Libguestfs - Nov 2018 - Re: [PATCH 2/3] v2v: linux: install packages

On Tue, Nov 06, 2018 at 11:44:14AM +0100, Tomáš Golembiovský
wrote:
> Install packages from local files without touching network.
In fact, not limited to local files, but is limited to guests which
use ‘yum’.  So I think the function needs a better name unless you're
planning to combine it with
customize/customize_run.ml:guest_install_command (which would be overkill).
> Signed-off-by: Tomáš Golembiovský <tgolembi@redhat.com>
> ---
>  v2v/linux.ml  | 19 +++++++++++++++++++
>  v2v/linux.mli |  3 +++
>  2 files changed, 22 insertions(+)
> 
> diff --git a/v2v/linux.ml b/v2v/linux.ml
> index 177724e39..6a5cae512 100644
> --- a/v2v/linux.ml
> +++ b/v2v/linux.ml
> @@ -31,6 +31,25 @@ let augeas_reload g >    g#aug_load ();
>    debug_augeas_errors g
>  
> +let rec install g inspect packages > +  if packages <> [] then (
> +    do_install g inspect packages;
> +    (* Reload Augeas in case anything changed. *)
> +    augeas_reload g
> +  )
> +
> +and do_install g { i_package_format = package_format } packages 
It's purely a matter of style, but it's also possible to nest
functions, so:

  let install g inspect packages     let do_install ()       ...
    in
    if packages <> [] then (
      do_install ();
      ...

Of course you could also inline do_install.

Rich.
> +  assert (List.length packages > 0);
> +  match package_format with
> +  | "rpm" ->
> +    let cmd = [ "yum"; "--assumeyes";
"install" ] @ packages in
> +    let cmd = Array.of_list cmd in
> +    ignore (g#command cmd)
> +
> +  | format ->
> +    error (f_"don’t know how to install packages using %s: packages:
%s")
> +      format (String.concat " " packages)
> +
>  let rec remove g inspect packages >    if packages <> [] then (
>      do_remove g inspect packages;
> diff --git a/v2v/linux.mli b/v2v/linux.mli
> index 1c604665e..0036f4769 100644
> --- a/v2v/linux.mli
> +++ b/v2v/linux.mli
> @@ -23,6 +23,9 @@ val augeas_reload : Guestfs.guestfs -> unit
>      additional debugging information about parsing problems
>      that augeas found. *)
>  
> +val install: Guestfs.guestfs -> Types.inspect -> string list ->
unit
> +(** Install pacakge(s). *)
> +
>  val remove : Guestfs.guestfs -> Types.inspect -> string list ->
unit
>  (** Uninstall package(s). *)
>  
> -- 
> 2.19.0
> 
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> Libguestfs mailing list
> Libguestfs@redhat.com
> https://www.redhat.com/mailman/listinfo/libguestfs
-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-top is 'top' for virtual machines.  Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://people.redhat.com/~rjones/virt-top

On Tue, 6 Nov 2018 11:32:38 +0000
"Richard W.M. Jones" <rjones@redhat.com> wrote:
> On Tue, Nov 06, 2018 at 11:44:14AM +0100, Tomáš Golembiovský wrote:
> > Install packages from local files without touching network.  
> 
> In fact, not limited to local files, but is limited to guests which
> use ‘yum’.  So I think the function needs a better name unless you're
> planning to combine it with
> customize/customize_run.ml:guest_install_command (which would be overkill).
Uh, somehow I totally screwed this up. The plan was to use "rpm".
> 
> > Signed-off-by: Tomáš Golembiovský <tgolembi@redhat.com>
> > ---
> >  v2v/linux.ml  | 19 +++++++++++++++++++
> >  v2v/linux.mli |  3 +++
> >  2 files changed, 22 insertions(+)
> > 
> > diff --git a/v2v/linux.ml b/v2v/linux.ml
> > index 177724e39..6a5cae512 100644
> > --- a/v2v/linux.ml
> > +++ b/v2v/linux.ml
> > @@ -31,6 +31,25 @@ let augeas_reload g > >    g#aug_load ();
> >    debug_augeas_errors g
> >  
> > +let rec install g inspect packages > > +  if packages <>
[] then (
> > +    do_install g inspect packages;
> > +    (* Reload Augeas in case anything changed. *)
> > +    augeas_reload g
> > +  )
> > +
> > +and do_install g { i_package_format = package_format } packages =  
> 
> It's purely a matter of style, but it's also possible to nest
> functions, so:
> 
>   let install g inspect packages >     let do_install () >       ...
>     in
>     if packages <> [] then (
>       do_install ();
>       ...
> 
> Of course you could also inline do_install.
I used the same style as remove(). I will inline the code as I prefer
that.

    Tomas
> 
> Rich.
> 
> > +  assert (List.length packages > 0);
> > +  match package_format with
> > +  | "rpm" ->
> > +    let cmd = [ "yum"; "--assumeyes";
"install" ] @ packages in
> > +    let cmd = Array.of_list cmd in
> > +    ignore (g#command cmd)
> > +
> > +  | format ->
> > +    error (f_"don’t know how to install packages using %s:
packages: %s")
> > +      format (String.concat " " packages)
> > +
> >  let rec remove g inspect packages > >    if packages <>
[] then (
> >      do_remove g inspect packages;
> > diff --git a/v2v/linux.mli b/v2v/linux.mli
> > index 1c604665e..0036f4769 100644
> > --- a/v2v/linux.mli
> > +++ b/v2v/linux.mli
> > @@ -23,6 +23,9 @@ val augeas_reload : Guestfs.guestfs -> unit
> >      additional debugging information about parsing problems
> >      that augeas found. *)
> >  
> > +val install: Guestfs.guestfs -> Types.inspect -> string list
-> unit
> > +(** Install pacakge(s). *)
> > +
> >  val remove : Guestfs.guestfs -> Types.inspect -> string list
-> unit
> >  (** Uninstall package(s). *)
> >  
> > -- 
> > 2.19.0
> > 
> > _______________________________________________
> > Libguestfs mailing list
> > Libguestfs@redhat.com
> > https://www.redhat.com/mailman/listinfo/libguestfs  
> 
> -- 
> Richard Jones, Virtualization Group, Red Hat
http://people.redhat.com/~rjones
> Read my programming and virtualization blog: http://rwmj.wordpress.com
> virt-top is 'top' for virtual machines.  Tiny program with many
> powerful monitoring features, net stats, disk stats, logging, etc.
> http://people.redhat.com/~rjones/virt-top

-- 
Tomáš Golembiovský <tgolembi@redhat.com>

On Wed, Nov 07, 2018 at 11:24:48AM +0100, Tomáš Golembiovský
wrote:
> I used the same style as remove(). I will inline the code as I prefer
> that.
This is a stylistic point, so whichever style is easier to read,
more consistent, etc.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
libguestfs lets you edit virtual machines.  Supports shell scripting,
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