Merge lp:~mpontillo/maas/fix-long-bridge-names--bug-1672327 into lp:~maas-committers/maas/trunk

[Mike Pontillo]

When creating a bridge name, keep the name under 16 characters.

Uses the same algorithm as proposed for Juju in https://github.com/juju/juju/pull/7204.

[Blake Rouse (blake-rouse)]

Looks good.

review: Approve

[MAAS Lander (maas-lander)]

The attempt to merge lp:~mpontillo/maas/fix-long-bridge-names--bug-1672327 into lp:maas failed. Below is the output from the failed tests.

Get:1 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]
Hit:2 http://prodstack-zone-2.clouds.archive.ubuntu.com/ubuntu xenial InRelease
Get:3 http://prodstack-zone-2.clouds.archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB]
Get:4 http://prodstack-zone-2.clouds.archive.ubuntu.com/ubuntu xenial-backports InRelease [102 kB]
Fetched 306 kB in 0s (393 kB/s)
Reading package lists...
sudo DEBIAN_FRONTEND=noninteractive apt-get -y \
    --no-install-recommends install apache2 archdetect-deb authbind avahi-utils bash bind9 bind9utils build-essential bzr bzr-builddeb chromium-browser chromium-chromedriver curl daemontools debhelper dh-apport dh-systemd distro-info dnsutils firefox freeipmi-tools git gjs ipython isc-dhcp-common isc-dhcp-server libjs-angularjs libjs-jquery libjs-jquery-hotkeys libjs-yui3-full libjs-yui3-min libnss-wrapper libpq-dev make nodejs-legacy npm postgresql psmisc pxelinux python3-all python3-apt python3-attr python3-bson python3-convoy python3-crochet python3-cssselect python3-curtin python3-dev python3-distro-info python3-django python3-django-nose python3-django-piston3 python3-dnspython python3-docutils python3-formencode python3-hivex python3-httplib2 python3-jinja2 python3-jsonschema python3-lxml python3-netaddr python3-netifaces python3-novaclient python3-oauth python3-oauthlib python3-openssl python3-paramiko python3-petname python3-pexpect python3-psycopg2 python3-pyinotify python3-pyparsing python3-pyvmomi python3-requests python3-seamicroclient python3-setuptools python3-simplestreams python3-sphinx python3-tempita python3-twisted python3-txtftp python3-tz python3-yaml python3-zope.interface python-bson python-crochet python-django python-django-piston python-djorm-ext-pgarray python-formencode python-lxml python-netaddr python-netifaces python-pocket-lint python-psycopg2 python-simplejson python-tempita python-twisted python-yaml socat syslinux-common tgt ubuntu-cloudimage-keyring wget xvfb
Reading package lists...
Building dependency tree...
Reading state information...
authbind is already the newest version (2.1.1+nmu1).
avahi-utils is already the newest version (0.6.32~rc+dfsg-1ubuntu2).
build-essential is already the newest version (12.1ubuntu2).
debhelper is already the newest version (9.20160115ubuntu3).
distro-info is already the newest version (0.14build1).
git is already the newest version (1:2.7.4-0ubuntu1).
libjs-angularjs is already the newest version (1.2.28-1ubuntu2).
libjs-jquery is already the newest version (1.11.3+dfsg-4).
libjs-yui3-full is already the newest version (3.5.1-1ubuntu3).
libjs-yui3-min is already the newest version (3.5.1-1ubuntu3).
make is already the newest version (4.1-6).
postgresql is already the newest version (9.5+173).
psmisc is already the newest version (22.21-2.1build1).
pxelinux is already the newest version (3:6.03+dfsg-11ubuntu1).
python-formencode is already the newest version (1.3.0-0ubuntu5).
python-lxml is already the newest version (3.5.0-1build1).
python-netaddr is already the newest version (0.7.18-1...

=== modified file 'src/maasserver/models/interface.py'
--- src/maasserver/models/interface.py	2017-04-17 14:11:28 +0000
+++ src/maasserver/models/interface.py	2017-04-20 03:18:37 +0000
@@ -13,6 +13,7 @@
     ]
 
 from collections import OrderedDict
+from zlib import crc32
 
 from django.contrib.postgres.fields import ArrayField
 from django.core.exceptions import (
@@ -1182,6 +1183,21 @@
         auto_ip.save()
         return subnet, auto_ip
 
+    def get_default_bridge_name(self):
+        """Returns the default name for a bridge created on this interface."""
+        # This is a fix for bug #1672327, consistent with Juju's idea of what
+        # the bridge name should be.
+        ifname = self.get_name().encode('utf-8')
+        name = b"br-%s" % ifname
+        if len(name) > 15:
+            name = b"b-%s" % ifname
+            if ifname[:2] == b'en':
+                name = b"b-%s" % ifname[2:]
+            if len(name) > 15:
+                ifname_hash = (b"%06x" % (crc32(ifname) & 0xffffffff))[-6:]
+                name = b"b-%s-%s" % (ifname_hash, ifname[len(ifname) - 6:])
+        return name.decode('utf-8')
+
     def create_acquired_bridge(self, bridge_stp=None, bridge_fd=None):
         """Create an acquired bridge on top of this interface.
 
@@ -1200,10 +1216,10 @@
         }
         if 'mtu' in self.params:
             params['mtu'] = self.params['mtu']
+        name = self.get_default_bridge_name()
         bridge = BridgeInterface(
-            name="br-%s" % self.get_name(), node=self.node,
-            mac_address=self.mac_address, vlan=self.vlan,
-            enabled=True, acquired=True, params=params)
+            name=name, node=self.node, mac_address=self.mac_address,
+            vlan=self.vlan, enabled=True, acquired=True, params=params)
         bridge.save()
         # The order in which the creating and linkage between child and parent
         # is important. The IP addresses must first be moved from this

=== modified file 'src/maasserver/models/tests/test_interface.py'
--- src/maasserver/models/tests/test_interface.py	2017-03-29 21:13:51 +0000
+++ src/maasserver/models/tests/test_interface.py	2017-04-20 03:18:37 +0000
@@ -1409,7 +1409,7 @@
         parent.save()
         bridge = parent.create_acquired_bridge()
         self.assertThat(bridge, MatchesStructure(
-            name=Equals("br-%s" % parent.get_name()),
+            name=Equals("%s" % parent.get_default_bridge_name()),
             mac_address=Equals(parent.mac_address),
             node=Equals(parent.node),
             vlan=Equals(parent.vlan),
@@ -2986,7 +2986,7 @@
         parent = factory.make_Interface(INTERFACE_TYPE.PHYSICAL)
         bridge = parent.create_acquired_bridge()
         self.assertThat(bridge, MatchesStructure(
-            name=Equals("br-%s" % parent.get_name()),
+            name=Equals("%s" % parent.get_default_bridge_name()),
             mac_address=Equals(parent.mac_address),
             node=Equals(parent.node),
             vlan=Equals(parent.vlan),
@@ -3007,7 +3007,7 @@
         bridge = parent.create_acquired_bridge(
             bridge_stp=bridge_stp, bridge_fd=bridge_fd)
         self.assertThat(bridge, MatchesStructure(
-            name=Equals("br-%s" % parent.get_name()),
+            name=Equals("%s" % parent.get_default_bridge_name()),
             mac_address=Equals(parent.mac_address),
             node=Equals(parent.node),
             vlan=Equals(parent.vlan),
@@ -3029,7 +3029,7 @@
             alloc_type=IPADDRESS_TYPE.STICKY, interface=parent)
         bridge = parent.create_acquired_bridge()
         self.assertThat(bridge, MatchesStructure(
-            name=Equals("br-%s" % parent.get_name()),
+            name=Equals("%s" % parent.get_default_bridge_name()),
             mac_address=Equals(parent.mac_address),
             node=Equals(parent.node),
             vlan=Equals(parent.vlan),
@@ -3179,3 +3179,28 @@
             "Automatically created VLAN (observed by %s)." % (
                 iface.get_log_string()),
             new_vlan.description)
+
+
+class TestInterfaceGetDefaultBridgeName(MAASServerTestCase):
+
+    # Normally we would use scenarios for this, but this was copied and
+    # pasted from Juju code in bridgepolicy_test.go.
+    expected_bridge_names = {
+        "eno0": "br-eno0",
+        "twelvechars0": "br-twelvechars0",
+        "thirteenchars": "b-thirteenchars",
+        "enfourteenchar": "b-fourteenchar",
+        "enfifteenchars0": "b-fifteenchars0",
+        "fourteenchars1": "b-5590a4-chars1",
+        "fifteenchars.12": "b-7e0acf-ars.12",
+        "zeros0526193032": "b-000000-193032",
+        "enx00e07cc81e1d": "b-x00e07cc81e1d",
+    }
+
+    def test__returns_expected_bridge_names_consistent_with_juju(self):
+        interface = factory.make_Interface()
+        for ifname, expected_bridge_name in self.expected_bridge_names.items():
+            interface.name = ifname
+            self.assertThat(
+                interface.get_default_bridge_name(),
+                Equals(expected_bridge_name))