Use a plain old select loop

Use `select.select` to track subproc completion since `select.epoll`
isn't available on OSX.

Resolves #16

pysipp/launch.py

@@ -32,12 +32,12 @@ def __init__(
         self,
         subprocmod=subprocess,
         osmod=os,
-        poller=select.epoll,
+        select=select.select,
     ):
         # these could optionally be rpyc proxy objs
         self.spm = subprocmod
         self.osm = osmod
-        self.poller = poller()
+        self.select = select
         # collector thread placeholder
         self._waiter = None
         # store proc results
@@ -67,11 +67,9 @@ def __call__(self, cmds, block=True, rate=300, **kwargs):
                 stderr=sp.PIPE
             )
             fd = proc.stderr.fileno()
-            log.debug("registering fd '{}' for pid '{}'".format(
-                fd, proc.pid))
+            log.debug("registering fd '{}' for pid '{}'".format(fd, proc.pid))
             fds2procs[fd] = self._procs[cmd] = proc
-            # register for stderr hangup events
-            self.poller.register(proc.stderr.fileno(), select.EPOLLHUP)
+
             # limit launch rate
             time.sleep(1. / rate)
 
@@ -87,15 +85,39 @@ def _wait(self, fds2procs):
         signalled = None
         left = len(fds2procs)
         collected = 0
+        p2fd = {p: p.stderr for p in fds2procs.values()}
+        stderrs = {p: [] for p in fds2procs.values()}
+
+        # wait on stderr hangup events
         while collected < left:
-            pairs = self.poller.poll()  # wait on hangup events
-            log.debug("received hangup for pairs '{}'".format(pairs))
-            for fd, status in pairs:
+            try:
+                fds, _, _ = self.select(list(p2fd.values()), [], [])
+            except ValueError:
+                # all fds are now closed
+                hungup = p2fd.keys()
+            else:
+                hungup = []
+                for proc in (fds2procs[fd.fileno()] for fd in fds):
+                    data = proc.stderr.read()
+                    if data != '':
+                        stderrs[proc].append(data)  # append stderr
+                        continue
+
+                    p2fd.pop(proc)
+                    hungup.append(proc)
+
+                if not hungup:
+                    continue
+
+            for proc in hungup:
+                log.debug("received hangup for pid '{}'".format(proc.pid))
                 collected += 1
-                proc = fds2procs[fd]
                 # attach streams so they can be read more then once
                 log.debug("collecting streams for {}".format(proc))
-                proc.streams = Streams(*proc.communicate())  # timeout=2))
+                proc.streams = Streams(
+                    stdout=proc.communicate()[0],
+                    stderr=''.join(stderrs[proc]),
+                )  # timeout=2))
                 if proc.returncode != 0 and not signalled:
                     # stop all other agents if there is a failure
                     signalled = self.stop()