1 files changed, 115 insertions, 0 deletions
diff --git a/azurelinuxagent/distro/default/env.py b/azurelinuxagent/distro/default/env.py
new file mode 100644
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+++ b/azurelinuxagent/distro/default/env.py
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+# Windows Azure Linux Agent
+#
+# Copyright 2014 Microsoft Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Requires Python 2.4+ and Openssl 1.0+
+#
+
+import os
+import socket
+import threading
+import time
+import azurelinuxagent.logger as logger
+import azurelinuxagent.conf as conf
+from azurelinuxagent.utils.osutil import OSUTIL
+
+class EnvHandler(object):
+    """
+    Monitor changes to dhcp and hostname.
+    If dhcp clinet process re-start has occurred, reset routes, dhcp with fabric.
+
+    Monitor scsi disk.
+    If new scsi disk found, set
+    """
+    def __init__(self, handlers):
+        self.monitor = EnvMonitor(handlers.dhcp_handler)
+
+    def start(self):
+        self.monitor.start()
+
+    def stop(self):
+        self.monitor.stop()
+
+class EnvMonitor(object):
+
+    def __init__(self, dhcp_handler):
+        self.dhcp_handler = dhcp_handler
+        self.stopped = True
+        self.hostname = None
+        self.dhcpid = None
+        self.server_thread=None
+
+    def start(self):
+        if not self.stopped:
+            logger.info("Stop existing env monitor service.")
+            self.stop()
+
+        self.stopped = False
+        logger.info("Start env monitor service.")
+        self.hostname = socket.gethostname()
+        self.dhcpid = OSUTIL.get_dhcp_pid()
+        self.server_thread = threading.Thread(target = self.monitor)
+        self.server_thread.setDaemon(True)
+        self.server_thread.start()
+
+    def monitor(self):
+        """
+        Monitor dhcp client pid and hostname.
+        If dhcp clinet process re-start has occurred, reset routes.
+        """
+        while not self.stopped:
+            OSUTIL.remove_rules_files()
+            timeout = conf.get("OS.RootDeviceScsiTimeout", None)
+            if timeout is not None:
+                OSUTIL.set_scsi_disks_timeout(timeout)
+            if conf.get_switch("Provisioning.MonitorHostName", False):
+                self.handle_hostname_update()
+            self.handle_dhclient_restart()
+            time.sleep(5)
+
+    def handle_hostname_update(self):
+        curr_hostname = socket.gethostname()
+        if curr_hostname != self.hostname:
+            logger.info("EnvMonitor: Detected host name change: {0} -> {1}",
+                        self.hostname, curr_hostname)
+            OSUTIL.set_hostname(curr_hostname)
+            OSUTIL.publish_hostname(curr_hostname)
+            self.hostname = curr_hostname
+
+    def handle_dhclient_restart(self):
+        if self.dhcpid is None:
+            logger.warn("Dhcp client is not running. ")
+            self.dhcpid = OSUTIL.get_dhcp_pid()
+            return
+
+        #The dhcp process hasn't changed since last check
+        if os.path.isdir(os.path.join('/proc', self.dhcpid.strip())):
+            return
+
+        newpid = OSUTIL.get_dhcp_pid()
+        if newpid is not None and newpid != self.dhcpid:
+           logger.info("EnvMonitor: Detected dhcp client restart. "
+                       "Restoring routing table.")
+           self.dhcp_handler.conf_routes()
+           self.dhcpid = newpid
+
+    def stop(self):
+        """
+        Stop server comminucation and join the thread to main thread.
+        """
+        self.stopped = True
+        if self.server_thread is not None:
+            self.server_thread.join()
+