Use gitnamespaces for efficient storage

Instead of using one Git repository per package, use a single large
object storage for space efficiency. The refs of the individual package
bases are divided using gitnamespaces(7) which allows for exposing each
namespace as an independent repository easily. Also, git-serve is
modified to create a branch for each package, allowing to browse the
large repository with cgit.

Helped-by: Florian Pritz <bluewind@xinu.at>
Helped-by: Johannes Löthberg <johannes@kyriasis.com>
Signed-off-by: Lukas Fleischer <lfleischer@archlinux.org>

scripts/git-integration/git-serve.py

@@ -17,28 +17,23 @@ aur_db_user = config.get('database', 'user')
 aur_db_pass = config.get('database', 'password')
 aur_db_socket = config.get('database', 'socket')
 
-repo_base_path = config.get('serve', 'repo-base')
+repo_path = config.get('serve', 'repo-path')
 repo_regex = config.get('serve', 'repo-regex')
 git_shell_cmd = config.get('serve', 'git-shell-cmd')
 ssh_cmdline = config.get('serve', 'ssh-cmdline')
 template_path = config.get('serve', 'template-path')
 
-def repo_path_validate(path):
-    if not path.startswith(repo_base_path):
-        return False
-    if path.endswith('.git'):
-        repo = path[len(repo_base_path):-4]
-    elif path.endswith('.git/'):
-        repo = path[len(repo_base_path):-5]
-    else:
-        return False
-    return re.match(repo_regex, repo)
+def pkgbase_exists(pkgbase):
+    db = mysql.connector.connect(host=aur_db_host, user=aur_db_user,
+                                 passwd=aur_db_pass, db=aur_db_name,
+                                 unix_socket=aur_db_socket)
+    cur = db.cursor()
 
-def repo_path_get_pkgbase(path):
-    pkgbase = path.rstrip('/').rpartition('/')[2]
-    if pkgbase.endswith('.git'):
-        pkgbase = pkgbase[:-4]
-    return pkgbase
+    cur.execute("SELECT COUNT(*) FROM PackageBases WHERE Name = %s ",
+                [pkgbase])
+
+    db.close()
+    return (cur.fetchone()[0] > 0)
 
 def list_repos(user):
     db = mysql.connector.connect(host=aur_db_host, user=aur_db_user,
@@ -57,19 +52,17 @@ def list_repos(user):
         print((' ' if row[1] else '*') + row[0])
     db.close()
 
-def setup_repo(repo, user):
-    if not re.match(repo_regex, repo):
-        die('%s: invalid repository name: %s' % (action, repo))
+def setup_repo(pkgbase, user):
+    if not re.match(repo_regex, pkgbase):
+        die('%s: invalid repository name: %s' % (action, pkgbase))
+    if pkgbase_exists(pkgbase):
+        die('%s: package base already exists: %s' % (action, pkgbase))
 
     db = mysql.connector.connect(host=aur_db_host, user=aur_db_user,
                                  passwd=aur_db_pass, db=aur_db_name,
                                  unix_socket=aur_db_socket)
     cur = db.cursor()
 
-    cur.execute("SELECT COUNT(*) FROM PackageBases WHERE Name = %s ", [repo])
-    if cur.fetchone()[0] > 0:
-        die('%s: package base already exists: %s' % (action, repo))
-
     cur.execute("SELECT ID FROM Users WHERE Username = %s ", [user])
     userid = cur.fetchone()[0]
     if userid == 0:
@@ -77,7 +70,7 @@ def setup_repo(repo, user):
 
     cur.execute("INSERT INTO PackageBases (Name, SubmittedTS, ModifiedTS, " +
                 "SubmitterUID, MaintainerUID) VALUES (%s, UNIX_TIMESTAMP(), " +
-                "UNIX_TIMESTAMP(), %s, %s)", [repo, userid, userid])
+                "UNIX_TIMESTAMP(), %s, %s)", [pkgbase, userid, userid])
     pkgbase_id = cur.lastrowid
 
     cur.execute("INSERT INTO CommentNotify (PackageBaseID, UserID) " +
@@ -86,8 +79,11 @@ def setup_repo(repo, user):
     db.commit()
     db.close()
 
-    repo_path = repo_base_path + '/' + repo + '.git/'
-    pygit2.init_repository(repo_path, True, 48, template_path=template_path)
+    repo = pygit2.Repository(repo_path)
+    repo.create_reference('refs/heads/' + pkgbase,
+                          'refs/namespaces/' + pkgbase + '/refs/heads/master')
+    repo.create_reference('refs/namespaces/' + pkgbase + '/HEAD',
+                          'refs/namespaces/' + pkgbase + '/refs/heads/master')
 
 def check_permissions(pkgbase, user):
     db = mysql.connector.connect(host=aur_db_host, user=aur_db_user,
@@ -125,19 +121,25 @@ action = cmdargv[0]
 if action == 'git-upload-pack' or action == 'git-receive-pack':
     if len(cmdargv) < 2:
         die_with_help("%s: missing path" % (action))
-    path = repo_base_path.rstrip('/') + cmdargv[1]
-    if not repo_path_validate(path):
+
+    path = cmdargv[1].rstrip('/')
+    if not path.startswith('/') or not path.endswith('.git'):
         die('%s: invalid path: %s' % (action, path))
-    pkgbase = repo_path_get_pkgbase(path)
-    if not os.path.exists(path):
+    pkgbase = path[1:-4]
+    if not re.match(repo_regex, pkgbase):
+        die('%s: invalid repository name: %s' % (action, repo))
+
+    if not pkgbase_exists(pkgbase):
         setup_repo(pkgbase, user)
+
     if action == 'git-receive-pack':
         if not check_permissions(pkgbase, user):
             die('%s: permission denied: %s' % (action, user))
+
     os.environ["AUR_USER"] = user
-    os.environ["AUR_GIT_DIR"] = path
     os.environ["AUR_PKGBASE"] = pkgbase
-    cmd = action + " '" + path + "'"
+    os.environ["GIT_NAMESPACE"] = pkgbase
+    cmd = action + " '" + repo_path + "'"
     os.execl(git_shell_cmd, git_shell_cmd, '-c', cmd)
 elif action == 'list-repos':
     if len(cmdargv) > 1: