Delay creating external bridge until we are initializing

Previously, the snap set up a bridge using the default 10.20.20.0/24
network upon install. If there was a good reason not to use this
network (e.g., it already exists and is being used for another
purpose), MicroStack, and the host machine, could wind up in a broken
state.

This PR delays setting up the bridge until after we have given an
operator a chance to override the default settings.

This has been manually tested. To test, do the following:

1) Checkout the code, and run tox -e build
2) Run tools/make-a-microstack.sh
3) snapctl set config.network.ext-cidr and config.network.ext-gateway
4) Run microstack_init
5) Exit the snap shell and run microstack.launch

Change-Id: I9e268495f313b29d9781d80a2468fc0a1a450aa0
Closes-Bug: https://bugs.launchpad.net/microstack/+bug/1851521

snap-wrappers/init/wait-on-init

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+set -e
+
+if ! [ "$(snapctl get initialized)" == "true" ]; then
+   echo "Microstack not yet initliazed. Waiting to start."
+   exit 0;
+fi
+
+exec $@

snapcraft.yaml

@@ -209,7 +209,7 @@ apps:
 #      - network
 
   external-bridge:
-    command: bin/setup-br-ex
+    command: wait-on-init setup-br-ex
     daemon: oneshot
     passthrough:
       after: [ovs-vswitchd]
@@ -419,6 +419,12 @@ parts:
     organize:
       openstack-wrapper: bin/openstack-wrapper
 
+  init-wrapper:
+    source: ./snap-wrappers/init
+    plugin: dump
+    organize:
+      wait-on-init: bin/wait-on-init
+
   nova-config:
     after: [openstack-projects]
     plugin: dump

tools/init/init/main.py

@@ -95,10 +95,8 @@ def main() -> None:
     question_list = [
         questions.Clustering(),
         questions.Dns(),
-        questions.ExtGateway(),
-        questions.ExtCidr(),
+        questions.NetworkSettings(),
         questions.OsPassword(),  # TODO: turn this off if COMPUTE.
-        questions.IpForwarding(),
         questions.ForceQemu(),
         # The following are not yet implemented:
         # questions.VmSwappiness(),

tools/init/init/questions/__init__.py

@@ -31,7 +31,7 @@ from init.shell import (check, call, check_output, shell, sql, nc_wait,
                         log_wait, restart, download)
 from init.config import Env, log
 from init.questions.question import Question
-from init.questions import clustering
+from init.questions import clustering, network
 
 
 _env = Env().get_env()
@@ -128,6 +128,7 @@ class ConfigQuestion(Question):
         """
         check('snap-openstack', 'setup')
 
+        # TODO: get rid of this? (I think that it has become redundant)
         mstackrc = '{SNAP_COMMON}/etc/microstack.rc'.format(**_env)
         with open(mstackrc, 'r') as rc_file:
             for line in rc_file.readlines():
@@ -165,37 +166,24 @@ dnsmasq_dns_servers = {answer}
         # started. Need to figure that out.
 
 
-class ExtGateway(ConfigQuestion):
-    """Possibly override default ext gateway."""
-
-    _type = 'string'
-    _question = 'External Gateway'
-    config_key = 'config.network.ext-gateway'
+class NetworkSettings(Question):
+    """Write network settings, and """
+    _type = 'auto'
+    _question = 'Network settings'
 
     def yes(self, answer):
-        clustered = check_output('snapctl', 'get', 'config.clustered')
-        if clustered.lower() != 'true':
-            check('snapctl', 'set', 'config.network.control-ip={}'.format(
-                answer))
-            check('snapctl', 'set', 'config.network.compute-ip={}'.format(
-                answer))
-            _env['control_ip'] = _env['compute_ip'] = answer
-        else:
-            _env['control_ip'] = check_output('snapctl', 'get',
-                                              'config.network.control-ip')
-            _env['compute_ip'] = check_output('snapctl', 'get',
-                                              'config.network.compute-ip')
-
-
-class ExtCidr(ConfigQuestion):
-    """Possibly override the cidr."""
+        log.info('Configuring networking ...')
 
