[Glass] GsDevKit Server Blocks for Thin Client appications ... pre-announcement
Sebastian Heidbrink via Glass
glass at lists.gemtalksystems.com
Thu Apr 30 09:09:56 PDT 2015
Hi Pierre,
I dabbled around with the serverBlocks during CampSmalltalk, too and I
like your ObjectPointer solution.
I just wanted to ask whethere there is some kind of lazy initialiyation
in Roassal? I encountered some issues.
I also want to report a bug in the implementation and will file it as
soo nas I am working on this again.
For the executeOnServer code string creation there is printString
used,.... this results in issues once you would like to upload longer
csv strings because they are trimmed and end with "...".
I also have trouble using this functionality from outside the workspace.
E.g. this is more or less the same implementatin as the one in the
example and still the onserverDo: Block return an exception complaining
about a Parameter 1.
'mycsvFile.csv' asFileReference readStreamDo: [ :stream | | records
numRecords line buffer bufCnt|
stream nextLine.
buffer := Array new: 10000.
bufCnt := 0.
line:= stream nextLine.
[ line notNil ]
whileFalse: [
bufCnt := bufCnt + 1.
buffer at: bufCnt put: line.
bufCnt = buffer size
ifTrue: [
numRecords := bufCnt.
records := buffer.
DevKitShell
onServerDo: [
1 to: numRecords do: [ :index |
| record |
record := records at: index.
MyLineprocessor processLine: record.].
MySystemExtensionClass markForCollectionAndCommit .
nil ].
bufCnt := 0 ].
line:= stream nextLine].
].
Did you encounter these problems during your tests, too?
I also want to add that there seems to be a limitation on connections
this interface can handle. During debugging I accidently didn't qiot the
shell properly and it doesn'T take long until the server had to be
restarted due to too many open connections errors.
Cheers!
Sebastian
Am 29.04.2015 um 15:42 schrieb Pierre CHANSON via Glass:
> Thanks again Dale !
>
> here are three small examples using these blocks in the roassal
> workspace of tODE: https://vimeo.com/126435220
>
> I highlight here the server blocks in red.
>
> The first one is a Mondrian view of the class Collection (server side)
> with all it's subclasses.
> The classes are processed in the block and stocked statically on the
> variable "classes".
>
> --------------------------------------------------------------------------------------------------------------------------------------
> | b classes |
> classes :=shell onServerDo:[Collection withAllSubclasses collect: [ :c
> | c name -> {(c superClass name). ((c instVarNamed: #methDicts
> asString) numElements)}]].
>
> b := RTMondrian new.
> b shape circle.
> b nodes: classes.
> b edges connectFrom: [:e | classes detect: [ :c | c name = e value
> first ] ifNone:[ nil ]] .
>
> b shape bezierLineFollowing: [:e | classes detect: [ :c | c name = e
> value first ] ifNone:[ nil ]];
> color: (Color blue alpha: 0.2).
>
>
> b normalizer
> normalizeSize: [:e | e value second ] using: #sqrt;
> normalizeColor: [:e | e value second ] using: (Array with: Color
> green with: Color red) using: #sqrt.
> b layout cluster.
> b build.
> b view open
> --------------------------------------------------------------------------------------------------------------------------------------
>
> The second script use the RTExploraBuilder to do the same process, but
> this time the builder call dynamically the server on clics (we are
> using the oop of objects).
>
> --------------------------------------------------------------------------------------------------------------------------------------
> | builder |
> builder := RTExploraBuilder new.
> builder shape circle
> size: 30;
> color: (Color blue alpha: 0.5);
> if: [ :cls |
> (shell onServerDo: [ (Object _objectForOop: (cls value))
> subclasses size]) = 0 ] fillColor: (Color red alpha: 0.5).
> builder
> layout: [RTClusterLayout new horizontalGap: 80];
> onClickExplore: [ :cls |
> shell onServerDo: [ ((Object _objectForOop: (cls value)) subclasses
> collect: [:c | c asString -> c asOop]) asArray ]
> ];
> withPopup: [:cls | cls key];
> dragChildren;
> node: (shell onServerDo: [Collection asString -> Collection
> asOop]);
> open.
> --------------------------------------------------------------------------------------------------------------------------------------
>
>
> The last script is about users. This need the last version of Roassal.
> We present some selection menus, a button and a radar Chart. Created
> with the RTMenuBuilder the button add a new user on the server with
> the characteristics selected in the other menus and present the
> characteristics of the added users on a Kiviat chart on the view.
>
> --------------------------------------------------------------------------------------------------------------------------------------
> |nameMenus privilegeMenus groupMenus|
> v := RTView new.
>
> kiv := RTKiviatBuilder new view: v.
> n := RTMultiLinearColorForIdentity new objects: (kiv objects).
> kiv shape circle color: [ :value | n rtValue: value kiviatNode
> named]; size: 10.
