Hi Sajini, Yes that is what I meant. As the number of slots are proportional to the number of messages passing through the cluster, slot delivery should not be handled by the coordinator when there is only one coordinator in the cluster which is a bottleneck for scaling messages passing through the cluster. If there is only a single coordinator, it should handle operations that are not proportional to messages throughput of the cluster. Then only the tasks like subscriber adding / removing should be handled by the coordinator. As this is not the current implementation, we can consider multiple coordinator approach. Then the number of coordinators should be scalable with the message throughout. I am not sure whether locking the database per transaction would achieve this coordinator scalability in the multiple coordinator implementation.
Thanks. *Maninda Edirisooriya* Senior Software Engineer *WSO2, Inc.*lean.enterprise.middleware. *Blog* : http://maninda.blogspot.com/ *E-mail* : mani...@wso2.com *Skype* : @manindae *Twitter* : @maninda On Fri, Aug 5, 2016 at 2:42 PM, Sajini De Silva <saj...@wso2.com> wrote: > Hi Maninda, > > On Fri, Aug 5, 2016 at 2:28 PM, Maninda Edirisooriya <mani...@wso2.com> > wrote: > >> @Sajini, >> >> But the number of slots are proportional to the number of messages pass >> through the MB which needs to be handled by the coordinator. That is what I >> meant by "information related to meta data of messages pass through a >> single coordinator". Ideally after the senders and receivers are subscribed >> to the cluster, coordinator should have nothing to do until they are >> removed or changed. >> > > Even though it is possible to have multiple coordinators after having en > effort (Lock the database for a whole transaction or the work load > distribution as described by Ramith) , coordinator may have different work > to do other than subscriber adding and removing. As I said earlier our MB > message distribution system is based on slot architecture and slots will > managed by the coordinator. You can read [1] to understand more about slot > architecture in MB. > > [1] http://sajinid.blogspot.com/2015/03/wso2-message- > broker-300-slot-based.html > > Thanks > >> >> @Ramith, >> >> +1 for multiple coordinators by partitioning the cluster which maintains >> the simplicity and correctness of the algorithm than compromising >> simplicity with a less important factor like "delivering a good mix of >> messages". >> >> Thanks. >> >> >> *Maninda Edirisooriya* >> Senior Software Engineer >> >> *WSO2, Inc.*lean.enterprise.middleware. >> >> *Blog* : http://maninda.blogspot.com/ >> *E-mail* : mani...@wso2.com >> *Skype* : @manindae >> *Twitter* : @maninda >> >> On Fri, Aug 5, 2016 at 2:05 PM, Ramith Jayasinghe <ram...@wso2.com> >> wrote: >> >>> @Imesh, >>> We can prove that doing leader election using a lib (where we maintain >>> cluster state in another place, a.k.a DB) will not solve our original >>> problem (this also relates to our past experience with both the zookeeper >>> and hazelcast). >>> We can make this implementation a common component if other products >>> have a use of it. BPS might be able to use it since their data is also in >>> the database. >>> >>> @Malaka: >>> VFS scenario can't be solved by relying on this implementation. why? >>> you can have the access to DB but not VFS resources/file (and vice versa). >>> this is the same point we explained before. >>> in Ntask implementation, if tasks are stored in the database then >>> using this implementation makes sense. >>> >>> >>> @Akila, >>> implementing (distributed) a queue algorithm is non-trivial. Having one >>> coordinator (single source of truth) keeps things simple hence it's a >>> conscious design decision we agreed during the initial stages. However, >>> possible extension to this scheme is to have multiple coordinators ( each >>> responsible for coordinating a subset of queues in the cluster), that will >>> be some what similar to kafka. >>> Even if its preferable to have no coordinator at-all, (to decide how >>> messages are disseminated in the cluster) that will make us give up >>> desired behaviour such as delivering a good mix of messages (from different >>> publishers) to consumers in a cluster. having said this, we have an ongoing >>> research on how to improve the algorithm and we like to try out both these >>> approaches. >>> >>> >>> On Fri, Aug 5, 2016 at 1:31 PM, Malaka Silva <mal...@wso2.com> wrote: >>> >>>> The same issue with Hazelcast can be experienced with ESB inbounds >>>> (running on top of NTASK) and VFS distribution locks. >>>> >>>> The idea of only single worker works at a given time breaks if there is >>>> a Hazelcast heart beat fails. This will make two workers to work in >>>> parallel. >>>> >>>> Also with distributed locking there is no guarantee that file is only >>>> process only by one worker. >>>> >>>> So in the case of network fail >>>> with DB >>>> make sense to stop processing until it's recovered. >>>> Also making this component generic ESB can reuse. >>>> >>>> On Fri, Aug 5, 2016 at 9:21 AM, Asitha Nanayakkara <asi...@wso2.com> >>>> wrote: >>>> >>>>> Hi Imesh, >>>>> >>>>> On Fri, Aug 5, 2016 at 7:33 AM, Imesh Gunaratne <im...@wso2.com> >>>>> wrote: >>>>> >>>>>> >>>>>> >>>>>> On Fri, Aug 5, 2016 at 7:31 AM, Imesh Gunaratne <im...@wso2.com> >>>>>> wrote: >>>>>>> >>>>>>> >>>>>>> You can see here [3] how K8S has implemented leader election feature >>>>>>> for the products deployed on top of that to utilize. >>>>>>> >>>>>> >>>>>> Correction: Please refer [4]. >>>>>> >>>>>> >>>>>>> >>>>>>> >>>>>>>> On Thu, Aug 4, 2016 at 7:27 PM, Asanka Abeyweera <asank...@wso2.com >>>>>>>> > wrote: >>>>>>>> >>>>>>>>> Hi Imesh, >>>>>>>>> >>>>>>>>> We are not implementing this to overcome a limitation in the >>>>>>>>> coordination algorithm available in the Hazlecast. We are >>>>>>>>> implementing this >>>>>>>>> since we need an RDBMS based coordination algorithm (not a network >>>>>>>>> based >>>>>>>>> algorithm). >>>>>>>>> >>>>>>>> >>>>>>> Are you saying that database connections do not use the same >>>>>>> network used by Hazelcast? >>>>>>> >>>>>>> >>>>>>> >>>>>>>> The reason is, a network based election algorithm will always elect >>>>>>>>> multiple leaders when the network is partitioned. But if we use a >>>>>>>>> RDBMS >>>>>>>>> based algorithm this will not happen. >>>>>>>>> >>>>>>>> >>>>>>> I do not think your argument is correct. If there is a problem with >>>>>>> the network, it may apply to both Hazelcast based solution and database >>>>>>> based solution. >>>>>>> >>>>>> >>>>> Yes, if the same network interface is used network partion will cause >>>>> all types of connections to be partitioned. But user can use multiple >>>>> network interfaces for database, Hazelcast and thrift. >>>>> >>>>> Following is the scenario we are trying to solve in MB. >>>>> >>>>> In MB all the details related to messages, subscriptions, queues, >>>>> topics etc are stored