.agents/skills/lib_py/agents/sanitize.py

@@ -1,5 +1,6 @@
 import hashlib
 import re
+import shlex
 
 def sanitize_herdr_agent_name(name: str) -> str:
     """
@@ -29,3 +30,14 @@ def sanitize_herdr_agent_name(name: str) -> str:
     
     return s
 
+
+def attach_command(server, name):
+    """The registry row's attach_command (Issue #71).
+
+    A native herdr command, so it works from any shell: the server is always
+    named (`default` too - herdr's env-free default), and the agent by the name
+    herdr registered (sanitize_herdr_agent_name). create, resume and reconcile
+    all write it from here.
+    """
+    return "herdr --session %s agent attach %s" % (
+        shlex.quote(server or "default"), shlex.quote(sanitize_herdr_agent_name(name)))

.agents/skills/lib_py/atomic_yaml.py

@@ -4,6 +4,7 @@
 import os, sys, tempfile, shutil, glob, subprocess, json, sqlite3, fcntl
 from datetime import datetime, timezone
 import yaml
+from lib_py import registry_format
 
 def atomic_dump_yaml_main():
     yaml_path = os.environ['YAML_PATH']
@@ -114,6 +115,16 @@ def atomic_dump_yaml_main():
         elif 'herdr_sessions' not in d:
             d['herdr_sessions'] = []
 
+        # Issue #71: an older registry is migrated here, under the lock and
+        # before the caller's mutation. It changes row fields only, so the
+        # YAML is rewritten whether or not the mutation changes anything.
+        from_version = registry_format.stored_version(d)
+        migrated_rows = 0
+        force_yaml = False
+        if from_version < registry_format.CURRENT:
+            d, migrated_rows = registry_format.migrate(d)
+            force_yaml = True
+
         old_sessions = get_all_sessions_status(d)
         # a mutation that replaces a row the monitor registered for a pane it
         # created itself (create_session.sh) drops that name from old_roles
@@ -167,7 +178,7 @@ def atomic_dump_yaml_main():
 
         conn.commit()
         
-        if new_sessions != old_sessions:
+        if force_yaml or new_sessions != old_sessions:
             if os.path.exists(yaml_path):
                 try:
                     shutil.copy2(yaml_path, yaml_path + '.bak')
@@ -207,6 +218,7 @@ def atomic_dump_yaml_main():
             _flock_f.close()
         except Exception:
             pass
+    return from_version, registry_format.stored_version(d), migrated_rows
 
 if __name__ == '__main__':
     atomic_dump_yaml_main()

.agents/skills/lib_py/registry_format.py

@@ -0,0 +1,92 @@
+"""Registry format version and its migration (Issue #71).
+
+The session registry (agent-sessions.yaml + agent-sessions.db) carries a
+top-level `registry_format` key; it lives in the DB `state` row like every
+other top-level key. A registry without it is format 1.
+
+  1: rows may carry `kill_command` and `start_command`, and `attach_command`
+     reads `HERDR_SESSION_NAME=<server> herdr agent attach <original name>`.
+  2: no `kill_command` / `start_command`; `attach_command` is
+     lib_py.agents.sanitize.attach_command(<row server>, <row name>).
+
+The writer (lib_py.atomic_yaml, the only code that writes the registry)
+migrates an older registry under its lock before the caller's mutation, and
+then rewrites the YAML as well as the DB. Readers (lib_py.state) never
+migrate; they see the old rows until the first write.
+
+Entry point (for #72, the update skill):
+
+    python -m lib_py.registry_format --yaml <agent-sessions.yaml>
+
+runs that migration through the writer (same lock, YAML rewritten), prints one
+line `registry-format: <from> -> <to>, rows changed: <n>` and exits 0 when the
+registry was migrated or already current, nonzero on error. Run it with the
+skills directory on PYTHONPATH (as lib.sh does), e.g.
+`PYTHONPATH=.agents/skills python3 -m lib_py.registry_format --yaml .mam/agent-sessions.yaml`.
+"""
+
+import argparse
+import copy
+import os
+import sys
+
+from lib_py.agents.sanitize import attach_command
+
+FORMAT_KEY = "registry_format"
+CURRENT = 2
+_DROPPED = ("kill_command", "start_command")
+
+
+def stored_version(d):
+    """The format a registry dict says it has (1 when it says nothing)."""
+    v = d.get(FORMAT_KEY) if isinstance(d, dict) else None
+    return v if isinstance(v, int) and not isinstance(v, bool) else 1
+
+
+def _row_server(s):
+    return s.get("herdr_session") or s.get("herdr_server") or "default"
+
+
+def migrate(d):
+    """Return (new registry dict, rows changed). Pure and idempotent: `d` is
+    not modified, and migrating the result again changes nothing. Every row is
+    migrated, `stopped` and `terminated` ones included."""
+    out = copy.deepcopy(d) if isinstance(d, dict) else {}
+    changed = 0
+    for s in out.get("herdr_sessions") or []:
+        if not isinstance(s, dict) or not s.get("name"):
+            continue
+        before = dict(s)
+        for k in _DROPPED:
+            s.pop(k, None)
+        s["attach_command"] = attach_command(_row_server(s), s["name"])
+        if s != before:
+            changed += 1
+    out[FORMAT_KEY] = CURRENT
+    return out, changed
+
+
+def main(argv=None):
+    ap = argparse.ArgumentParser(prog="python -m lib_py.registry_format",
+                                 description="Migrate the session registry to the current format.")
+    ap.add_argument("--yaml", required=True, help="path of agent-sessions.yaml")
+    a = ap.parse_args(argv)
+    yaml_path = os.path.abspath(a.yaml)
+    db_path = os.path.splitext(yaml_path)[0] + ".db"
+    if not (os.path.exists(yaml_path) or os.path.exists(db_path)):
+        print("registry-format: error: no registry at %s" % yaml_path, file=sys.stderr)
+        return 1
+    from lib_py.atomic_yaml import atomic_dump_yaml_main
+    os.environ["YAML_PATH"] = yaml_path
+    os.environ["AGENT_SESSIONS_MUTATION"] = "pass"
+    try:
+        frm, to, n = atomic_dump_yaml_main()
+    except (Exception, SystemExit) as exc:  # the writer refuses with SystemExit
+        print("registry-format: error: %s" % (exc,), file=sys.stderr)
+        return 1
+    print("registry-format: %d -> %d, rows changed: %d" % (frm, to, n), flush=True)
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())