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From Chinmoy Chakraborty <cch...@gmail.com>
Subject Re: Supporting hierarchical service deployment
Date Fri, 04 Sep 2009 07:15:26 GMT
As I mentioned, if we add the namespace/version (if exists) along with
service name including AAR file name, would it be bad design? May be in this
case we do not need extra parameter in services xml. We get all the info
from the AAR file name itself and the service name should also be with the
namespace/version in the services.xml (if we have one).

Chinmoy

On Fri, Sep 4, 2009 at 12:12 PM, Isuru Suriarachchi <isurues@gmail.com>wrote:

>
>
>   On Fri, Sep 4, 2009 at 11:32 AM, Chinmoy Chakraborty <cchinu@gmail.com>wrote:
>
>>
>>
>>  On Fri, Sep 4, 2009 at 10:22 AM, Amila Suriarachchi <
>> amilasuriarachchi@gmail.com> wrote:
>>
>>>
>>>
>>>  On Fri, Sep 4, 2009 at 10:05 AM, Chinmoy Chakraborty <cchinu@gmail.com>wrote:
>>>
>>>> Paul,
>>>>
>>>> May be I dropped in from nowhere but I like to understand the idea. What
>>>> is the purpose of maintaining duplicate data by allowing exact same AAR to
>>>> be deployed in two different parts of hierarchy?
>>>>
>>> It is not exact AAR file. It is basically organise your AAR file in a
>>> directory structure without putting all of the in the root directory.
>>>
>>> eg.
>>> repository/services/admin/AdminService.aar
>>> repository/services/management/Management.aar
>>> repository/services/tech/v1.1/Tech.aar
>>> repository/services/tech/v1.0/Tech.aar
>>>
>>> if you take latter two cases, it may be two versions of same .aar file
>>> which user wants to active at the same time.
>>>
>>
>> CHINMOY>> OK.
>>
>>
>>>
>>>
>>>> I guess Axis2 should also support same service name with different
>>>> namespaces. I have this kind of requirement in our project but right now
>>>> it's a limitation.
>>>>
>>> if you can describe your requirement then we can see how it can be
>>> supported.
>>>
>>> As I understood what you want to have is same service name with different
>>> name spaces to distinguish the version.
>>> (I assume version depends on the namespace in your case)
>>>
>>
>> CHINMOY>> Not exactly. I have two different services with same service
>> name and they do absolutely two different tasks. let me explain: I have one
>> function called ABS (returns absolute value, generally long) and a
>> routine called ABS (does some other work than ABS function). Let's say
>> the namespace for ABS function is abc.function.ABS and the namespace for
>> ABS routine is abc.routine.ABS.
>>
>> So we can have two different services for the same service name. In AXIS
>> 1.x we could do that since there was concept of jws deployment and the
>> directory structure was part of the url.
>>
>>>
>>> Now the problem is what is the epr for these two services. In the above
>>> solution epr is mapped to the folder structure. So people can invoke two
>>> services with different eprs.
>>>
>>> In your solution how to determine the service to invoke once a request
>>> receive?
>>>
>>
>> CHINMOY>> If we have a parameter in services.xml like
>> <serviceNameSpace>abc.function/routine</serviceNameSpace> then in the
url
>> the service name should be appened with namespace. e.g
>>
>> ../services/ABS (now)
>> ../service/abc.function.ABS
>>
>> The logic should be just add namespace along with the servicename and the
>> namespace is available from the services.xml.
>>
>
> Then how are we going to do this for the services like POJO, JAXWS etc..
> which doesn't contain a services.xml?
>
> And also, even with AAR services, you have to name your .aar file
> differently as they are in the same folder.
>
> Actually hierarchical services using directories address wider range of
> problems. It allows you to manage your services separately  as you wish.
> That is the natural way of managing stuff. And also that concept caters your
> requirement as well.
>
> Put your first ABS service in abc/function/ folder.