-    _type = 'string'
-    _question = 'External Ip Range'
-    config_key = 'config.network.ext-cidr'
+        network.ExtGateway().ask()
+        network.ExtCidr().ask()
 
-    def yes(self, answer):
-        _env['extcidr'] = answer
+        # Now that we have default or overriden values, setup the
+        # bridge and write all the proper values into our config
+        # files.
+        check('setup-br-ex')
+        check('snap-openstack', 'setup')
+
+        network.IpForwarding().ask()
 
 
 class OsPassword(ConfigQuestion):
@@ -209,20 +197,6 @@ class OsPassword(ConfigQuestion):
     # TODO obfuscate the password!
 
 
-class IpForwarding(Question):
-    """Possibly setup IP forwarding."""
-
-    _type = 'boolean'  # Auto for now, to maintain old behavior.
-    _question = 'Do you wish to setup ip forwarding? (recommended)'
-    config_key = 'config.host.ip-forwarding'
-
-    def yes(self, answer: str) -> None:
-        """Use sysctl to setup ip forwarding."""
-        log.info('Setting up ipv4 forwarding...')
-
-        check('sysctl', 'net.ipv4.ip_forward=1')
-
-
 class ForceQemu(Question):
     _type = 'boolean'
     config_key = 'config.host.check-qemu'

tools/init/init/questions/network.py

@@ -0,0 +1,52 @@
+from init.config import Env, log
+from init.questions.question import Question
+from init.shell import check, check_output
+
+_env = Env().get_env()
+
+
+class ExtGateway(Question):
+    """Possibly override default ext gateway."""
+
+    _type = 'string'
+    _question = 'External Gateway'
+    config_key = 'config.network.ext-gateway'
+
+    def yes(self, answer):
+        clustered = check_output('snapctl', 'get', 'config.clustered')
+        if clustered.lower() != 'true':
+            check('snapctl', 'set', 'config.network.control-ip={}'.format(
+                answer))
+            check('snapctl', 'set', 'config.network.compute-ip={}'.format(
+                answer))
+            _env['control_ip'] = _env['compute_ip'] = answer
+        else:
+            _env['control_ip'] = check_output('snapctl', 'get',
+                                              'config.network.control-ip')
+            _env['compute_ip'] = check_output('snapctl', 'get',
+                                              'config.network.compute-ip')
+
+
+class ExtCidr(Question):
+    """Possibly override the cidr."""
+
+    _type = 'string'
+    _question = 'External Ip Range'
+    config_key = 'config.network.ext-cidr'
+
+    def yes(self, answer):
+        _env['extcidr'] = answer
+
+
+class IpForwarding(Question):
+    """Possibly setup IP forwarding."""
+
+    _type = 'boolean'  # Auto for now, to maintain old behavior.
+    _question = 'Do you wish to setup ip forwarding? (recommended)'
+    config_key = 'config.host.ip-forwarding'
+
+    def yes(self, answer: str) -> None:
+        """Use sysctl to setup ip forwarding."""
+        log.info('Setting up ipv4 forwarding...')
+
+        check('sysctl', 'net.ipv4.ip_forward=1')

tools/init/init/questions/question.py

@@ -74,7 +74,7 @@ class Question():
             raise InvalidQuestion(
                 'Invalid type {} specified'.format(self._type))
 
-        if self.config_key is None:
+        if self.config_key is None and self._type != 'auto':
             raise InvalidQuestion(
                 "No config key specified. "
                 "We don't know how to load or save this question!")
@@ -118,6 +118,9 @@ class Question():
         operator specified settings during updates.
 
         """
+        if self._type == 'auto':
+            return
+
         answer = shell.check_output(
             'snapctl', 'get', '{key}'.format(key=self.config_key)
         )
@@ -144,6 +147,9 @@ class Question():
         # By this time in the process 'yes' or 'no' answers will have
         # been converted to booleans. Convert them to a lowercase
         # 'true' or 'false' string for storage in the snapctl config.
+        if self._type == 'auto':
+            return
+
         if self._type == 'boolean':
             answer = str(answer).lower()