Implement blackbox in Golang (#250)

* Initial release

pkg/vcs/git/git.go

@@ -0,0 +1,226 @@
+package git
+
+import (
+	"fmt"
+	"path/filepath"
+	"strings"
+
+	"github.com/StackExchange/blackbox/v2/pkg/bbutil"
+	"github.com/StackExchange/blackbox/v2/pkg/commitlater"
+	"github.com/StackExchange/blackbox/v2/pkg/makesafe"
+	"github.com/StackExchange/blackbox/v2/pkg/vcs"
+)
+
+var pluginName = "GIT"
+
+func init() {
+	vcs.Register(pluginName, 100, newGit)
+}
+
+// VcsHandle is the handle
+type VcsHandle struct {
+	commitTitle         string
+	commitHeaderPrinted bool              // Has the "NEXT STEPS" header been printed?
+	toCommit            *commitlater.List // List of future commits
+}
+
+func newGit() (vcs.Vcs, error) {
+	l := &commitlater.List{}
+	return &VcsHandle{toCommit: l}, nil
+}
+
+// Name returns my name.
+func (v VcsHandle) Name() string {
+	return pluginName
+}
+
+func ultimate(s string) int { return len(s) - 1 }
+
+// Discover returns true if we are a repo of this type; along with the Abs path to the repo root (or "" if we don't know).
+func (v VcsHandle) Discover() (bool, string) {
+	out, err := bbutil.RunBashOutputSilent("git", "rev-parse", "--show-toplevel")
+	if err != nil {
+		return false, ""
+	}
+	if out == "" {
+		fmt.Printf("WARNING: git rev-parse --show-toplevel has NO output??.  Seems broken.")
+		return false, ""
+	}
+	if out[ultimate(out)] == '\n' {
+		out = out[0:ultimate(out)]
+	}
+	return err == nil, out
+}
+
+// SetFileTypeUnix informs the VCS that files should maintain unix-style line endings.
+func (v VcsHandle) SetFileTypeUnix(repobasedir string, files ...string) error {
+	seen := make(map[string]bool)
+
+	// Add to the .gitattributes in the same directory as the file.
+	for _, file := range files {
+		d, n := filepath.Split(file)
+		af := filepath.Join(repobasedir, d, ".gitattributes")
+		err := bbutil.Touch(af)
+		if err != nil {
+			return err
+		}
+		err = bbutil.AddLinesToFile(af, fmt.Sprintf("%q text eol=lf", n))
+		if err != nil {
+			return err
+		}
+		seen[af] = true
+	}
+
+	var changedfiles []string
+	for k := range seen {
+		changedfiles = append(changedfiles, k)
+	}
+
+	v.NeedsCommit(
+		"set gitattr=UNIX "+strings.Join(makesafe.RedactMany(files), " "),
+		repobasedir,
+		changedfiles,
+	)
+
+	return nil
+}
+
+// IgnoreAnywhere tells the VCS to ignore these files anywhere rin the repo.
+func (v VcsHandle) IgnoreAnywhere(repobasedir string, files []string) error {
+	// Add to the .gitignore file in the repobasedir.
+	ignore := filepath.Join(repobasedir, ".gitignore")
+	err := bbutil.Touch(ignore)
+	if err != nil {
+		return err
+	}
+
+	err = bbutil.AddLinesToFile(ignore, files...)
+	if err != nil {
+		return err
+	}
+
+	v.NeedsCommit(
+		"gitignore "+strings.Join(makesafe.RedactMany(files), " "),
+		repobasedir,
+		[]string{".gitignore"},
+	)
+	return nil
+}
+
+func gitSafeFilename(name string) string {
+	// TODO(tlim): Add unit tests.
+	// TODO(tlim): Confirm that *?[] escaping works.
+	if name == "" {
+		return "ERROR"
+	}
+	var b strings.Builder
+	b.Grow(len(name) + 2)
+	for _, r := range name {
+		if r == ' ' || r == '*' || r == '?' || r == '[' || r == ']' {
+			b.WriteRune('\\')
+			b.WriteRune(r)
+		} else {
+			b.WriteRune(r)
+		}
+	}
+	if name[0] == '!' || name[0] == '#' {
+		return `\` + b.String()
+	}
+	return b.String()
+}
+
+// IgnoreFiles tells the VCS to ignore these files, specified relative to RepoBaseDir.
+func (v VcsHandle) IgnoreFiles(repobasedir string, files []string) error {
+
+	var lines []string
+	for _, f := range files {
+		lines = append(lines, "/"+gitSafeFilename(f))
+	}
+
+	// Add to the .gitignore file in the repobasedir.
+	ignore := filepath.Join(repobasedir, ".gitignore")
+	err := bbutil.Touch(ignore)
+	if err != nil {
+		return err
+	}
+	err = bbutil.AddLinesToFile(ignore, lines...)
+	if err != nil {
+		return err
+	}
+
+	v.NeedsCommit(
+		"gitignore "+strings.Join(makesafe.RedactMany(files), " "),
+		repobasedir,
+		[]string{".gitignore"},
+	)
+	return nil
+}
+
+// Add makes a file visible to the VCS (like "git add").
+func (v VcsHandle) Add(repobasedir string, files []string) error {
+
+	if len(files) == 0 {
+		return nil
+	}
+
+	// TODO(tlim): Make sure that files are within repobasedir.
+
+	var gpgnames []string
+	for _, n := range files {
+		gpgnames = append(gpgnames, n+".gpg")
+	}
+	return bbutil.RunBash("git", append([]string{"add"}, gpgnames...)...)
+}
+
+// CommitTitle indicates what the next commit title will be.
+// This is used if a group of commits are merged into one.
+func (v *VcsHandle) CommitTitle(title string) {
+	v.commitTitle = title
+}
+
+// NeedsCommit queues up commits for later execution.
+func (v *VcsHandle) NeedsCommit(message string, repobasedir string, names []string) {
+	v.toCommit.Add(message, repobasedir, names)
+}
+
+// DebugCommits dumps the list of future commits.
+func (v VcsHandle) DebugCommits() commitlater.List {
+	return *v.toCommit
+}
+
+// FlushCommits informs the VCS to do queued up commits.
+func (v VcsHandle) FlushCommits() error {
+	return v.toCommit.Flush(
+		v.commitTitle,
+		func(files []string) error {
+			return bbutil.RunBash("git", append([]string{"add"}, files...)...)
+		},
+		v.suggestCommit,
+	)
+	// TODO(tlim): Some day we can add a command line flag that indicates that commits are
+	// to be done for real, not just suggested to the user.  At that point, this function
+	// can call v.toCommit.Flush() with a function that actually does the commits instead
+	// of suggesting them.  Flag could be called --commit=auto vs --commit=suggest.
+}
+
+// suggestCommit tells the user what commits are needed.
+func (v *VcsHandle) suggestCommit(messages []string, repobasedir string, files []string) error {
+	if !v.commitHeaderPrinted {
+		fmt.Printf("NEXT STEP: You need to manually check these in:\n")
+	}
+	v.commitHeaderPrinted = true
+
+	fmt.Print(`     git commit -m'`, strings.Join(messages, `' -m'`)+`'`)
+	fmt.Print(" ")
+	fmt.Print(strings.Join(makesafe.ShellMany(files), " "))
+	fmt.Println()
+	return nil
+}
+
+// The following are "secret" functions only used by the integration testing system.
+
+// TestingInitRepo initializes a repo.
+func (v VcsHandle) TestingInitRepo() error {
+	return bbutil.RunBash("git", "init")
+
+}