Libguestfs - Jul 2015 - Re: \n didn't lead to a new line while using remote model

On Wed, Jul 29, 2015 at 04:18:02PM +0800, Yu Liu wrote:
[...]
> Let's make an example:
> 
> #guestfish -a disk.img
> >run
> >mount /dev/sda1 /
> >write-append /a.txt "Hello\n"
> >write-append /a.txt "World\n"
> >cat /a.txt
> Hello
> World
> 
> >quit
> 
> Another try:
> eval `guestfish --listen`
> guestfish --remote add disk.img
> guestfish --remote run
> guestfish --remote mount /dev/sda1 /
> guestfish --remote write-append /a.txt "Hello\n"
> guestfish --remote write-append /a.txt "World\n"
> guestfish --remote cat /a.txt
> Hello\nWorld\n
> 
> #
> libguestfs-1.20.11-11.el6.x86_64
The problem is that \n is handled "specially" by guestfish when it is
reading the ><fs> command line, but not when it is parsing commands
sent via --remote.

The way to do this is:

$ guestfish --remote write /a.txt "hello
world"
$ guestfish --remote cat /a.txt
hello
world

Note that you have to actually press the [Return] key after "hello

Probably a better plan is to use something like python remoting:

https://rwmj.wordpress.com/2013/05/07/using-libguestfs-remotely-with-python-and-rpyc/#content

which will be more predictable.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-builder quickly builds VMs from scratch
http://libguestfs.org/virt-builder.1.html

Ah, I see. Many thanks.

BTW, I see a function that it can add a ssh remote image, like guestfish 
-a ssh://root@example.com/path/disk.img,  it's really powerful, but why 
couldn't I secceed?

#guestfish -a http://slcn03cn15.us.oracle.com/packages/test1.img
http://slcn03cn15.us.oracle.com/packages/test1.img: No such file or 
directory

On 2015/7/29 20:42, Richard W.M. Jones wrote:
> On Wed, Jul 29, 2015 at 04:18:02PM +0800, Yu Liu wrote:
> [...]
>> Let's make an example:
>>
>> #guestfish -a disk.img
>>> run
>>> mount /dev/sda1 /
>>> write-append /a.txt "Hello\n"
>>> write-append /a.txt "World\n"
>>> cat /a.txt
>> Hello
>> World
>>
>>> quit
>> Another try:
>> eval `guestfish --listen`
>> guestfish --remote add disk.img
>> guestfish --remote run
>> guestfish --remote mount /dev/sda1 /
>> guestfish --remote write-append /a.txt "Hello\n"
>> guestfish --remote write-append /a.txt "World\n"
>> guestfish --remote cat /a.txt
>> Hello\nWorld\n
>>
>> #
>> libguestfs-1.20.11-11.el6.x86_64
> The problem is that \n is handled "specially" by guestfish when
it is
> reading the ><fs> command line, but not when it is parsing
commands
> sent via --remote.
>
> The way to do this is:
>
> $ guestfish --remote write /a.txt "hello
> world"
> $ guestfish --remote cat /a.txt
> hello
> world
>
> Note that you have to actually press the [Return] key after "hello
>
> Probably a better plan is to use something like python remoting:
>
>
https://rwmj.wordpress.com/2013/05/07/using-libguestfs-remotely-with-python-and-rpyc/#content
>
> which will be more predictable.
>
> Rich.
>
-- 
Thanks!
Luis Liu

On Thu, Jul 30, 2015 at 09:45:38AM +0800, Yu Liu wrote:
> Ah, I see. Many thanks.
> 
> BTW, I see a function that it can add a ssh remote image, like
> guestfish -a ssh://root@example.com/path/disk.img,  it's really
> powerful, but why couldn't I secceed?
> 
> #guestfish -a http://slcn03cn15.us.oracle.com/packages/test1.img
> http://slcn03cn15.us.oracle.com/packages/test1.img: No such file or
> directory
> >>libguestfs-1.20.11-11.el6.x86_64
For a couple of reasons:

(1) This feature wasn't available in 1.20 (added in 1.22).

(2) We disable this feature in RHEL 7.  It works upstream and in
Fedora & Debian.

This is because we don't want to support it for RHEL customers.  OEL
is free to enable it if you want to support that -- it requires
changes to the block device whitelist in the qemu spec file, as well
as removing the disabling patch from the libguestfs spec file
(0098-RHEL-7-Disable-unsupported-remote-drive-protocols-RH.patch).

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v