From 1c80f506db9ee3b660b0e1177de2afdb494c3685 Mon Sep 17 00:00:00 2001
From: Antoine Musso <hashar@free.fr>
Date: Mon, 5 Mar 2018 11:17:19 +0100
Subject: [PATCH] Import Zuul modules at top of files

We had to make sure to not import Paramiko before daemonization.  The
zuul-server would hang when establishing a Gerrit ssh connection due to
Random.Crypto() failling to acquire random number from /dev/urandom. It
would block on read() and never process.

When the Server command line invokes the daemonization, python-daemon
closes all file descriptors. Including /dev/urandom. Then the daemonized
establishes the SSH connection and fails to get random number because
Random.Crypto() locks on read() on a closed file description.

Paramiko issue is https://github.com/paramiko/paramiko/issues/59 and the
fix is to use os.random:
https://github.com/paramiko/paramiko/commit/6f211115f49edcea7d23b764d7cf3a84ff12f5f0

That has been released with Paramiko 1.11.6 and we now require 2.0+.

Move Zuul imports at top of files and drop the comments hinting at the
Paramiko bug.

Change-Id: I5fe956df74815761e3eac2bd25f6fd7f167fc854
---
 zuul/cmd/__init__.py  |  5 -----
 zuul/cmd/executor.py  |  6 +-----
 zuul/cmd/merger.py    |  7 -------
 zuul/cmd/scheduler.py | 19 ++++++-------------
 4 files changed, 7 insertions(+), 30 deletions(-)

diff --git a/zuul/cmd/__init__.py b/zuul/cmd/__init__.py
index 6ab759833b..ee73386f09 100755
--- a/zuul/cmd/__init__.py
+++ b/zuul/cmd/__init__.py
@@ -40,11 +40,6 @@ from zuul.ansible import logconfig
 import zuul.lib.connections
 from zuul.lib.config import get_default
 
-# Do not import modules that will pull in paramiko which must not be
-# imported until after the daemonization.
-# https://github.com/paramiko/paramiko/issues/59
-# Similar situation with gear and statsd.
-
 
 def stack_dump_handler(signum, frame):
     signal.signal(signal.SIGUSR2, signal.SIG_IGN)
diff --git a/zuul/cmd/executor.py b/zuul/cmd/executor.py
index b050a5979c..5e5ea377d2 100755
--- a/zuul/cmd/executor.py
+++ b/zuul/cmd/executor.py
@@ -22,12 +22,8 @@ import tempfile
 
 import zuul.cmd
 import zuul.executor.server
-from zuul.lib.config import get_default
 
-# No zuul imports that pull in paramiko here; it must not be
-# imported until after the daemonization.
-# https://github.com/paramiko/paramiko/issues/59
-# Similar situation with gear and statsd.
+from zuul.lib.config import get_default
 
 
 class Executor(zuul.cmd.ZuulDaemonApp):
diff --git a/zuul/cmd/merger.py b/zuul/cmd/merger.py
index 8c4798923c..1d4b6fefff 100755
--- a/zuul/cmd/merger.py
+++ b/zuul/cmd/merger.py
@@ -20,11 +20,6 @@ import sys
 import zuul.cmd
 import zuul.merger.server
 
-# No zuul imports here because they pull in paramiko which must not be
-# imported until after the daemonization.
-# https://github.com/paramiko/paramiko/issues/59
-# Similar situation with gear and statsd.
-
 
 class Merger(zuul.cmd.ZuulDaemonApp):
     app_name = 'merger'
@@ -48,8 +43,6 @@ class Merger(zuul.cmd.ZuulDaemonApp):
         sys.exit(0)
 
     def run(self):
-        # See comment at top of file about zuul imports
-        import zuul.merger.server
         if self.args.command in zuul.merger.server.COMMANDS:
             self.send_command(self.args.command)
             sys.exit(0)
diff --git a/zuul/cmd/scheduler.py b/zuul/cmd/scheduler.py
index a3a53cfe89..c782d4a68b 100755
--- a/zuul/cmd/scheduler.py
+++ b/zuul/cmd/scheduler.py
@@ -20,14 +20,14 @@ import sys
 import signal
 
 import zuul.cmd
+import zuul.executor.client
+import zuul.merger.client
+import zuul.nodepool
+import zuul.scheduler
+import zuul.zk
+
 from zuul.lib.config import get_default
 from zuul.lib.statsd import get_statsd_config
-import zuul.scheduler
-
-# No zuul imports here because they pull in paramiko which must not be
-# imported until after the daemonization.
-# https://github.com/paramiko/paramiko/issues/59
-# Similar situation with gear and statsd.
 
 
 class Scheduler(zuul.cmd.ZuulDaemonApp):
@@ -111,16 +111,9 @@ class Scheduler(zuul.cmd.ZuulDaemonApp):
             os.kill(self.gear_server_pid, signal.SIGKILL)
 
     def run(self):
-        # See comment at top of file about zuul imports
-        import zuul.scheduler
         if self.args.command in zuul.scheduler.COMMANDS:
             self.send_command(self.args.command)
             sys.exit(0)
-        # See comment at top of file about zuul imports
-        import zuul.executor.client
-        import zuul.merger.client
-        import zuul.nodepool
-        import zuul.zk
 
         if (self.config.has_option('gearman_server', 'start') and
             self.config.getboolean('gearman_server', 'start')):