> Put your second ABS service in abc/routine/ folder.
>
> Thanks,
> ~Isuru
>
>
>>
>> Chinmoy
>>
>>>
>>> thanks,
>>> Amila.
>>>
>>>>
>>>> Chinmoy
>>>>
>>>>   On Thu, Sep 3, 2009 at 4:46 PM, Paul Fremantle <pzfreo@gmail.com>wrote:
>>>>
>>>>> Chinmoy
>>>>>
>>>>> I think that is cool, but I guess the aim of Isuru's initial proposal
>>>>> was to allow the exact same AAR to be deployed independently in two
>>>>> parts of the hierarchy. To me that is a good objective.
>>>>>
>>>>> Paul
>>>>>
>>>>> On Thu, Sep 3, 2009 at 11:59 AM, Chinmoy Chakraborty<cchinu@gmail.com>
>>>>> wrote:
>>>>> > Guys,
>>>>> >
>>>>> > How about introducing a new parameter (e.g ServiceClassNameSpace)
in
>>>>> the
>>>>> > services.xml to support directory hierarchy in the service?
>>>>> >
>>>>> > Chinmoy
>>>>> >
>>>>> > On Thu, Sep 3, 2009 at 3:47 PM, Isuru Suriarachchi <
>>>>> isurues@gmail.com>
>>>>> > wrote:
>>>>> >>
>>>>> >> Hi all,
>>>>> >>
>>>>> >> As using '/' character may cause problems in dispatching, I
just
>>>>> used a
>>>>> >> separate character ('!') to represent the directory hierarchy
in the
>>>>> >> service. This allows all types of services to be deployed
>>>>> hierarchically
>>>>> >> without any problems (Including RESTful services).
>>>>> >>
>>>>> >> Ex: if we deploy the Echo service at
>>>>> >> /repository/services/foo/bar/1.0.0/echo.aar, service name will
be
>>>>> >> foo!bar!1.0.0!Echo and the EPR will be like
>>>>> >> ../axis2/services/foo!bar!1.0.0!Echo/echoString
>>>>> >>
>>>>> >> I've attached a new patch to the JIRA
>>>>> >> (https://issues.apache.org/jira/browse/AXIS2-4479). This patch
>>>>> doesn't
>>>>> >> contain any changes in dispatching logics. And also I've implemented
>>>>> the
>>>>> >> ability to deploy JAXWS, Pojo etc.. (which are coming from the
>>>>> axis2.xml)
>>>>> >> services hierarchically to make this effort complete. In addition
to
>>>>> that,
>>>>> >> I've written some deployment tests for hierarchical services.
>>>>> >>
>>>>> >> Thanks,
>>>>> >> ~Isuru
>>>>> >>
>>>>> >> On Sun, Aug 30, 2009 at 2:48 AM, keith chapman <
>>>>> keithgchapman@gmail.com>
>>>>> >> wrote:
>>>>> >>>
>>>>> >>> I've been out of touch with the Axis2 list for some time.
Took a
>>>>> while to
>>>>> >>> read this thread. Just a few thouths on it.
>>>>> >>>
>>>>> >>> I don't think that this patch would effect the RESTfull
behaviour
>>>>> in any
>>>>> >>> way. Its just that the user needs to be extra carefull if
he wants
>>>>> to use
>>>>> >>> RESTfull services in cunjunction with the hierarchical services
>>>>> concept. i.e
>>>>> >>> if he has a services called foo do not use foo as a top
level
>>>>> folder in your
>>>>> >>> hierarchy. Its simple as that. I guess been careful is the
price
>>>>> you have to
>>>>> >>> pay if you wanna use hierarchical services.
>>>>> >>>
>>>>> >>> I like the idea of having hierarchical services in Axis2.
Well I
>>>>> did it
>>>>> >>> once using the extension points of Axis2 but I'm +1 for
having this
>>>>> concept
>>>>> >>> baked into Axis2.
