这里都是通过pdb调试的，pdb教程见这里：http://iceyao.blog.51cto.com/9426658/1599320
# 先从nova-manage这个程序开始
[root@ceph01 ~]# which nova-manage
/usr/bin/nova-manage
[root@ceph01 ~]#
[root@ceph01 ~]# vim /usr/bin/nova-manage
#!/usr/bin/python
# PBR Generated from u‘console_scripts‘
import sys
from nova.cmd.manage import main
if __name__ == "__main__":
sys.exit(main())
[root@ceph01 ~]# nova-manage service list
> /usr/lib/python2.7/site-packages/nova/cmd/manage.py(1402)main()
-> ret = fn(*fn_args, **fn_kwargs)
(Pdb) l
1397 CONF.print_help()
1398 print(e)
1399 return(1)
1400 try:
1401 import pdb;pdb.set_trace() # 断点设在这里，前面是一些cfg、rpc的过程，这里不介绍
1402 -> ret = fn(*fn_args, **fn_kwargs)
1403 rpc.cleanup()
1404 return(ret)
1405 except Exception:
1406 print(_("Command failed, please check log for more info"))
1407 raise(Pdb) s # 进入函数内部 --Call-- > /usr/lib/python2.7/site-packages/nova/cmd/manage.py(696)list() -> @args(‘--host‘, metavar=‘<host>‘, help=‘Host‘) (Pdb) l 691 692 693 class ServiceCommands(object): # ServiceCommands类 694 """Enable and disable running services.""" 695 696 -> @args(‘--host‘, metavar=‘<host>‘, help=‘Host‘) 697 @args(‘--service‘, metavar=‘<service>‘, help=‘Nova service‘) 698 def list(self, host=None, service=None): 699 """Show a list of all running services. Filter by host & service 700 name 701 """ (Pdb) 702 servicegroup_api = servicegroup.API() # s进入函数内部，提供三种servicegroup driver(可配置)，这里返回db 703 ctxt = context.get_admin_context() 704 services = db.service_get_all(ctxt) # 获得nova service表所有数据 705 services = availability_zones.set_availability_zones(ctxt, services) # 获得的service，按availablity_zone划分 706 if host: 707 services = [s for s in services if s[‘host‘] == host] 708 if service: 709 services = [s for s in services if s[‘binary‘] == service] 710 print_format = "%-16s %-36s %-16s %-10s %-5s %-10s" 711 print(print_format % ( 712 _(‘Binary‘),
713 _(‘Host‘), (Pdb) 714 _(‘Zone‘), 715 _(‘Status‘), 716 _(‘State‘), 717 _(‘Updated_At‘))) 718 for svc in services: 719 alive = servicegroup_api.service_is_up(svc) # 这里有判断服务是否是up的 720 art = (alive and ":-)") or "XXX" 721 active = ‘enabled‘ 722 if svc[‘disabled‘]: 723 active = ‘disabled‘ 724 print(print_format % (svc[‘binary‘], svc[‘host‘], (Pdb) l 725 svc[‘availability_zone‘], active, art, 726 svc[‘updated_at‘]))
-> alive = servicegroup_api.service_is_up(svc)
(Pdb) l
714 _(‘Zone‘),
715 _(‘Status‘),
716 _(‘State‘),
717 _(‘Updated_At‘)))
718 for svc in services:
719 -> alive = servicegroup_api.service_is_up(svc) # s，进入service_ip_up函数内部
720 art = (alive and ":-)") or "XXX"
721 active = ‘enabled‘
722 if svc[‘disabled‘]:
723 active = ‘disabled‘
724 print(print_format % (svc[‘binary‘], svc[‘host‘],
(Pdb) s
--Call--
> /usr/lib/python2.7/site-packages/nova/servicegroup/api.py(112)service_is_up()
-> def service_is_up(self, member):
(Pdb) l
107 ‘%(group_id)s group, service = %(service)s‘)
108 LOG.debug(msg, {‘member_id‘: member_id, ‘group_id‘: group_id,
109 ‘service‘: service})
110 return self._driver.join(member_id, group_id, service)
111
112 -> def service_is_up(self, member):
113 """Check if the given member is up."""
114 # NOTE(johngarbutt) no logging in this method,
115 # so this doesn‘t slow down the scheduler
116 return self._driver.is_up(member) # s, 进入is_up函数
117-> return self._driver.is_up(member)
(Pdb) l
111
112 def service_is_up(self, member):
113 """Check if the given member is up."""
114 # NOTE(johngarbutt) no logging in this method,
115 # so this doesn‘t slow down the scheduler
116 -> return self._driver.is_up(member)
117
118 def leave(self, member_id, group_id):
119 """Explicitly remove the given member from the ServiceGroup
120 monitoring.
121 """
(Pdb) s
--Call--
> /usr/lib/python2.7/site-packages/nova/servicegroup/drivers/db.py(55)is_up()
-> def is_up(self, service_ref):
(Pdb) l
50 report_interval = service.report_interval
51 if report_interval:
52 service.tg.add_timer(report_interval, self._report_state,
53 api.INITIAL_REPORTING_DELAY, service)
54
55 -> def is_up(self, service_ref):
56 """Moved from nova.utils
57 Check whether a service is up based on last heartbeat.
58 """
59 last_heartbeat = service_ref[‘updated_at‘] or service_ref[‘created_at‘] # 获得服务最后一次更新时间或是第一次创建的时间
60 if isinstance(last_heartbeat, six.string_types):
61 # NOTE(russellb) If this service_ref came in over rpc via
62 # conductor, then the timestamp will be a string and needs to be
63 # converted back to a datetime.
64 last_heartbeat = timeutils.parse_strtime(last_heartbeat)
(Pdb) l
65 else:
66 # Objects have proper UTC timezones, but the timeutils comparison
67 # below does not (and will fail)
68 last_heartbeat = last_heartbeat.replace(tzinfo=None)
69 # Timestamps in DB are UTC.
70 elapsed = timeutils.delta_seconds(last_heartbeat, timeutils.utcnow()) # 与当前时间的差值
71 is_up = abs(elapsed) <= self.service_down_time # 如果这个差值小于service_down_time，就认为这个服务是up的，service_down_time是可配置的
72 if not is_up:
73 msg = _(‘Seems service is down. Last heartbeat was %(lhb)s. ‘
74 ‘Elapsed time is %(el)s‘)
75 LOG.debug(msg, {‘lhb‘: str(last_heartbeat), ‘el‘: str(elapsed)})
(Pdb)
76 return is_up本文出自 “the-way-to-cloud” 博客，请务必保留此出处http://iceyao.blog.51cto.com/9426658/1727154
nova-manage service list函数调用过程
原文地址：http://iceyao.blog.51cto.com/9426658/1727154
