Allows non standard OVS setups

Changes the checks to be based around the availability of the command
line OVS tools instead of the availability of the service installed
under apt. This allows netplan to consume OVS when it is provided as part
of another package such as in snap environments.

This involves minor changes to lots of the OVS code and also modifies
the unit tests as to handle OVS from both standard and nonstandard setups.

Signed-off-by: MJ Ponsonby <mj.ponsonby@canonical.com>

Author: crypticC0der

meson.build

@@ -32,6 +32,8 @@ find = find_program('find')
 
 add_project_arguments(
     '-DSBINDIR="' + join_paths(get_option('prefix'), get_option('sbindir')) + '"',
+    '-DPREFIX="' + get_option('prefix') + '"',
+    '-DBINDIR="' + get_option('bindir') + '"',
     '-D_GNU_SOURCE',
     '-Wconversion',
     language: 'c')

netplan_cli/cli/ovs.py

@@ -19,10 +19,7 @@
 import os
 import subprocess
 
-from .utils import systemctl_is_active, systemctl_is_installed
-
-OPENVSWITCH_OVS_VSCTL = '/usr/bin/ovs-vsctl'
-OPENVSWITCH_OVSDB_SERVER_UNIT = 'ovsdb-server.service'
+OPENVSWITCH_OVS_VSCTL = 'ovs-vsctl'
 # Defaults for non-optional settings, as defined here:
 # http://www.openvswitch.org/ovs-vswitchd.conf.db.5.pdf
 DEFAULTS = {
@@ -46,25 +43,43 @@ class OvsDbServerNotInstalled(Exception):
     pass
 
 
+def _ovs_vsctl_path():  # pragma: nocover
+    if os.path.exists('/snap/bin/'+OPENVSWITCH_OVS_VSCTL):
+        return '/snap/bin/'+OPENVSWITCH_OVS_VSCTL
+    else:
+        return '/usr/bin/'+OPENVSWITCH_OVS_VSCTL
+
+
+OVS_VSCTL_PATH = _ovs_vsctl_path()
+
+
+def _ovs_installed():  # pragma: nocover
+    return os.path.exists(OVS_VSCTL_PATH)
+
+
+def _ovs_active():  # pragma: nocover
+    return subprocess.call([OVS_VSCTL_PATH, 'show'], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL) == 0
+
+
 def _del_col(type, iface, column, value):
     """Cleanup values from a column (i.e. "column=value")"""
     default = DEFAULTS.get(column)
     if default is None:
         # removes the exact value only if it was set by netplan
-        cmd = [OPENVSWITCH_OVS_VSCTL, 'remove', type, iface, column, value]
+        cmd = [OVS_VSCTL_PATH, 'remove', type, iface, column, value]
         logging.debug('Running: %s' % ' '.join(cmd))
         subprocess.check_call(cmd)
     elif default and default != value:
         # reset to default, if its not the default already
-        cmd = [OPENVSWITCH_OVS_VSCTL, 'set', type, iface, '%s=%s' % (column, default)]
+        cmd = [OVS_VSCTL_PATH, 'set', type, iface, '%s=%s' % (column, default)]
         logging.debug('Running: %s' % ' '.join(cmd))
         subprocess.check_call(cmd)
 
 
 def _del_dict(type, iface, column, key, value):
     """Cleanup values from a dictionary (i.e. "column:key=value")"""
     # removes the exact value only if it was set by netplan
-    cmd = [OPENVSWITCH_OVS_VSCTL, 'remove', type, iface, column, '%s=\"%s\"' % (key, value)]
+    cmd = [OVS_VSCTL_PATH, 'remove', type, iface, column, '%s=\"%s\"' % (key, value)]
     logging.debug('Running: %s' % ' '.join(cmd))
     subprocess.check_call(cmd)
 
@@ -76,8 +91,8 @@ def _del_global(type, iface, key, value):
         iface = None
 
     if del_cmd:
-        args_get = [OPENVSWITCH_OVS_VSCTL, get_cmd]
-        args_del = [OPENVSWITCH_OVS_VSCTL, del_cmd]
+        args_get = [OVS_VSCTL_PATH, get_cmd]
+        args_del = [OVS_VSCTL_PATH, del_cmd]
         if iface:
             args_get.append(iface)
             args_del.append(iface)
@@ -112,7 +127,7 @@ def clear_setting(type, iface, setting, value):
     else:
         _del_col(type, iface, split[1], value)
     # Cleanup the tag itself (i.e. "netplan/column[/key]")
-    subprocess.check_call([OPENVSWITCH_OVS_VSCTL, 'remove', type, iface, 'external-ids', setting])
+    subprocess.check_call([OVS_VSCTL_PATH, 'remove', type, iface, 'external-ids', setting])
 
 
 def is_ovs_interface(iface, np_interface_dict):
@@ -129,11 +144,11 @@ def apply_ovs_cleanup(config_manager, ovs_old, ovs_current):  # pragma: nocover
     Also filter for individual settings tagged netplan/<column>[/<key]=value
     in external-ids and clear them if they have been set by netplan.
     """
-    if not systemctl_is_installed(OPENVSWITCH_OVSDB_SERVER_UNIT):
-        raise OvsDbServerNotInstalled("Cannot apply OVS cleanup: %s is 'not-found'" %
-                                      OPENVSWITCH_OVSDB_SERVER_UNIT)
-    if not systemctl_is_active(OPENVSWITCH_OVSDB_SERVER_UNIT):
-        raise OvsDbServerNotRunning('{} is not running'.format(OPENVSWITCH_OVSDB_SERVER_UNIT))
+    if not _ovs_installed():
+        raise OvsDbServerNotInstalled("Cannot apply OpenvSwitch cleanup: ovs-vsctl is 'not-found'")
+
+    if not _ovs_active():
+        raise OvsDbServerNotRunning('OpenvSwitch database is not running')
 
