From 01b2f455d99bafd9e27d1d3a520a7031d82831de Mon Sep 17 00:00:00 2001
From: oppiliappan <me@oppi.li>
Date: Thu, 4 Dec 2025 17:56:46 +0000
Subject: [PATCH] knotserver: use local clones if repo is hosted on the same
 knot
Change-Id: mozkrnmzvkruwlvwxsmwwqvxkswsyuww

detect the host to clone from and use a local clone if possible.

Signed-off-by: oppiliappan <me@oppi.li>
---
 knotserver/git/fork.go         | 40 ++++++++++++++++++++++++++++++++--
 knotserver/xrpc/create_repo.go |  2 +-
 2 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/knotserver/git/fork.go b/knotserver/git/fork.go
index 1ed9b5e8..5093de8f 100644
--- a/knotserver/git/fork.go
+++ b/knotserver/git/fork.go
@@ -3,14 +3,27 @@ package git
 import (
 	"errors"
 	"fmt"
+	"log/slog"
+	"net/url"
 	"os/exec"
+	"path/filepath"
 
 	"github.com/go-git/go-git/v5"
 	"github.com/go-git/go-git/v5/config"
+	knotconfig "tangled.org/core/knotserver/config"
 )
 
-func Fork(repoPath, source string) error {
-	cloneCmd := exec.Command("git", "clone", "--bare", source, repoPath)
+func Fork(repoPath, source string, cfg *knotconfig.Config) error {
+	u, err := url.Parse(source)
+	if err != nil {
+		return fmt.Errorf("failed to parse source URL: %w", err)
+	}
+
+	if o := optimizeClone(u, cfg); o != nil {
+		u = o
+	}
+
+	cloneCmd := exec.Command("git", "clone", "--bare", u.String(), repoPath)
 	if err := cloneCmd.Run(); err != nil {
 		return fmt.Errorf("failed to bare clone repository: %w", err)
 	}
@@ -23,6 +36,29 @@ func Fork(repoPath, source string) error {
 	return nil
 }
 
+func optimizeClone(u *url.URL, cfg *knotconfig.Config) *url.URL {
+	// only optimize if it's the same host
+	if u.Host != cfg.Server.Hostname {
+		return nil
+	}
+
+	local := filepath.Join(cfg.Repo.ScanPath, u.Path)
+
+	// sanity check: is there a git repo there?
+	if _, err := PlainOpen(local); err != nil {
+		return nil
+	}
+
+	// create optimized file:// URL
+	optimized := &url.URL{
+		Scheme: "file",
+		Path:   local,
+	}
+
+	slog.Debug("performing local clone", "url", optimized.String())
+	return optimized
+}
+
 func (g *GitRepo) Sync() error {
 	branch := g.h.String()
 
diff --git a/knotserver/xrpc/create_repo.go b/knotserver/xrpc/create_repo.go
index b35c72bd..d0654336 100644
--- a/knotserver/xrpc/create_repo.go
+++ b/knotserver/xrpc/create_repo.go
@@ -84,7 +84,7 @@ func (h *Xrpc) CreateRepo(w http.ResponseWriter, r *http.Request) {
 	repoPath, _ := securejoin.SecureJoin(h.Config.Repo.ScanPath, relativeRepoPath)
 
 	if data.Source != nil && *data.Source != "" {
-		err = git.Fork(repoPath, *data.Source)
+		err = git.Fork(repoPath, *data.Source, h.Config)
 		if err != nil {
 			l.Error("forking repo", "error", err.Error())
 			writeError(w, xrpcerr.GenericError(err), http.StatusInternalServerError)
-- 
2.43.0