[Glass] Debugging a multiple process system ... ?

[Dale Henrichs via Glass]

https://github.com/SeasideSt/Seaside/blob/master/repository/Seaside-GemStone-Environment.package/GRGemStonePlatform.extension/instance/canDebugInteractively.st


On 01/22/2018 12:54 PM, Marten Feldtmann via Glass wrote:
>
> Do you have the implementation of #canDebugInteractively ?
>
> Marten
>
>
>> Mariano Martinez Peck <marianopeck at gmail.com> hat am 22. Januar 2018 
>> um 19:30 geschrieben:
>>
>>
>>
>> On Mon, Jan 22, 2018 at 3:14 PM, Marten Feldtmann via Glass 
>> <glass at lists.gemtalksystems.com 
>> <mailto:glass at lists.gemtalksystems.com>> wrote:
>>
>>     Hmm,
>>
>>     honestly I simply do not understand how this works :-(((((
>>
>>     If I have an exception within my REST API calls I normally have
>>     to abort the transaction, so that nothing has changed ... 
>>     therefore how can I save a continuation into the database ??
>>
>>     Its a shame I know, but I simply do not get it ...
>>
>>
>> It's not a shame. I think the word "continuation" has been confusing 
>> since several years already. And I think its confusing because of its 
>> association with Seaside and the back button etc.
>> Let's talk about what it is for GemStone (well, at least what I 
>> understand from it):
>>
>> When an exception is signaled, and you read to an exception handler, 
>> from the exception you can get the signaler context, right? That 
>> means that somehow you have access the the stack that triggered that 
>> error (stack of method context instances).  As far as I understand, 
>> the # callCC does something *like* a deep copy of the stack. Its not 
>> a full 100% deep copy as you might end up copying the whole extent. I 
>> guess there is a treshold somewhere.
>>
>> Once the continuation has been created (imageine you now have a kind 
>> of a deep copy of the stack), then you are able to persist it as any 
>> other persistent object. The object log is just one persistent object 
>> that makes it easy to store this but it could be anywhere.
>>
>> Then, you can simply open a debugger on a persisted continuation.
>>
>> So... I imagine you can do something like this:
>>
>>
>>
>> [
>>
>>  " Your rest code here"
>>  ]
>> on: Error do: [ :ex |
>>
>>    System abortTransaction.
>> Sytem beginTransaction.
>>     FaSmalltalkPlatform current saveExceptionContinuation: ex.
>> System commitTransaction.
>> ]
>>
>>
>>
>> Hope this is clearer...if not let me know. And maybe GemStone people 
>> may have something to correct from what I said.
>>
>>
>> Best,
>>
>>
>>
>>>     Mariano Martinez Peck via Glass < glass at lists.gemtalksystems.com
>>>     <mailto:glass at lists.gemtalksystems.com>> hat am 22. Januar 2018
>>>     um 13:05 geschrieben:
>>>
>>>
>>>     On Sun, Jan 21, 2018 at 1:35 PM, Dale Henrichs via Glass <
>>>     glass at lists.gemtalksystems.com
>>>     <mailto:glass at lists.gemtalksystems.com>> wrote:
>>>
>>>         Marten,
>>>
>>>         Did you know that you should be able to open a debugger on a
>>>         continuation - it is possible with tODE and GemTools. I
>>>         think that most folks find this a reasonable solution.
>>>
>>>
>>>     That's what I do. I do it at Seaside error handler as well as in
>>>     some other error handlers (like background jobs).
>>>
>>>     What I do is basically:
>>>
>>>     -----
>>>
>>>     [ self codeThatCouldTriggerErrorAndIW
>>>     antToSaveAContinuationForLater Debugging ]
>>>     on: Error do: [ :ex |
>>>
>>>         FaSmalltalkPlatform current saveExceptionContinuation:
>>>     exception.
>>>     ]
>>>
>>>     ----
>>>
>>>     FaGemStonePlatform class >> saveExceptionContinuation: anException
>>>       | continuation action |
>>>       GRPlatform current canDebugInteractively
>>>         ifTrue: [ anException pass ].
>>>       GRPlatform current
>>>         logError: anException description
>>>         title: 'Continuation saved to object log'.
>>>       action := [ :cont |
>>>       continuation := cont.
>>>       #'create' ] callCC.
>>>       action == #'create'
>>>         ifTrue: [
>>>           | logEntry |
>>>           logEntry := WAObjectLogEntry
>>>             error: anException description
>>>             continuation: continuation. "the continuation is not
>>>     resumable"
>>>           logEntry resumeContinuation.
>>>           logEntry addToLog.
>>>           ^ continuation ].
>>>       action == #'debug'
>>>         ifTrue: [ self halt ]
>>>
>>>
>>>     That uses Grease which I would expect you have it loaded.
>>>     WAObjectLogEntry is from Seaside but it's a very stupid
>>>     subclass. so if you are not using Seaside you could just copy
>>>     that class and give it whatever name and put it in your code.
>>>
>>>     Once the continuation has been created and stored in the
>>>     ObjectLog all you have to do is to connect with tODE and open a
>>>     debugger on it.
>>>
>>>     BTW, be sure to cleanup the object log as continuations are
>>>     heavy: http://ws.stfx.eu/2LSEXBAMZT23
>>>
>>>
>>>     -- 
>>>     Mariano
>>>     http://marianopeck.wordpress.com <http://marianopeck.wordpress.com>
>>>     _______________________________________________
>>>     Glass mailing list
>>>     Glass at lists.gemtalksystems.com
>>>     <mailto:Glass at lists.gemtalksystems.com>
>>>     http://lists.gemtalksystems.com/mailman/listinfo/glass
>>>     <http://lists.gemtalksystems.com/mailman/listinfo/glass>
>>
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>>
>>
>>
>> -- 
>> Mariano
>> http://marianopeck.wordpress.com
>
>
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