>>>>> >>>
>>>>> >>> Also it would be good to base arguments on facts rather
than
>>>>> religious
>>>>> >>> beleifs. Quite a few design desicions made back then when
Axis2 was
>>>>> designed
>>>>> >>> did not take stuff such as this into consideration. Well
i'm not
>>>>> blaming the
>>>>> >>> initial Axis2 community for that. As the project evolves
new
>>>>> features such
>>>>> >>> as this can be added. Good examples are features such as
plugable
>>>>> message
>>>>> >>> builders/formatters (post 1.1), custom deployers (post 1.2
IIRC),
>>>>> the
>>>>> >>> binding hierarchy concept (post 1.3) are features that were
added
>>>>> later in
>>>>> >>> the cycle. I see the hierarchical service deployment feature
as
>>>>> just another
>>>>> >>> addition to the wide variety of features of Axis2.
>>>>> >>>
>>>>> >>> Thanks,
>>>>> >>> Keith.
>>>>> >>>
>>>>> >>> On Sat, Aug 29, 2009 at 1:24 PM, Sanjiva Weerawarana
>>>>> >>> <sanjiva@opensource.lk> wrote:
>>>>> >>>>
>>>>> >>>> I forgot to address the issue with not being able to
support
>>>>> RESTful
>>>>> >>>> services. I think we can- we just need to change the
REST
>>>>> dispatcher (argh
>>>>> >>>> if that's what its called its a terrible name!) to look
at the
>>>>> context path
>>>>> >>>> of the service(s) and try filtering those out first.
>>>>> >>>>
>>>>> >>>> Sanjiva.
>>>>> >>>>
>>>>> >>>> On Sat, Aug 29, 2009 at 8:51 PM, Sanjiva Weerawarana
>>>>> >>>> <sanjiva@opensource.lk> wrote:
>>>>> >>>>>
>>>>> >>>>> Deepal, I've read this entire thread and I'm confused
as to why
>>>>> you're
>>>>> >>>>> objecting.
>>>>> >>>>>
>>>>> >>>>> First of all, I think Isuru sent this thread into
a bad start by
>>>>> using
>>>>> >>>>> versioning as the reason for wanting to introduce
hierarchical
>>>>> service
>>>>> >>>>> deployment. That was a mistake but as Andreas' comment
pointed
>>>>> out, this is
>>>>> >>>>> nothing more than the contextPath concept found
in Java
>>>>> containers.
>>>>> >>>>> Versioning is at most a special case but let's just
take that out
>>>>> of the
>>>>> >>>>> discussion because this is not about versioning.
If you disagree
>>>>> please
>>>>> >>>>> explain why.
>>>>> >>>>>
>>>>> >>>>> Secondly, this can be done outside of Axis2 totally.
All we need
>>>>> to do
>>>>> >>>>> is write a new deployer and a dispatcher. There's
no need to
>>>>> waste time with
>>>>> >>>>> this type of pretty un-objective / emotional debate.
However, it
>>>>> was
>>>>> >>>>> proposed as a mod to axis2 because it significantly
improves
>>>>> axis2 usability
>>>>> >>>>> WITHOUT breaking any existing behavior. Or so was
the belief. So
>>>>> let's go
>>>>> >>>>> thru the discussion and if the view is that this
is not necessary
>>>>> in axis2's
>>>>> >>>>> default deployers etc. then no problem.
>>>>> >>>>>
>>>>> >>>>> Now I will explain why this approach is better than
alternatives.
>>>>> The
>>>>> >>>>> basic requirement is that having a single flat naming
scheme for
>>>>> services is
>>>>> >>>>> unnecessarily limiting. Why? Because it requires
everyone to
>>>>> agree on the
>>>>> >>>>> service name as those names are global. If you're
using Axis2 as
>>>>> a library
>>>>> >>>>> on a single developer machine that's not an issue.