in database. And we operate depending on that >>>>> information. If the MB node can't connect to the database that means the >>>>> node is ineffective in the cluster until it can make a database >>>>> connection. >>>>> >>>>> We have seen instances where Hazelcast cluster get partitioned for >>>>> some time period in networks, Reasons were, >>>>> >>>>> 1. Due to heavy load Hazelcast couldn't process or send (some >>>>> times both) hearbeats, hence a network partition for Hazelcast cluster >>>>> 2. An actual network partition of Hazelcast cluster >>>>> >>>>> In both scenarios the database connection was working. In that case we >>>>> get two coordinators elected through Hazelcast and working on the same >>>>> database to deliver the messages. this leads to inconsistencies in the >>>>> cluster behavior (for instances duplicate message delivery, corrupred >>>>> subscription states etc) . >>>>> >>>>> Since the point of interest for MB is the database, we decided to do >>>>> the coordinator election through database as well. If the node can't >>>>> connect to the database, then the MB won't operate anyway. >>>>> >>>>> Regards, >>>>> Asitha >>>>> >>>>> >>>>>>> [4] http://blog.kubernetes.io/2016/01/simple-leader-election >>>>>>> -with-Kubernetes.html >>>>>>> >>>>>>> Thanks >>>>>>> >>>>>>>> >>>>>>>>> >>>>>>>>> On Thu, Aug 4, 2016 at 7:16 PM, Imesh Gunaratne <im...@wso2.com> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Hi Asanka, >>>>>>>>>> >>>>>>>>>> Do we really need to implement a leader election algorithm on our >>>>>>>>>> own? AFAIU this is a complex problem which has been already solved by >>>>>>>>>> several algorithms [1]. IMO it would be better to go ahead with an >>>>>>>>>> existing >>>>>>>>>> well established implementation on etcd [1] or Consul [2]. >>>>>>>>>> >>>>>>>>>> Those provide HTTP APIs for clients to make leader election >>>>>>>>>> calls. [3] is a client library written in Node.js for etcd based >>>>>>>>>> leader >>>>>>>>>> election. >>>>>>>>>> >>>>>>>>>> [1] https://www.projectcalico.org/using-etcd-for-elections >>>>>>>>>> [2] https://www.consul.io/docs/guides/leader-election.html >>>>>>>>>> [3] https://www.npmjs.com/package/etcd-leader >>>>>>>>>> >>>>>>>>>> Thanks >>>>>>>>>> >>>>>>>>>> On Wed, Aug 3, 2016 at 5:12 PM, Asanka Abeyweera < >>>>>>>>>> asank...@wso2.com> wrote: >>>>>>>>>> >>>>>>>>>>> Hi Maninda, >>>>>>>>>>> >>>>>>>>>>> Since we are using RDBMS to poll the node status, the cluster >>>>>>>>>>> will not end up in situation 1,2 or 3. With this approach we >>>>>>>>>>> consider a >>>>>>>>>>> node unreachable when it cannot access the database. Therefore an >>>>>>>>>>> unreachable node can never be the leader. >>>>>>>>>>> >>>>>>>>>>> As you have mentioned, we are currently using the RDBMS as an >>>>>>>>>>> atomic global variable to create the coordinator entry. >>>>>>>>>>> >>>>>>>>>>> On Tue, Aug 2, 2016 at 5:22 PM, Maninda Edirisooriya < >>>>>>>>>>> mani...@wso2.com> wrote: >>>>>>>>>>> >>>>>>>>>>>> Hi Asanka, >>>>>>>>>>>> >>>>>>>>>>>> As I understand the accuracy of electing the leader correctly >>>>>>>>>>>> is dependent on the election mechanism with RDBMS because there >>>>>>>>>>>> can be edge >>>>>>>>>>>> cases like, >>>>>>>>>>>> >>>>>>>>>>>> 1. Unreachable leader activates during the election process: >>>>>>>>>>>> Then who becomes the leader? >>>>>>>>>>>> 2. The elected leader becomes unreachable before the election >>>>>>>>>>>> is completed: Then will there be a situation where there is no >>>>>>>>>>>> leader? >>>>>>>>>>>> 3. A leader and a set of nodes are disconnected from the other >>>>>>>>>>>> part of the cluster and while the leader is trying to remove >>>>>>>>>>>> unreachable >>>>>>>>>>>> members other part is calling an election to make a leader: Who >>>>>>>>>>>> will win? >>>>>>>>>>>> >>>>>>>>>>>> RDBMS based election algorithm should handle such cases without >>>>>>>>>>>> bringing the cluster to an inconsistent state or dead lock in all >>>>>>>>>>>> concurrent cases. If all these kind of cases cannot be handled >>>>>>>>>>>> isn't it >>>>>>>>>>>> better to keep the current hazelcast clustering and use the RDBMS >>>>>>>>>>>> only to >>>>>>>>>>>> handle the split brain scenario? In other words when a new >>>>>>>>>>>> hazelcast leader >>>>>>>>>>>> is elected it should be updated in the RDBMS. If another split >>>>>>>>>>>> party has >>>>>>>>>>>> already elected a leader, the node who is going to write it to >>>>>>>>>>>> RDBMS should >>>>>>>>>>>> avoid updating it. Simply, the RDBMS can be used as an atomic >>>>>>>>>>>> global >>>>>>>>>>>> variable to keep the leader name by modifying the hazelcast >>>>>>>>>>>> clustering. >>>>>>>>>>>> WDYT? >>>>>>>>>>>> >>>>>>>>>>>> Thanks. >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> *Maninda Edirisooriya* >>>>>>>>>>>> Senior Software Engineer >>>>>>>>>>>> >>>>>>>>>>>> *WSO2, Inc.*lean.enterprise.middleware. >>>>>>>>>>>> >>>>>>>>>>>> *Blog* : http://maninda.blogspot.com/ >>>>>>>>>>>> *E-mail* : mani...@wso2.com >>>>>>>>>>>> *Skype* : @manindae >>>>>>>>>>>> *Twitter* : @maninda >>>>>>>>>>>> >>>>>>>>>>>> On Thu, Jul 28, 2016 at 4:38 PM, Asanka Abeyweera < >>>>>>>>>>>> asank...@wso2.com> wrote: >>>>>>>>>>>> >>>>>>>>>>>>> Hi Akila, >>>>>>>>>>>>> >>>>>>>>>>>>> Let me explain the issue in a different way. Let's assume the >>>>>>>>>>>>> MB nodes are using two different network interfaces for Hazelcast >>>>>>>>>>>>> communication and database communication. With such a >>>>>>>>>>>>> configuration, there >>>>>>>>>>>>> can be failures only in the network interface used for Hazelcast >>>>>>>>>>>>> communication in some nodes. When this happens, there will be two >>>>>>>>>>>>> or more >>>>>>>>>>>>> Hazelcast clusters due to the network segmentation, and as a >>>>>>>>>>>>> result there >>>>>>>>>>>>> will be multiple coordinators. Since every node still have access >>>>>>>>>>>>> to the >>>>>>>>>>>>> database, multiple coordinators can affect the correctness of the >>>>>>>>>>>>> data >>>>>>>>>>>>> stored in the DB. But if we used a RDBMS based approach we won't >>>>>>>>>>>>> have >>>>>>>>>>>>> multiple coordinators due to a network partition in Hazelcast. >>>>>>>>>>>>> This is one >>>>>>>>>>>>> advantage we get from this approach. >>>>>>>>>>>>> >>>>>>>>>>>>> Even when we use Zookeeper or RAFT the same issue will be >>>>>>>>>>>>> there since we are using different interfaces for Hazelcast >>>>>>>>>>>>> communication >>>>>>>>>>>>> and DB communication. >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> On Thu, Jul 28, 2016 at 2:56 PM, Akila Ravihansa Perera < >>>>>>>>>>>>> raviha...