fetching mails in batch mode

fetching mails in batch mode

[Andrea Russo]

Hi all,

Reading the gnus manual:

,----[ (info "(gnus)Batching Agents") ]
|    You can run a complete batch command from the command line with the
| following incantation:
| 
|      #!/bin/sh
|      emacs -batch -l ~/.emacs -l ~/.gnus.el gnus-agent-batch >/dev/null 2>&1
`----

My concern is that if I use this script to download asynchronously
mails while using an instance of gnus on a non batch emacs to read and
write mails, there are race conditions that can lead to currupted or
lost files?

And in case of concurrent running of the same batch script? 

Thanks,
Andrea.

-- 
Lisp is a programmable programming language.
     -— John Foderaro

Re: fetching mails in batch mode

[Andrea Russo]

Andrea Russo <rastandy@salug.it> writes:

> My concern is that if I use this script to download asynchronously
> mails while using an instance of gnus on a non batch emacs to read and
> write mails, there are race conditions that can lead to currupted or
> lost files?

Well... sorry for my english.

-- 
Fashion is a form of ugliness so intolerable that we have to alter it
every six months.
		-- Oscar Wilde

Re: fetching mails in batch mode

[Andrea Russo]

Phillip Lord <phillip.lord@newcastle.ac.uk> writes:

> I was talking about the nnmaildir backend. I don't know about remote
> usage. As I said, I've never actually tried it. But if it can cope
> with concurrency, I presume it's not using locking which is hard to
> get to work, but is just robust. It should work remotely.

Right.  This is also explained in the manual:

,----[ (info "(gnus)Mail Source Specifiers") ]
| 
|           You can also get mails from remote hosts (because maildirs
|           don't suffer from locking problems).
`----

Thanks for your help,
Andrea.

-- 
four five, how to stay alive
six seven, go to hell or go to heaven!
-- Roy Batty

Re: fetching mails in batch mode

[Phillip Lord]

>>>>> "AR" == Andrea Russo <rastandy@salug.it> writes:

  AR> Phillip Lord <phillip.lord@newcastle.ac.uk> writes:

  >> It will all go horrible wrong if you do this. If you are already
  >> running an Emacs, I presume that you want to read in batch
  >> because emacs hangs while reading?

  AR> Yes, although I actually use fetchmail for mails and leafnode
  AR> for news.  But I'm searching for a solution where I can't manage
  AR> to have these tools installed.

Okay, makes sense.

  >> In which case, you might want to use the gnus-demon instead which
  >> will read in the idle cycle.

  AR> But it'll anyway stop emacs from accepting user input.

Sure. But if it's running in the idle cycle the user is probably not
actually inputting anything. 

I have mine set to read mail every 4-5 minutes. Occasionally, I get to
my mail reader when it's hung, but it's rare for me. 

  >> You might also want to look at the nnmaildir backend which is
  >> supposed to cope with concurrent modification. Never tried it,
  >> although I mean to at some time.

  AR> Interesting. I use it with a remote path
  AR> (`/user@host:/etc..../').  Is this property of coping with
  AR> concurrency valid also for the corresponding gnus backend
  AR> nnmaildir?

I was talking about the nnmaildir backend. I don't know about remote
usage. As I said, I've never actually tried it. But if it can cope
with concurrency, I presume it's not using locking which is hard to
get to work, but is just robust. It should work remotely.

Phil

Re: fetching mails in batch mode

[Andrea Russo]

Phillip Lord <phillip.lord@newcastle.ac.uk> writes:

> It will all go horrible wrong if you do this. If you are already
> running an Emacs, I presume that you want to read in batch because
> emacs hangs while reading? 

Yes, although I actually use fetchmail for mails and leafnode for
news.  But I'm searching for a solution where I can't manage to have
these tools installed.

> In which case, you might want to use the gnus-demon instead which
> will read in the idle cycle. 

But it'll anyway stop emacs from accepting user input.

> You might also want to look at the nnmaildir backend which is
> supposed to cope with concurrent modification. Never tried it,
> although I mean to at some time.

Interesting. I use it with a remote path (`/user@host:/etc..../').
Is this property of coping with concurrency valid also for the
corresponding gnus backend nnmaildir?

Thanks for your help,
Andrea.

-- 
`To alcohol!  The cause of, and solution to,
 all of life's problems' --Homer J. Simpson

Re: fetching mails in batch mode

[Phillip Lord]

>>>>> "AR" == Andrea Russo <rastandy@salug.it> writes:

  AR> Hi all,

  AR> Reading the gnus manual:

  AR> ,----[ (info "(gnus)Batching Agents") ] | You can run a complete
  AR> batch command from the command line with the | following
  AR> incantation:
  AR> | 
  AR> |      #!/bin/sh
  AR> |      emacs -batch -l ~/.emacs -l ~/.gnus.el gnus-agent-batch >/dev/null 2>&1
  AR> `----

  AR> My concern is that if I use this script to download
  AR> asynchronously mails while using an instance of gnus on a non
  AR> batch emacs to read and write mails, there are race conditions
  AR> that can lead to currupted or lost files?

  AR> And in case of concurrent running of the same batch script?

It will all go horrible wrong if you do this. If you are already
running an Emacs, I presume that you want to read in batch because
emacs hangs while reading? In which case, you might want to use the
gnus-demon instead which will read in the idle cycle. You might also
want to look at the nnmaildir backend which is supposed to cope with
concurrent modification. Never tried it, although I mean to at some
time. 

Phil