new hook: granular ramdisk detection

bin/hooks/README.md

@@ -28,6 +28,9 @@ these are `--xiu` hooks; unlike `xbu` and `xau` (which get executed on every sin
 * [reject-extension.py](reject-extension.py) rejects uploads if they match a list of file extensions
 * [reloc-by-ext.py](reloc-by-ext.py) redirects an upload to another destination based on the file extension
   * good example of the `reloc` [hook effect](https://github.com/9001/copyparty/blob/hovudstraum/docs/devnotes.md#hook-effects)
+* [reject-and-explain.py](reject-and-explain.py) shows a custom error-message when it rejects an upload
+* [reject-ramdisk.py](reject-ramdisk.py) rejects the upload if the destination is a ramdisk
+  * this hook uses the `I` flag which makes it 140x faster, but if the plugin has a bug it may crash copyparty
 
 
 # on message
@@ -35,3 +38,7 @@ these are `--xiu` hooks; unlike `xbu` and `xau` (which get executed on every sin
 * [qbittorrent-magnet.py](qbittorrent-magnet.py) starts downloading a torrent if you post a magnet url
 * [usb-eject.py](usb-eject.py) adds web-UI buttons to safe-remove usb flashdrives shared through copyparty
 * [msg-log.py](msg-log.py) is a guestbook; logs messages to a doc in the same folder
+
+
+# general concept demos
+* [import-me.py](import-me.py) shows how the `I` flag makes the hook 140x faster (but you need to be Very Careful when writing the plugin)

bin/hooks/import-me.py

@@ -38,7 +38,7 @@ IMPORTANT NOTE:
 """
 
 
-def main(ka: dict[str, Any]) -> dict[str, str]:
+def main(ka: dict[str, Any]) -> dict[str, Any]:
     # "ka" is a dictionary with info from copyparty...
 
     # but because we are running inside copyparty, we don't need such courtesies;
@@ -47,7 +47,8 @@ def main(ka: dict[str, Any]) -> dict[str, str]:
     cf = inspect.currentframe().f_back.f_back.f_back
     t = "hello from hook; I am able to peek into copyparty's memory like so:\n  function name: %s\n  variables:\n    %s\n"
     t2 = "\n    ".join([("%r: %r" % (k, v))[:99] for k, v in cf.f_locals.items()][:9])
-    print(t % (cf.f_code, t2))
+    logger = ka["log"]
+    logger(t % (cf.f_code, t2))
 
     # must return a dictionary with:
     #  "rc": the retcode; 0 is ok

bin/hooks/reject-ramdisk.py

@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+
+import os
+import threading
+from argparse import Namespace
+
+from jinja2.nodes import Name
+from copyparty.fsutil import Fstab
+from typing import Any, Optional
+
+
+_ = r"""
+reject an upload if the target folder is on a ramdisk; useful when you
+have a volume where some folders inside are ramdisks but others aren't
+
+example usage as global config:
+    --xbu I,bin/hooks/reject-ramdisk.py
+
+example usage as a volflag (per-volume config):
+    -v srv/inc:inc:r:rw,ed:c,xbu=I,bin/hooks/reject-ramdisk.py
+                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+    (share filesystem-path srv/inc as volume /inc,
+     readable by everyone, read-write for user 'ed',
+     running this plugin on all uploads with the params listed below)
+
+example usage as a volflag in a copyparty config file:
+    [/inc]
+      srv/inc
+      accs:
+        r: *
+        rw: ed
+      flags:
+        xbu: I,bin/hooks/reject-ramdisk.py
+
+parameters explained,
+    I = import; do not fork / subprocess
+
+IMPORTANT NOTE:
+    because this hook is imported inside copyparty, you need to
+    be EXCEPTIONALLY CAREFUL to avoid side-effects, for example
+    DO NOT os.chdir() or anything like that, and also make sure
+    that the name of this file is unique (cannot be the same as
+    an existing python module/library)
+"""
+
+
+mutex = threading.Lock()
+fstab: Optional[Fstab] = None
+
+
+def main(ka: dict[str, Any]) -> dict[str, Any]:
+    global fstab
+    with mutex:
+        log = ka["log"]  # this is a copyparty NamedLogger function
+        if not fstab:
+            log("<HOOK:RAMDISK> creating fstab", 6)
+            args = Namespace()
+            args.mtab_age = 1  # cache the filesystem info for 1 sec
+            fstab = Fstab(log, args, False)
+
+        ap = ka["ap"]  # abspath the upload is going to
+        fs, mp = fstab.get(ap)  # figure out what the filesystem is
+        ramdisk = fs in ("tmspfs", "overlay")  # looks like a ramdisk?
+
+        # log("<HOOK:RAMDISK> fs=%r" % (fs,))
+
+        if ramdisk:
+            t = "Upload REJECTED because destination is a ramdisk"
+            return {"rc": 1, "rejectmsg": t}
+
+        return {"rc": 0}

copyparty/util.py

@@ -3629,7 +3629,7 @@ def retchk(
 
 def _parsehook(
     log: Optional["NamedLogger"], cmd: str
-) -> tuple[str, bool, bool, bool, float, dict[str, Any], list[str]]:
+) -> tuple[str, bool, bool, bool, bool, float, dict[str, Any], list[str]]:
     areq = ""
     chk = False
     fork = False
@@ -3906,6 +3906,7 @@ def _runhook(
             "txt": txt,
         }
         if imp:
+            ja["log"] = log
             mod = loadpy(acmd[0], False)
             return mod.main(ja)
         arg = json.dumps(ja)
@@ -4003,7 +4004,7 @@ def runhook(
                 else:
                     ret[k] = v
         except Exception as ex:
-            (log or print)("hook: {}".format(ex))
+            (log or print)("hook: %r, %s" % (ex, ex))
             if ",c," in "," + cmd:
                 return {}
             break

docs/devnotes.md

@@ -15,6 +15,7 @@
     * [general](#general)
 * [event hooks](#event-hooks) - on writing your own [hooks](../README.md#event-hooks)
     * [hook effects](#hook-effects) - hooks can cause intentional side-effects
+    * [hook import](#hook-import) - the `I` flag runs the hook inside copyparty
 * [assumptions](#assumptions)
     * [mdns](#mdns)
 * [sfx repack](#sfx-repack) - reduce the size of an sfx by removing features
@@ -310,7 +311,7 @@ a subset of effect types are available for a subset of hook types,
 to trigger indexing of files `/foo/1.txt` and `/foo/bar/2.txt`, a hook can `print(json.dumps({"idx":{"vp":["/foo/1.txt","/foo/bar/2.txt"]}}))` (and replace "idx" with "del" to delete instead)
 * note: paths starting with `/` are absolute URLs, but you can also do `../3.txt` relative to the destination folder of each uploaded file
 
-### hook import
+## hook import
 
 the `I` flag runs the hook inside copyparty,  which can be very useful and dangerous: