[Newbies] CommandShell/OSPRocess primCreatePipe failing. How to        debug?

gettimothy gettimothy at zoho.com
Fri Aug 30 14:15:11 UTC 2019

Hi David.

I am looping over 3221 classes that represent Lua modules and asking OSProcess to create the directories where their content to be stored should go and using Filestream to create and write the file contents.

Transcript clear.

[(WikitextModule allSubclasses select:[:module  |  (module pagetitle indexOf:$/ ifAbsent:[0]) > 0])

   do:[:m | |ss f d cmd shell content  ios|

       ss := m pagetitle squeakToUtf8 findBetweenSubStrs: '/'.

      d := ss collect:[:each | each] from: 1 to: (ss size -1).

     ((d at:1) = 'Sandbox') | ((d at:1) beginsWith:'User:')     "handle Sandbox and User: here"



                d := d inject:'' into:[:a :b | a, '/',  b].

                f := ('lua',d, '/', ss last, '.lua') squeakToUtf8  .    "ios writes to shared by default"

                cmd := 'mkdir -p shared/lua', d.   "commandshell writes to squeak root directory, so we prepende 'shared' to it"

               Transcript show: (m name), ' : ', cmd; cr.

               shell := PipeableOSProcess bash. 

               shell pipeFromOutput reader setNonBlocking. 

               shell exec: cmd.

               (Delay forMilliseconds: 400) wait. 

               Transcript show: shell upToEnd ; cr.

               shell close. 

               content := m lua squeakToUtf8.

               ios := FileStream newFileNamed: f.

               ios isNil


                        content storeOn: ios.

                         ios close.

       ]]]] ifError:[:x :y | Transcript show: x;cr. y close. thisContext resume]

The OSPRocess repeatedly executes the command 'mkdir -p path/stored/in/the/class' .

Since I posted my question, I have broken the loop into subsets of the 3221. I initially attempted 500 record blocks, and that worked up to about 1500 loops.
I then broke the 1500 to 2000 into increments of 100 and it just completed the 1500->2000 stretch. (eliminating the possibility that something within the modules were the cause of the error)

copyFrom: 501 to: 1000

copyFrom: 1001 to: 1500

copyFrom: 1501 to: 1600

copyFrom: 1601 to: 1700

copyFrom: 1701 to: 1800

copyFrom: 1801 to: 1900

copyFrom: 1901 to: 2000

copyFrom: 2001 to: 2500

copyFrom: 2501 to: 3000

My hunch is that pounding OSPRocess is causing the bug.

BTW, OSProcess and CommandShell are GREAT tools and I very much appreciate you having developed them. 

Thank you for your time.


---- On Fri, 30 Aug 2019 10:04:09 -0400 David T. Lewis <mailto:lewis at mail.msen.com> wrote ----

Can you say something about how you get to the point of getting
this error, and what operating system you are using? The code
snippet looks odd to me because it appears to be a decompiled
version of the method in OSProcess. Maybe you do not have a
changes file to go with your image file?

A typical reason for failing to create pipes is that you have
somehow opened too many file handles for your VM, possibly by
opening a lot of pipes and not closing them completely.


On Fri, Aug 30, 2019 at 07:58:50AM -0500, tty wrote:
> In 
> ExternalPipe>>
> makePipe
>     | t1 |
>     *t1 := OSProcess accessor makePipeHandles.*
>     t1 isNil
>         ifTrue: [self error: 'cannot create OS pipe']
>         ifFalse: [self
>                 reader: (AttachableFileStream
>                         name: 'pipeReader'
>                         attachTo: (t1 at: 1)
>                         writable: false).
>             self
>                 writer: (AttachableFileStream
>                         name: 'pipeWriter'
>                         attachTo: (t1 at: 2)
>                         writable: true)]
> OSProcess accessor is a  * 'a UnixOSProcessAccessor on pid 19790'*
> Where *self makePipeHandles* returns and undefined object.
> How should I think about this?
> thnks
> --
> Sent from: http://forum.world.st/Squeak-Beginners-f107673.html
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