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From Alexey Goncharuk <alexey.goncha...@gmail.com>
Subject Re: Terms clarification and modules splitting logic
Date Wed, 31 Mar 2021 12:09:54 GMT
This won't work with the Java Jigsaw module system because it prohibits
having two identical packages in different modules. I really hope that we
will adopt Jigsaw in the near future. Unless you are suggesting moving all
utility classes under org.apache.ignite.api.util package, bit this looks
really odd to me - why would IgniteUuid be in api.util package?

As for the public and private utilities, I think there may be some classes
that may be common for all modules, but should not be treated as public API
because we should be free to change them without any compatibility
contract. An example of such a class is GridFunc. Arguably, many of its
methods should be removed for good, but I am sure there will be a few
really useful ones. Nevertheless, we should not encourage or allow users to
use GridFunc.

--AG

ср, 31 мар. 2021 г. в 14:27, Alexei Scherbakov <alexey.scherbakoff@gmail.com
>:

> Alexey,
>
> I would instead  suggest moving the public utility classes to
> org.apache.ignite.api. package in the util module to separate them from
> internal classes, if we really need this.
>
> Actually, I don't think there is a point in separating public/internal
> classes in the util module. What are the benefits of this ?
>
> ср, 31 мар. 2021 г. в 12:16, Alexey Goncharuk <alexey.goncharuk@gmail.com
> >:
>
> > Alexei,
> >
> > I had the same opinion regarding the internal package, but we still need
> to
> > somehow distinguish between public and internal classes in the
> ignite-util
> > module. If we introduce the internal package in the util, we should
> follow
> > the same structure in other modules.
> >
> > Thoughts?
> >
> > вт, 30 мар. 2021 г. в 18:37, Alexei Scherbakov <
> > alexey.scherbakoff@gmail.com
> > >:
> >
> > > +1 to package and module naming.
> > > +1 to service definition as "component providing a high-level API to
> > > user/other components/services"
> > >
> > > I would avoid defining strict rules for Manager and Processor.
> > > For me it just adds confusion without real value.
> > > A component can be a Manager if it manages something, a Processor if it
> > > processes something, and so on.
> > > I think having Component and Service (which is also a Component) is
> > enough.
> > > Any component can be singleton or not - it's defined by its lifecycle.
> > >
> > > +1 to renaming core to something more meaningful, but the name lang
> > doesn't
> > > fit for a collection of utility classes for me, I would prefer
> > ignite-util.
> > > Apache Tomcat has the same jar, for reference. I'm also fine to leave
> it
> > as
> > > is.
> > > -1 to have an "internal" package. All modules are known to be internal
> > > except api and (partially) util, so why bother at all?
> > >
> > >
> > > вт, 30 мар. 2021 г. в 12:05, Andrey Mashenkov <
> > andrey.mashenkov@gmail.com
> > > >:
> > >
> > > > Agree with package and module naming.
> > > >
> > > > I just thought that
> > > > Service is a self-suffucient component and provides high-level API to
> > > > user/other components/services (e.g. RaftService to TableService).
> > > > Manager is internal component - a logical brick of the Service (e.g.
> > > > RaftGroupManager or TableSchemaManager, TableAffinityManager), it is
> > not
> > > > self-sufficient as affinity or schema make no sense without the
> table.
> > > > Processor is just helper-component of the Service that routes
> messages,
> > > > executes async tasks, manages subscriptions and implements some
> > secondary
> > > > functions.
> > > >
> > > > On Tue, Mar 30, 2021 at 11:24 AM Alexey Goncharuk <
> > > > alexey.goncharuk@gmail.com> wrote:
> > > >
> > > > > Hello Alexander, Igniters,
> > > > >
> > > > > I support the suggestion, we need to work out some ground rules to
> > > have a
> > > > > consistent naming convention. Agree with having at most one
> component
> > > per
> > > > > project module - this requirement may turn out to be too strict in
> > the
> > > > > future, but now it seems reasonable and may help us to better
> > structure
> > > > the
> > > > > code. Additionally, I would encourage us to make package names
> > > consistent
> > > > > with the module's structure to make modules Jigsaw-compliant. We
do
> > not
> > > > > have module definitions now, but I think it would be great to have
> > > them,
> > > > it
> > > > > should help us to enforce component boundaries and proper
> > > responsibility
> > > > > encapsulation.
> > > > >
> > > > > As for the naming, it's not entirely clear for me when to use the
> > term
> > > > > Service vs Manager. Serice is an entry point to a component/server,
> > but
> > > > so
> > > > > is Manager - a Manager defines an API that is exposed by a module
> to
> > > > other
> > > > > modules. Subjectively, I see the following difference between a
> > Manager
> > > > and
> > > > > a Service in the examples of entities you provided:
> > > > >  * A Manager is a node singleton. Its whole purpose is to provide
> an
> > > API
> > > > > gateway for other components into a particular subsystem of a node
> > > > >  * A Service is an object that is bound to a particular runtime
> > entity
> > > > > (raft group service is bound to a raft group, and we can have
> > multiple
> > > > Raft
> > > > > groups; partition service is bound to a particular partition). We
> can
