added service executable check, added error message to gui for service load errors

daemon/core/corehandlers.py

@@ -17,13 +17,13 @@ from core import logger
 from core.api import coreapi
 from core.api import dataconversion
 from core.conf import ConfigShim
-from core.data import ConfigData
+from core.data import ConfigData, ExceptionData
 from core.data import EventData
 from core.data import FileData
 from core.emulator.emudata import InterfaceData
 from core.emulator.emudata import LinkOptions
 from core.emulator.emudata import NodeOptions
-from core.enumerations import ConfigDataTypes
+from core.enumerations import ConfigDataTypes, ExceptionLevels
 from core.enumerations import ConfigFlags
 from core.enumerations import ConfigTlvs
 from core.enumerations import EventTlvs
@@ -551,6 +551,14 @@ class CoreHandler(SocketServer.BaseRequestHandler):
         # set initial session state
         self.session.set_state(EventTypes.DEFINITION_STATE)
 
+        # send service errors, if present
+        if self.coreemu.service_errors:
+            self.send_exception(
+                ExceptionLevels.ERROR,
+                "ServiceManager.load()",
+                "Failed to load services: %s" % " ".join(self.coreemu.service_errors)
+            )
+
         while True:
             try:
                 message = self.receive_message()
@@ -579,6 +587,26 @@ class CoreHandler(SocketServer.BaseRequestHandler):
                 logger.debug("BROADCAST TO OTHER CLIENT: %s", client)
                 client.sendall(message.raw_message)
 
+    def send_exception(self, level, source, text, node=None):
+        """
+        Sends an exception for display within the GUI.
+
+        :param core.enumerations.ExceptionLevel level: level for exception
+        :param str source: source where exception came from
+        :param str text: details about exception
+        :param int node: node id, if related to a specific node
+        :return:
+        """
+        exception_data = ExceptionData(
+            session=str(self.session.session_id),
+            node=node,
+            date=time.ctime(),
+            level=level.value,
+            source=source,
+            text=text
+        )
+        self.handle_broadcast_exception(exception_data)
+
     def add_session_handlers(self):
         logger.debug("adding session broadcast handlers")
         self.session.event_handlers.append(self.handle_broadcast_event)

daemon/core/emulator/coreemu.py

@@ -15,6 +15,7 @@ from core.enumerations import LinkTypes
 from core.enumerations import NodeTypes
 from core.misc import nodemaps
 from core.misc import nodeutils
+from core.service import ServiceManager
 from core.session import Session
 from core.xml.xmlparser import core_document_parser
 from core.xml.xmlwriter import core_document_writer
@@ -813,12 +814,26 @@ class CoreEmu(object):
         node_map = nodemaps.NODES
         nodeutils.set_node_map(node_map)
 
-        # load default services
-        core.services.load()
+        # load services
+        self.service_errors = []
+        self.load_services()
 
         # catch exit event
         atexit.register(self.shutdown)
 
+    def load_services(self):
+        # load default services
+        self.service_errors = core.services.load()
+
+        # load custom services
+        service_paths = self.config.get("custom_services_dir")
+        logger.debug("custom service paths: %s", service_paths)
+        if service_paths:
+            for service_path in service_paths.split(','):
+                service_path = service_path.strip()
+                custom_service_errors = ServiceManager.add_services(service_path)
+                self.service_errors.extend(custom_service_errors)
+
     def update_nodes(self, node_map):
         """
         Updates node map used by core.

daemon/core/service.py

@@ -7,6 +7,8 @@ a list of available services to the GUI and for configuring individual
 services.
 """
 
+from core.constants import which
+
 from core import CoreCommandError
 from core import logger
 from core.data import FileData
@@ -126,8 +128,18 @@ class ServiceManager(object):
         """
         logger.info("loading service: %s", service.__name__)
         name = service.name
+
+        # avoid duplicate services
         if name in cls.services:
             raise ValueError("duplicate service being added: %s" % name)
+
+        # validate dependent executables are present
+        for executable in service.executables:
+            if not which(executable):
+                logger.error("service(%s) missing executable: %s", service.name, executable)
+                raise ValueError("service(%s) missing executable: %s" % (service.name, executable))
+
+        # make service available
         cls.services[name] = service
 
     @classmethod
@@ -147,15 +159,22 @@ class ServiceManager(object):
         Method for retrieving all CoreServices from a given path.
 
         :param str path: path to retrieve services from
-        :return: list of core services
-        :rtype: list
+        :return: list of core services that failed to load
+        :rtype: list[str]
         """
+        service_errors = []
         services = utils.load_classes(path, CoreService)
         for service in services:
             if not service.name:
                 continue
             service.on_load()
-            cls.add(service)
+
+            try:
+                cls.add(service)
+            except ValueError as e:
+                service_errors.append(service.name)
+                logger.error("failure loading service: %s", e.message)
+        return service_errors
 
 
 class CoreServices(object):
@@ -623,6 +642,9 @@ class CoreService(object):
     # service name should not include spaces
     name = None
 
+    # executables that must exist for service to run
+    executables = ()
+
     # group string allows grouping services together
     group = None
 

daemon/core/services/__init__.py

@@ -15,6 +15,7 @@ def load():
     """
     Loads all services from the modules that reside under core.services.
 
