.

wcfs/__init__.py

@@ -38,7 +38,8 @@ import logging as log
 from os.path import dirname
 from errno import ENOENT, EEXIST
 
-from golang import go, chan, select, default
+from golang import chan, select, default
+from golang import sync, context
 from golang.gcompat import qq
 
 from ZODB.FileStorage import FileStorage
@@ -51,11 +52,16 @@ class Conn(object):
     # .mountpoint   path to wcfs mountpoint
     # ._fwcfs       /.wcfs/zurl opened to keep the server from going away (at least cleanly)
 
-    def __init__(self, mountpoint, fwcfs):
+    # XXX 4testing only?
+    # ._proc        wcfs process if it was opened by this conn | None
+
+    def __init__(self, mountpoint, fwcfs, proc):
         self.mountpoint = mountpoint
         self._fwcfs     = fwcfs
+        self._proc      = proc
 
     def close(self):
+        # XXX unmount wcfs as well?
         self._fwcfs.close()
 
     # open creates wcfs file handle, which can be mmaped to give data of ZBigFile.
@@ -171,7 +177,7 @@ def join(zurl, autostart=_default_autostart(), shared=False):   # -> Conn
             raise
     else:
         # already have it
-        return Conn(mntpt, f)
+        return Conn(mntpt, f, None)
 
     if not autostart:
         raise RuntimeError("wcfs: join %s: server not started" % zurl)
@@ -190,51 +196,40 @@ def _start(zurl, *optv):    # -> Conn
     mntpt = _mntpt_4zurl(zurl)
     log.info("wcfs: starting for %s ...", zurl)
 
-    cancel = chan()     # cancels wcfs server running (and waitmounted in initialization phase)
-    startedok = chan()  # indicates to wcfs server that whole startup was ok
+    # XXX errctx "wcfs: start"
 
-    # spawn spawns and monitors wcfs server. it is running until either wcfs
-    # server terminates, or cancel or startedok are ready.
-    ewcfs = chan(1)     # err | None
-    def spawn():
-        err = None
-        try:
+    # spawn wcfs and wait till filesystem-level access to it is ready
+    conn = Conn(mntpt, None, None)
+    wg = sync.WorkGroup(context.background())
+    fsready = chan()
+    def _(ctx):
+        # XXX errctx "spawn"
         argv = [_wcfs_exe()] + list(optv) + [zurl, mntpt]
-            p = subprocess.Popen(argv, close_fds=True)
+        proc = subprocess.Popen(argv, close_fds=True)
         while 1:
-                ret = p.poll()
+            ret = proc.poll()
             if ret is not None:
-                    err = "spawn: exited with %s" % ret
-                    break
+                raise "exited with %s" % ret
 
             _, _rx = select(
-                    cancel.recv,    # 0
-                    startedok.recv, # 1
+                ctx.done().recv,    # 0
+                fsready.recv,       # 1
                 default,            # 2
             )
             if _ == 0:
-                    p.terminate()
-                    break
+                proc.terminate()
+                raise ctx.err()
 
             if _ == 1:
                 # startup was ok - don't monitor spawned wcfs any longer
-                    break
+                conn._proc = proc
+                return
 
             time.sleep(0.1)
+    wg.go(_)
 
-        except Exception as e:
-            log.exception("wcfs server")
-            err = "spawn: %s" % e    # XXX wrap with errctx
-
-        ewcfs.send(err)
-
-    # waitmounted waits till wcfs mount is ready.
-    mounted = chan(1)   # file | err
-    def waitmounted():
-        res = None
-
-        # XXX errctx
-        try:
+    def _(ctx):
+        # XXX errctx "waitmount"
         while 1:
             try:
                 f = open("%s/.wcfs/zurl" % mntpt)
@@ -242,61 +237,26 @@ def _start(zurl, *optv):    # -> Conn
                 if e.errno != ENOENT:
                     raise
             else:
-                    res = f
                 dotwcfs = f.read()
                 if dotwcfs != zurl:
                     raise RuntimeError(".wcfs/zurl != zurl  (%s != %s)" % (qq(dotwcfs), qq(zurl)))
-                    break
 
+                conn._fwcfs = f
+                fsready.close()
+                return
 
             _, _rx = select(
-                    cancel.recv,    # 0
+                ctx.done().recv,    # 0
                 default,            # 1
             )
             if _ == 0:
-                    res = "waitmounted: cancel"
-                    break
+                raise ctx.err()
 
             time.sleep(0.1)
+    wg.go(_)
 
-        except Exception as e:
-            res = "waitmounted: %s" % e     # XXX errctx
-
-        mounted.send(res)
-
-
-    # spawn wcfs and wait till it is mounted.
-    go(spawn)
-    go(waitmounted)
-
-    _, _rx = select(
-        ewcfs.recv,     # 0
-        mounted.recv,   # 1
-    )
-    if _ == 0:
-        # wcfs error
-        err = _rx
-
-    if _ == 1:
-        if isinstance(_rx, file):
-            # mounted ok - return Conn object.
-            #
-            # NOTE: we tell `spawn` thread to exit and stop monitoring spawned
-            # wcfs, because we want spawned wcfs to potentially overlive our
-            # process and to serve other processes. For the same reason we do
-            # not preserve cancel channel in returned Conn.
-            f = _rx
-            startedok.close()
-            return Conn(mntpt, f)
-
-        # waitmounted error
-        err = _rx
-
-
-    cancel.close()
-    raise RuntimeError("wcfs: start: %s" % err) # XXX errctx
-
-
+    wg.wait()
+    return conn
 
 
 # _wcfs_exe returns path to wcfs executable.

wcfs/wcfs_test.py

@@ -78,7 +78,7 @@ def setup_function(f):
 
 # make sure we unmount wcfs after every test.
 def teardown_function(f):
-    mounted = not subprocess.call(["mountpoint", "-q", testmntpt])
+    mounted = (0 == subprocess.call(["mountpoint", "-q", testmntpt]))
     if mounted:
         subprocess.check_call(["fusermount", "-u", testmntpt])
     if os.path.exists(testmntpt):
@@ -188,7 +188,10 @@ class DFile:
 class tDB:
     def __init__(t):
         t.root  = testdb.dbopen()
+        assert not os.path.exists(testmntpt)
         t.wc    = wcfs.join(testzurl, autostart=True)
+        assert os.path.exists(testmntpt)
+        assert 0 == subprocess.call(["mountpoint", "-q", testmntpt])
 
         # ZBigFile(s) scheduled for commit
         t._changed = {} # ZBigFile -> {} blk -> data
@@ -227,6 +230,27 @@ class tDB:
     # it also prints change history to help developer overview current testcase.
     @func
     def close(t):
+        # unmount and wait for wcfs to exit
+        def _():
+            assert 0 == subprocess.call(["mountpoint", "-q", testmntpt])
+            subprocess.check_call(["fusermount", "-u", testmntpt])
+
+            wg = sync.WorkGroup(timeout())
+            def _(ctx):
+                while 1:
+                    if ready(ctx.done()):
+                        raise ctx.err()
+                    ret = t.wc._proc.poll()
+                    if ret is not None:
+                        return
+                    tdelay()
+            wg.go(_)
+            wg.wait()
+
+            assert 0 != subprocess.call(["mountpoint", "-q", testmntpt])
+            os.rmdir(testmntpt)
+        defer(_)
+
         defer(t.dump_history)
         for tf in t._files.copy():
             tf.close()