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From Sergey Kozlov <skoz...@gridgain.com>
Subject Re: Thin client: compute support
Date Thu, 21 Nov 2019 09:32:02 GMT
Hi Pavel

On Thu, Nov 21, 2019 at 11:30 AM Pavel Tupitsyn <ptupitsyn@apache.org>
wrote:

> 1. I believe that Cluster operations for Thin Client protocol are already
> in the works
> by Alexandr Shapkin. Can't find the ticket though.
> Alexandr, can you please confirm and attach the ticket number?
>
> 2. Proposed changes will work only for Java tasks that are already deployed
> on server nodes.
> This is mostly useless for other thin clients we have (Python, PHP, .NET,
> C++).
>

I don't guess so. The task (execution) is a way to implement own layer for
the thin client application.


> We should think of a way to make this useful for all clients.
> For example, we may allow sending tasks in some scripting language like
> Javascript.
> Thoughts?
>

The arbitrary code execution from a remote client must be protected
from malicious code.
I don't know how it could be designed but without that we open the hole to
kill cluster.


>
> On Thu, Nov 21, 2019 at 11:21 AM Sergey Kozlov <skozlov@gridgain.com>
> wrote:
>
> > Hi Alex
> >
> > The idea is great. But I have some concerns that probably should be taken
> > into account for design:
> >
> >    1. We need to have the ability to stop a task execution, smth like
> >    OP_COMPUTE_CANCEL_TASK  operation (client to server)
> >    2. What's about task execution timeout? It may help to the cluster
> >    survival for buggy tasks
> >    3. Ignite doesn't have roles/authorization functionality for now. But
> a
> >    task is the risky operation for cluster (for security reasons). Could
> we
> >    add for Ignite configuration new options:
> >       - Explicit turning on for compute task support for thin protocol
> >       (disabled by default) for whole cluster
> >       - Explicit turning on for compute task support for a node
> >       - The list of task names (classes) allowed to execute by thin
> client.
> >    4. Support the labeling for task that may help to investigate issues
> on
> >    cluster (the idea from IEP-34 [1])
> >
> > 1.
> >
> >
> https://cwiki.apache.org/confluence/display/IGNITE/IEP-34+Thin+client%3A+transactions+support
> >
> >
> >
> > On Thu, Nov 21, 2019 at 10:58 AM Alex Plehanov <plehanov.alex@gmail.com>
> > wrote:
> >
> > > Hello, Igniters!
> > >
> > > I have plans to start implementation of Compute interface for Ignite
> thin
> > > client and want to discuss features that should be implemented.
> > >
> > > We already have Compute implementation for binary-rest clients
> > > (GridClientCompute), which have the following functionality:
> > > - Filtering cluster nodes (projection) for compute
> > > - Executing task by the name
> > >
> > > I think we can implement this functionality in a thin client as well.
> > >
> > > First of all, we need some operation types to request a list of all
> > > available nodes and probably node attributes (by a list of nodes). Node
> > > attributes will be helpful if we will decide to implement analog of
> > > ClusterGroup#forAttribute or ClusterGroup#forePredicate methods in the
> > thin
> > > client. Perhaps they can be requested lazily.
> > >
> > > From the protocol point of view there will be two new operations:
> > >
> > > OP_CLUSTER_GET_NODES
> > > Request: empty
> > > Response: long topologyVersion, int minorTopologyVersion, int
> nodesCount,
> > > for each node set of node fields (UUID nodeId, Object or String
> > > consistentId, long order, etc)
> > >
> > > OP_CLUSTER_GET_NODE_ATTRIBUTES
> > > Request: int nodesCount, for each node: UUID nodeId
> > > Response: int nodesCount, for each node: int attributesCount, for each
> > node
> > > attribute: String name, Object value
> > >
> > > To execute tasks we need something like these methods in the client
> API:
> > > Object execute(String task, Object arg)
> > > Future<Object> executeAsync(String task, Object arg)
> > > Object affinityExecute(String task, String cache, Object key, Object
> arg)
> > > Future<Object> affinityExecuteAsync(String task, String cache, Object
> > key,
> > > Object arg)
> > >
> > > Which can be mapped to protocol operations:
> > >
> > > OP_COMPUTE_EXECUTE_TASK
> > > Request: UUID nodeId, String taskName, Object arg
> > > Response: Object result
> > >
> > > OP_COMPUTE_EXECUTE_TASK_AFFINITY
> > > Request: String cacheName, Object key, String taskName, Object arg
> > > Response: Object result
> > >
> > > The second operation is needed because we sometimes can't calculate and
> > > connect to affinity node on the client-side (affinity awareness can be
> > > disabled, custom affinity function can be used or there can be no
> > > connection between client and affinity node), but we can make best
> effort
> > > to send request to target node if affinity awareness is enabled.
> > >
> > > Currently, on the server-side requests always processed synchronously
> and
> > > responses are sent right after request was processed. To execute long
> > tasks
> > > async we should whether change this logic or introduce some kind
> two-way
> > > communication between client and server (now only one-way requests from
> > > client to server are allowed).
> > >
> > > Two-way communication can also be useful in the future if we will send
> > some
> > > server-side generated events to clients.
> > >
> > > In case of two-way communication there can be new operations
> introduced:
> > >
> > > OP_COMPUTE_EXECUTE_TASK (from client to server)
> > > Request: UUID nodeId, String taskName, Object arg
> > > Response: long taskId
> > >
> > > OP_COMPUTE_TASK_FINISHED (from server to client)
> > > Request: taskId, Object result
> > > Response: empty
> > >
> > > The same for affinity requests.
> > >
> > > Also, we can implement not only execute task operation, but some other
> > > operations from IgniteCompute (broadcast, run, call), but it will be
> > useful
> > > only for java thin client. And even with java thin client we should
> > whether
> > > implement peer-class-loading for thin clients (this also requires
> two-way
> > > client-server communication) or put classes with executed closures to
> the
> > > server locally.
> > >
> > > What do you think about proposed protocol changes?
> > > Do we need two-way requests between client and server?
> > > Do we need support of compute methods other than "execute task"?
> > > What do you think about peer-class-loading for thin clients?
> > >
> >
> >
> > --
> > Sergey Kozlov
> > GridGain Systems
> > www.gridgain.com
> >
>


-- 
Sergey Kozlov
GridGain Systems
www.gridgain.com

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