From 6c898796f1c4d385571812a469e52d4c19a8e360 Mon Sep 17 00:00:00 2001
From: "Ruben S. Montero" <rsmontero@opennebula.org>
Date: Thu, 18 Feb 2021 18:06:25 +0100
Subject: [PATCH] F #1428: fix race condition on wait method

co-authored-by: Alejandro Huertas <ahuertas@opennebula.io>
---
 src/oca/ruby/opennebula/wait_ext.rb | 86 +++++++++++++++--------------
 1 file changed, 46 insertions(+), 40 deletions(-)

diff --git a/src/oca/ruby/opennebula/wait_ext.rb b/src/oca/ruby/opennebula/wait_ext.rb
index 5df9f1f395..e2e8dac746 100644
--- a/src/oca/ruby/opennebula/wait_ext.rb
+++ b/src/oca/ruby/opennebula/wait_ext.rb
@@ -118,13 +118,38 @@ module OpenNebula::WaitExt
                 wait2(state_str, '', timeout, cycles)
             end
 
+            def wait_event(ctx, event, timeout)
+                subscriber = ctx.socket(ZMQ::SUB)
+
+                # Create subscriber
+                key        = ''
+                content    = ''
+
+                subscriber.setsockopt(ZMQ::RCVTIMEO, timeout * 1000)
+                subscriber.setsockopt(ZMQ::SUBSCRIBE, event)
+                subscriber.connect('tcp://localhost:2101')
+
+                rc = subscriber.recv_string(key)
+                rc = subscriber.recv_string(content) if rc != -1
+
+                return if ZMQ::Util.errno == ZMQ::EAGAIN || rc == -1
+
+                content
+            ensure
+                subscriber.setsockopt(ZMQ::UNSUBSCRIBE, event)
+                subscriber.close
+            end
+
             def wait2(sstr1, sstr2, timeout = 60, cycles = -1)
                 wfun = WAIT[self.class]
 
-                # Create subscriber
-                subscriber = ZMQ::Context.new(1).socket(ZMQ::SUB)
-                key        = ''
-                content    = ''
+                # Start with a timeout of 2 seconds, to wait until the first
+                # info.
+                #
+                # The timeout is increased later, to avoid multiple info calls.
+                c_timeout = 2
+                recvs     = 0
+                in_state  = false
 
                 # Subscribe with timeout seconds
                 #
@@ -134,51 +159,32 @@ module OpenNebula::WaitExt
                 #
                 #   - element_name: is the element name to find in the message
                 #   - self.ID: returns element ID to find in the message
-                begin
-                    subscriber.setsockopt(ZMQ::RCVTIMEO, timeout * 1000)
-                    subscriber.setsockopt(
-                        ZMQ::SUBSCRIBE,
-                        wfun[:event].call(self, sstr1, sstr2)
-                    )
+                ctx = ZMQ::Context.new(1)
 
-                    subscriber.connect('tcp://localhost:2101')
+                until in_state || (cycles != -1 && recvs >= cycles)
+                    content = wait_event(ctx,
+                                         wfun[:event].call(self, sstr1, sstr2),
+                                         c_timeout)
+
+                    if content && !content.empty?
+                        in_state = wfun[:in_state_e].call(sstr1, sstr2, content)
+
+                        break if in_state
+                    end
+
+                    c_timeout *= 10
+                    c_timeout  = timeout if c_timeout > timeout
 
                     rco = info
 
                     return false if OpenNebula.is_error?(rco)
 
                     in_state = wfun[:in_state].call(self, sstr1, sstr2)
-                    recvs    = 0
 
-                    until in_state || (cycles != -1 && recvs >= cycles)
-                        rc = subscriber.recv_string(key)
-                        rc = subscriber.recv_string(content) if rc != -1
-
-                        if rc == -1
-                            return false if ZMQ::Util.errno != ZMQ::EAGAIN
-
-                            rco = info
-
-                            return false if OpenNebula.is_error?(rco)
-
-                            in_state = wfun[:in_state].call(self, sstr1, sstr2)
-                        else
-                            in_state = wfun[:in_state_e].call(sstr1, sstr2,
-                                                              content)
-                        end
-
-                        recvs += 1
-                    end
-
-                    in_state
-                ensure
-                    subscriber.setsockopt(
-                        ZMQ::UNSUBSCRIBE,
-                        wfun[:event].call(self, sstr1, sstr2)
-                    )
-
-                    subscriber.close
+                    recvs += 1
                 end
+
+                in_state
             end
 
         end