autodefault -nc based on OS limits

contrib/nginx/copyparty.conf

@@ -1,11 +1,11 @@
 # when running copyparty behind a reverse proxy,
 # the following arguments are recommended:
 #
-#   -nc 512         important, see next paragraph
 #   --http-only     lower latency on initial connection
 #   -i 127.0.0.1    only accept connections from nginx
 #
 # -nc must match or exceed the webserver's max number of concurrent clients;
+# copyparty default is 1024 if OS permits it (see "max clients:" on startup),
 # nginx default is 512  (worker_processes 1, worker_connections 512)
 #
 # you may also consider adding -j0 for CPU-intensive configurations

copyparty/__main__.py

@@ -411,7 +411,9 @@ def showlic() -> None:
         print(f.read().decode("utf-8", "replace"))
 
 
-def run_argparse(argv: list[str], formatter: Any, retry: bool) -> argparse.Namespace:
+def run_argparse(
+    argv: list[str], formatter: Any, retry: bool, nc: int
+) -> argparse.Namespace:
     ap = argparse.ArgumentParser(
         formatter_class=formatter,
         prog="copyparty",
@@ -569,7 +571,7 @@ def run_argparse(argv: list[str], formatter: Any, retry: bool) -> argparse.Names
     u = unicode
     ap2 = ap.add_argument_group('general options')
     ap2.add_argument("-c", metavar="PATH", type=u, action="append", help="add config file")
-    ap2.add_argument("-nc", metavar="NUM", type=int, default=64, help="max num clients")
+    ap2.add_argument("-nc", metavar="NUM", type=int, default=nc, help="max num clients")
     ap2.add_argument("-j", metavar="CORES", type=int, default=1, help="max num cpu cores, 0=all")
     ap2.add_argument("-a", metavar="ACCT", type=u, action="append", help="add account, \033[33mUSER\033[0m:\033[33mPASS\033[0m; example [\033[32med:wark\033[0m]")
     ap2.add_argument("-v", metavar="VOL", type=u, action="append", help="add volume, \033[33mSRC\033[0m:\033[33mDST\033[0m:\033[33mFLAG\033[0m; examples [\033[32m.::r\033[0m], [\033[32m/mnt/nas/music:/music:r:aed\033[0m]")
@@ -855,10 +857,20 @@ def main(argv: Optional[list[str]] = None) -> None:
     except:
         pass
 
+    nc = 1024
+    try:
+        import resource
+
+        _, hard = resource.getrlimit(resource.RLIMIT_NOFILE)
+        if hard > 0:  # -1 == infinite
+            nc = min(nc, hard // 4)
+    except:
+        nc = 512
+
     retry = False
     for fmtr in [RiceFormatter, RiceFormatter, Dodge11874, BasicDodge11874]:
         try:
-            al = run_argparse(argv, fmtr, retry)
+            al = run_argparse(argv, fmtr, retry, nc)
         except SystemExit:
             raise
         except:

copyparty/svchub.py

@@ -140,6 +140,11 @@ class SvcHub(object):
         if args.ls:
             self.asrv.dbg_ls()
 
+        if not ANYWIN:
+            self._setlimits()
+
+        self.log("root", "max clients: {}".format(self.args.nc))
+
         self.tcpsrv = TcpSrv(self)
         self.up2k = Up2k(self)
 
@@ -245,6 +250,46 @@ class SvcHub(object):
 
         Daemon(self.sd_notify, "sd-notify")
 
+    def _setlimits(self) -> None:
+        try:
+            import resource
+
+            soft, hard = [
+                x if x > 0 else 1024 * 1024
+                for x in list(resource.getrlimit(resource.RLIMIT_NOFILE))
+            ]
+        except:
+            self.log("root", "failed to read rlimits from os", 6)
+            return
+
+        if not soft or not hard:
+            t = "got bogus rlimits from os ({}, {})"
+            self.log("root", t.format(soft, hard), 6)
+            return
+
+        want = self.args.nc * 4
+        new_soft = min(hard, want)
+        if new_soft < soft:
+            return
+
+        # t = "requesting rlimit_nofile({}), have {}"
+        # self.log("root", t.format(new_soft, soft), 6)
+
+        try:
+            import resource
+
+            resource.setrlimit(resource.RLIMIT_NOFILE, (new_soft, hard))
+            soft = new_soft
+        except:
+            t = "rlimit denied; max open files: {}"
+            self.log("root", t.format(soft), 3)
+            return
+
+        if soft < want:
+            t = "max open files: {} (wanted {} for -nc {})"
+            self.log("root", t.format(soft, want, self.args.nc), 3)
+            self.args.nc = min(self.args.nc, soft // 2)
+
     def _logname(self) -> str:
         dt = datetime.utcnow()
         fn = str(self.args.lo)