Add missing hooks and files, tidy lint

hooks/cluster-relation-joined

@@ -0,0 +1 @@
+percona_hooks.py

hooks/percona_hooks.py

@@ -15,7 +15,7 @@ from charmhelpers.core.hookenv import (
     relation_ids,
     unit_get,
     config,
-    service_name
+    service_name,
 )
 from charmhelpers.core.host import (
     service_restart,
@@ -34,7 +34,8 @@ from percona_utils import (
     get_cluster_hosts,
     configure_sstuser,
     seeded, mark_seeded,
-    configure_mysql_root_password
+    configure_mysql_root_password,
+    relation_clear,
 )
 from mysql import get_mysql_password
 from charmhelpers.contrib.hahelpers.cluster import (
@@ -67,15 +68,15 @@ def render_config(clustered=False, hosts=[]):
     if not os.path.exists(os.path.dirname(MY_CNF)):
         os.makedirs(os.path.dirname(MY_CNF))
     with open(MY_CNF, 'w') as conf:
-        conf.write(render_template(os.path.basename(MY_CNF),
-           {'cluster_name': 'juju_cluster',
+        context = {
+            'cluster_name': 'juju_cluster',
             'private_address': get_host_ip(),
             'clustered': clustered,
             'cluster_hosts': ",".join(hosts),
             'sst_password': get_mysql_password(username='sstuser',
                                                password=config('sst-password'))
-            })
-       )
+        }
+        conf.write(render_template(os.path.basename(MY_CNF), context))
     # TODO: set 0640 and change group to mysql if avaliable
     os.chmod(MY_CNF, 0644)
 
@@ -197,7 +198,7 @@ def ha_relation_joined():
 
     resources = {'res_mysql_vip': 'ocf:heartbeat:IPaddr2'}
     resource_params = {
-        'res_mysql_vip': 'params ip="%s" cidr_netmask="%s" nic="%s"' % \
+        'res_mysql_vip': 'params ip="%s" cidr_netmask="%s" nic="%s"' %
                          (vip, vip_cidr, vip_iface),
         }
     groups = {'grp_percona_cluster': 'res_mysql_vip'}
@@ -221,8 +222,10 @@ def ha_relation_changed():
             relation_set(rid=r_id,
                          db_host=config('vip'))
     else:
-        # TODO: Unset any data already set if not leader
-        pass
+        # Clear any settings data for non-leader units
+        log('Cluster configured, not leader, clearing relation data')
+        for r_id in relation_ids('shared-db'):
+            relation_clear(r_id)
 
 
 def main():

hooks/percona_utils.py

@@ -11,6 +11,8 @@ from charmhelpers.core.hookenv import (
     relation_ids,
     related_units,
     relation_get,
+    relation_set,
+    local_unit,
 )
 from charmhelpers.fetch import (
     apt_install,
@@ -121,3 +123,15 @@ def configure_mysql_root_password(password):
                       (package, package, root_pass))
     dconf.communicate()
     dconf.wait()
+
+
+# TODO: Submit for charmhelper
+def relation_clear(r_id):
+    ''' Clears any relation data already set on relation r_id '''
+    settings = relation_get(rid=r_id,
+                            unit=local_unit())
+    for setting in settings:
+        if setting not in ['public-address', 'private-address']:
+            settings[setting] = None
+    relation_set(relation_id=r_id,
+                 **settings)

