detect free RAM on startup for sane defaults

* if free ram on startup is less than 2 GiB,
   use smaller chunks for parallel file hashing

* if --th-max-ram is lower than 0.25 (256 MiB),
   print a warning that thumbnails will not work

* make thumbnail cleaner immediately do a sweep on startup,
   forgetting any failed conversions so they can be retried
   in case the memory limit was increased since last run

copyparty/__main__.py

@@ -50,6 +50,8 @@
     PARTFTPY_VER,
     PY_DESC,
     PYFTPD_VER,
+    RAM_AVAIL,
+    RAM_TOTAL,
     SQLITE_VER,
     UNPLICATIONS,
     Daemon,
@@ -1325,14 +1327,16 @@ def add_admin(ap):
 
 
 def add_thumbnail(ap):
+    th_ram = (RAM_AVAIL or RAM_TOTAL or 9) * 0.6
+    th_ram = int(max(min(th_ram, 6), 1) * 10) / 10
     ap2 = ap.add_argument_group('thumbnail options')
     ap2.add_argument("--no-thumb", action="store_true", help="disable all thumbnails (volflag=dthumb)")
     ap2.add_argument("--no-vthumb", action="store_true", help="disable video thumbnails (volflag=dvthumb)")
     ap2.add_argument("--no-athumb", action="store_true", help="disable audio thumbnails (spectrograms) (volflag=dathumb)")
     ap2.add_argument("--th-size", metavar="WxH", default="320x256", help="thumbnail res (volflag=thsize)")
     ap2.add_argument("--th-mt", metavar="CORES", type=int, default=CORES, help="num cpu cores to use for generating thumbnails")
     ap2.add_argument("--th-convt", metavar="SEC", type=float, default=60.0, help="conversion timeout in seconds (volflag=convt)")
-    ap2.add_argument("--th-ram-max", metavar="GB", type=float, default=6.0, help="max memory usage (GiB) permitted by thumbnailer; not very accurate")
+    ap2.add_argument("--th-ram-max", metavar="GB", type=float, default=th_ram, help="max memory usage (GiB) permitted by thumbnailer; not very accurate")
     ap2.add_argument("--th-crop", metavar="TXT", type=u, default="y", help="crop thumbnails to 4:3 or keep dynamic height; client can override in UI unless force. [\033[32my\033[0m]=crop, [\033[32mn\033[0m]=nocrop, [\033[32mfy\033[0m]=force-y, [\033[32mfn\033[0m]=force-n (volflag=crop)")
     ap2.add_argument("--th-x3", metavar="TXT", type=u, default="n", help="show thumbs at 3x resolution; client can override in UI unless force. [\033[32my\033[0m]=yes, [\033[32mn\033[0m]=no, [\033[32mfy\033[0m]=force-yes, [\033[32mfn\033[0m]=force-no (volflag=th3x)")
     ap2.add_argument("--th-dec", metavar="LIBS", default="vips,pil,ff", help="image decoders, in order of preference")

copyparty/svchub.py

@@ -211,6 +211,15 @@ def __init__(
             t = "WARNING: --s-rd-sz (%d) is larger than --iobuf (%d); this may lead to reduced performance"
             self.log("root", t % (args.s_rd_sz, args.iobuf), 3)
 
+        zs = ""
+        if args.th_ram_max < 0.22:
+            zs = "generate thumbnails"
+        elif args.th_ram_max < 1:
+            zs = "generate audio waveforms or spectrograms"
+        if zs:
+            t = "WARNING: --th-ram-max is very small (%.2f GiB); will not be able to %s"
+            self.log("root", t % (args.th_ram_max, zs), 3)
+
         if args.chpw and args.idp_h_usr:
             t = "ERROR: user-changeable passwords is incompatible with IdP/identity-providers; you must disable either --chpw or --idp-h-usr"
             self.log("root", t, 1)

copyparty/th_srv.py

@@ -20,7 +20,6 @@
     FFMPEG_URL,
     Cooldown,
     Daemon,
-    Pebkac,
     afsenc,
     fsenc,
     min_ex,
@@ -164,6 +163,7 @@ def __init__(self, hub: "SvcHub") -> None:
         self.ram: dict[str, float] = {}
         self.memcond = threading.Condition(self.mutex)
         self.stopping = False
+        self.rm_nullthumbs = True  # forget failed conversions on startup
         self.nthr = max(1, self.args.th_mt)
 
         self.q: Queue[Optional[tuple[str, str, str, VFS]]] = Queue(self.nthr * 4)
@@ -862,7 +862,6 @@ def poke(self, tdir: str) -> None:
     def cleaner(self) -> None:
         interval = self.args.th_clean
         while True:
-            time.sleep(interval)
             ndirs = 0
             for vol, histpath in self.asrv.vfs.histtab.items():
                 if histpath.startswith(vol):
@@ -876,6 +875,8 @@ def cleaner(self) -> None:
                     self.log("\033[Jcln err in %s: %r" % (histpath, ex), 3)
 
             self.log("\033[Jcln ok; rm {} dirs".format(ndirs))
+            self.rm_nullthumbs = False
+            time.sleep(interval)
 
     def clean(self, histpath: str) -> int:
         ret = 0
@@ -939,6 +940,10 @@ def _clean(self, cat: str, thumbpath: str) -> int:
 
                 continue
 
+            if self.rm_nullthumbs and not inf.st_size:
+                bos.unlink(fp)
+                continue
+
             if b64 == prev_b64:
                 self.log("rm replaced [{}]".format(fp))
                 bos.unlink(prev_fp)

copyparty/util.py

@@ -436,6 +436,27 @@ def _add_mimes() -> None:
 VF_CAREFUL = {"mv_re_t": 5, "rm_re_t": 5, "mv_re_r": 0.1, "rm_re_r": 0.1}
 
 
+def read_ram() -> tuple[float, float]:
+    a = b = 0
+    try:
+        with open("/proc/meminfo", "rb", 0x10000) as f:
+            zsl = f.read(0x10000).decode("ascii", "replace").split("\n")
+
+        p = re.compile("^MemTotal:.* kB")
+        zs = next((x for x in zsl if p.match(x)))
+        a = int((int(zs.split()[1]) / 0x100000) * 100) / 100
+
+        p = re.compile("^MemAvailable:.* kB")
+        zs = next((x for x in zsl if p.match(x)))
+        b = int((int(zs.split()[1]) / 0x100000) * 100) / 100
+    except:
+        pass
+    return a, b
+
+
+RAM_TOTAL, RAM_AVAIL = read_ram()
+
+
 pybin = sys.executable or ""
 if EXE:
     pybin = ""
@@ -1030,6 +1051,7 @@ def __init__(self, cores: int):
         self.sz = 0
         self.csz = 0
         self.stop = False
+        self.readsz = 1024 * 1024 * (2 if (RAM_AVAIL or 2) < 1 else 12)
         self.omutex = threading.Lock()
         self.imutex = threading.Lock()
         self.work_q: Queue[int] = Queue()
@@ -1105,7 +1127,7 @@ def hash_at(self, nch: int) -> tuple[int, str, int, int]:
         while chunk_rem > 0:
             with self.imutex:
                 f.seek(ofs)
-                buf = f.read(min(chunk_rem, 1024 * 1024 * 12))
+                buf = f.read(min(chunk_rem, self.readsz))
 
             if not buf:
                 raise Exception("EOF at " + str(ofs))