However, if
>>>>> you want to
>>>>> >>>>> deploy an axis2 engine to host some number of services
for a
>>>>> larger
>>>>> >>>>> organization then that invariably results in name
conflicts. I
>>>>> assume you
>>>>> >>>>> agree that's global names are a limitation.
>>>>> >>>>>
>>>>> >>>>> How do you fix it? One option is to use some naming
convention
>>>>> like
>>>>> >>>>> what Java packages did for Java classes. So you
can have
>>>>> >>>>> /services/us.finance.address and /uk.services/marketing.address
>>>>> if (say) US
>>>>> >>>>> finance and UK marketing orgs both want to have
a service called
>>>>> "address".
>>>>> >>>>> That basically makes the fact that what you have
are
>>>>> hierarchically named
>>>>> >>>>> services opaque to the Web infrastructure. For example,
if you
>>>>> were
>>>>> >>>>> analyzing http logs to see the traffic you can't
get a simple
>>>>> answer to "how
>>>>> >>>>> many times have UK guys' services been used?". That's
*exactly*
>>>>> the kind of
>>>>> >>>>> wrong-headed thinking that got WS-* in trouble with
the REST guys
>>>>> for
>>>>> >>>>> improper use of REST (and I'm absolutely one of
the early
>>>>> culprits who made
>>>>> >>>>> the mistake).
>>>>> >>>>>
>>>>> >>>>> Another approach is to have a way to specify the
context path in
>>>>> the
>>>>> >>>>> service itself. If you remember, we used to have
the concept of
>>>>> service name
>>>>> >>>>> you could specify in service.xml itself (maybe its
still there; I
>>>>> have no
>>>>> >>>>> idea) - the idea was it would override the .aar
file name if
>>>>> thats' there.
>>>>> >>>>> This is similar- you can have in foo.aar a setting
saying
>>>>> >>>>> contextPath="finance/foo" and that means that's
where the service
>>>>> is
>>>>> >>>>> deployed.
>>>>> >>>>>
>>>>> >>>>> The advantage of simply using the file system hierarchy
to
>>>>> compute that
>>>>> >>>>> is just simplicity. The context hierarchy is visible
to everyone
>>>>> by simply
>>>>> >>>>> looking at the directory structure. If you check
in the
>>>>> repository into SVN
>>>>> >>>>> (which I know a bunch of people do) it gives a simple
way to
>>>>> manage
>>>>> >>>>> authorization for deployment for different people.
>>>>> >>>>>
>>>>> >>>>> I actually think we should support a contextPath=xxx
option in
>>>>> >>>>> services.xml as well. However, treating the file
system hierarchy
>>>>> as a
>>>>> >>>>> hierarchy is, you know, rather natural.
>>>>> >>>>>
>>>>> >>>>> I think Isuru has shown that there is no extra performance
loss
>>>>> or any
>>>>> >>>>> other loss by supporting hierachically deployed
services. You
>>>>> DON'T need to
>>>>> >>>>> use them unless you want to of course - and if there's
no
>>>>> hierarchy there's
>>>>> >>>>> no change at all (subject to having enough unit
tests to make
>>>>> sure that old
>>>>> >>>>> and new behavior for the old feature is not changed).
>>>>> >>>>>
>>>>> >>>>> Sanjiva.
>>>>> >>>>>
>>>>> >>>>> On Sat, Aug 29, 2009 at 7:05 PM, Deepal jayasinghe
<
>>>>> deepalk@gmail.com>
>>>>> >>>>> wrote:
>>>>> >>>>>>
>>>>> >>>>>> >
>>>>> >>>>>> >
>>>>> >>>>>> > On Fri, Aug 28, 2009 at 8:30 PM, Andreas
Veithen
>>>>> >>>>>> > <andreas.veithen@gmail.com <mailto:andreas.veithen@gmail.com
>>>>> >>
>>>>> >>>>>> > wrote:
>>>>> >>>>>> >
>>>>> >>>>>> >     Guys,
>>>>> >>>>>> >
>>>>> >>>>>> >     Are we actually discussing the right
question? Looking at
>>>>> the
>>>>> >>>>>> > patch
>>>>> >>>>>> >     proposed by Isuru, I have the impression
that versioning
>>>>> is
>>>>> >>>>>> > merely one
>>>>> >>>>>> >     use case, but that (in contrast to
modules) the code
>>>>> doesn't
>>>>> >>>>>> > make any
>>>>> >>>>>> >     assumption about the meaning of the
hierarchy in the
>>>>> repository
>>>>> >>>>>> > (it
>>>>> >>>>>> >     could be version number, but it could
also something
>>>>> completely
>>>>> >>>>>> >     different). Fundamentally the change
is not about
>>>>> versioning,
>>>>> >>>>>> > but
>>>>> >>>>>> >     about giving the user the possibility
to define the
>>>>> structure of
>>>>> >>>>>> > the
>>>>> >>>>>> >     endpoint URL.
>>>>> >>>>>> >
>>>>> >>>>>> >
>>>>> >>>>>> > yes. this should be the idea. it is to
support hierarchical
>>>>> service
>>>>> >>>>>> > folder structure to mange
>>>>> >>>>>> > services. Versioning is only one possible
use case.
>>>>> >>>>>> > I think this is a common requirement. For
an example if we
>>>>> take a
>>>>> >>>>>> > web
>>>>> >>>>>> > site people don't put
>>>>> >>>>>> > all their .jsp or .html files in the root
directory. They
>>>>> manage
>>>>> >>>>>> > them
>>>>> >>>>>> > in a some meaningful
>>>>> >>>>>> > folder structure and even page url maps
to it.
>>>>> >>>>>> You are mistaken in the case of web site .jsp
files are like
>>>>> .class
>>>>> >>>>>> files. So even in Web Service we have package
hierarchy.
>>>>> >>>>>> > I can hardly think of any reason for opposing
to introduce
>>>>> such
>>>>> >>>>>> > feature to axis2 service deployment provided
>>>>> >>>>>> > that it *does not break existing functionality*.
>>>>> >>>>>> If you look at the directory structure (as I
told you before)
>>>>> >>>>>> information repeat it self. It is analogous
to "Shop is closed
>>>>> because
>>>>> >>>>>> it is not open".
>>>>> >>>>>> Just because feature X is good in project Y,
we should not
>>>>> introduce
>>>>> >>>>>> that to Axis2.
>>>>> >>>>>> If you or someone want to do such a feature
of course they can
>>>>> do
>>>>> >>>>>> that,
>>>>> >>>>>> just ad a new deployer  to handle the they want,
even in you
>>>>> case we
>>>>> >>>>>> can
>>>>> >>>>>> do the same. Let's create a new deployer and
manage anyway you
>>>>> like,
>>>>> >>>>>> and
>>>>> >>>>>> then if you think it is ok, then commit the
new deployer to
>>>>> Axis2.
>>>>> >>>>>>
>>>>> >>>>>> However I am not ok with introducing new URL
pattern, I think
>>>>> Isuru
>>>>> >>>>>> already agreed to replace "/" with "-"
>>>>> >>>>>> >
>>>>> >>>>>> > Deepal,
>>>>> >>>>>> > I feel you have given over weight to the
versioning support
>>>>> which is
>>>>> >>>>>> > a
>>>>> >>>>>> > use case of this. In the way to have told
>>>>> >>>>>> > people can have versioning without any
support of axis2, by
>>>>> just
>>>>> >>>>>> > naming service in the way they need.
>>>>> >>>>>> Yes. At the end of the day whether it is "/"
or "-" would become
>>>>> a
>>>>> >>>>>> unique name. So it is the service name.
>>>>> >>>>>> >
>>>>> >>>>>> > Comming into the other point of probable
break of existing
>>>>> >>>>>> > functionality Can you please come up with
the
>>>>> >>>>>> > set of use case scenarios for this? Then
we can ask Isuru to
>>>>> provide
>>>>> >>>>>> > integration test for all these scenarios.