> > > > > re-create services based on changing runtime state and/or
> > > configuration.
> > > > > Does this make sense?
> > > > >
> > > > > Finally, I would use lang module name instead of core (the core is
> > > > > confusing because right now core contains all necessary classes
> > > required
> > > > to
> > > > > start a minimal Ignite instance; this sets up wrong expectations
> for
> > > > Ignite
> > > > > 3). Additionally, I think it would be good to exploit the old
> > > > > org.apache.ignite and org.apache.ignite.internal naming scheme: all
> > > > public
> > > > > classes must go to the non-internal package. The ignite-lang module
> > > will
> > > > > have both public and internal packages. This automatically implies
> > that
> > > > all
> > > > > modules except ignite-api and ignite-lang must reside solely in
> > > > > org.apache.ignite.internal.* packages. This will be easy to check
> and
> > > > > maintain.
> > > > >
> > > > > Throughts?
> > > > >
> > > > > --AG
> > > > >
> > > > > пт, 26 мар. 2021 г. в 20:28, Alexander Lapin <lapin1702@gmail.com
> >:
> > > > >
> > > > > > Igniters,
> > > > > >
> > > > > > Seems that within Ignite-3 we have some mess in terms like
> manager,
> > > > cpu,
> > > > > > service, module, etc. Let's clarify this point. Also It'll be
> great
> > > to
> > > > > > discuss the rules of dividing code into modules.
> > > > > > I'll use the context of Ignite cluster & node lifecycle
> > > > > > <
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/ignite-3/blob/ignite-14393/modules/runner/README.md
> > > > > > >
> > > > > > for terms definition and as an example source.
> > > > > >
> > > > > > *Terms clarification.*
> > > > > >
> > > > > >    - Component - semantically consistent part of Ignite that
in
> > most
> > > > > cases
> > > > > >    will have component-public but ignite-internal API and a
> > > lifecycle,
> > > > > > somehow
> > > > > >    related to the lifecycle of a node or cluster. So,
> > *structurally*
> > > > > >    TableManager, SchemaManager, AffinityManager, etc are all
> > > > components.
> > > > > > For
> > > > > >    example, TableManager will have methods like createTable(),
> > > > > > alterTable(),
> > > > > >    dropTable(), etc and a lifecycle that will create listeners
> (aka
> > > > > >    DistributedMetastorage watches) on schema and affinity updates
> > in
> > > > > order
> > > > > > to
> > > > > >    create/drop raft servers for particular partitions that should
> > be
> > > > > > hosted on
> > > > > >    local node). Components are lined up in a graph without
> cycles,
> > > for
> > > > > more
> > > > > >    details please see mentioned above Ignite cluster & node
> > > lifecycle.
> > > > > >    <
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/ignite-3/blob/ignite-14393/modules/runner/README.md
> > > > > > >
> > > > > >    - Manager is a driving point of a component with high level
> > > > lifecycle
> > > > > >    logic and API methods. My intention here is to agree about
> > naming:
> > > > > > should
> > > > > >    we use the term Manager, Processor or anything else?
> > > > > >    - Service is an entry point to some component/server or a
> group
> > of
> > > > > >    components/servers. See RaftGroupService.java
> > > > > >    <
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/ignite-3/blob/main/modules/raft-client/src/main/java/org/apache/ignite/raft/client/service/RaftGroupService.java
> > > > > > >
> > > > > >    as an example.
> > > > > >    - Server, for example RaftServer, seems to be self-explanatory
> > > > itself.
> > > > > >
> > > > > >
> > > > > > *Dividing code into modules.*
> > > > > > It seems useful to introduce a restriction that a module should
> > > contain
> > > > > at
> > > > > > most one component. So that, combining component-specific modules
> > and
> > > > > ones
> > > > > > of api, lang, etc we will end up with something like following:
> > > > > >
> > > > > >    - affinity // TO be created.
> > > > > >    - api [public]
> > > > > >    - baseline // TO be created.
> > > > > >    - bytecode
> > > > > >    - cli
> > > > > >    - cli-common
> > > > > >    - configuration
> > > > > >    - configuration-annotation-processor
> > > > > >    - core // Module with classes like IgniteUuid. Should we
> raname
> > it
> > > > to
> > > > > >    lang/utils/commons?
> > > > > >    - metastorage-client // To be created.
> > > > > >    - metastorage-common // To be created.
> > > > > >    - metastorage-server // TO be created.
> > > > > >    - network
> > > > > >    - raft // raft-server?
> > > > > >    - raft-client
> > > > > >    - rest
> > > > > >    - runner
> > > > > >    - schema
> > > > > >    - table // Seems that there might be a conflict between the
> > > meaning
> > > > of
> > > > > >    table module that we already have and table module with
> > > > > > create/dropTable()
> > > > > >    - vault
> > > > > >
> > > > > > Also it's not quite clear to me how we should split lang and
util
> > > > classes
> > > > > > some of which belong to the public api, and some to the private.
> > > > > >
> > > > > > Please share your thoughts about topics mentioned above.
> > > > > >
> > > > > > Best regards,
> > > > > > Alexander
> > > > > >
> > > > >
> > > >
> > > >
> > > > --
> > > > Best regards,
> > > > Andrey V. Mashenkov
> > > >
> > >
> > >
> > > --
> > >
> > > Best regards,
> > > Alexei Scherbakov
> > >
> >
>
>
> --
>
> Best regards,
> Alexei Scherbakov
>

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