limit max number of users

bincio/serve/cli.py

@@ -18,8 +18,10 @@ console = Console()
 @click.option("--port", default=4041, help="Bind port (default: 4041)")
 @click.option("--strava-client-id", default=None, envvar="STRAVA_CLIENT_ID", help="Strava OAuth client ID (enables per-user Strava sync)")
 @click.option("--strava-client-secret", default=None, envvar="STRAVA_CLIENT_SECRET", help="Strava OAuth client secret")
+@click.option("--max-users", default=None, type=int, help="Override max users for this instance (0 = unlimited; updates the DB setting)")
 def serve(data_dir: str, site_dir: Optional[str], host: str, port: int,
-          strava_client_id: Optional[str], strava_client_secret: Optional[str]) -> None:
+          strava_client_id: Optional[str], strava_client_secret: Optional[str],
+          max_users: Optional[int]) -> None:
     """Start the bincio multi-user application server.
 
     Handles auth, user management, and write operations.
@@ -29,6 +31,7 @@ def serve(data_dir: str, site_dir: Optional[str], host: str, port: int,
     """
     import uvicorn
     import bincio.serve.server as srv
+    from bincio.serve.db import open_db, set_setting, get_setting
 
     dd = Path(data_dir).expanduser().resolve()
     if not (dd / "instance.db").exists():
@@ -36,6 +39,11 @@ def serve(data_dir: str, site_dir: Optional[str], host: str, port: int,
             f"No instance.db found in {dd}. Run `bincio init --data-dir {dd}` first."
         )
 
+    if max_users is not None:
+        db = open_db(dd)
+        set_setting(db, "max_users", str(max_users))
+        db.close()
+
     srv.data_dir = dd
     if site_dir:
         srv.site_dir = Path(site_dir).expanduser().resolve()
@@ -44,11 +52,19 @@ def serve(data_dir: str, site_dir: Optional[str], host: str, port: int,
     if strava_client_secret:
         srv.strava_client_secret = strava_client_secret
 
+    db = open_db(dd)
+    current_limit = get_setting(db, "max_users")
+    db.close()
+
     console.print(f"[bold]bincio serve[/bold]")
     console.print(f"  Data:  [cyan]{dd}[/cyan]")
     if srv.site_dir:
         console.print(f"  Site:  [cyan]{srv.site_dir}[/cyan]")
     console.print(f"  URL:   [cyan]http://{host}:{port}[/cyan]")
+    if current_limit and int(current_limit) > 0:
+        console.print(f"  Users: [yellow]max {current_limit}[/yellow]")
+    else:
+        console.print(f"  Users: [dim]unlimited[/dim]")
     console.print()
 
     uvicorn.run(srv.app, host=host, port=port, log_level="info")

bincio/serve/db.py

@@ -45,6 +45,11 @@ CREATE TABLE IF NOT EXISTS invites (
     used_at     INTEGER
 );
 
+CREATE TABLE IF NOT EXISTS settings (
+    key   TEXT PRIMARY KEY,
+    value TEXT NOT NULL
+);
+
 CREATE INDEX IF NOT EXISTS sessions_handle ON sessions(handle);
 CREATE INDEX IF NOT EXISTS invites_created_by ON invites(created_by);
 """
@@ -149,6 +154,28 @@ def delete_user(db: sqlite3.Connection, handle: str) -> None:
     db.commit()
 
 
+def count_users(db: sqlite3.Connection) -> int:
+    """Return the total number of registered users."""
+    row = db.execute("SELECT COUNT(*) FROM users").fetchone()
+    return row[0] if row else 0
+
+
+# ── Settings ──────────────────────────────────────────────────────────────────
+
+def get_setting(db: sqlite3.Connection, key: str) -> Optional[str]:
+    row = db.execute("SELECT value FROM settings WHERE key = ?", (key,)).fetchone()
+    return row["value"] if row else None
+
+
+def set_setting(db: sqlite3.Connection, key: str, value: str) -> None:
+    db.execute(
+        "INSERT INTO settings (key, value) VALUES (?, ?) "
+        "ON CONFLICT(key) DO UPDATE SET value = excluded.value",
+        (key, value),
+    )
+    db.commit()
+
+
 # ── Sessions ──────────────────────────────────────────────────────────────────
 
 def create_session(db: sqlite3.Connection, handle: str) -> str:

bincio/serve/init_cmd.py

@@ -17,13 +17,14 @@ console = Console()
 @click.option("--password", required=True, hide_input=True, confirmation_prompt=True, help="Admin password")
 @click.option("--display-name", default="", help="Admin display name (defaults to handle)")
 @click.option("--name", default="", help="Instance name shown in the feed")
-def init(data_dir: str, handle: str, password: str, display_name: str, name: str) -> None:
+@click.option("--max-users", default=0, type=int, help="Maximum number of users allowed (0 = unlimited)")
+def init(data_dir: str, handle: str, password: str, display_name: str, name: str, max_users: int) -> None:
     """Bootstrap a fresh bincio multi-user instance.
 
     Creates the SQLite database, the admin user, the per-user data directory,
     and prints a first invite code. Safe to re-run — skips steps already done.
     """
-    from bincio.serve.db import create_invite, create_user, get_user, open_db
+    from bincio.serve.db import create_invite, create_user, get_user, open_db, set_setting
 
     dd = Path(data_dir).expanduser().resolve()
     dd.mkdir(parents=True, exist_ok=True)
@@ -67,6 +68,13 @@ def init(data_dir: str, handle: str, password: str, display_name: str, name: str
     else:
         console.print("  [yellow]·[/yellow] root index.json already exists — skipping")
 
+    # ── User limit ────────────────────────────────────────────────────────────
+    if max_users > 0:
+        set_setting(db, "max_users", str(max_users))
+        console.print(f"  [green]✓[/green] user limit set to {max_users}")
+    else:
+        console.print("  [dim]·[/dim] no user limit (unlimited)")
+
     # ── First invite code ─────────────────────────────────────────────────────
     code = create_invite(db, handle)
 

bincio/serve/server.py

@@ -25,10 +25,12 @@ from bincio.serve.db import (
     authenticate,
     create_invite,
     create_session,
+    count_users,
     create_user,
     delete_session,
     get_invite,
     get_session,
+    get_setting,
     get_user,
     list_invites,
     list_users,
@@ -221,6 +223,12 @@ async def register(request: Request) -> JSONResponse:
     if get_user(_get_db(), handle):
         raise HTTPException(409, "Handle already taken")
 
+    max_users_val = get_setting(_get_db(), "max_users")
+    if max_users_val is not None:
+        limit = int(max_users_val)
+        if limit > 0 and count_users(_get_db()) >= limit:
+            raise HTTPException(403, f"This instance has reached its user limit ({limit})")
+
     create_user(_get_db(), handle, display, password, is_admin=False)
     use_invite(_get_db(), code, handle)