Clearer docs on the service runner/container about nameko HOT 6 OPEN

Hi matt, it seems neither invoking start() on container or runner will start service unless I call wait(). Is this expected?

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@laike9m start() does start the service, but you must wait() on the container or the runner to stop your process or thread from exiting.

The best way to run a service is nameko run on the command line. Or, if you want to embed the service in another application, wrap the run function in nameko.cli.run -- https://github.com/onefinestay/nameko/blob/master/nameko/cli/run.py#L117 (which is what the command line tool uses under the hood)

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Thank you. I'm using a runner because in this way I'm able to stop the service programmatically. Actually there's another issue: I have to call kill() to stop it while stop() doesn't work.

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Sorry, I forgot about this thread.

stop() waits for all running workers and managed threads to exit gracefully. You can't expose container.stop() in an entrypoint and expect to the container to stop when you call it -- this would create a deadlock between the container trying to stop and the worker or managed thread running the stop() method.

If you want to expose an entrypoint that is capable of stopping the container, you'd need to do it "out of band" (i.e. using a thread that wasn't created by the container)

Here is a toy example that does that:

from nameko.rpc import rpc
from nameko.extensions import DependencyProvider
import eventlet

class Stopper(DependencyProvider):

    def stop(self):
        # can't use container.spawn_managed_thread here either
        eventlet.spawn_n(self.container.stop)

    def get_dependency(self, worker_ctx):
        return self


class Service(object):
    name = "stop"

    stopper = Stopper()

    @rpc
    def stop(self):
        self.stopper.stop()
        return "stopping"

(tmp-6d6e28416a4d3fa9)Matts-13-inch-Macbook-Pro:tmp mattbennett$ nameko run stop
starting services: stop
Connected to amqp://guest:**@127.0.0.1:5672//

(tmp-6d6e28416a4d3fa9)Matts-13-inch-Macbook-Pro:~ mattbennett$ nameko shell
Nameko Python 2.7.10 (default, Jul  6 2015, 15:19:48)
[GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)] shell on darwin
Broker: amqp://guest:guest@localhost
>>> n.rpc.stop.stop()

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it seems unusual to expose an endpoint to remotely shut down a service. is this definitely what you want when you say "stop the service programatically". Typically this is done e.g. via a process manager like supervisor, which stops (or kills) the service via posix signals. E.g. nameko run listens for SIGTERM and calls stop

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Yes indeed, the example above is not a demonstration of how you should achieve this. It is only meant to illustrate an "out of band" thread.

Generating a SIGTERM signal is a much better way to have the container to stop gracefully.

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