Added microstack.remove command

Running microstack.remove will remove the br-ex virtual bridge device,
then uninstall MicroStack.

We do this because we can't use ovs-ctl to remove the bridge as part
of a remove hook, as the Open vSwitch daemons are not running at that
point. The microstack.remove command gives operators a way to cleanly
uninstall the snap, without needing to reboot to get rid of br-ex.

Added test exercising the code to test_basic.py.

Rerranged entry points a bit (moved some things into main.py) to make
code sharing easier, and to prevent a proliferation of entry point
scripts in our root dir.

Change-Id: I9ff25864cd96ada3a9b3da8992c2b33955eff0b4
Closes-Bug: #1852147

README.md

@@ -67,6 +67,23 @@ credentials are:
     username: admin
     password: keystone
 
+## Removing MicroStack
+
+To remove MicroStack, run:
+
+    sudo microstack.remove --auto
+
+This will clean up the Open vSwitch bridge device and uninstall
+MicroStack. If you remove MicroStack with the `snap remove` command
+instead, don't worry -- the Open vSwitch bridge will disappear the
+next time that you reboot your system.
+
+Note that you can pass any arguments that you'd pass to the `snap
+remove` command to `microstack.remove`. To purge the snap,
+for example, run:
+
+    sudo microstack.remove --auto --purge
+
 ## Customising and contributing
 
 To customise services and settings, look in the `.d` directories under

snap-overlay/bin/set-default-config

@@ -52,3 +52,9 @@ snapctl set \
         cluster.role=control \
         cluster.password=null \
         ;
+
+# Uninstall stuff
+snapctl set \
+        config.cleanup.delete-bridge=true \
+        config.cleanup.remove=true \
+        ;

snapcraft.yaml

@@ -27,6 +27,9 @@ apps:
 #    plugs:
 #      - network
 
+  remove:
+    command: microstack_remove
+
   # Keystone
   keystone-uwsgi:
     command: snap-openstack launch keystone-uwsgi

tests/framework.py

@@ -141,7 +141,9 @@ class Host():
             check('sudo', 'multipass', 'delete', self.machine)
             check('sudo', 'multipass', 'purge')
         else:
-            check('sudo', 'snap', 'remove', '--purge', 'microstack')
+            if call('snap', 'list', 'microstack'):
+                # Uninstall microstack if it is installed (it may not be).
+                check('sudo', 'snap', 'remove', '--purge', 'microstack')
 
 
 class Framework(unittest.TestCase):
@@ -241,7 +243,7 @@ class Framework(unittest.TestCase):
         self.driver.find_element(By.LINK_TEXT, "Images").click()
 
     def setUp(self):
-        self.passed = False  # HACK: trigger (or skip) cleanup.
+        self.passed = False  # HACK: trigger (or skip) log dumps.
 
     def tearDown(self):
         """Clean hosts up, possibly leaving debug information behind."""

tests/test_basic.py

@@ -65,6 +65,27 @@ class TestBasics(Framework):
         # The Horizon Dashboard should function
         self.verify_gui(host)
 
+        # Verify that we can uninstall the snap cleanly, and that the
+        # ovs bridge goes away.
+
+        # Check to verify that our bridge is there.
+        self.assertTrue('br-ex' in check_output(*prefix, 'ip', 'a'))
+
+        # Try to uninstall snap without sudo.
+        self.assertFalse(call(*prefix, '/snap/bin/microstack.remove',
+                              '--purge', '--auto'))
+
+        # Retry with sudo (should succeed).
+        check(*prefix, 'sudo', '/snap/bin/microstack.remove',
+              '--purge', '--auto')
+
+        # Verify that MicroStack is gone.
+        self.assertFalse(call(*prefix, 'snap', 'list', 'microstack'))
+
+        # Verify that bridge is gone.
+        self.assertFalse('br-ex' in check_output(*prefix, 'ip', 'a'))
+
+        # We made it to the end. Set passed to True!
         self.passed = True
 
 

tools/init/init/main.py

@@ -35,13 +35,27 @@ import secrets
 import string
 import sys
 
+from functools import wraps
+
 from init.config import log
-from init.shell import check
+from init.shell import default_network, check, check_output
 
 from init import questions
 
 
-def parse_args():
+def requires_sudo(func):
+    @wraps(func)
+    def wrapper(*args, **kwargs):
+        if int(check_output('id', '-u')):
+            log.error("This script must be run with root privileges. "
+                      "Please re-run with sudo.")
+            sys.exit(1)
+
+        return func(*args, **kwargs)
+    return wrapper
+
+
+def parse_init_args():
     parser = argparse.ArgumentParser()
     parser.add_argument('--auto', '-a', action='store_true',
                         help='Run non interactively.')
@@ -53,7 +67,7 @@ def parse_args():
     return args
 
 
-def process_args(args):
+def process_init_args(args):
     """Look through our args object and set the proper default config
     values in our snap config, based on those args.
 
