anvil/devstack/runners/screen.py
2012-03-08 18:17:05 -08:00

276 lines
11 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import json
import re
import tempfile
import time
from devstack import date
from devstack import exceptions as excp
from devstack import log as logging
from devstack import runner as base
from devstack import settings
from devstack import shell as sh
from devstack import trace as tr
from devstack import utils
LOG = logging.getLogger("devstack.runners.screen")
#my type
RUN_TYPE = settings.RUN_TYPE_SCREEN
TYPE = settings.RUN_TYPE_TYPE
#trace constants
SCREEN_TEMPL = "%s.screen"
ARGS = "ARGS"
NAME = "NAME"
SESSION_ID = 'SESSION_ID'
#screen session name
SESSION_NAME = 'stack'
SESSION_DEF_TITLE = SESSION_NAME
SESSION_NAME_MTCHER = re.compile(r"^\s*([\d]+\.%s)\s*(.*)$" % (SESSION_NAME))
#how we setup screens status bar
STATUS_BAR_CMD = r'hardstatus alwayslastline "%-Lw%{= BW}%50>%n%f* %t%{-}%+Lw%< %= %H"'
#cmds
SESSION_INIT = ['screen', '-d', '-m', '-S', SESSION_NAME, '-t', SESSION_DEF_TITLE, '-s', "/bin/bash"]
BAR_INIT = ['screen', '-r', SESSION_NAME, '-X', STATUS_BAR_CMD]
CMD_INIT = ['screen', '-S', '%SESSION_NAME%', '-X', 'screen', '-t', "%NAME%"]
CMD_KILL = ['screen', '-S', '%SESSION_NAME%', '-p', "%NAME%", '-X', 'kill']
CMD_WIPE = ['screen', '-S', '%SESSION_NAME%', '-wipe']
CMD_START = ['screen', '-S', '%SESSION_NAME%', '-p', "%NAME%", '-X', 'stuff', "\"%CMD%\r\""]
LIST_CMD = ['screen', '-ls']
SCREEN_KILLER = ['screen', '-X', '-S', '%SCREEN_ID%', 'quit']
#where our screen sockets will go
SCREEN_SOCKET_DIR_NAME = "devstack-screen-sockets"
SCREEN_SOCKET_PERM = 0700
#used to wait until started before we can run the actual start cmd
WAIT_ONLINE_TO = settings.WAIT_ALIVE_SECS
#run screen as root?
ROOT_GO = True
#screen RC file
SCREEN_RC = settings.RC_FN_TEMPL % ('screen')
class ScreenRunner(base.RunnerBase):
def __init__(self, cfg, component_name, trace_dir):
base.RunnerBase.__init__(self, cfg, component_name, trace_dir)
self.socket_dir = sh.joinpths(tempfile.gettempdir(), SCREEN_SOCKET_DIR_NAME)
def stop(self, app_name):
trace_fn = tr.trace_fn(self.trace_dir, SCREEN_TEMPL % (app_name))
session_id = self._find_session(app_name, trace_fn)
self._do_stop(app_name, session_id)
sh.unlink(trace_fn)
def _find_session(self, app_name, trace_fn):
session_id = None
for (key, value) in tr.TraceReader(trace_fn).read():
if key == SESSION_ID and value:
session_id = value
if not session_id:
msg = "Could not find a screen session id for %s in file [%s]" % (app_name, trace_fn)
raise excp.StopException(msg)
return session_id
def _do_stop(self, app_name, session_id):
mp = dict()
mp['SESSION_NAME'] = session_id
mp['NAME'] = app_name
LOG.info("Stopping program running in session [%s] in window named [%s]." % (session_id, app_name))
kill_cmd = self._gen_cmd(CMD_KILL, mp)
sh.execute(*kill_cmd,
shell=True,
run_as_root=ROOT_GO,
env_overrides=self._get_env(),
check_exit_code=False)
#we have really no way of knowing if it worked or not, screen sux...
