Add support for prsetpdeathsig config option on Linux only.

* Original pull inspired by: Supervisor#199
* If the supervisor process dies, that the child process will receive this signal set in prsetpdeathsig.

Author: lukeweber

supervisor/options.py

@@ -906,6 +906,15 @@ def get(section, opt, *args, **kwargs):
         process_name = process_or_group_name(
             get(section, 'process_name', '%(program_name)s', do_expand=False))
 
+        prsetpdeathsig = get(section, 'prsetpdeathsig', None)
+        if prsetpdeathsig is not None:
+            if sys.platform.startswith("linux"):
+                prsetpdeathsig = signal_number(prsetpdeathsig)
+            else:
+                raise ValueError(
+                    "Cannot set prsetpdeathsig on non-linux os"
+                    )
+
         if numprocs > 1:
             if not '%(process_num)' in process_name:
                 # process_name needs to include process_num when we
@@ -1002,7 +1011,8 @@ def get(section, opt, *args, **kwargs):
                 exitcodes=exitcodes,
                 redirect_stderr=redirect_stderr,
                 environment=environment,
-                serverurl=serverurl)
+                serverurl=serverurl,
+                prsetpdeathsig=prsetpdeathsig)
 
             programs.append(pconfig)
 
@@ -1797,7 +1807,7 @@ class ProcessConfig(Config):
         'stderr_logfile_backups', 'stderr_logfile_maxbytes',
         'stderr_events_enabled', 'stderr_syslog',
         'stopsignal', 'stopwaitsecs', 'stopasgroup', 'killasgroup',
-        'exitcodes', 'redirect_stderr' ]
+        'exitcodes', 'redirect_stderr', 'prsetpdeathsig' ]
     optional_param_names = [ 'environment', 'serverurl' ]
 
     def __init__(self, options, **params):

supervisor/process.py

@@ -1,3 +1,4 @@
+import sys
 import os
 import time
 import errno
@@ -296,6 +297,21 @@ def _spawn_as_child(self, filename, argv):
             # supervisord from being sent to children.
             options.setpgrp()
 
+            # Send this process a kill signal if supervisor crashes.
+            # Uses system call prctl(PR_SET_PDEATHSIG, <signal>).
+            # This will only work on Linux.
+            if self.config.prsetpdeathsig is not None \
+                    and sys.platform.startswith("linux"):
+                # Constant from http://linux.die.net/include/linux/prctl.h
+                PR_SET_PDEATHSIG = 1
+                try:
+                    import ctypes
+                    import ctypes.util
+                    libc = ctypes.cdll.LoadLibrary(ctypes.util.find_library('c'))
+                    libc.prctl(PR_SET_PDEATHSIG, self.config.prsetpdeathsig)
+                except Exception:
+                    options.logger.debug("Could not set parent death signal.")
+
             self._prepare_child_fds()
             # sending to fd 2 will put this output in the stderr log
 

supervisor/tests/base.py

@@ -516,7 +516,7 @@ def __init__(self, options, name, command, directory=None, umask=None,
                  stderr_logfile_backups=0, stderr_logfile_maxbytes=0,
                  redirect_stderr=False,
                  stopsignal=None, stopwaitsecs=10, stopasgroup=False, killasgroup=False,
-                 exitcodes=(0,2), environment=None, serverurl=None):
+                 exitcodes=(0,2), environment=None, serverurl=None, prsetpdeathsig=None):
         self.options = options
         self.name = name
         self.command = command
@@ -550,6 +550,7 @@ def __init__(self, options, name, command, directory=None, umask=None,
         self.umask = umask
         self.autochildlogs_created = False
         self.serverurl = serverurl
+        self.prsetpdeathsig = prsetpdeathsig
 
     def create_autochildlogs(self):
         self.autochildlogs_created = True

supervisor/tests/test_options.py

@@ -1423,6 +1423,68 @@ def test_processes_from_section_host_node_name_expansion(self):
         expected = "/bin/foo --host=" + platform.node()
         self.assertEqual(pconfigs[0].command, expected)
 