@wso2.com> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>>> Hi, >>>>>>>>>>>>>> >>>>>>>>>>>>>> What's the advantage of using RDBMS (even as an alternative) >>>>>>>>>>>>>> to implement a leader/coordinator election? If the network >>>>>>>>>>>>>> connection to DB >>>>>>>>>>>>>> fails then this will be a single point of failure. I don't think >>>>>>>>>>>>>> we can >>>>>>>>>>>>>> scale RDBMS instances and expect the election algorithm to work. >>>>>>>>>>>>>> That would >>>>>>>>>>>>>> be reducing this problem to another problem (electing >>>>>>>>>>>>>> coordinator RDBMS >>>>>>>>>>>>>> instance). >>>>>>>>>>>>>> >>>>>>>>>>>>>> IMHO it would be better to look at Zookeeper Atomic Broadcast >>>>>>>>>>>>>> (ZAB) [1] or RAFT leader election [2] algorithms which have >>>>>>>>>>>>>> already proven >>>>>>>>>>>>>> results. >>>>>>>>>>>>>> >>>>>>>>>>>>>> [1] https://cwiki.apache.org/confluence/display/ZOOKEEPER/Za >>>>>>>>>>>>>> b1.0 >>>>>>>>>>>>>> [2] http://libraft.io/ >>>>>>>>>>>>>> >>>>>>>>>>>>>> Thanks. >>>>>>>>>>>>>> >>>>>>>>>>>>>> On Thu, Jul 28, 2016 at 1:42 PM, Nandika Jayawardana < >>>>>>>>>>>>>> nand...@wso2.com> wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>>> +1 to make it a common component . We have the clustering >>>>>>>>>>>>>>> implementation for BPEL component based on hazelcast. If the >>>>>>>>>>>>>>> coordination >>>>>>>>>>>>>>> is available at RDBMS level, we can remove hazelcast dependancy. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Regards >>>>>>>>>>>>>>> Nandika >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Thu, Jul 28, 2016 at 1:28 PM, Hasitha Aravinda < >>>>>>>>>>>>>>> hasi...@wso2.com> wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Can we make it a common component, which is not hard >>>>>>>>>>>>>>>> coupled with MB. BPS has the same requirement. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Thanks, >>>>>>>>>>>>>>>> Hasitha. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> On Thu, Jul 28, 2016 at 9:47 AM, Asanka Abeyweera < >>>>>>>>>>>>>>>> asank...@wso2.com> wrote: >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> Hi All, >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> In MB, we have used a coordinator based approach to manage >>>>>>>>>>>>>>>>> distributed messaging algorithm in the cluster. Currently >>>>>>>>>>>>>>>>> Hazelcast is used >>>>>>>>>>>>>>>>> to elect the coordinator. But one issue we faced with >>>>>>>>>>>>>>>>> Hazelcast is, during >>>>>>>>>>>>>>>>> a network segmentation (split brain), Hazelcast can elect two >>>>>>>>>>>>>>>>> or more >>>>>>>>>>>>>>>>> coordinators in the cluster. This affects the correctness of >>>>>>>>>>>>>>>>> the >>>>>>>>>>>>>>>>> distributed messaging algorithm since there are some tables >>>>>>>>>>>>>>>>> in the database >>>>>>>>>>>>>>>>> that should only be edited by a single node (i.e. >>>>>>>>>>>>>>>>> coordinator). >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> As a solution to this problem we have implemented minimum >>>>>>>>>>>>>>>>> node count based approach [1] to deactivate set of >>>>>>>>>>>>>>>>> partitioned nodes to >>>>>>>>>>>>>>>>> stop multiple nodes becoming coordinators until the network >>>>>>>>>>>>>>>>> segmentation >>>>>>>>>>>>>>>>> issue is fixed. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> As an alternative solution, we are thinking of >>>>>>>>>>>>>>>>> implementing an RDBMS based approach to elect the coordinator >>>>>>>>>>>>>>>>> node in the >>>>>>>>>>>>>>>>> cluster. By doing this we can make sure that even during a >>>>>>>>>>>>>>>>> network >>>>>>>>>>>>>>>>> segmentation only one node will be elected as the coordinator >>>>>>>>>>>>>>>>> node since >>>>>>>>>>>>>>>>> the election is happening through the database. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> The algorithm will use a polling mechanism to check the >>>>>>>>>>>>>>>>> validity of the nodes. To make the election algorithm >>>>>>>>>>>>>>>>> scalable, only the >>>>>>>>>>>>>>>>> coordinator node will be checking status of all the nodes in >>>>>>>>>>>>>>>>> the cluster >>>>>>>>>>>>>>>>> and it will inform other nodes through database when a member >>>>>>>>>>>>>>>>> is >>>>>>>>>>>>>>>>> added/left. The nodes will be only checking for the status of >>>>>>>>>>>>>>>>> the >>>>>>>>>>>>>>>>> coordinator node. When a node detect that coordinator is >>>>>>>>>>>>>>>>> invalid it will go >>>>>>>>>>>>>>>>> for a election to elect a new coordinator. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> We are currently working on a POC to test how this works >>>>>>>>>>>>>>>>> with MB's slot based messaging algorithm. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> thoughts? >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> [1] https://wso2.org/jira/browse/MB-1664 >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>>>> Asanka Abeyweera >>>>>>>>>>>>>>>>> Senior Software Engineer >>>>>>>>>>>>>>>>> WSO2 Inc. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> Phone: +94 712228648 >>>>>>>>>>>>>>>>> Blog: a5anka.github.io >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> <https://wso2.com/signature> >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>>>> Architecture mailing list >>>>>>>>>>>>>>>>> Architecture@wso2.org >>>>>>>>>>>>>>>>> https://mail.wso2.org/cgi-bin/ >>>>>>>>>>>>>>>>> mailman/listinfo/architecture >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>>> Hasitha Aravinda, >>>>>>>>>>>>>>>> Associate Technical Lead, >>>>>>>>>>>>>>>> WSO2 Inc. >>>>>>>>>>>>>>>> Email: hasi...@wso2.com >>>>>>>>>>>>>>>> Mobile : +94 718 210 200 >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>>> Architecture mailing list >>>>>>>>>>>>>>>> Architecture@wso2.org >>>>>>>>>>>>>>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>> Nandika Jayawardana >>>>>>>>>>>>>>> WSO2 Inc ; http://wso2.com >>>>>>>>>>>>>>> lean.enterprise.middleware >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>> Architecture mailing list >>>>>>>>>>>>>>> Architecture@wso2.org >>>>>>>>>>>>>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> -- >>>>>>>>>>>>>> Akila Ravihansa Perera >>>>>>>>>>>>>> WSO2 Inc.; http://wso2.com/ >>>>>>>>>>>>>> >>>>>>>>>>>>>> Blog: http://ravihansa3000.blogspot.com >>>>>>>>>>>>>> >>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>> Architecture mailing list >>>>>>>>>>>>>> Architecture@wso2.org >>>>>>>>>>>>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> -- >>>>>>>>>>>>> Asanka Abeyweera >>>>>>>>>>>>> Senior Software Engineer >>>>>>>>>>>>> WSO2 Inc. >>>>>>>>>>>>> >>>>>>>>>>>>> Phone: +94 712228648 >>>>>>>>>>>>> Blog: a5anka.github.io >>>>>>>>>>>>> >>>>>>>>>>>>> <https://wso2.com/signature> >>>>>>>>>>>>> >>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>> Architecture mailing list >>>>>>>>>>>>> Architecture@wso2.org >>>>>>>>>>>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> -- >>>>>>>>>>> Asanka Abeyweera >>>>>>>>>>> Senior Software Engineer >>>>>>>>>>> WSO2 Inc. >>>>>>>>>>> >>>>>>>>>>> Phone: +94 712228648 >>>>>>>>>>> Blog: a5anka.github.io >>>>>>>>>>> >>>>>>>>>>> <https://wso2.com/signature> >>>>>>>>>>> >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> Architecture mailing list >>>>>>>>>>> Architecture@wso2.org >>>>>>>>>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> *Imesh Gunaratne* >>>>>>>>>> Software Architect >>>>>>>>>> WSO2 Inc: http://wso2.com >>>>>>>>>> T: +94 11 214 5345 M: +94 77 374 2057 >>>>>>>>>> W: https://medium.com/@imesh TW: @imesh >>>>>>>>>> lean. enterprise. middleware >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> Architecture mailing list >>>>>>>>>> Architecture@wso2.org >>>>>>>>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> Asanka Abeyweera >>>>>>>>> Senior Software Engineer >>>>>>>>> WSO2 Inc. >>>>>>>>> >>>>>>>>> Phone: +94 712228648 >>>>>>>>> Blog: a5anka.github.io >>>>>>>>> >>>>>>>>> <https://wso2.com/signature> >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> Architecture mailing list >>>>>>>>> Architecture@wso2.org >>>>>>>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> Ramith Jayasinghe >>>>>>>> Technical Lead >>>>>>>> WSO2 Inc., http://wso2.com >>>>>>>> lean.enterprise.middleware >>>>>>>> >>>>>>>> E: ram...@wso2.com >>>>>>>> P: +94 772534930 >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> Architecture mailing list >>>>>>>> Architecture@wso2.org >>>>>>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> *Imesh Gunaratne* >>>>>>> Software Architect >>>>>>> WSO2 Inc: http://wso2.com >>>>>>> T: +94 11 214 5345 M: +94 77 374 2057 >>>>>>> W: https://medium.com/@imesh TW: @imesh >>>>>>> lean. enterprise. middleware >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> *Imesh Gunaratne* >>>>>> Software Architect >>>>>> WSO2 Inc: http://wso2.com >>>>>> T: +94 11 214 5345 M: +94 77 374 2057 >>>>>> W: https://medium.com/@imesh TW: @imesh >>>>>> lean. enterprise. middleware >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> Architecture mailing list >>>>>> Architecture@wso2.org >>>>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>>>>> >>>>>> >>>>> >>>>> >>>>> -- >>>>> *Asitha Nanayakkara* <http://asitha.github.io/> >>>>> Senior Software Engineer >>>>> WSO2, Inc. <http://wso2.com/> >>>>> Mob: +94 77 853 0682 >>>>> [image: https://wso2.com/signature] <https://wso2.com/signature> >>>>> >>>>> >>>>> _______________________________________________ >>>>> Architecture mailing list >>>>> Architecture@wso2.org >>>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>>>> >>>>> >>>> >>>> >>>> -- >>>> >>>> Best Regards, >>>> >>>> Malaka Silva >>>> Senior Technical Lead >>>> M: +94 777 219 791 >>>> Tel : 94 11 214 5345 >>>> Fax :94 11 2145300 >>>> Skype : malaka.sampath.silva >>>> LinkedIn : http://www.linkedin.com/pub/malaka-silva/6/33/77 >>>> Blog : http://mrmalakasilva.blogspot.com/ >>>> >>>> WSO2, Inc. >>>> lean . enterprise . middleware >>>> https://wso2.com/signature >>>> http://www.wso2.com/about/team/malaka-silva/ >>>> <http://wso2.com/about/team/malaka-silva/> >>>> https://store.wso2.com/store/ >>>> >>>> Don't make Trees rare, we should keep them with care >>>> >>>> _______________________________________________ >>>> Architecture mailing list >>>> Architecture@wso2.org >>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>>> >>>> >>> >>> >>> -- >>> Ramith Jayasinghe >>> Technical Lead >>> WSO2 Inc., http://wso2.com >>> lean.enterprise.middleware >>> >>> E: ram...@wso2.com >>> P: +94 772534930 >>> >>> _______________________________________________ >>> Architecture mailing list >>> Architecture@wso2.org >>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>> >>> >> > > > -- > Sajini De SIlva > Senior Software Engineer; WSO2 Inc.; http://wso2.com , > Email: saj...@wso2.com > Blog: http://sajinid.blogspot.com/ > Git hub profile: https://github.com/sajinidesilva > > Phone: +94 712797729 > >
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