wipe_cmd = self._gen_cmd(CMD_WIPE, mp)
sh.execute(*wipe_cmd,
shell=True,
run_as_root=ROOT_GO,
env_overrides=self._get_env(),
check_exit_code=False)
def _get_env(self):
env = dict()
env['SCREENDIR'] = self.socket_dir
return env
def _gen_cmd(self, base_cmd, params=dict()):
return utils.param_replace_list(base_cmd, params)
def _active_sessions(self):
knowns = list()
list_cmd = self._gen_cmd(LIST_CMD)
(sysout, _) = sh.execute(*list_cmd,
check_exit_code=False,
run_as_root=ROOT_GO,
env_overrides=self._get_env())
if sysout.lower().find("No Sockets found") != -1:
return knowns
for line in sysout.splitlines():
mtch = SESSION_NAME_MTCHER.match(line)
if mtch:
knowns.append(mtch.group(1))
return knowns
def _get_session(self):
sessions = self._active_sessions()
LOG.debug("Found sessions [%s]" % ", ".join(sessions))
if not sessions:
return None
if len(sessions) > 1:
msg = [
"You are running multiple screen sessions [%s], please reduce the set to zero or one." % (", ".join(sessions)),
]
for s in sorted(sessions):
mp = {'SCREEN_ID': s}
cmd_msg = self._gen_cmd(SCREEN_KILLER, mp)
env = self._get_env()
for (k, v) in env.items():
cmd_msg.insert(0, "%s=%s" % (k, v))
msg.append("Try running '%s' to quit that session." % (" ".join(cmd_msg)))
raise excp.StartException(utils.joinlinesep(msg))
return sessions[0]
def _do_screen_init(self):
LOG.info("Creating a new screen session named [%s]" % (SESSION_NAME))
session_init_cmd = self._gen_cmd(SESSION_INIT)
sh.execute(*session_init_cmd,
shell=True,
run_as_root=ROOT_GO,
env_overrides=self._get_env())
LOG.info("Waiting %s seconds before we attempt to set the title bar for that session." % (WAIT_ONLINE_TO))
time.sleep(WAIT_ONLINE_TO)
bar_init_cmd = self._gen_cmd(BAR_INIT)
sh.execute(*bar_init_cmd,
shell=True,
run_as_root=ROOT_GO,
env_overrides=self._get_env())
def _do_start(self, session, prog_name, cmd):
init_cmd = list()
mp = dict()
run_cmd = " ".join(cmd)
mp['SESSION_NAME'] = session
mp['NAME'] = prog_name
mp['CMD'] = run_cmd
init_cmd = self._gen_cmd(CMD_INIT, mp)
LOG.info("Creating a new screen window named [%s] in session [%s]" % (prog_name, session))
sh.execute(*init_cmd,
shell=True,
run_as_root=ROOT_GO,
env_overrides=self._get_env())
LOG.info("Waiting %s seconds before we attempt to run command [%s] in that window." % (WAIT_ONLINE_TO, run_cmd))
time.sleep(WAIT_ONLINE_TO)
start_cmd = self._gen_cmd(CMD_START, mp)
sh.execute(*start_cmd,
shell=True,
run_as_root=ROOT_GO,
env_overrides=self._get_env())
#we have really no way of knowing if it worked or not, screen sux...
def _do_socketdir_init(self, socketdir, perm):
LOG.debug("Making screen socket directory [%s] (with permissions %o)" % (socketdir, perm))
with sh.Rooted(ROOT_GO):
dirs = sh.mkdirslist(socketdir)
for d in dirs:
sh.chmod(d, perm)
def _begin_start(self, name, program, args):
run_trace = tr.TraceWriter(tr.trace_fn(self.trace_dir, SCREEN_TEMPL % (name)))
run_trace.trace(TYPE, RUN_TYPE)
run_trace.trace(NAME, name)
run_trace.trace(ARGS, json.dumps(args))
full_cmd = [program] + list(args)
session_name = self._get_session()
inited_screen = False
if session_name is None:
inited_screen = True
self._do_screen_init()
session_name = self._get_session()
if session_name is None:
msg = "After initializing screen with session named [%s], no screen session with that name was found!" % (SESSION_NAME)
raise excp.StartException(msg)
run_trace.trace(SESSION_ID, session_name)
if inited_screen or not sh.isfile(SCREEN_RC):
rc_gen = ScreenRcGenerator(self)
rc_contents = rc_gen.create(session_name, self._get_env())
out_fn = sh.abspth(SCREEN_RC)
LOG.info("Writing your created screen rc file to [%s]" % (out_fn))
sh.write_file(out_fn, rc_contents)
self._do_start(session_name, name, full_cmd)
return run_trace.filename()
def start(self, app_name, runtime_info):
(program, _, program_args) = runtime_info
if not sh.isdir(self.socket_dir):
self._do_socketdir_init(self.socket_dir, SCREEN_SOCKET_PERM)
return self._begin_start(app_name, program, program_args)
class ScreenRcGenerator(object):
def __init__(self, sr):
self.runner = sr
def _generate_help(self, session_name, env_exports):
lines = list()
lines.append("# Screen help stuff")
cmd_pieces = list()
for (k, v) in env_exports.items():
cmd_pieces.append("%s=%s" % (k, sh.shellquote(v)))
cmd_pieces.append("screen -r %s" % (session_name))
if ROOT_GO:
cmd_pieces.insert(0, "sudo")
lines.append("# To connect to this session run the following command: ")
lines.append("# %s" % (" ".join(cmd_pieces)))
lines.append("")
return lines
def _generate_lines(self, session_name, env_exports):
lines = list()
lines.append("# RC file generated on %s" % (date.rcf8222date()))
lines.append("")
if env_exports:
lines.append("# Environment settings (these will need to be exported)")
for (k, v) in env_exports.items():
lines.append("# export %s=%s" % (k, sh.shellquote(v)))
lines.append("")
if ROOT_GO:
lines.append("# Screen sockets & programs were created/ran as the root user")
lines.append("# So you will need to run as user root (or sudo) to enter the following sessions")
lines.append("")
lines.append("# Session settings")
lines.append("sessionname %s" % (session_name))
lines.append(STATUS_BAR_CMD)
lines.append("screen -t %s bash" % (SESSION_DEF_TITLE))
lines.append("")
lines.extend(self._generate_help(session_name, env_exports))
return lines
def create(self, session_name, env_exports):
lines = self._generate_lines(session_name, env_exports)
contents = utils.joinlinesep(*lines)
return contents