-    :return: nothing
+    :return: list of services that failed to load
+    :rtype: list[str]
     """
-    ServiceManager.add_services(_PATH)
+    return ServiceManager.add_services(_PATH)

daemon/core/services/bird.py

@@ -10,6 +10,7 @@ class Bird(CoreService):
     Bird router support
     """
     name = "bird"
+    executables = ("bird",)
     group = "BIRD"
     depends = ()
     dirs = ("/etc/bird",)
@@ -91,6 +92,7 @@ class BirdService(CoreService):
     """
 
     name = None
+    executables = ("bird",)
     group = "BIRD"
     depends = ("bird",)
     dirs = ()

daemon/core/services/dockersvc.py

@@ -113,6 +113,7 @@ class DockerService(CoreService):
         node.
     """
     name = "Docker"
+    executables = ("docker",)
     group = "Docker"
     depends = ()
     dirs = ('/var/lib/docker/containers/', '/run/shm', '/run/resolvconf',)

daemon/core/services/sdn.py

@@ -11,14 +11,8 @@ class SdnService(CoreService):
     """
     Parent class for SDN services.
     """
-    name = None
     group = "SDN"
-    depends = ()
-    dirs = ()
-    configs = ()
     startindex = 50
-    startup = ()
-    shutdown = ()
 
     @classmethod
     def generateconfig(cls, node, filename, services):
@@ -27,6 +21,7 @@ class SdnService(CoreService):
 
 class OvsService(SdnService):
     name = "OvsService"
+    executables = ("ovs-ofctl", "ovs-vsctl")
     group = "SDN"
     depends = ()
     dirs = ("/etc/openvswitch", "/var/run/openvswitch", "/var/log/openvswitch")
@@ -101,6 +96,7 @@ class OvsService(SdnService):
 
 class RyuService(SdnService):
     name = "ryuService"
+    executables = ("ryu-manager",)
     group = "SDN"
     depends = ()
     dirs = ()

daemon/core/services/xorp.py

@@ -12,6 +12,7 @@ class XorpRtrmgr(CoreService):
     enabled XORP services, and launches necessary daemons upon startup.
     """
     name = "xorp_rtrmgr"
+    executables = ("xorp_rtrmgr",)
     group = "XORP"
     depends = ()
     dirs = ("/etc/xorp",)
@@ -75,6 +76,7 @@ class XorpService(CoreService):
     common to XORP's routing daemons.
     """
     name = None
+    executables = ("xorp_rtrmgr",)
     group = "XORP"
     depends = ("xorp_rtrmgr",)
     dirs = ()

daemon/examples/myservices/sample.py

@@ -4,7 +4,6 @@ Sample user-defined service.
 
 from core.misc.ipaddress import Ipv4Prefix
 from core.service import CoreService
-from core.service import ServiceManager
 
 
 class MyService(CoreService):
@@ -12,22 +11,22 @@ class MyService(CoreService):
     This is a sample user-defined service.
     """
     # a unique name is required, without spaces
-    _name = "MyService"
+    name = "MyService"
     # you can create your own group here
-    _group = "Utility"
+    group = "Utility"
     # list of other services this service depends on
-    _depends = ()
+    depends = ()
     # per-node directories
-    _dirs = ()
+    dirs = ()
     # generated files (without a full path this file goes in the node's dir,
     #  e.g. /tmp/pycore.12345/n1.conf/)
-    _configs = ('myservice.sh',)
+    configs = ('myservice.sh',)
     # this controls the starting order vs other enabled services
-    _startindex = 50
+    startindex = 50
     # list of startup commands, also may be generated during startup
-    _startup = ('sh myservice.sh',)
+    startup = ('sh myservice.sh',)
     # list of shutdown commands
-    _shutdown = ()
+    shutdown = ()
 
     @classmethod
     def generateconfig(cls, node, filename, services):
@@ -57,9 +56,3 @@ class MyService(CoreService):
         else:
             net = Ipv4Prefix(x)
             return 'echo "  network %s"' % net
-
-
-# this is needed to load desired services when being integrated into core, otherwise this is not needed
-def load_services():
-    # this line is required to add the above class to the list of available services
-    ServiceManager.add(MyService)

daemon/scripts/core-daemon

@@ -16,7 +16,6 @@ from core import logger
 from core.corehandlers import CoreHandler
 from core.coreserver import CoreServer
 from core.misc.utils import close_onexec
-from core.service import ServiceManager
 
 
 def banner():
@@ -116,14 +115,6 @@ def main():
     for a in args:
         logger.error("ignoring command line argument: %s", a)
 
-    # attempt load custom services
-    service_paths = cfg.get("custom_services_dir")
-    logger.debug("custom service paths: %s", service_paths)
-    if service_paths:
-        for service_path in service_paths.split(','):
-            service_path = service_path.strip()
-            ServiceManager.add_services(service_path)
-
     banner()
 
     # check if ovs flag was provided