Pavel, in this case, we will mix entities from different layers (transport
layer and request body), it's not very good. The same behavior we can
achieve with generated on client-side task id, but there will be no
inter-layer data intersection and I think it will be easier to implement on
both client and server-side. But we still can't be sure that the task is
successfully started on a server. We won't ever know about topology change,
because topology changed flag will be sent from server to client only with
a response when the task will be completed. Are we accept that?
пн, 25 нояб. 2019 г. в 19:07, Pavel Tupitsyn <ptupit...@apache.org>:
> Alex,
>
> I have a simpler idea. We already do request id handling in the protocol,
> so:
> - Client sends a normal request to execute compute task. Request ID is
> generated as usual.
> - As soon as task is completed, a response is received.
>
> As for cancellation - client can send a new request (with new request ID)
> and (in the body) pass the request ID from above
> as a task identifier. As a result, there are two responses:
> - Cancellation response
> - Task response (with proper cancelled status)
>
> That's it, no need to modify the core of the protocol. One request - one
> response.
>
> On Mon, Nov 25, 2019 at 6:20 PM Alex Plehanov <plehanov.a...@gmail.com>
> wrote:
>
> > Pavel, we need to inform the client when the task is completed, we need
> the
> > ability to cancel the task. I see several ways to implement this:
> >
> > 1. Сlient sends a request to the server to start a task, server return
> task
> > id in response. Server notifies client when task is completed with a new
> > request (from server to client). Client can cancel the task by sending a
> > new request with operation type "cancel" and task id. In this case, we
> > should implement 2-ways requests.
> > 2. Client generates unique task id and sends a request to the server to
> > start a task, server don't reply immediately but wait until task is
> > completed. Client can cancel task by sending new request with operation
> > type "cancel" and task id. In this case, we should decouple request and
> > response on the server-side (currently response is sent right after
> request
> > was processed). Also, we can't be sure that task is successfully started
> on
> > a server.
> > 3. Client sends a request to the server to start a task, server return id
> > in response. Client periodically asks the server about task status.
> Client
> > can cancel the task by sending new request with operation type "cancel"
> and
> > task id. This case brings some overhead to the communication channel.
> >
> > Personally, I think that the case with 2-ways requests is better, but I'm
> > open to any other ideas.
> >
> > Aleksandr,
> >
> > Filtering logic for OP_CLUSTER_GROUP_GET_NODE_IDS looks overcomplicated.
> Do
> > we need server-side filtering at all? Wouldn't it be better to send basic
> > info (ids, order, flags) for all nodes (there is relatively small amount
> of
> > data) and extended info (attributes) for selected list of nodes? In this
> > case, we can do basic node filtration on client-side (forClients(),
> > forServers(), forNodeIds(), forOthers(), etc).
> >
> > Do you use standard ClusterNode serialization? There are also metrics
> > serialized with ClusterNode, do we need it on thin client? There are
> other
> > interfaces exist to show metrics, I think it's redundant to export
> metrics
> > to thin clients too.
> >
> > What do you think?
> >
> >
> >
> >
> > пт, 22 нояб. 2019 г. в 20:15, Aleksandr Shapkin <lexw...@gmail.com>:
> >
> > > Alex,
> > >
> > >
> > >
> > > I think you can create a new IEP page and I will fill it with the
> Cluster
> > > API details.
> > >
> > >
> > >
> > > In short, I’ve introduced several new codes:
> > >
> > >
> > >
> > > Cluster API is pretty straightforward:
> > >
> > >
> > >
> > > OP_CLUSTER_IS_ACTIVE = 5000
> > >
> > > OP_CLUSTER_CHANGE_STATE = 5001
> > >
> > > OP_CLUSTER_CHANGE_WAL_STATE = 5002
> > >
> > > OP_CLUSTER_GET_WAL_STATE = 5003
> > >
> > >
> > >
> > > Cluster group codes:
> > >
> > >
> > >
> > > OP_CLUSTER_GROUP_GET_NODE_IDS = 5100
> > >
> > > OP_CLUSTER_GROUP_GET_NODE_INFO = 5101
> > >
> > >
> > >
> > > The underlying implementation is based on the thick client logic.
> > >
> > >
> > >
> > > For every request, we provide a known topology version and if it has
> > > changed,
> > >
> > > a client updates it firstly and then re-sends the filtering request.
> > >
> > >
> > >
> > > Alongside the topVer a client sends a serialized nodes projection
> object
> > >
> > > that could be considered as a code to value mapping.
> > >
> > > Consider: [{Code = 1, Value= [“DotNet”, “MyAttribute”}, {Code=2,
> > Value=1}]
> > >
> > > Where “1” stands for Attribute filtering and “2” – serverNodesOnly
> flag.
> > >
> > >
> > >
> > > As a result of request processing, a server sends nodeId UUIDs and a
> > > current topVer.
> > >
> > >
> > >
> > > When a client obtains nodeIds, it can perform a NODE_INFO call to get a
> > >
> > > serialized ClusterNode object. In addition there should be a different
> > API
> > >
> > > method for accessing/updating node metrics.
> > >
> > > чт, 21 нояб. 2019 г. в 12:32, Sergey Kozlov <skoz...@gridgain.com>:
> > >
> > > > Hi Pavel
> > > >
> > > > On Thu, Nov 21, 2019 at 11:30 AM Pavel Tupitsyn <
> ptupit...@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 <
> skoz...@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.a...@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
> > > >
> > >
> > >
> > > --
> > > Alex.
> > >
> >
>
