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"""
A hello world module
See doc/mgr/hello.rst for more info.
"""
from mgr_module import MgrModule, HandleCommandResult
from threading import Event
import errno
class Hello(MgrModule):
# these are CLI commands we implement
COMMANDS = [
{
"cmd": "hello "
"name=person_name,type=CephString,req=false",
"desc": "Say hello",
"perm": "r"
},
{
"cmd": "count "
"name=num,type=CephInt",
"desc": "Do some counting",
"perm": "r"
},
]
# These are module options we understand. These can be set with
#
# ceph config set global mgr/hello/<name> <value>
#
# e.g.,
#
# ceph config set global mgr/hello/place Earth
#
MODULE_OPTIONS = [
{
'name': 'place',
'default': 'world',
'desc': 'a place in the world',
'runtime': True, # can be updated at runtime (no mgr restart)
},
{
'name': 'emphatic',
'type': 'bool',
'desc': 'whether to say it loudly',
'default': True,
'runtime': True,
},
{
'name': 'foo',
'type': 'enum',
'enum_allowed': [ 'a', 'b', 'c' ],
'default': 'a',
'runtime': True,
},
]
# These are "native" Ceph options that this module cares about.
NATIVE_OPTIONS = [
'mgr_tick_period',
]
def __init__(self, *args, **kwargs):
super(Hello, self).__init__(*args, **kwargs)
# set up some members to enable the serve() method and shutdown()
self.run = True
self.event = Event()
# ensure config options members are initialized; see config_notify()
self.config_notify()
def config_notify(self):
"""
This method is called whenever one of our config options is changed.
"""
# This is some boilerplate that stores MODULE_OPTIONS in a class
# member, so that, for instance, the 'emphatic' option is always
# available as 'self.emphatic'.
for opt in self.MODULE_OPTIONS:
setattr(self,
opt['name'],
self.get_module_option(opt['name']))
self.log.debug(' mgr option %s = %s',
opt['name'], getattr(self, opt['name']))
# Do the same for the native options.
for opt in self.NATIVE_OPTIONS:
setattr(self,
opt,
self.get_ceph_option(opt))
self.log.debug(' native option %s = %s', opt, getattr(self, opt))
def handle_command(self, inbuf, cmd):
ret = 0
out = ''
err = ''
if cmd['prefix'] == 'hello':
if 'person_name' in cmd:
out = "Hello, " + cmd['person_name']
else:
out = "Hello " + self.get_module_option('place')
if self.get_module_option('emphatic'):
out += '!'
elif cmd['prefix'] == 'count':
num = cmd.get('num', 0)
if num < 1:
err = 'That\'s too small a number'
ret = -errno.EINVAL
elif num > 10:
err = 'That\'s too big a number'
ret = -errno.EINVAL
else:
out = 'Hello, I am the count!\n'
out += ', '.join([str(x) for x in range(1, num + 1)]) + '!'
return HandleCommandResult(
retval=ret, # exit code
stdout=out, # stdout
stderr=err)
def serve(self):
"""
This method is called by the mgr when the module starts and can be
used for any background activity.
"""
self.log.info("Starting")
while self.run:
# Do some useful background work here.
# Use mgr_tick_period (default: 2) here just to illustrate
# consuming native ceph options. Any real background work
# would presumably have some more appropriate frequency.
sleep_interval = self.mgr_tick_period
self.log.debug('Sleeping for %d seconds', sleep_interval)
ret = self.event.wait(sleep_interval)
self.event.clear()
def shutdown(self):
"""
This method is called by the mgr when the module needs to shut
down (i.e., when the serve() function needs to exit).
"""
self.log.info('Stopping')
self.run = False
self.event.set()
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