hooks/start

@@ -0,0 +1 @@
+percona_hooks.py

hooks/stop

@@ -0,0 +1 @@
+percona_hooks.py

hooks/unison.py

@@ -0,0 +1,221 @@
+#!/usr/bin/python
+#
+# Easy file synchronization among peer units using ssh + unison.
+#
+# From *both* peer relation -joined and -changed, add a call to
+# ssh_authorized_peers() describing the peer relation and the desired
+# user + group.  After all peer relations have settled, all hosts should
+# be able to connect to on another via key auth'd ssh as the specified user.
+#
+# Other hooks are then free to synchronize files and directories using
+# sync_to_peers().
+#
+# For a peer relation named 'cluster', for example:
+#
+# cluster-relation-joined:
+# ...
+# ssh_authorized_peers(peer_interface='cluster',
+#                      user='juju_ssh', group='juju_ssh',
+#                      ensure_user=True)
+# ...
+#
+# cluster-relation-changed:
+# ...
+# ssh_authorized_peers(peer_interface='cluster',
+#                      user='juju_ssh', group='juju_ssh',
+#                      ensure_user=True)
+# ...
+#
+# Hooks are now free to sync files as easily as:
+#
+# files = ['/etc/fstab', '/etc/apt.conf.d/']
+# sync_to_peers(peer_interface='cluster',
+#                user='juju_ssh, paths=[files])
+#
+# It is assumed the charm itself has setup permissions on each unit
+# such that 'juju_ssh' has read + write permissions.  Also assumed
+# that the calling charm takes care of leader delegation.
+
+import os
+import sys
+import subprocess
+import grp
+import pwd
+from charmhelpers.core.hookenv import (
+    log,
+    relation_ids,
+    related_units,
+    relation_get,
+    relation_set,
+    unit_get
+)
+
+
+def get_homedir(user):
+    try:
+        user = pwd.getpwnam(user)
+        return user.pw_dir
+    except KeyError:
+        log('Could not get homedir for user %s: user exists?')
+        sys.exit(1)
+
+
+def get_keypair(user):
+    home_dir = get_homedir(user)
+    ssh_dir = os.path.join(home_dir, '.ssh')
+    if not os.path.isdir(ssh_dir):
+        os.mkdir(ssh_dir)
+
+    priv_key = os.path.join(ssh_dir, 'id_rsa')
+    if not os.path.isfile(priv_key):
+        log('Generating new ssh key for user %s.' % user)
+        cmd = ['ssh-keygen', '-q', '-N', '', '-t', 'rsa', '-b', '2048',
+               '-f', priv_key]
+        subprocess.check_call(cmd)
+
+    pub_key = '%s.pub' % priv_key
+    if not os.path.isfile(pub_key):
+        log('Generatring missing ssh public key @ %s.' %
+            pub_key)
+        cmd = ['ssh-keygen', '-y', '-f', priv_key]
+        p = subprocess.check_output(cmd).strip()
+        with open(pub_key, 'wb') as out:
+            out.write(p)
+    subprocess.check_call(['chown', '-R', user, ssh_dir])
+    return open(priv_key, 'r').read().strip(), \
+           open(pub_key, 'r').read().strip()
+
+
+def write_authorized_keys(user, keys):
+    home_dir = get_homedir(user)
+    ssh_dir = os.path.join(home_dir, '.ssh')
+    auth_keys = os.path.join(ssh_dir, 'authorized_keys')
+    log('Syncing authorized_keys @ %s.' % auth_keys)
+    with open(auth_keys, 'wb') as out:
+        for k in keys:
+            out.write('%s\n' % k)
+
+
+def write_known_hosts(user, hosts):
+    home_dir = get_homedir(user)
+    ssh_dir = os.path.join(home_dir, '.ssh')
+    known_hosts = os.path.join(ssh_dir, 'known_hosts')
+    khosts = []
+    for host in hosts:
+        cmd = ['ssh-keyscan', '-H', '-t', 'rsa', host]
+        remote_key = subprocess.check_output(cmd).strip()
+        khosts.append(remote_key)
+    log('Syncing known_hosts @ %s.' % known_hosts)
+    with open(known_hosts, 'wb') as out:
+        for host in khosts:
+            out.write('%s\n' % host)
+
+
+def ensure_user(user, group=None):
+    # need to ensure a bash shell'd user exists.
+    try:
+        pwd.getpwnam(user)
+    except KeyError:
+        log('Creating new user %s.%s.' % (user, group))
+        cmd = ['adduser', '--system', '--shell', '/bin/bash', user]
+        if group:
+            try:
+                grp.getgrnam(group)
+            except KeyError:
+                subprocess.check_call(['addgroup', group])
+            cmd += ['--ingroup', group]
+        subprocess.check_call(cmd)
+
+
+def ssh_authorized_peers(peer_interface, user, group=None, ensure_local_user=False):
+    """
+    Main setup function, should be called from both peer -changed and -joined
+    hooks with the same parameters.
+    """
+    if ensure_local_user:
+        ensure_user(user, group)
+    priv_key, pub_key = get_keypair(user)
+    hook = os.path.basename(sys.argv[0])
+    if hook == '%s-relation-joined' % peer_interface:
+        relation_set(ssh_pub_key=pub_key)
+        print 'joined'
+    elif hook == '%s-relation-changed' % peer_interface:
+        hosts = []
+        keys = []
+        for r_id in relation_ids(peer_interface):
+            for unit in related_units(r_id):
+                settings = relation_get(rid=r_id,
+                                        unit=unit)
+                if 'ssh_pub_key' in settings:
+                    keys.append(settings['ssh_pub_key'])
+                    hosts.append(settings['private-address'])
+                else:
+                    log('ssh_authorized_peers(): ssh_pub_key '
+                        'missing for unit %s, skipping.' % unit)
+        write_authorized_keys(user, keys)
+        write_known_hosts(user, hosts)
+        authed_hosts = ':'.join(hosts)
+        relation_set(ssh_authorized_hosts=authed_hosts)
+
+
+def _run_as_user(user):
+    try:
+        user = pwd.getpwnam(user)
+    except KeyError:
+        log('Invalid user: %s' % user)
+        sys.exit(1)
+    uid, gid = user.pw_uid, user.pw_gid
+    os.environ['HOME'] = user.pw_dir
+
+    def _inner():
+        os.setgid(gid)
+        os.setuid(uid)
+    return _inner
+
+
+def run_as_user(user, cmd):
+    return subprocess.check_output(cmd, preexec_fn=_run_as_user(user), cwd='/')
+
+
+def sync_to_peers(peer_interface, user, paths=[], verbose=False):
+    base_cmd = ['unison', '-auto', '-batch=true', '-confirmbigdel=false',
+                '-fastcheck=true', '-group=false', '-owner=false',
+                '-prefer=newer']
+    if not verbose:
+        base_cmd.append('-silent')
+
+    hosts = []
+    for r_id in (relation_ids(peer_interface) or []):
+        for unit in related_units(r_id):
+            settings = relation_get(rid=r_id,
+                                    unit=unit)
+            try:
+                authed_hosts = settings['ssh_authorized_hosts'].split(':')
+            except KeyError:
+                log('unison sync_to_peers: peer has not authorized *any* '
+                    'hosts yet.')
+                return
+
+            unit_hostname = unit_get('private-address')
+            add_host = None
+            for authed_host in authed_hosts:
+                if unit_hostname == authed_host:
+                    add_host = settings['private-address']
+            if add_host:
+                hosts.append(settings['private-address'])
+            else:
+                log('unison sync_to_peers: peer (%s) has not authorized '
+                    '*this* host yet, skipping.' %
+                    settings['private-address'])
+
+    for path in paths:
+        # removing trailing slash from directory paths, unison
+        # doesn't like these.
+        if path.endswith('/'):
+            path = path[:(len(path) - 1)]
+        for host in hosts:
+            cmd = base_cmd + [path, 'ssh://%s@%s/%s' % (user, host, path)]
+            log('Syncing local path %s to %s@%s:%s' %
+                (path, user, host, path))
+            log(' '.join(cmd))
+            run_as_user(user, cmd)