[Cook] (ingredients-)fingerprint question.

[Pieter den Hertog]

I was trying to understand the effects of (ingredients-)fingerprint and 
constructed a simple
example, hence the use of [glob *.txt]. The example entails an empty dir 
with files appearing
one by one... so something like: (1.txt, 2.txt, ... n.txt) -> summary. 
On each file appearing
I wanted to (re)build the summary.

That's when I noticed the rebuild doesn't happen if 2.txt is added, but 
after adding 3.txt
everything works exactly as expected.

Using your suggestion, I can work around the special case (i.e. the 
second run for the
summary target) with the following recipe:

inp = [glob "*.txt"];
summ : [inp]
set fingerprint ingredients-fingerprint
["if" [in [count [inp]] 2] "then" forced]
{
cat [need] > [target];
}

So that works and my problem is solved, but it still has me puzzled 
about the
ingredients-fingerprint: its purpose is to track a changes to the list 
of ingredients
for which it would be necessary to record the very first 
ingredients-list used to
build the original first incarnation of the target... right?

The background to all this is that I'm trying to automate part of a 
reporting process
where cisco syslog files (after duplicate removals and some name 
mangling which totally
destroys their timestamps) are shoved into a directory where I can read 
them.

The logs are daily files and the summary should reflect a (running) 
monthly totals on
some specific events in the network. I wanted to be selective about 
rebuild the totals
since they take a looong time to complete.

I'll have a look at aegis as well to see if that's a better fit for my 
particular challenge
(though cook seemed a pretty straightforward tool for such a job).


Thanks for the feedback!


Aryeh M. Friedman wrote:
> I forgot to ask last time (and I guess this time) why your using [glob 
> *.txt] instead of %.txt or %0%.txt as your ingredient list (it 
> shouldn't matter in this case but it is non-standard)
>
> Aryeh M. Friedman wrote:
>> Does set force do the job?
>>
>> Also unless I am not sure of what your doing this seems more like a 
>> job for aegis or an other cms then for cook (I am assuming that 
>> XXX.txt are infrequently updated in the real world)
>>
>> pdh wrote:
>>> In this case I'm just working with text files where the actual 
>>> content and presence
>>> of the input files are more important than timestamps... (it is not 
>>> about building a
>>> program)... timestamps are messed up by other tools beyond my 
>>> control...
>>>
>>> The recipe actually works, except for the second run ... and as far 
>>> as I can tell,
>>> that's because the ingredients-list is not fingerprinted on the 
>>> first run.
>>>
>>> Using only the ingredients-fingerprint feature, I still have strange 
>>> results:
>>>
>>> recipe:
>>>
>>> summ : [glob "*.txt"]
>>> set ingredients-fingerprint
>>> {
>>> cat [need] > [target];
>>> }
>>> then
>>> {
>>> function print "Ingredients-list:" [need];
>>> }
>>>
>>> Starting with an empty directory with only this recipe present:
>>>
>>> $ echo 1 > 1.txt
>>> $ cook
>>> /* .cookrc.list, /home/pdh/dev/buildtools/cook, Sun Nov 15 15:06 
>>> 2009 */
>>> cook: cat 1.txt > summ
>>> cook: Ingredients-list: 1.txt
>>> $
>>> $ echo 2 > 2.txt
>>> $ touch summ
>>> $ cook
>>> /* .cookrc.list, /home/pdh/dev/buildtools/cook, Sun Nov 15 15:06 
>>> 2009 */
>>> cook: Ingredients-list: 1.txt 2.txt
>>> cook: the "summ" file is already up to date, no action required
>>> $
>>>
>>> From the documentation I expected cook to rebuild the target 
>>> (regardless
>>> of its timestamp) because it's ingredients-list changed but that's 
>>> not the
>>> case.
>>>
>>> So, it that correct behavior then? I am not a programmer so this could
>>> very well be desired behaviour for cook as a build tool for programs.
>>> (If so, I need to solve my problem through other means).
>>>
>>> Thanks
>>>
>>>
>>> Aryeh M. Friedman wrote:
>>>> Fingerprints are based on file content not on time stamp (i.e. I 
>>>> can "touch" the file and cook will still see it as the same)... the 
>>>> only way to fix this is to use time stamps not finger print on the 
>>>> particular file (I don't have the manual handy so you will have to 
>>>> look the syntex up)... but you really should be sure if this is 
>>>> what you *REALLY* want because fingerprint using actual file 
>>>> contents is 99.9999...% of the time correct (namely every time I 
>>>> think I have a problem like this it turns out to be something else)
>>>>
>>>> dwark wrote:
>>>>> Hi List,
>>>>>
>>>>> I am new to cook and I'm trying to create a recipe that will
>>>>> create a summary out of a changing set of files. The summary
>>>>> should be rebuilt whenever a file is added/removed or updated
>>>>> (i.e. contents changed).
>>>>>
>>>>> The combination of fingerprints and ingredients-fingerprint
>>>>> looks to be a perfect match and indeed works largely as advertised.
>>>>> Except for when the set of input files grows from 1 to 2 files,
>>>>> for the first time.
>>>>>
>>>>> It looks like the ingredients-fingerprint is not taken when
>>>>> the target is being built for the first time. The second
>>>>> time around, cook can't see if the list has changed.
>>>>>
>>>>> Another thing is that fingerprinting the target itself, seems
>>>>> to rejuvenate the target file to an age younger than it should
>>>>> be (in the example below, summ should not be younger than 2.txt
>>>>> during the second run).
>>>>>
>>>>> Am I missing something, like an additional flag or something? The 
>>>>> current workaround is to force the recipe when there are only 2 
>>>>> input files.
>>>>>
>>>>> Any hints/pointers would be appreciated.
>>>>>
>>>>> Thanks,
>>>>>
>>>
>>>
>>
>>
>
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