This may test the
>>>>> existing
>>>>> >>>>>> > functionality as well :)
>>>>> >>>>>> I am sorry I do not have time to comeup with
scenarios when
>>>>> someone
>>>>> >>>>>> add
>>>>> >>>>>> new features, specially even without going through
the existing
>>>>> JIRA.
>>>>> >>>>>> >
>>>>> >>>>>> > I think we should not be pessimistic and
think deployment
>>>>> engine is
>>>>> >>>>>> > done for ever and any change will break
it.
>>>>> >>>>>> Not at all, how many changes we made, in this
case my concern is
>>>>> not
>>>>> >>>>>> the
>>>>> >>>>>> deployment engine it is the URL pattern.
>>>>> >>>>>> >
>>>>> >>>>>> > Isuru,
>>>>> >>>>>> > Please provide a set of integration tests
for the scenarios
>>>>> >>>>>> > mentioned.
>>>>> >>>>>> :)
>>>>> >>>>>>
>>>>> >>>>>> Thanks,
>>>>> >>>>>> Deepal
>>>>> >>>>>
>>>>> >>>>>
>>>>> >>>>>
>>>>> >>>>> --
>>>>> >>>>> Sanjiva Weerawarana, Ph.D.
>>>>> >>>>> Founder, Director & Chief Scientist; Lanka Software
Foundation;
>>>>> >>>>> http://www.opensource.lk/
>>>>> >>>>> Founder, Chairman & CEO; WSO2, Inc.; http://www.wso2.com/
>>>>> >>>>> Member; Apache Software Foundation; http://www.apache.org/
>>>>> >>>>> Visiting Lecturer; University of Moratuwa;
>>>>> http://www.cse.mrt.ac.lk/
>>>>> >>>>>
>>>>> >>>>> Blog: http://sanjiva.weerawarana.org/
>>>>> >>>>
>>>>> >>>>
>>>>> >>>>
>>>>> >>>> --
>>>>> >>>> Sanjiva Weerawarana, Ph.D.
>>>>> >>>> Founder, Director & Chief Scientist; Lanka Software
Foundation;
>>>>> >>>> http://www.opensource.lk/
>>>>> >>>> Founder, Chairman & CEO; WSO2, Inc.; http://www.wso2.com/
>>>>> >>>> Member; Apache Software Foundation; http://www.apache.org/
>>>>> >>>> Visiting Lecturer; University of Moratuwa;
>>>>> http://www.cse.mrt.ac.lk/
>>>>> >>>>
>>>>> >>>> Blog: http://sanjiva.weerawarana.org/
>>>>> >>>
>>>>> >>>
>>>>> >>>
>>>>> >>> --
>>>>> >>> Keith Chapman
>>>>> >>>
>>>>> >>> blog: http://www.keith-chapman.org
>>>>> >>
>>>>> >>
>>>>> >>
>>>>> >> --
>>>>> >> Senior Software Engineer,
>>>>> >> WSO2 Inc. http://wso2.org/
>>>>> >> Blog : http://isurues.wordpress.com/
>>>>> >
>>>>> >
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Paul Fremantle
>>>>> Co-Founder and CTO, WSO2
>>>>> Apache Synapse PMC Chair
>>>>> OASIS WS-RX TC Co-chair
>>>>>
>>>>> blog: http://pzf.fremantle.org
>>>>> paul@wso2.com
>>>>>
>>>>> "Oxygenating the Web Service Platform", www.wso2.com
>>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Amila Suriarachchi
>>> WSO2 Inc.
>>> blog: http://amilachinthaka.blogspot.com/
>>>
>>
>>
>
>
> --
>  Senior Software Engineer,
> WSO2 Inc. http://wso2.org/
> Blog : http://isurues.wordpress.com/
>

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