Re: Customizing Sample Pinger of Uima

[Eddie Epstein]

Hi Florian,

The documentation for this is at
http://uima.apache.org/d/uima-as-2.10.3/uima_async_scaleout.html#ugr.ref.async.api.usage_targetservice

There is a test case at
https://svn.apache.org/viewvc/uima/uima-as/trunk/uimaj-as-activemq/src/test/java/org/apache/uima/ee/test/TestUimaASExtended.java?revision=1826882&view=markup#l2238

Regards,
Eddie

On Mon, May 6, 2019 at 10:13 AM Florian  wrote:

> Hi,
>
> is there eventual an example or demo for sending request to individual
> service instances? I couldn't find an example in the repository.
>
> Best regards,
> Florian
>
> On Mi, Mai 1, 2019 at 12:13 AM, Eddie Epstein 
> wrote:
> > Hi Florian,
> >
> > Interesting questions. First, yes the intended behavior is to leave 1
> > instance running. Services are either started by having
> > autostart=true, or
> > by a job or another service having a dependency on the service.
> > Logically
> > it could be possible to let a pinger stop all instances and have the
> > service still be in some kind of "running" state so that the pinger
> > would
> > continue running and be able to restart instances when it detected a
> > need;
> > all that is needed is a bit of programming :)
> >
> > A hacky approach would be not to use autostart, rather to start
> > service-A
> > by using a dummy service-B with a dependency on A. When service A
> > pinger
> > wants to stop A, it could issue a command to stop B which would allow
> > service A to be stopped. Restarting A would require an external
> > program
> > requesting B to be started again.
> >
> > For the second question, the answer is yes for UIMA-AS services. The
> > latest
> > version of UIMA-AS supports sending process requests to specific
> > service
> > instances. A pinger could send such requests, and when an instance
> > fails to
> > reply the pinger can direct that instance to be stopped and another
> > instance started. The answer is also yes for custom services for
> > which the
> > pinger knows how to address each instance.
> >
> > Regards,
> > Eddie
> >
> > On Tue, Apr 30, 2019 at 1:43 PM Florian  > > wrote:
> >
> >>  Hello everyone,
> >>
> >>  I have two questions about the given sample pinger example of Uima.
> >>
> >>  It is possible to set the minimal numbers of instances of a service
> >> to
> >>  zero? If I set the min-variable to zero uima is always starting a
> >> new
> >>  instance, when the last one is shutdown. Is this behavior intended
> >> or
> >>  is there a way to prevent the start of a new instance, when there
> >> is no
> >>  calls to the service? As we have some services that a rarely used,
> >> we
> >>  would only like to start instances on demand.
> >>
> >>  Secondly is there also a option to call specific instances of a
> >> service
> >>  and restart them? We would like to do health checks for individual
> >>  instances and restart them if needed.
> >>
> >>  Best Regards
> >>
> >>  Florian
> >>
> >>
> >>
> >>
>
>

Re: Customizing Sample Pinger of Uima

[Florian]

Hi,

is there eventual an example or demo for sending request to individual
service instances? I couldn't find an example in the repository.

Best regards,
Florian

On Mi, Mai 1, 2019 at 12:13 AM, Eddie Epstein 
wrote:

Hi Florian,

Interesting questions. First, yes the intended behavior is to leave 1
instance running. Services are either started by having
autostart=true, or
by a job or another service having a dependency on the service.
Logically
it could be possible to let a pinger stop all instances and have the
service still be in some kind of "running" state so that the pinger
would
continue running and be able to restart instances when it detected a
need;
all that is needed is a bit of programming :)

A hacky approach would be not to use autostart, rather to start
service-A
by using a dummy service-B with a dependency on A. When service A
pinger
wants to stop A, it could issue a command to stop B which would allow
service A to be stopped. Restarting A would require an external
program
requesting B to be started again.

For the second question, the answer is yes for UIMA-AS services. The
latest
version of UIMA-AS supports sending process requests to specific
service
instances. A pinger could send such requests, and when an instance
fails to
reply the pinger can direct that instance to be stopped and another
instance started. The answer is also yes for custom services for
which the
pinger knows how to address each instance.

Regards,
Eddie

On Tue, Apr 30, 2019 at 1:43 PM Florian mailto:f.allgoe...@web.de>> wrote:


 Hello everyone,

 I have two questions about the given sample pinger example of Uima.

 It is possible to set the minimal numbers of instances of a service
to
 zero? If I set the min-variable to zero uima is always starting a
new
 instance, when the last one is shutdown. Is this behavior intended
or
 is there a way to prevent the start of a new instance, when there
is no
 calls to the service? As we have some services that a rarely used,
we
 would only like to start instances on demand.

 Secondly is there also a option to call specific instances of a
service
 and restart them? We would like to do health checks for individual
 instances and restart them if needed.

 Best Regards

 Florian

Re: Customizing Sample Pinger of Uima

[Eddie Epstein]

Hi Florian,

Interesting questions. First, yes the intended behavior is to leave 1
instance running. Services are either started by having autostart=true, or
by a job or another service having a dependency on the service. Logically
it could be possible to let a pinger stop all instances and have the
service still be in some kind of "running" state so that the pinger would
continue running and be able to restart instances when it detected a need;
all that is needed is a bit of programming :)

A hacky approach would be not to use autostart, rather to start service-A
by using a dummy service-B with a dependency on A. When service A pinger
wants to stop A, it could issue a command to stop B which would allow
service A to be stopped. Restarting A would require an external program
requesting B to be started again.

For the second question, the answer is yes for UIMA-AS services. The latest
version of UIMA-AS supports sending process requests to specific service
instances. A pinger could send such requests, and when an instance fails to
reply the pinger can direct that instance to be stopped and another
instance started. The answer is also yes for custom services for which the
pinger knows how to address each instance.

Regards,
Eddie

On Tue, Apr 30, 2019 at 1:43 PM Florian  wrote:

> Hello everyone,
>
> I have two questions about the given sample pinger example of Uima.
>
> It is possible to set the minimal numbers of instances of a service to
> zero? If I set the min-variable to zero uima is always starting a new
> instance, when the last one is shutdown. Is this behavior intended or
> is there a way to prevent the start of a new instance, when there is no
> calls to the service? As we have some services that a rarely used, we
> would only like to start instances on demand.
>
> Secondly is there also a option to call specific instances of a service
> and restart them? We would like to do health checks for individual
> instances and restart them if needed.
>
> Best Regards
>
> Florian
>
>
>
>

Customizing Sample Pinger of Uima

[Florian]

Hello everyone,

I have two questions about the given sample pinger example of Uima.

It is possible to set the minimal numbers of instances of a service to
zero? If I set the min-variable to zero uima is always starting a new
instance, when the last one is shutdown. Is this behavior intended or
is there a way to prevent the start of a new instance, when there is no
calls to the service? As we have some services that a rarely used, we
would only like to start instances on demand.

Secondly is there also a option to call specific instances of a service
and restart them? We would like to do health checks for individual
instances and restart them if needed.

Best Regards

Florian