+
+	cmd := exec.Command("git")
+	cmd.Args = append(cmd.Args, "clone", "--quiet", remoteURL, ".")
+	cmd.Dir = dest
+	cmd.Stdout = _stdout
+	cmd.Stderr = _stderr
+
+	if _debug >= 1 {
+		fmt.Printf("= Clone %s %s %s\n", remoteURL, cmd.Dir, cmd.Args)
+	}
+
+	err = cmd.Run()
+	if err != nil {
+		err = fmt.Errorf("Clone: %s", err)
+	}
+
+	return
+}
+
+//
+// FetchAll will fetch the latest commits from remote.
+//
+func FetchAll(repoDir string) error {
+	cmd := exec.Command("git")
+	cmd.Args = append(cmd.Args, "fetch", "--quiet", "--all")
+	cmd.Dir = repoDir
+	cmd.Stdout = _stdout
+	cmd.Stderr = _stderr
+
+	if _debug >= 1 {
+		fmt.Printf("= FetchAll %s %s\n", cmd.Dir, cmd.Args)
+	}
+
+	err := cmd.Run()
+	if err != nil {
+		err = fmt.Errorf("FetchAll: %s", err)
+	}
+
+	return err
+}
+
+//
+// GetRemoteURL return remote URL or error if repository is not git or url is
+// empty.
+// If remoteName is empty, it will be set to default ("origin").
+//
+func GetRemoteURL(repoDir, remoteName string) (url string, err error) {
+	if len(remoteName) == 0 {
+		remoteName = _defRemoteName
+	}
+
+	gitConfig := filepath.Join(repoDir, ".git", "config")
+
+	gitIni, err := ini.Open(gitConfig)
+	if err != nil {
+		err = fmt.Errorf("GetRemote: %s", err)
+		return
+	}
+
+	url, ok := gitIni.Get("remote", remoteName, "url")
+	if !ok {
+		err = fmt.Errorf("GetRemote: Empty or invalid remote name")
+	}
+
+	return
+}
+
+//
+// GetTag get the tag from revision.  If revision is empty it's default to
+// "HEAD".
+//
+func GetTag(repoDir, revision string) (tag string, err error) {
+	if len(revision) == 0 {
+		revision = "HEAD"
+	}
+
+	cmd := exec.Command("git")
+	cmd.Args = append(cmd.Args, "describe", "--tags", "--exact-match", revision)
+	cmd.Dir = repoDir
+	cmd.Stderr = _stderr
+
+	if _debug >= 1 {
+		fmt.Printf("GetTag %s %s\n", cmd.Dir, cmd.Args)
+	}
+
+	btag, err := cmd.Output()
+	if err != nil {
+		err = fmt.Errorf("GetTag: %s", err)
+		return
+	}
+
+	tag = string(bytes.TrimSpace(btag))
+
+	return
+}
+
+//
+// LatestCommit get the latest commit hash in short format from "ref".
+// If ref is empty, its default to "origin/master".
+//
+func LatestCommit(repoDir, ref string) (commit string, err error) {
+	if len(ref) == 0 {
+		ref = _defRef
+	}
+
+	cmd := exec.Command("git")
+	cmd.Args = append(cmd.Args, "rev-parse", "--short", ref)
+	cmd.Dir = repoDir
+	cmd.Stderr = _stderr
+
+	if _debug >= 1 {
+		fmt.Printf("LatestCommit %s %s\n", cmd.Dir, cmd.Args)
+	}
+
+	bcommit, err := cmd.Output()
+	if err != nil {
+		err = fmt.Errorf("LatestCommit: %s", err)
+		return
+	}
+
+	commit = string(bytes.TrimSpace(bcommit))
+
+	return
+}
+
+//
+// LatestTag get latest tag.
+//
+func LatestTag(repoDir string) (tag string, err error) {
+	cmd := exec.Command("git")
+	cmd.Args = append(cmd.Args, "rev-list", "--tags", "--max-count=1")
+	cmd.Dir = repoDir
+	cmd.Stderr = _stderr
+
+	if _debug >= 1 {
+		fmt.Printf("= LatestTag %s %s\n", cmd.Dir, cmd.Args)
+	}
+
+	bout, err := cmd.Output()
+	if err != nil {
+		err = fmt.Errorf("LatestTag: %s", err)
+		return
+	}
+
+	out := string(bytes.TrimSpace(bout))
+
+	cmd = exec.Command("git")
+	cmd.Args = append(cmd.Args, "describe", "--tags", "--abbrev=0", out)
+	cmd.Dir = repoDir
+	cmd.Stderr = _stderr
+
+	if _debug >= 1 {
+		fmt.Printf("= LatestTag %s %s\n", cmd.Dir, cmd.Args)
+	}
+
+	bout, err = cmd.Output()
+	if err != nil {
+		err = fmt.Errorf("LatestTag: %s", err)
+		return
+	}
+
+	tag = string(bytes.TrimSpace(bout))
+
+	return
+}
+
+//
+// LatestVersion will try to get latest tag from repository.
+// If it's fail get the latest commit hash.
+//
+func LatestVersion(repoDir string) (version string, err error) {
+	version, err = LatestTag(repoDir)
+	if err == nil {
+		return
+	}
+
+	version, err = LatestCommit(repoDir, "")
+	if err == nil {
+		return
+	}
+
+	err = fmt.Errorf("GetVersion: %s", err)
+	return
+}
+
+//
+// LogRevisions get commits between two revisions.
+//
+func LogRevisions(repoDir, prevRevision, nextRevision string) error {
+	cmd := exec.Command("git")
+	cmd.Args = append(cmd.Args, "--no-pager", "log", "--oneline",
+		prevRevision+"..."+nextRevision)
+	cmd.Dir = repoDir
+	cmd.Stdout = _stdout
+	cmd.Stderr = _stderr
+
+	if _debug >= 1 {
+		fmt.Printf("= CompareRevisions %s %s\n", cmd.Dir, cmd.Args)
+	}
+
+	err := cmd.Run()
+	if err != nil {
+		err = fmt.Errorf("CompareRevisions: %s", err)
+	}
+
+	return err
+}
+
+//
+// RemoteChange change current repository remote name (e.g. "origin") to new
+// remote name and URL.
+//
+func RemoteChange(repoDir, oldName, newName, newURL string) error {
+	if len(repoDir) == 0 {
+		return nil
+	}
+
+	cmd := exec.Command("git")
+	cmd.Args = append(cmd.Args, "remote", "remove", oldName)
+	cmd.Dir = repoDir
+	cmd.Stdout = _stdout
+	cmd.Stderr = _stderr
+
+	if _debug >= 1 {
+		fmt.Printf("= RemoteChange %s %s\n", cmd.Dir, cmd.Args)
+	}
+
+	err := cmd.Run()
+	if err != nil {
+		err = fmt.Errorf("RemoteChange: %s", err)
+		return err
+	}
+
+	cmd = exec.Command("git")
+	cmd.Args = append(cmd.Args, "remote", "add", newName, newURL)
+	cmd.Dir = repoDir
+	cmd.Stdout = _stdout
+	cmd.Stderr = _stderr
+
+	if _debug >= 1 {
+		fmt.Printf("= RemoteChange %s %s\n", cmd.Dir, cmd.Args)
+	}
+
+	err = cmd.Run()
+	if err != nil {
+		err = fmt.Errorf("RemoteChange: %s", err)
+	}
+
+	return err
+}