     config_manager.parse()
     ovs_ifaces = set()
@@ -144,47 +159,42 @@ def apply_ovs_cleanup(config_manager, ovs_old, ovs_current):  # pragma: nocover
     # Tear down old OVS interfaces, not defined in the current config.
     # Use 'del-br' on the Interface table, to delete any netplan created VLAN fake bridges.
     # Use 'del-bond-iface' on the Interface table, to delete netplan created patch port interfaces
-    if os.path.isfile(OPENVSWITCH_OVS_VSCTL):
-        # Step 1: Delete all interfaces, which are not part of the current OVS config
-        for t in (('Port', 'del-port'), ('Bridge', 'del-br'), ('Interface', 'del-br')):
-            out = subprocess.check_output([OPENVSWITCH_OVS_VSCTL, '--columns=name,external-ids',
-                                           '-f', 'csv', '-d', 'bare', '--no-headings', 'list', t[0]],
-                                          text=True)
-            for line in out.splitlines():
-                if 'netplan=true' in line:
-                    iface = line.split(',')[0]
-                    # Skip cleanup if this OVS interface is part of the current netplan OVS config
-                    if iface in ovs_ifaces:
-                        continue
-                    if t[0] == 'Interface' and subprocess.run([OPENVSWITCH_OVS_VSCTL, 'br-exists', iface]).returncode > 0:
-                        subprocess.check_call([OPENVSWITCH_OVS_VSCTL, '--if-exists', 'del-bond-iface', iface])
-                    else:
-                        subprocess.check_call([OPENVSWITCH_OVS_VSCTL, '--if-exists', t[1], iface])
-
-        # Step 2: Clean up the settings of the remaining interfaces
-        for t in ('Port', 'Bridge', 'Interface', 'Open_vSwitch', 'Controller'):
-            cols = 'name,external-ids'
-            if t == 'Open_vSwitch':
-                cols = 'external-ids'
-            elif t == 'Controller':
-                cols = '_uuid,external-ids'  # handle _uuid as if it would be the iface 'name'
-            out = subprocess.check_output([OPENVSWITCH_OVS_VSCTL, '--columns=%s' % cols,
-                                           '-f', 'csv', '-d', 'bare', '--no-headings', 'list', t],
-                                          text=True)
-            for line in out.splitlines():
-                if 'netplan/' in line:
-                    iface = '.'
-                    extids = line
-                    if t != 'Open_vSwitch':
-                        iface, extids = line.split(',', 1)
-                    # Check each line (interface) if it contains any netplan tagged settings, e.g.:
-                    # ovs0,"iface-id=myhostname netplan=true netplan/external-ids/iface-id=myhostname"
-                    # ovs1,"netplan=true netplan/global/set-fail-mode=standalone netplan/mcast_snooping_enable=false"
-                    for entry in extids.strip('"').split(' '):
-                        if entry.startswith('netplan/') and '=' in entry:
-                            setting, val = entry.split('=', 1)
-                            clear_setting(t, iface, setting, val)
-
-    # Show the warning only if we are or have been working with OVS definitions
-    elif ovs_old or ovs_current:
-        logging.warning('ovs-vsctl is missing, cannot tear down old OpenVSwitch interfaces')
+    # Step 1: Delete all interfaces, which are not part of the current OVS config
+    for t in (('Port', 'del-port'), ('Bridge', 'del-br'), ('Interface', 'del-br')):
+        out = subprocess.check_output([OVS_VSCTL_PATH, '--columns=name,external-ids',
+                                       '-f', 'csv', '-d', 'bare', '--no-headings', 'list', t[0]],
+                                      text=True)
+        for line in out.splitlines():
+            if 'netplan=true' in line:
+                iface = line.split(',')[0]
+                # Skip cleanup if this OVS interface is part of the current netplan OVS config
+                if iface in ovs_ifaces:
+                    continue
+                if t[0] == 'Interface' and subprocess.run([OVS_VSCTL_PATH, 'br-exists', iface]).returncode > 0:
+                    subprocess.check_call([OVS_VSCTL_PATH, '--if-exists', 'del-bond-iface', iface])
+                else:
+                    subprocess.check_call([OVS_VSCTL_PATH, '--if-exists', t[1], iface])
+
+    # Step 2: Clean up the settings of the remaining interfaces
+    for t in ('Port', 'Bridge', 'Interface', 'Open_vSwitch', 'Controller'):
+        cols = 'name,external-ids'
+        if t == 'Open_vSwitch':
+            cols = 'external-ids'
+        elif t == 'Controller':
+            cols = '_uuid,external-ids'  # handle _uuid as if it would be the iface 'name'
+        out = subprocess.check_output([OVS_VSCTL_PATH, '--columns=%s' % cols,
+                                       '-f', 'csv', '-d', 'bare', '--no-headings', 'list', t],
+                                      text=True)
+        for line in out.splitlines():
+            if 'netplan/' in line:
+                iface = '.'
+                extids = line
+                if t != 'Open_vSwitch':
+                    iface, extids = line.split(',', 1)
+                # Check each line (interface) if it contains any netplan tagged settings, e.g.:
+                # ovs0,"iface-id=myhostname netplan=true netplan/external-ids/iface-id=myhostname"
+                # ovs1,"netplan=true netplan/global/set-fail-mode=standalone netplan/mcast_snooping_enable=false"
+                for entry in extids.strip('"').split(' '):
+                    if entry.startswith('netplan/') and '=' in entry:
+                        setting, val = entry.split('=', 1)
+                        clear_setting(t, iface, setting, val)