sbb-remote 0.10.0: config-get/config-set; GUI watches its config

Keystone's settings pages edit both configs. config-get returns the VM
config text, the defaults and the path; config-set validates new text
with the same check() as load_config, keeps .bak and replaces the file
atomically. Both run before load_config, so a broken config can still be
read and fixed. The GUI reloads its config when the file changes,
re-adding the watch after an atomic write replaces the inode.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 54 insertions, 9 deletions

diff --git a/remote/sbb-remote b/remote/sbb-remote
index 1c87f80..cabb8d1 100755
--- a/remote/sbb-remote
+++ b/remote/sbb-remote
@@ -18,7 +18,8 @@
 """Helper run over ssh by the sb-builder GUI.
 
 Every command prints one JSON object on stdout, except job-follow, which
-streams raw log bytes. gpg-unlock reads the passphrase from stdin. Jobs run detached (setsid, stdin=/dev/null), one at a
+streams raw log bytes. gpg-unlock reads the passphrase from stdin, config-set
+the new config text. Jobs run detached (setsid, stdin=/dev/null), one at a
 time under a flock, from a fixed table of kinds: the GUI sends a kind and
 its arguments, this file validates them and builds the argv itself.
 """
@@ -40,7 +41,7 @@ import time
 import tomllib
 import urllib.request
 
-VERSION = "0.9.0"
+VERSION = "0.10.0"
 DEFAULTS = {
     "state_dir": "/var/lib/sb-builder",
     "repo_dir": "/var/lib/sbopkg/SBo-danix",
@@ -75,16 +76,24 @@ class Error(Exception):
     pass
 
 
+def config_path():
+    return os.environ.get("SBB_CONFIG", "/etc/sb-builder/config.toml")
+
+
 def load_config(path=None):
-    path = path or os.environ.get("SBB_CONFIG", "/etc/sb-builder/config.toml")
-    cfg = dict(DEFAULTS)
     try:
-        with open(path, "rb") as f:
+        with open(path or config_path(), "rb") as f:
             data = tomllib.load(f)
     except FileNotFoundError:
-        return cfg
+        return dict(DEFAULTS)
     except tomllib.TOMLDecodeError as e:
         raise Error(f"config: {e}")
+    return check(data)
+
+
+def check(data):
+    """The config from parsed TOML over the defaults; Error on an unknown key or a wrong type."""
+    cfg = dict(DEFAULTS)
     for k, v in data.items():
         if k not in DEFAULTS:
             raise Error(f"config: {k}: unknown key")
@@ -1086,6 +1095,38 @@ def cmd_gpg_unlock(cfg, stdin=None):
     return {"unlocked": True}
 
 
+# ── config editing (Keystone's settings page): no cfg, a broken file must stay fixable ──
+
+def cmd_config_get():
+    try:
+        with open(config_path()) as f:
+            text = f.read()
+    except FileNotFoundError:
+        text = ""
+    return {"text": text, "defaults": DEFAULTS, "path": config_path()}
+
+
+def cmd_config_set(stdin=None):
+    """New config text on stdin: validated, the old file to .bak, then an atomic replace."""
+    try:
+        text = (stdin or sys.stdin.buffer).read().decode()
+        check(tomllib.loads(text))
+    except (UnicodeDecodeError, tomllib.TOMLDecodeError) as e:
+        raise Error(f"config: {e}")
+    path = config_path()
+    mode = 0o644
+    if os.path.exists(path):
+        mode = os.stat(path).st_mode & 0o777
+        shutil.copy2(path, path + ".bak")
+    with tempfile.NamedTemporaryFile("w", dir=os.path.dirname(path), delete=False) as t:
+        t.write(text)
+    os.chmod(t.name, mode)
+    os.replace(t.name, path)
+    return {"ok": True}
+
+
+CONFIG_COMMANDS = {"config-get": cmd_config_get, "config-set": cmd_config_set}
+
 COMMANDS = {
     "version": cmd_version,
     "stats": cmd_stats,
@@ -1108,6 +1149,7 @@ COMMANDS = {
     "fix-current-now": cmd_fix_current_now,
     "_run": cmd_run,
     "_hint": cmd_hint,
+    **CONFIG_COMMANDS,
 }
 
 
@@ -1116,9 +1158,12 @@ def main(argv):
         if not argv or argv[0] not in COMMANDS:
             names = ",".join(c for c in COMMANDS if not c.startswith("_"))
             raise Error(f"usage: sbb-remote {{{names}}} [args]")
-        cfg = load_config()
-        os.makedirs(os.path.join(cfg["state_dir"], "jobs"), exist_ok=True)
-        result = COMMANDS[argv[0]](cfg, *argv[1:])
+        if argv[0] in CONFIG_COMMANDS:
+            result = CONFIG_COMMANDS[argv[0]](*argv[1:])
+        else:
+            cfg = load_config()
+            os.makedirs(os.path.join(cfg["state_dir"], "jobs"), exist_ok=True)
+            result = COMMANDS[argv[0]](cfg, *argv[1:])
     except BrokenPipeError:
         # the GUI hung up on job-follow; silence the flush at exit too
         os.dup2(os.open(os.devnull, os.O_WRONLY), sys.stdout.fileno())