Add --capture-output option to glance-control.

Fixes bug 923894

Previously all stdout/err from glance services was discarded
if launched via glance-control.

The --capture-output option allows such output to be instead
captured in the syslog.

Non-termination output should be flushed to ensure timely
arrival in /var/log/messages.

Change-Id: I5c11ad4b9f7f321a3d1cab71e34c2a6707ef1b5e

bin/glance-control

@@ -24,10 +24,12 @@ Thanks for some of the code, Swifties ;)
 from __future__ import with_statement
 
 import errno
+import fcntl
 import gettext
 import os
 import resource
 import signal
+import subprocess
 import sys
 import time
 
@@ -123,6 +125,40 @@ def do_start(server, conf, args):
                     break
                 time.sleep(0.05)
 
+    def redirect_to_null(fds):
+        with open(os.devnull, 'r+b') as nullfile:
+            for desc in fds:  # close fds
+                try:
+                    os.dup2(nullfile.fileno(), desc)
+                except OSError:
+                    pass
+
+    def redirect_to_syslog(fds, server):
+        log_cmd = '/usr/bin/logger -t "%s[%d]"' % (server, os.getpid())
+        process = subprocess.Popen(log_cmd,
+                                   shell=True,
+                                   stdin=subprocess.PIPE)
+        for desc in fds:  # pipe to logger command
+            try:
+                os.dup2(process.stdin.fileno(), desc)
+            except OSError:
+                pass
+
+    def redirect_stdio(conf, server):
+        input = [sys.stdin.fileno()]
+        output = [sys.stdout.fileno(), sys.stderr.fileno()]
+
+        redirect_to_null(input)
+        if conf.capture_output:
+            redirect_to_syslog(output, server)
+        else:
+            redirect_to_null(output)
+
+    def close_stdio_on_exec():
+        fds = [sys.stdin.fileno(), sys.stdout.fileno(), sys.stderr.fileno()]
+        for desc in fds:  # set close on exec flag
+            fcntl.fcntl(desc, fcntl.F_SETFD, fcntl.FD_CLOEXEC)
+
     def launch(pid_file, conf_file=None):
         args = [server]
         print 'Starting %s' % server,
@@ -131,15 +167,12 @@ def do_start(server, conf, args):
             print 'with %s' % conf_file,
         print
 
+        close_stdio_on_exec()
+
         pid = os.fork()
         if pid == 0:
             os.setsid()
-            with open(os.devnull, 'r+b') as nullfile:
-                for desc in (0, 1, 2):  # close stdio
-                    try:
-                        os.dup2(nullfile.fileno(), desc)
-                    except OSError:
-                        pass
+            redirect_stdio(conf, server)
             try:
                 os.execlp('%s' % server, *args)
             except OSError, e:
@@ -197,16 +230,25 @@ if __name__ == '__main__':
     exitcode = 0
 
     conf = config.GlanceConfigOpts(usage=USAGE)
-    conf.register_cli_opt(cfg.StrOpt('pid-file',
-                                     metavar='PATH',
-                                     help='File to use as pid file. Default: '
-                                          '/var/run/glance/$server.pid'))
-    conf.register_cli_opt(cfg.IntOpt('await-child',
-                                     metavar='DELAY',
-                                     default=0,
-                                     help='Period to wait for service death '
-                                          'in order to report exit code '
-                                          '(default is to not wait at all)'))
+
+    opts = [
+            cfg.StrOpt('pid-file',
+                       metavar='PATH',
+                       help='File to use as pid file. Default: '
+                       '/var/run/glance/$server.pid'),
+            cfg.IntOpt('await-child',
+                       metavar='DELAY',
+                       default=0,
+                       help='Period to wait for service death '
+                            'in order to report exit code '
+                            '(default is to not wait at all)'),
+            cfg.BoolOpt('capture-output',
+                        default=False,
+                        help='Capture stdout/err in syslog '
+                        'instead of discarding'),
+        ]
+    conf.register_cli_opts(opts)
+
     args = conf()
 
     if len(args) < 2:

doc/source/controllingservers.rst

@@ -149,7 +149,7 @@ To start a Glance server with ``glance-control``, simply call
 any command-line options you wish to provide. Start the server with ``glance-control``
 in the following way::
 
-  $> sudo glance-control <SERVER> start [CONFPATH]
+  $> sudo glance-control [OPTIONS] <SERVER> start [CONFPATH]
 
 .. note::
 
@@ -172,9 +172,17 @@ with the ``glance-control`` wrapper script. ::
   jsuh     20042  0.0  0.0   3368   744 pts/1    S+   12:51   0:00 grep glance
 
  
-The same ``paste.deploy`` configuration files are used by ``glance-control``
-to start the Glance server programs, and you can specify (as the example above
-shows) a configuration file when starting the server.
+The same configuration files are used by ``glance-control`` to start the
+Glance server programs, and you can specify (as the example above shows)
+a configuration file when starting the server.
+
+
+By default, output from glance services is discarded when launched with ``glance-control``.
+In order to capture such output via syslog, use the following option:
+
+
+  $ sudo glance-control --capture-output ...
+
 
 Stopping a server
 -----------------

glance/tests/functional/__init__.py

@@ -203,6 +203,7 @@ class ApiServer(Server):
         self.image_cache_driver = 'sqlite'
         self.policy_file = policy_file
         self.policy_default_rule = 'default'
+        self.server_control_options = '--capture-output'
         self.conf_base = """[DEFAULT]
 verbose = %(verbose)s
 debug = %(debug)s
@@ -292,6 +293,7 @@ class RegistryServer(Server):
                                          "registry.pid")
         self.log_file = os.path.join(self.test_dir, "registry.log")
         self.owner_is_tenant = True
+        self.server_control_options = '--capture-output'
         self.conf_base = """[DEFAULT]
 verbose = %(verbose)s
 debug = %(debug)s