@@ -80,7 +94,8 @@ def process_args(args):
     if auto and not args.cluster_password:
         alphabet = string.ascii_letters + string.digits
         password = ''.join(secrets.choice(alphabet) for i in range(10))
-        check('snapctl', 'set', 'config.cluster.password={}'.format(password))
+        check('snapctl', 'set', 'config.cluster.password={}'.format(
+            password))
 
     if args.debug:
         log.setLevel(logging.DEBUG)
@@ -88,9 +103,10 @@ def process_args(args):
     return auto
 
 
-def main() -> None:
-    args = parse_args()
-    auto = process_args(args)
+@requires_sudo
+def init() -> None:
+    args = parse_init_args()
+    auto = process_init_args(args)
 
     question_list = [
         questions.Clustering(),
@@ -125,5 +141,47 @@ def main() -> None:
             sys.exit(1)
 
 
-if __name__ == '__main__':
-    main()
+def set_network_info() -> None:
+    """Find and use the  default network on a machine.
+
+    Helper to find the default network on a machine, and configure
+    MicroStack to use it in its default settings.
+
+    """
+    try:
+        ip, gate, cidr = default_network()
+    except Exception:
+        # TODO: more specific exception handling.
+        log.exception(
+            'Could not determine default network info. '
+            'Falling back on 10.20.20.1')
+        return
+
+    check('snapctl', 'set', 'config.network.ext-gateway={}'.format(gate))
+    check('snapctl', 'set', 'config.network.ext-cidr={}'.format(cidr))
+    check('snapctl', 'set', 'config.network.control-ip={}'.format(ip))
+    check('snapctl', 'set', 'config.network.control-ip={}'.format(ip))
+
+
+@requires_sudo
+def remove() -> None:
+    """Helper to cleanly uninstall MicroStack."""
+
+    # Strip '--auto' out of the args passed to this command, as we
+    # need to check it, but also pass the other args off to the
+    # snapd's uninstall command. TODO: make this less hacky.
+    auto = False
+    if '--auto' in questions.uninstall.ARGS:
+        auto = True
+    questions.uninstall.ARGS = [
+        arg for arg in questions.uninstall.ARGS if 'auto' not in arg]
+
+    question_list = [
+        questions.uninstall.DeleteBridge(),
+        questions.uninstall.RemoveMicrostack(),
+    ]
+
+    for question in question_list:
+        if auto:
+            question.interactive = False
+        question.ask()

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, network
+from init.questions import clustering, network, uninstall  # noqa F401
 
 
 _env = Env().get_env()

tools/init/init/questions/uninstall.py

@@ -0,0 +1,47 @@
+import sys
+
+from init.config import Env, log
+from init.questions.question import Question
+from init.shell import check, call
+
+_env = Env().get_env()
+
+
+# Save off command line args. If you use any of these to answer a
+# question, pop it from this list -- the remaining args will get
+# passed to "snap remove"
+ARGS = list(sys.argv)
+
+
+class DeleteBridge(Question):
+    _type = 'boolean'
+    _question = 'Do you wish to delete the ovs bridge? (br-ex)'
+    interactive = True
+    config_key = 'config.cleanup.delete-bridge'
+
+    def yes(self, answer):
+        log.info('Removing ovs bridge.')
+        # Remove bridge. This may not exist, so we silently skip on error.
+        # TODO get bridge name from config (if it gets added to config)
+        # TODO clean up other ovs artifacts?
+        call('ovs-vsctl', 'del-br', 'br-ex')
+
+
+# TODO: cleanup system optimizations
+# TODO: cleanup kernel modules?
+# TODO: cleanup iptables rules
+
+
+class RemoveMicrostack(Question):
+    _type = 'auto'
+    _question = 'Do you really wish to remove MicroStack?'
+    interactive = True
+    config_key = 'config.cleanup.remove'
+
+    def yes(self, answer):
+        """Uninstall MicroStack, passing any command line options to snapd."""
+
+        log.info('Uninstalling MicroStack (this may take a while) ...')
+        check('snap', 'remove', '{SNAP_INSTANCE_NAME}'.format(**_env),
+              *ARGS)
+        log.info('MicroStack has been removed from your system!')

tools/init/init/set_network_info.py

@@ -1,24 +0,0 @@
-#!/usr/bin/env/python3
-from init.shell import default_network, check
-
-from init.config import log  # TODO name log.
-
-
-def main():
-    try:
-        ip, gate, cidr = default_network()
-    except Exception:
-        # TODO: more specific exception handling.
-        log.exception(
-            'Could not determine default network info. '
-            'Falling back on 10.20.20.1')
-        return
-
-    check('snapctl', 'set', 'config.network.ext-gateway={}'.format(gate))
-    check('snapctl', 'set', 'config.network.ext-cidr={}'.format(cidr))
-    check('snapctl', 'set', 'config.network.control-ip={}'.format(ip))
-    check('snapctl', 'set', 'config.network.control-ip={}'.format(ip))
-
-
-if __name__ == '__main__':
-    main()

tools/init/setup.py

@@ -7,8 +7,9 @@ setup(
     version="0.0.1",
     entry_points={
         'console_scripts': [
-            'microstack_init = init.main:main',
-            'set_network_info = init.set_network_info:main',
+            'microstack_init = init.main:init',
+            'set_network_info = init.main:set_network_info',
+            'microstack_remove = init.main:remove',
         ],
     },
 )