add timeouts for mtp calls

README.md

@@ -129,11 +129,11 @@ see the beautiful mess of a dictionary in [mtag.py](https://github.com/9001/copy
 
 ## file parser plugins
 
-copyparty can invoke external programs to collect additional metadata for files using `mtp` (as argument or volume flag)
+copyparty can invoke external programs to collect additional metadata for files using `mtp` (as argument or volume flag), there is a default timeout of 30sec
 
-* `-mtp key=~/bin/audio-key.py` will execute `~/bin/audio-key.py` with filename as argument 1 to provide the `key` tag if that does not exist in the audio metadata
-* `-mtp .bpm=f,~/bin/audio-bpm.py` replaces (`f,`) any existing `.bpm` tag using the `~/bin/audio-bpm.py` program
-* `-v ~/music::r:cmtp=key=~/bin/audio-key.py:cmtp=.bpm=f,~/bin/audio-bpm.py` both as a per-volume config wow this is getting ugly
+* `-mtp .bpm=~/bin/audio-bpm.py` will execute `~/bin/audio-bpm.py` with the audio file as argument 1 to provide the `.bpm` tag, if that does not exist in the audio metadata
+* `-mtp key=f,t5,~/bin/audio-key.py` uses `~/bin/audio-key.py` to get the `key` tag, replacing any existing metadata tag (`f,`), aborting if it takes longer than 5sec (`t5,`)
+* `-v ~/music::r:cmtp=.bpm=~/bin/audio-bpm.py:cmtp=key=f,t5,~/bin/audio-key.py` both as a per-volume config wow this is getting ugly
 
 
 # client examples

copyparty/mtag.py

@@ -321,12 +321,11 @@ class MTag(object):
         env["PYTHONPATH"] = pypath
 
         ret = {}
-        for tagname, binpath in parsers.items():
+        for tagname, (binpath, timeout) in parsers.items():
             try:
-                binpath = os.path.expanduser(binpath)
                 cmd = [sys.executable, binpath, abspath]
                 cmd = [fsenc(x) for x in cmd]
-                v = sp.check_output(cmd, env=env).strip()
+                v = sp.check_output(cmd, env=env, timeout=timeout).strip()
                 if v:
                     ret[tagname] = v.decode("utf-8")
             except:

copyparty/up2k.py

@@ -506,14 +506,37 @@ class Up2k(object):
         sz0 = os.path.getsize(db_path)
 
         force = {}
+        timeout = {}
         parsers = {}
         for parser in self.flags[ptop]["mtp"]:
+            orig = parser
             tag, parser = parser.split("=", 1)
-            if parser.lower().startswith("f,"):
-                parser = parser[2:]
-                force[tag] = True
+            while True:
+                try:
+                    bp = os.path.expanduser(parser)
+                    if os.path.exists(bp):
+                        parsers[tag] = [bp, timeout.get(tag, 30)]
+                        break
+                except:
+                    pass
 
-            parsers[tag] = parser
+                try:
+                    arg, parser = parser.split(",", 1)
+                    arg = arg.lower()
+
+                    if arg == "f":
+                        force[tag] = True
+                        continue
+
+                    if arg.startswith("t"):
+                        timeout[tag] = int(arg[1:])
+                        continue
+
+                    raise Exception()
+
+                except:
+                    self.log("invalid argument: " + orig, 1)
+                    return
 
         q = "select count(w) from mt where k = 't:mtp'"
         with self.mutex: