Remove eventlet dependency, migrate to asyncio/concurrent.futures

Replace eventlet.greenpool with concurrent.futures.ThreadPoolExecutor
in the BMC discovery script, using as_completed() for proper exception
propagation and main-thread result aggregation to avoid race conditions.

Remove dead eventlet socket compatibility code (.fd attribute checks)
from the IPMI session layer, and clean up stale eventlet references
in comments across the codebase.

Closes: xcat2/confluent#197

confluent_server/aiohmi/ipmi/private/session.py

@@ -57,12 +57,8 @@ except AttributeError:
 # in case of congestion
 initialtimeout = 0.5
 # the thread in which all IO will be performed
-# While the model as-is works fine for it's own coroutine
-# structure, when combined with threading or something like
-# eventlet, it becomes difficult for the calling code to cope
-# This thread will tuck away the threading situation such that
-# calling code doesn't have to do any gymnastics to cope with
-# the nature of things.
+# This thread tucks away the threading situation such that
+# calling code doesn't have to do any gymnastics.
 iothread = None
 # whether io thread is yet ready to work
 iothreadready = False
@@ -186,24 +182,13 @@ async def _io_wait(timeout, myaddr=None, evq=None):
         evq.append(evt)
     deadline = timeout + _monotonic_time()
     ioqueue.append((deadline, evt, myaddr))
-    # Unfortunately, at least with eventlet patched threading, the wait()
-    # is a somewhat busy wait if given a deadline.  Workaround by having
-    # it piggy back on the select() in the io thread, which is a truly
-    # lazy wait even with eventlet involvement
     if deadline < selectdeadline:
-        intsock = iosockets[0]
-        if hasattr(intsock, 'fd'):
-            # if in eventlet, go for the true sendto, which is less glitchy
-            intsock = intsock.fd
-        intsock.sendto(b'\x01', (myself, iosockets[0].getsockname()[1]))
+        iosockets[0].sendto(b'\x01', (myself, iosockets[0].getsockname()[1]))
     await evt.wait()
 
 
 def _io_sendto(mysocket, packet, sockaddr):
-    # Want sendto to act reasonably sane..
     mysocket.setblocking(1)
-    if hasattr(mysocket, 'fd'):
-        mysocket = mysocket.fd
     try:
         mysocket.sendto(packet, sockaddr)
     except Exception:

confluent_server/confluent/debugger.py

@@ -5,8 +5,6 @@ import socket
 import sys
 import confluent.tasks as tasks
 
-#this will ultimately fill the role of the 'backdoor' of eventlet
-
 # since we have to asyncio up the input and output, we use InteractiveInterpreter and handle the
 # input ourselves, since code is not asyncio friendly in and of itself
 #code.InteractiveConsole().interact()

confluent_server/confluent/syncfiles.py

@@ -199,9 +199,8 @@ async def sync_list_to_node(sl, node, suffixes, peerip=None):
             'rsync', '-rvLD', targdir + '/', 'root@[{}]:/'.format(targip))
     except Exception as e:
         if 'CalledProcessError' not in repr(e):
-            # https://github.com/eventlet/eventlet/issues/413
-            # for some reason, can't catch the calledprocesserror normally
-            # for this exception, implement a hack workaround
+            # CalledProcessError can't be caught normally in some contexts,
+            # so check via repr as a workaround
             raise
         unreadablefiles = []
         for root, dirnames, filenames in os.walk(targdir):

misc/cfg-dhcp-redfish-bmcs-by-switch.py

@@ -32,18 +32,17 @@
 
 import sys
 sys.path.append('/opt/confluent/lib/python')
+import concurrent.futures
 import confluent.client as cli
-import eventlet.greenpool
 import gzip
 import io
 import json
 import os
 import struct
 import subprocess
+import pyghmi.util.webclient as webclient
 import time
 
-webclient = eventlet.import_patched('pyghmi.util.webclient')
-
 
 bmcsbyuuid = {}
 def checkfish(addr, mac):
@@ -57,10 +56,10 @@ def checkfish(addr, mac):
     try:
         body = json.loads(body)
     except json.decoder.JSONDecodeError:
-        return
+        return None
     uuid = body.get('UUID', None)
     if not uuid:
-        return
+        return None
     #This part is needed if a bmc sticks 'wire format' uuid in the json body
     #Should be skipped for bmcs that present it sanely
     uuidparts = uuid.split('-')
@@ -68,14 +67,10 @@ def checkfish(addr, mac):
     uuidparts[1] = '{:04x}'.format(struct.unpack('!H', struct.pack('<H', int(uuidparts[1], 16)))[0])
     uuidparts[2] = '{:04x}'.format(struct.unpack('!H', struct.pack('<H', int(uuidparts[2], 16)))[0])
     uuid = '-'.join(uuidparts)
-    if uuid in bmcsbyuuid:
-        bmcsbyuuid[uuid]['bmcs'][mac] = addr
-    else:
-        bmcsbyuuid[uuid] = {'bmcs': {mac: addr}}
+    return (uuid, mac, addr)
 
 
 if __name__ == '__main__':
-    gpool = eventlet.greenpool.GreenPool()
     with open('/var/lib/dhcpd/dhcpd.leases', 'r') as leasefile:
         leases = leasefile.read()
     inlease = False
@@ -115,9 +110,25 @@ if __name__ == '__main__':
         for inf in macinfo:
             if inf.get('possiblenode', None):
                 mactonode[mac] = inf['possiblenode']
-    for mac in sorted(mactonode):
-        gpool.spawn(checkfish, mactoips[mac], mac)
-    gpool.waitall()
+    with concurrent.futures.ThreadPoolExecutor() as executor:
+        futures = {}
+        for mac in sorted(mactonode):
+            futures[executor.submit(checkfish, mactoips[mac], mac)] = mac
+        for future in concurrent.futures.as_completed(futures):
+            mac = futures[future]
+            try:
+                result = future.result()
+            except Exception as e:
+                sys.stderr.write('Failed to probe {}: {}\n'.format(
+                    mactoips[mac], e))
+                continue
+            if result is None:
+                continue
+            uuid, mac, addr = result
+            if uuid in bmcsbyuuid:
+                bmcsbyuuid[uuid]['bmcs'][mac] = addr
+            else:
+                bmcsbyuuid[uuid] = {'bmcs': {mac: addr}}
     for uuid in sorted(bmcsbyuuid):
         macd = bmcsbyuuid[uuid]['bmcs']
         macs = sorted(macd)