feat: cancel git clone ops gracefully

See #528

pkg/git/clone.go

@@ -1,7 +1,10 @@
 package git
 
 import (
+	"context"
+	"fmt"
 	"os"
+	"os/signal"
 	"strings"
 
 	"coopcloud.tech/abra/pkg/log"
@@ -22,46 +25,81 @@ func gitCloneIgnoreErr(err error) bool {
 	return false
 }
 
-// Clone runs a git clone which accounts for different default branches.
+// Clone runs a git clone which accounts for different default branches. This
+// function respects Ctrl+C (SIGINT) calls from the user, cancelling the
+// context and deleting the (typically) half-baked clone of the repository.
+// This avoids broken state for future clone / recipe ops.
 func Clone(dir, url string) error {
-	if _, err := os.Stat(dir); os.IsNotExist(err) {
-		log.Debugf("git clone: %s", url)
+	ctx := context.Background()
+	ctx, cancelCtx := context.WithCancel(ctx)
 
-		_, err := git.PlainClone(dir, false, &git.CloneOptions{
-			URL:           url,
-			Tags:          git.AllTags,
-			ReferenceName: plumbing.ReferenceName("refs/heads/main"),
-			SingleBranch:  true,
-		})
+	sigIntCh := make(chan os.Signal, 1)
+	signal.Notify(sigIntCh, os.Interrupt)
+	defer func() {
+		signal.Stop(sigIntCh)
+		cancelCtx()
+	}()
 
-		if err != nil && gitCloneIgnoreErr(err) {
-			log.Debugf("git clone: %s cloned successfully", dir)
-			return nil
-		}
+	errCh := make(chan error)
 
-		if err != nil {
-			log.Debug("git clone: main branch failed, attempting master branch")
+	go func() {
+		if _, err := os.Stat(dir); os.IsNotExist(err) {
+			log.Debugf("git clone: %s", url)
 
-			_, err := git.PlainClone(dir, false, &git.CloneOptions{
+			_, err := git.PlainCloneContext(ctx, dir, false, &git.CloneOptions{
 				URL:           url,
 				Tags:          git.AllTags,
-				ReferenceName: plumbing.ReferenceName("refs/heads/master"),
+				ReferenceName: plumbing.ReferenceName("refs/heads/main"),
 				SingleBranch:  true,
 			})
 
 			if err != nil && gitCloneIgnoreErr(err) {
 				log.Debugf("git clone: %s cloned successfully", dir)
-				return nil
+				errCh <- nil
+			}
+
+			if err := ctx.Err(); err != nil {
+				errCh <- fmt.Errorf("git clone %s: cancelled due to interrupt", dir)
 			}
 
 			if err != nil {
-				return err
+				log.Debug("git clone: main branch failed, attempting master branch")
+
+				_, err := git.PlainCloneContext(ctx, dir, false, &git.CloneOptions{
+					URL:           url,
+					Tags:          git.AllTags,
+					ReferenceName: plumbing.ReferenceName("refs/heads/master"),
+					SingleBranch:  true,
+				})
+
+				if err != nil && gitCloneIgnoreErr(err) {
+					log.Debugf("git clone: %s cloned successfully", dir)
+					errCh <- nil
+				}
+
+				if err != nil {
+					errCh <- err
+				}
 			}
+
+			log.Debugf("git clone: %s cloned successfully", dir)
+		} else {
+			log.Debugf("git clone: %s already exists", dir)
 		}
 
-		log.Debugf("git clone: %s cloned successfully", dir)
-	} else {
-		log.Debugf("git clone: %s already exists", dir)
+		errCh <- nil
+	}()
+
+	select {
+	case <-sigIntCh:
+		cancelCtx()
+		fmt.Println() // NOTE(d1): newline after ^C
+		if err := os.RemoveAll(dir); err != nil {
+			return fmt.Errorf("unable to clean up git clone of %s: %s", dir, err)
+		}
+		return fmt.Errorf("git clone %s: cancelled due to interrupt", dir)
+	case err := <-errCh:
+		return err
 	}
 
 	return nil