>
>
> kiv addMetric: [ :v | v second size] max: 5 title: 'groups'.
> kiv addMetric: [ :v | v third size] max: 5 title: 'privileges'.
> kiv addMetric: [ :v | v first size] max: 10 title: 'name'.
>
>
> kiv activatePolygons.
> kiv build.
>
> b := RTMenuBuilder new view: v.
>
> nameMenus := Array with: ('Henri'->[:m |]) with: ('Bob'->[:m |])
> with: ('Robert'->[:m |]).
> groupMenus := Array with: ('Subscribers'->[:m |])
> with:('Publishers'->[:m |]).
> privilegeMenus := Array with: ('ObsoleteStatistics'->[:m |])
> with:('UserPassword'->[:m |]) with:('SessionAccess'->[:m |]).
>
>
> b menu: 'add User' callback: [
> |name groups privileges |
>
> name := (nameMenus detect: [ :m | m selected ]) name.
> groups := (groupMenus select: [:m | m selected]) collect: [:g
> | g name].
> privileges := (privilegeMenus select: [:m | m selected])
> collect: [:p | p name].
> shell onServerDo: [
> AllUsers addNewUserWithId: name password: ''
> defaultObjectSecurityPolicy: nil privileges: privileges inGroups:
> groups .
> System commitTransaction.].
> kiv addDynamicObject: (Array with: (name) with: (groups) with:
> (privileges))
> ].
>
> nameMenus := b menu: 'user' subcheckmenus: nameMenus background:
> (Color red alpha: 0.3).
> RTMenuGroup on: nameMenus.
> nameMenus first selected: true.
>
>
> groupMenus := b menu: 'groups' subcheckmenus: groupMenus
> background: (Color blue alpha: 0.3).
> groupMenus first selected: true.
>
>
> privilegeMenus := b menu: 'privileges' subcheckmenus:
> privilegeMenus background: (Color green alpha: 0.3).
>
> privilegeMenus first selected: true.
>
> b view open.
> --------------------------------------------------------------------------------------------------------------------------------------
>
> Pierre
>
>
>
>
> 2015-04-23 19:58 GMT+02:00 Mariano Martinez Peck via Glass
> <glass at lists.gemtalksystems.com <mailto:glass at lists.gemtalksystems.com>>:
>
>
>
> On Wed, Apr 22, 2015 at 1:53 AM, Richard Sargent
> <richard.sargent at gemtalksystems.com
> <mailto:richard.sargent at gemtalksystems.com>> wrote:
>
> Mariano,
>
> Depending on what you mean by "execute stuff on server Y", 3.2
> includes something called GsExternalSession. It it capable of
> executing Smalltalk specified in Block on a separate session
> against the same stone or a different one.
>
> It doesn't support copying object graphs, but if your
> definition of execute stuff has limited requirements for
> exchanging data, it could be what you are looking for.
> See the 3.2 documentation for details.
>
>
> Good to know too. Thanks Richard.
>
> On Apr 21, 2015 7:01 PM, "Mariano Martinez Peck via Glass"
> <glass at lists.gemtalksystems.com
> <mailto:glass at lists.gemtalksystems.com>> wrote:
>
>
>
> On Thu, Apr 16, 2015 at 2:23 AM, Dale Henrichs via Glass
> <glass at lists.gemtalksystems.com
> <mailto:glass at lists.gemtalksystems.com>> wrote:
>
> A GsDevKit Server Block[1] is a block that is written
> in-line in client Smalltalk, but is executed in
> GemStone. For example the following expression is
> executed in a standard Pharo workspace:
>
> | shell x y |
> shell := TDShell forSessionNamed: 'devKit'.
> x := 3.
> y := 4.
> shell onServerDo: [ x + y ].
>
>
>
> Dale,
>
> I know (because I already asked a few months/years ago)
> that from a stone X you can do a remote login on stone Y
> and execute stuff in Y. But now I wonder....could server
> blocks also work for gemstone-gemstone? (my gut feelings
> tell me that yes) I mean, could I run the above code from
> GemStone itself? That would automatically resolve all
> the remote login stuff and the ston serialization.
> Thanks in advance,
>
>
>
> and the `[3 + 4 ]` block is executed in GemStone using
> the `devKit` session description to log into the
> stone. The temp vars x and y referenced in the server
> block and defined in Pharo are shipped across the wire
> to GemStone along with block source where the block
> source is compiled and executed. The result is then
> shipped back across the wire and returned as the
> result of #onServerDo: message in Pharo. Pharo
> execution can continue on using the result. STON[2] is
> used to serialize the objects that are shipped across
> the wire.
>
> For any of you familiar with underpinnings of
> GemTools, Jade or tODE, this is not necessarily
> ground-breaking technology, however, exposing this
> capability to developers just may be.
