openstack/mistral
Code Issues Proposed changes

Allow launch script to start any combination of servers

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Currently, the launch options are only all, api, engine, and
executor. We want to allow launch options to start any combination
of servers such as api and engine or engine and executor. The
launch script is modified to the --server command line option to
accept a comma delimited list.

Change-Id: I4ce31f5fabd4de3b2f8f0e4c5ef661ed4ec7e5b2
Implements: blueprint mistral-launch-options
This commit is contained in:
Winson Chan 2014-05-14 09:58:22 -07:00
parent ecec340b52
commit 2b1a2ea7d9
4 changed files with 60 additions and 39 deletions
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8
README.rst
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@ -37,6 +37,14 @@ To run Mistral Task Executor instance perform the following command in a shell:
Note that at least one Engine instance and one Executor instance should be running so that workflow tasks are processed by Mistral. Note that at least one Engine instance and one Executor instance should be running so that workflow tasks are processed by Mistral.
Running Multiple Mistral Servers Under the Same Process
-------------------------------------------------------
To run more than one server (API, Engine, or Task Executor) on the same process, perform the following command in a shell:
tox -evenv -- python mistral/cmd/launch.py --server api,engine --config-file path_to_config
The --server command line option can be a comma delimited list. The valid options are "all" (by default if not specified) or any combination of "api", "engine", and "executor". It's important to note that the "fake" transport for the rpc_backend defined in the config file should only be used if "all" the Mistral servers are launched on the same process. Otherwise, messages do not get delivered if the Mistral servers are launched on different processes because the "fake" transport is using an in process queue.
Debugging Debugging
--------- ---------

5
etc/mistral.conf.example
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@ -25,8 +25,9 @@ rabbit_password = guest
# Options for oslo.messaging # Options for oslo.messaging
#rpc_backend=rabbit #rpc_backend=rabbit
# Specifies which mistral server to start by the launch script. (string value) # Specifies which mistral server(s) to start by the launch script. (string value)
# Choices are all, api, engine, and executor. # Choices are all (default) or comma delimited list of api, engine, and/or executor.
# Example: server=api,engine
#server=all #server=all
[api] [api]

77
mistral/cmd/launch.py
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@ -53,20 +53,20 @@ def launch_executor(transport):
# Since engine and executor are tightly coupled, use the engine # Since engine and executor are tightly coupled, use the engine
# configuration to decide which executor to get. # configuration to decide which executor to get.
endpoints = [executor.get_executor(cfg.CONF.engine.engine, transport)] endpoints = [executor.get_executor(cfg.CONF.engine.engine, transport)]
ex_server = messaging.get_rpc_server( server = messaging.get_rpc_server(
transport, target, endpoints, executor='eventlet') transport, target, endpoints, executor='eventlet')
ex_server.start() server.start()
ex_server.wait() server.wait()
def launch_engine(transport): def launch_engine(transport):
target = messaging.Target(topic=cfg.CONF.engine.topic, target = messaging.Target(topic=cfg.CONF.engine.topic,
server=cfg.CONF.engine.host) server=cfg.CONF.engine.host)
endpoints = [engine.get_engine(cfg.CONF.engine.engine, transport)] endpoints = [engine.get_engine(cfg.CONF.engine.engine, transport)]
en_server = messaging.get_rpc_server( server = messaging.get_rpc_server(
transport, target, endpoints, executor='eventlet') transport, target, endpoints, executor='eventlet')
en_server.start() server.start()
en_server.wait() server.wait()
def launch_api(transport): def launch_api(transport):
@ -79,12 +79,20 @@ def launch_api(transport):
server.serve_forever() server.serve_forever()
def launch_all(transport): def launch_any(transport, options):
# Launch the servers on different threads. # Launch the servers on different threads.
t1 = eventlet.spawn(launch_executor, transport) threads = [eventlet.spawn(LAUNCH_OPTIONS[option], transport)
t2 = eventlet.spawn(launch_engine, transport) for option in options]
t3 = eventlet.spawn(launch_api, transport) [thread.wait() for thread in threads]
t1.wait() and t2.wait() and t3.wait()
# Map cli options to appropriate functions. The cli options are
# registered in mistral's config.py.
LAUNCH_OPTIONS = {
'api': launch_api,
'engine': launch_engine,
'executor': launch_executor
}
def main(): def main():
@ -92,31 +100,34 @@ def main():
config.parse_args() config.parse_args()
logging.setup('Mistral') logging.setup('Mistral')
# Map cli options to appropriate functions. The cli options are
# registered in mistral's config.py.
launch_options = {
'all': launch_all,
'api': launch_api,
'engine': launch_engine,
'executor': launch_executor
}
# Please refer to the oslo.messaging documentation for transport # Please refer to the oslo.messaging documentation for transport
# configuration. The default transport for oslo.messaging is rabbitMQ. # configuration. The default transport for oslo.messaging is
# The available transport drivers are listed under oslo.messaging at # rabbitMQ. The available transport drivers are listed in the
# ./oslo/messaging/rpc/_drivers. The drivers are prefixed with "impl". # setup.cfg file in oslo.messaging under the entry_points section for
# The transport driver is specified using the rpc_backend option in the # oslo.messaging.drivers. The transport driver is specified using the
# default section of the oslo configuration file. The expected value # rpc_backend option in the default section of the oslo configuration
# for rpc_backend is the last part of the driver name. For example, # file. The expected value for the rpc_backend is one of the key
# the driver for rabbit is impl_rabbit and for the fake driver is # values available for the oslo.messaging.drivers (i.e. rabbit, fake).
# impl_fake. The rpc_backend value for these are "rabbit" and "fake" # There are additional options such as ssl and credential that can be
# respectively. There are additional options such as ssl and credential # specified depending on the driver. Please refer to the driver
# that can be specified depending on the driver. Please refer to the # implementation for those additional options. It's important to note
# driver implementation for those additional options. # that the "fake" transport should only be used if "all" the Mistral
# servers are launched on the same process. Otherwise, messages do not
# get delivered if the Mistral servers are launched on different
# processes because the "fake" transport is using an in process queue.
transport = messaging.get_transport(cfg.CONF) transport = messaging.get_transport(cfg.CONF)
# Launch server(s). if (cfg.CONF.server == ['all']):
launch_options[cfg.CONF.server](transport) # Launch all servers.
launch_any(transport, LAUNCH_OPTIONS.keys())
else:
# Validate launch option.
if set(cfg.CONF.server) - set(LAUNCH_OPTIONS.keys()):
raise Exception('Valid options are all or any combination of '
'api, engine, and executor.')
# Launch distinct set of server(s).
launch_any(transport, set(cfg.CONF.server))
except RuntimeError, e: except RuntimeError, e:
sys.stderr.write("ERROR: %s\n" % e) sys.stderr.write("ERROR: %s\n" % e)

9
mistral/config.py
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@ -86,11 +86,12 @@ executor_opts = [
help='The version of the executor.') help='The version of the executor.')
] ]
launch_opt = cfg.StrOpt( launch_opt = cfg.ListOpt(
'server', 'server',
default='all', default=['all'],
choices=('all', 'api', 'engine', 'executor'), help='Specifies which mistral server to start by the launch script. '
help='Specifies which mistral server to start by the launch script.' 'Valid options are all or any combination of '
'api, engine, and executor.'
) )