+    def test_processes_from_section_prsetdeathsig_error(self):
+        instance = self._makeOne()
+        text = lstrip("""\
+        [program:foo]
+        command = /bin/foo
+        prsetpdeathsig = SIGKILL
+        """)
+        from supervisor.options import UnhosedConfigParser
+        config = UnhosedConfigParser()
+        config.read_string(text)
+
+        platform_mock = Mock()
+        platform_mock.return_value = "darwin"
+        @patch('sys.platform', platform_mock)
+        def parse_config(instance, config):
+            instance.processes_from_section(config, 'program:foo', 'bar')
+
+        try:
+            parse_config(instance, config)
+        except ValueError as exc:
+            self.assertTrue(exc.args[0].startswith(
+                'Cannot set prsetpdeathsig on non-linux os in section'))
+
+    def test_processes_from_section_prsetdeathsig_linux(self):
+        instance = self._makeOne()
+        text = lstrip("""\
+        [program:foo]
+        command = /bin/foo
+        prsetpdeathsig = SIGKILL
+        """)
+        from supervisor.options import UnhosedConfigParser
+        config = UnhosedConfigParser()
+        config.read_string(text)
+
+        platform_mock = Mock()
+        platform_mock.return_value = "linux"
+        @patch('sys.platform', platform_mock)
+        def parse_config(instance, config):
+            return instance.processes_from_section(config, 'program:foo', 'bar')
+
+        pconfig = parse_config(instance, config)
+        self.assertEqual(pconfig[0].prsetpdeathsig, signal.SIGKILL)
+
+    def test_processes_from_section_prsetdeathsig_linux_default(self):
+        instance = self._makeOne()
+        text = lstrip("""\
+        [program:foo]
+        command = /bin/foo
+        """)
+        from supervisor.options import UnhosedConfigParser
+        config = UnhosedConfigParser()
+        config.read_string(text)
+
+        platform_mock = Mock()
+        platform_mock.return_value = "linux"
+        @patch('sys.platform', platform_mock)
+        def parse_config(instance, config):
+            return instance.processes_from_section(config, 'program:foo', 'bar')
+
+        pconfig = parse_config(instance, config)
+        self.assertEqual(pconfig[0].prsetpdeathsig, None)
+
     def test_processes_from_section_process_num_expansion(self):
         instance = self._makeOne()
         text = lstrip("""\
@@ -2677,7 +2739,7 @@ def _makeOne(self, *arg, **kw):
                      'stderr_events_enabled', 'stderr_syslog',
                      'stopsignal', 'stopwaitsecs', 'stopasgroup',
                      'killasgroup', 'exitcodes', 'redirect_stderr',
-                     'environment'):
+                     'environment', 'prsetpdeathsig'):
             defaults[name] = name
         for name in ('stdout_logfile_backups', 'stdout_logfile_maxbytes',
                      'stderr_logfile_backups', 'stderr_logfile_maxbytes'):
@@ -2759,7 +2821,7 @@ def _makeOne(self, *arg, **kw):
                      'stderr_events_enabled', 'stderr_syslog',
                      'stopsignal', 'stopwaitsecs', 'stopasgroup',
                      'killasgroup', 'exitcodes', 'redirect_stderr',
-                     'environment'):
+                     'environment', 'prsetpdeathsig'):
             defaults[name] = name
         for name in ('stdout_logfile_backups', 'stdout_logfile_maxbytes',
                      'stderr_logfile_backups', 'stderr_logfile_maxbytes'):
@@ -2807,7 +2869,7 @@ def _makeOne(self, *arg, **kw):
                      'stderr_events_enabled', 'stderr_syslog',
                      'stopsignal', 'stopwaitsecs', 'stopasgroup',
                      'killasgroup', 'exitcodes', 'redirect_stderr',
-                     'environment'):
+                     'environment', 'prsetpdeathsig'):
             defaults[name] = name
         for name in ('stdout_logfile_backups', 'stdout_logfile_maxbytes',
                      'stderr_logfile_backups', 'stderr_logfile_maxbytes'):

supervisor/tests/test_supervisord.py

@@ -332,6 +332,7 @@ def make_pconfig(name, command, **params):
                 'stopasgroup': False,
                 'killasgroup': False,
                 'exitcodes': (0,2), 'environment': None, 'serverurl': None,
+                'prsetpdeathsig': None
             }
             result.update(params)
             return ProcessConfig(options, **result)