updates to fail early for required executables that are not in PATH

daemon/core/nodes/base.py

@@ -14,17 +14,16 @@ import threading
 from builtins import range
 from socket import AF_INET, AF_INET6
 
-from core import CoreCommandError, constants, utils
+from core import constants, utils
 from core.emulator.data import LinkData, NodeData
 from core.emulator.enumerations import LinkTypes, NodeTypes
+from core.errors import CoreCommandError
 from core.nodes import client, ipaddress
 from core.nodes.interface import CoreInterface, TunTap, Veth
 from core.nodes.netclient import LinuxNetClient, OvsNetClient
 
 _DEFAULT_MTU = 1500
 
-utils.check_executables([constants.IP_BIN])
-
 
 class NodeBase(object):
     """

daemon/core/nodes/client.py

@@ -8,7 +8,8 @@ import logging
 import os
 from subprocess import PIPE, Popen
 
-from core import CoreCommandError, constants, utils
+from core import constants, utils
+from core.errors import CoreCommandError
 
 
 class VnodeClient(object):

daemon/core/nodes/docker.py

@@ -2,8 +2,9 @@ import json
 import logging
 import os
 
-from core import CoreCommandError, utils
+from core import utils
 from core.emulator.enumerations import NodeTypes
+from core.errors import CoreCommandError
 from core.nodes.base import CoreNode
 
 

daemon/core/nodes/interface.py

@@ -6,9 +6,8 @@ import logging
 import time
 from builtins import int, range
 
-from core import CoreCommandError, constants, utils
-
-utils.check_executables([constants.IP_BIN])
+from core import constants, utils
+from core.errors import CoreCommandError
 
 
 class CoreInterface(object):

daemon/core/nodes/lxd.py

@@ -3,8 +3,9 @@ import logging
 import os
 import time
 
-from core import CoreCommandError, utils
+from core import utils
 from core.emulator.enumerations import NodeTypes
+from core.errors import CoreCommandError
 from core.nodes.base import CoreNode
 
 

daemon/core/nodes/network.py

@@ -9,17 +9,14 @@ import threading
 import time
 from socket import AF_INET, AF_INET6
 
-from core import CoreCommandError, CoreError, constants, utils
+from core import constants, utils
 from core.emulator.data import LinkData
 from core.emulator.enumerations import LinkTypes, NodeTypes, RegisterTlvs
+from core.errors import CoreCommandError, CoreError
 from core.nodes import ipaddress
 from core.nodes.base import CoreNetworkBase
 from core.nodes.interface import GreTap, Veth
 
-utils.check_executables(
-    [constants.BRCTL_BIN, constants.IP_BIN, constants.EBTABLES_BIN, constants.TC_BIN]
-)
-
 ebtables_lock = threading.Lock()
 
 

daemon/core/nodes/physical.py

@@ -7,8 +7,9 @@ import os
 import subprocess
 import threading
 
-from core import CoreCommandError, constants, utils
+from core import constants, utils
 from core.emulator.enumerations import NodeTypes
+from core.errors import CoreCommandError
 from core.nodes.base import CoreNodeBase
 from core.nodes.interface import CoreInterface
 from core.nodes.network import CoreNetwork, GreTap