Does CRON work on GAE?

[Vidul Petrov]

Probably this topic has been discussed in the past, but I wasn't able
to find anything.
The cron script works fine (it's implemented as a controller method)
unless running in the GAE testing environment.
The username in app.yml is web2py, the same goes for the username in
"crontab" file.

Thank you for the help.

[AchipA]

GAE is not supported at the moment, but only because I don't use it
and there was no particular interest in it so far. If GAE has no means
of starting cron-style or long running processes, soft cron should
stil work, provided someone implements a locking mechanism that works
with GAE. The current implementation uses file operations as they are
universal on all platforms (i.e. move file is atomic - that's what the
infamous cron.master is for). Now, AFAIK this would not work on GAE,
but if you give/write an example that would replace that conditional
in a GAE-friendly way it should be no fus to gain cron on GAE out of
the box.

[Hans Donner]

gae has its own implemementation

- http://code.google.com/appengine/docs/python/config/cron.html
- http://code.google.com/appengine/docs/python/config/queue.html
- http://code.google.com/appengine/docs/python/taskqueue/

perhaps some kind of remapping (like cache) can do the trick

[AchipA]

Hm, if I understand correctly, we just need a smart crontab ->
cron.yaml converter then, right ? I can imagine other people needing
that too, so there might alredy be such things in the open, could
someone verify that ?

On Jul 21, 11:58 am, Hans Donner <hans.don...@pobox.com> wrote:
> gae has its own implemementation
>
> -http://code.google.com/appengine/docs/python/config/cron.html
> -http://code.google.com/appengine/docs/python/config/queue.html

> -http://code.google.com/appengine/docs/python/taskqueue/

>
> perhaps some kind of remapping (like cache) can do the trick
>

[Vidul Petrov]

It turnes out that the GAE cron daemon does the same work if it comes
to a method invocation (should be a valid URL).
I.e. there is no need for conversion. The problem, as I see it, is the
method protection, what I did is something like:

# the GAE cron file:
# /cron.yaml
cron:
- description: daily note addition
url: /test/default/insert_a_note
schedule: every 1 days

# the default.py controller in init app
# for some reasons Google uses this ip:
valid_inner_ip = "0.1.0.1"

def insert_a_note():
if request.env.remote_addr != valid_inner_ip:
redirect(URL(r=request,f="index"))
...
db.note.insert(name=some_new_name)
...

That's all.

On Jul 21, 1:16 pm, AchipA <attila.cs...@gmail.com> wrote:
> Hm, if I understand correctly, we just need a smart crontab ->cron.yaml converter then, right ? I can imagine other people needing
> that too, so there might alredy be such things in the open, could
> someone verify that ?
>
> On Jul 21, 11:58 am, Hans Donner <hans.don...@pobox.com> wrote:
>
>
>

> >gaehas its own implemementation

>
> > -http://code.google.com/appengine/docs/python/config/cron.html
> > -http://code.google.com/appengine/docs/python/config/queue.html
> > -http://code.google.com/appengine/docs/python/taskqueue/
>
> > perhaps some kind of remapping (like cache) can do the trick
>
> > On Tue, Jul 21, 2009 at 11:39, AchipA<attila.cs...@gmail.com> wrote:
>

> > >GAEis not supported at the moment, but only because I don't use it

> > > and there was no particular interest in it so far. IfGAEhas no means
> > > of startingcron-style or long running processes, softcronshould
> > > stil work, provided someone implements a locking mechanism that works

> > > withGAE. The current implementation uses file operations as they are

> > > universal on all platforms (i.e. move file is atomic - that's what the

> > > infamouscron.master is for). Now, AFAIK this would not work onGAE,

> > > but if you give/write an example that would replace that conditional

> > > in aGAE-friendly way it should be no fus to gaincrononGAEout of

> > > the box.
>
> > > On Jul 21, 7:03 am, Vidul Petrov <vidul.r...@gmail.com> wrote:
> > >> Probably this topic has been discussed in the past, but I wasn't able
> > >> to find anything.

> > >> Thecronscript works fine (it's implemented as a controller method)
> > >> unless running in theGAEtesting environment.

[AchipA]

Yes, but the advantage of an automatic conversion on deploment would
still be transparent compatibility across all platforms, which is not
a bad thing to have :)

Also, I wished we had a sort of standardized way of having a
@local_only or @auth.ip_in(...) decorator of sorts (maybe we already
do?).

[Fran]

On Jul 23, 10:36 am, AchipA <attila.cs...@gmail.com> wrote:
> I wished we had a sort of standardized way of having a
> @local_only or @auth.ip_in(...) decorator of sorts

I like it :)
- perhaps reusing the IS_IPV4 validator code

Not sure it would work through proxies though...

> (maybe we already do?).

No - just the template at the top of appadmin.py...

F

[mdipierro]

you can do:

@auth.requires(lambda: IS_IPV4()(request.client)[1])

works behind a proxy if the proxy uses HTTP_X_FORWARDED_FOR but it can
be spoofed

@auth.requires(lambda: IS_IPV4()(request.addr)[1])

does not work behind a proxy and cannot be spoofed.

Massimo

[mdipierro]

ERRATA

On Jul 23, 6:56 am, mdipierro <mdipie...@cs.depaul.edu> wrote:
> you can do:

@auth.requires(lambda: not IS_IPV4()(request.client)[1])

> works behind a proxy if the proxy uses HTTP_X_FORWARDED_FOR but it can
> be spoofed

@auth.requires(lambda: not IS_IPV4()(request.addr)[1])

[Fran]

On Jul 23, 12:59 pm, mdipierro <mdipie...@cs.depaul.edu> wrote:
> > you can do:
> @auth.requires(lambda: not IS_IPV4()(request.client)[1])
> > works behind a proxy if the proxy uses HTTP_X_FORWARDED_FOR but it can
> > be spoofed
> @auth.requires(lambda: not IS_IPV4()(request.addr)[1])
> > does not work behind a proxy and cannot be spoofed.

A great example for the new book then :)

F