Fix flake8 linting

- Remove unused imports
- Search for ip executables in known locations
- Fix f-string
- Ignore assert warnings

diff --git a/test/linux/netem.py b/test/linux/netem.py
index cc2b03fdc35fc008a3164d00a2d886c68f1d7b29..8dc8f520903ff965be849c440282a136fac9ccc3 100644 (file)
--- a/test/linux/netem.py
+++ b/test/linux/netem.py
@@ -68,7 +68,7 @@ from dataclasses import dataclass
 from enum import Enum
 from functools import partial
 from io import IOBase
-from typing import Any, Dict, List, Optional, Tuple, Union, Type, cast
+from typing import Any, Dict, List, Optional, Tuple, Union, cast
 
 # Third-party imports
 from ctypes import CDLL, get_errno
@@ -115,8 +115,6 @@ class Rule():
     fwmark: Optional[int] = 0 # Optional firewall mark
     table: Optional[int] = None # Routing table ID
 
-from typing import Callable
-
 class LifecycleException(Exception):
     pass
 
@@ -282,7 +280,7 @@ class Host(NetworkObject):
                 **kwargs
             ))
         else:
-            assert len(kwargs) == 0
+            assert len(kwargs) == 0 # noqa: B101
             self._routes.append(prefix_or_route)
 
     @config_method
@@ -355,7 +353,8 @@ class Network():
         '''
 
         assert self._phase == Lifecycle.CONFIG, \
-                "Repeated calls to create() on a single network object"
+                "Repeated calls to create() on a single network object" # noqa: B101
+
 
         for name, host in self._hosts.items():
             host.netns_name = f'{self.name}.{name}'
@@ -377,7 +376,8 @@ class Network():
         associated resources
         '''
         assert self._phase == Lifecycle.RUNTIME, \
-            "Network not setup"
+            "Network not setup" # noqa: B101
+
 
         destroy_network(self)
         self._phase = Lifecycle.CONFIG
@@ -473,6 +473,27 @@ class NetNamespace(object):
 # Enable tracing
 MTR_NETEM_TRACE = len(os.getenv('MTR_NETEM_TRACE', '')) > 0
 
+
+def find_ip_command() -> Optional[str]:
+    '''
+    Search for the location of the `ip` command in common directories.
+    '''
+    # List of possible locations where the `ip` command might be located
+    possible_locations = [
+        "/usr/bin/ip",
+        "/sbin/ip",
+        "/usr/sbin/ip",
+        "/bin/ip"
+    ]
+
+    # Loop through the possible locations
+    for location in possible_locations:
+        # Check if the file exists and is executable
+        if os.path.isfile(location) and os.access(location, os.X_OK):
+            return location
+
+    return None
+
 def run_cmd(*args, **kargs):
     '''
     Execute a shell command.
@@ -542,7 +563,7 @@ def set_kernel_opt(path : str, value : Union[str, int]):
         with open(path, 'w') as file:
             file.write(str(value))
     except Exception as e:
-        raise RuntimeError('Failed to configure kernel option: {str(e)}')
+        raise RuntimeError(f'Failed to configure kernel option: {str(e)}')
 
 def set_interface_rpfiler(intf_name : str, rpfilter : Rpfilter):
     '''
@@ -572,10 +593,12 @@ def create_network(net : Network):
 
     cmd = partial(run_cmd, check=True)
 
+    ip_cmd = cast(str, find_ip_command())
+
     # Add host namespaces
     host : Host
     for host in net._hosts.values():
-        cmd([ 'ip', 'netns', 'add', host.netns_name ], check=True)
+        cmd([ ip_cmd, 'netns', 'add', host.netns_name ], check=True)
 
     link : Link
     for link in net._links.values():
@@ -585,7 +608,7 @@ def create_network(net : Network):
 
         # Add a virtual ethernet link
         cmd([
-            'ip', 'link', 'add', intfs[0].name,
+            ip_cmd, 'link', 'add', intfs[0].name,
             'type', 'veth', 'peer', 'name',
             intfs[1].name
         ])
@@ -596,7 +619,7 @@ def create_network(net : Network):
             netns_name = cast(str, host.netns_name)
 
             # Move a end of the link pair into the host's network namespace
-            cmd(['ip', 'link', 'set', intf_name, 'netns', netns_name])
+            cmd([ip_cmd, 'link', 'set', intf_name, 'netns', netns_name])
 
             with NetNamespace(netns_name):
                 # Configure the reverse pass filter
@@ -604,10 +627,10 @@ def create_network(net : Network):
 
                 # Add IP addresses to the link
                 for addr in intf.addresses:
-                    cmd(['ip', 'addr', 'add', addr, 'dev', intf_name])
+                    cmd([ip_cmd, 'addr', 'add', addr, 'dev', intf_name])
 
                 # Activate the interface
-                cmd(['ip', 'link', 'set', intf.name, 'up'])
+                cmd([ip_cmd, 'link', 'set', intf.name, 'up'])
 
     for host in net._hosts.values():
 
@@ -617,11 +640,11 @@ def create_network(net : Network):
 
             # Add the host's routes
             for route in host._routes:
-                cmd(['ip', 'route', 'add', *route_spec(route)])
+                cmd([ip_cmd, 'route', 'add', *route_spec(route)])
 
             # Add the host's policy-database rules
             for rule in host._rules:
-                cmd(['ip', 'rule', 'add', *rule_spec(rule)])
+                cmd([ip_cmd, 'rule', 'add', *rule_spec(rule)])
 
 def destroy_network(net : Network):
     '''
@@ -630,15 +653,25 @@ def destroy_network(net : Network):
     This will remove all network namespaces and associated resources created during network setup.
     '''
 
+    ip_cmd = cast(str, find_ip_command())
+
     host : Host
     for host in net._hosts.values():
-        run_cmd([ 'ip', 'netns', 'delete', host.netns_name ])
+        run_cmd([ip_cmd, 'netns', 'delete', host.netns_name])
+
+# /usr/bin/ip
+# /sbin/ip
 
 def has_iproute() -> bool:
     '''Test if the host has iproute2 ensuring `ip -V` returns 0'''
 
+    ip_cmd = find_ip_command()
+
+    if ip_cmd is None:
+        return False
+
     try:
-        ip_result = subprocess.run(['ip', '-V'], capture_output=True)
+        ip_result = subprocess.run([ip_cmd, '-V'], capture_output=True)
     except:
         return False