>
> It has been a long standing crime that developers in
> the Pharo community choose to use MongoDB and MySQL
> over GemStone, but frankly the problem is that (until
> now) we have not had a simple client-based solution
> for adding GemStone-based persistence for native Pharo
> applications - the pharo developers have not really
> had a choice.
>
> Being able to embed server blocks in client code
> certainly qualifies as simple. Solution(?), well that
> remains to be seen, but I am optimistic.
>
> As a more concrete example, here's Pharo workspace
> code that uses NeoCSV running in Pharo to load stone
> objects in a Dictionary in GemStone:
>
> 'NeoCSVBenchmark.csv' asFileReference
> readStreamDo: [ :stream |
> | reader converter buffer bufCnt numRecords records |
> converter := [ :string | NeoNumberParser parse:
> string ].
> reader := NeoCSVReader on: (ZnBufferedReadStream on:
> stream).
> reader
> recordClass: NeoCSVTestObject;
> addIntegerField: #'x:';
> addIntegerField: #'y:';
> addIntegerField: #'z:'.
> buffer := Array new: 1000.
> bufCnt := 0.
> [ reader atEnd ]
> whileFalse: [
> bufCnt := bufCnt + 1.
> buffer at: bufCnt put: reader next.
> bufCnt = buffer size
> ifTrue: [
> numRecords := bufCnt.
> records := buffer.
> DevKitShell
> onServerDo: [
> 1 to: numRecords do: [ :index |
> | record |
> record := records at: index.
> NeoCSVDictionary at: record x put: record ].
> System commitTransaction.
> nil ].
> bufCnt := 0 ] ] ].
> DevKitShell onServerDo: [ System commitTransaction ]
>
> The code ships 1000 instances of NeoCSVTestObject at a
> pop to GemStone. Using the above technique, one can
> easily arrange to store some pretty large object
> graphs in GemStone ... Efficient queries based on
> standard Smalltalk can be written on the client and
> transparently performed in GemStone (see the
> GsDevKitServerBlocks doc[1] for the complete example).
>
> Server blocks do not duplicate the functionality
> GemBuilder for Smalltalk[6][7] which provides
> transparent replication and maintenance of objects
> between the client and server. With server blocks you
> end up with disconnected copies of server objects.
>
> Because of this disconnect, I think the best way to
> architect an application using server blocks, is to
> plan on "executing all business logic" on the server
> --- If you are using an MVC pattern, the M would
> primarily be managed on the server while the VC would
> be managed on the client.
>
> As an application evolves, the code can migrate back
> and forth between client and server as needed.
>
> Most of the server blocks code leverages tODE and has
> been in use for several years. The code that spelunks
> in the block structure and extracts the _value_ of
> temp variables is only a couple of days old and has
> some pretty rough edges (notice the odd placement of
> temp variables and declarations in the above example).
>
> The server-side debugger and inspectors, etc. will use
> tODE (at least for now) ... in the server blocks
> doc[1] I demonstrate an #exportClassToServer: to
> illustrate the potential to share code in weird and
> wonderful ways between the client and server.
>
> If you have the interest/opportunity to take this code
> for a spin, let me know. I have written
> instructions[5] for installing the experimental
> Roassal Visualization code[4] (GemStone and Pharo3.0
> or Pharo4.0) for Pierre Chanson and those instructions
> can be used for doing work with GsDevKit
> Server Blocks. There are a handful of obvious things
> that need to be done:
> - connection pools
> - coordinated client/server debuggers
> - client-side exception handlers for server errors
> - more???
> and if folks express interest in start to do
> exploratory work with server blocks, then I will make
> time to provide support.
>
> I am hoping to have something to announce by
> Smalltalks in November,so it would be useful if some
> experienced GemStoners tried things out before then...
>
> I do have to finish up the documentation for
> GsDevKitHome 1.0.0 and tODE 0.1.0 and I'm also
> committed to doing some work on the 3.3 GemStone
> release, so we'll see how that goes:)
>
> I also think that server blocks can be very useful for
> the "develop in Pharo, deploy in GemSstone" crowd,
> since it will be possible to write "pharo-based
> scripts" to perform server-side tasks ...
>
> Questions or comments?
>
> Dale
>
> [1]
> https://github.com/GsDevKit/gsDevKitHome/blob/dev/docs/articles/gsDevKitServerBlocks.md#gsdevkit-server-blocks
> [2]
> https://github.com/GsDevKit/ston#ston---smalltalk-object-notation
> [3] https://vimeo.com/123261640
> [4]
> https://github.com/GsDevKit/gsDevKitHome/tree/dev/projects/roassal#roassal-visualization
> [5]
> https://github.com/GsDevKit/gsDevKitHome/blob/dev/projects/roassal/devBootstrap.md
> [6] http://gemtalksystems.com/products/gbs-vw/
> [7] http://gemtalksystems.com/products/gbs-va/
>
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> --
> Mariano
> http://marianopeck.wordpress.com
>
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> --
> Mariano
> http://marianopeck.wordpress.com
>
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