Libguestfs - Sep 2013 - [PATCH] virt-v2v: Add verbose message logging

As a followup to the discussion on verbose logging for virt-v2v, this patch
adds basic verbose messages in the main virt-v2v code. As Matt pointed out,
the usefulness of these messages is limited as the time spent outside of data
copying is trivial. However, when converting smaller guests, these messages
can act as progress markers and show where time is being spent. (As I already
added this code for my testing, I thought it might be worth discussing further
here.)

This patch adds the following startup options:

  -v | --verbose
        Enables verbose messages logging
  -vv
        Verbose messages, plus sets LIBGUESTFS_TRACE=1
  -vvv
        Verbose messages, plus sets LIBGUESTFS_TRACE=1 and LIBGUESTFS_DEBUG=1

---
 v2v/virt-v2v.pl | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/v2v/virt-v2v.pl b/v2v/virt-v2v.pl
index 3832f67..eddcd16 100755
--- a/v2v/virt-v2v.pl
+++ b/v2v/virt-v2v.pl
@@ -354,6 +354,24 @@ my $list_profiles = 0;
 
 Display a list of target profile names specified in the configuration file.
 
+=cut
+
+my $verbose;
+
+=item B<-v | --verbose>
+
+Enable verbose message logging.
+
+=item B<-vv>
+
+Verbose messages, plus sets LIBGUESTFS_TRACE=1.
+
+=item B<-vvv>
+
+Verbose messages, plus sets LIBGUESTFS_TRACE=1 and LIBGUESTFS_DEBUG=1.
+
+=cut
+
 =item B<--help>
 
 Display brief help.
@@ -388,6 +406,16 @@ GetOptions ("help|?"      => sub {
                 print "$Sys::VirtConvert::VERSION\n";
                 exit(0);
             },
+            "v|verbose"   => \$verbose,
+            "vv"          => sub {
+                $verbose = 1;
+                $ENV{LIBGUESTFS_TRACE} = '1';
+            },
+            "vvv"         => sub {
+                $verbose = 1;
+                $ENV{LIBGUESTFS_TRACE} = '1';
+                $ENV{LIBGUESTFS_DEBUG} = '1';
+            },
             "c|connect"   => sub {
                 # -c|--connect is the default for other virt tools. Be nice to
                 # the user and point out that virt-v2v is different.
@@ -521,6 +549,10 @@ else {
 
 # Get an appropriate Source
 my $source;
+if (defined($verbose)) {
+    logmsg NOTICE, __x('Connecting to input '.
+                       '({input})', input => $input_method)
+}
 if ($input_method eq "libvirtxml") {
     my $path = shift(@ARGV) or
         pod2usage({ -message => __"You must specify a filename",
@@ -574,6 +606,10 @@ else {
 
 # Decide the name of the guest target.
 $output_name = $source->get_name() unless defined $output_name;
+if (defined($verbose)) {
+    logmsg NOTICE, __x('Validating guest: {output}',
+                       output => $output_name)
+}
 
 # Check that the guest doesn't already exist on the target
 v2vdie __x('Domain {name} already exists on the target.',
@@ -593,9 +629,14 @@ v2vdie __('Guest doesn\'t define any storage
devices')
     unless @{$meta->{disks}} > 0;
 
 # Copy source storage to target
+if (defined($verbose)) {
+    logmsg NOTICE, __x('Copying virtual machine storage to target '.
+                       '({output})', output => $output_method)
+}
 $source->copy_storage($target, $output_format, $output_sparse);
 
 # Open a libguestfs handle on the guest's storage devices
+if (defined($verbose)) { logmsg NOTICE, __x('Starting guestfs') }
 my @disks = map { [ $_->{device},
                     $_->{dst}->get_path(),
                     $_->{dst}->get_format() ] } @{$meta->{disks}};
@@ -623,13 +664,17 @@ my $guestcaps;
 my $root;
 eval {
     # Inspect the guest
+    if (defined($verbose)) { logmsg NOTICE, __x('Inspecting guest') }
     $root = inspect_guest($g, $transferdev);
 
     # Modify the guest and its metadata
+    if (defined($verbose)) { logmsg NOTICE, __x('Converting guest') }
     $guestcaps          Sys::VirtConvert::Converter->convert($g, $config,
$root, $meta,
                                              \%options);
 
+    # Create the guest
+    if (defined($verbose)) { logmsg NOTICE, __x('Creating guest') }
     $target->create_guest($g, $root, $meta, $config, $guestcaps,
$output_name);
 };
 
-- 
1.8.1.4

On Thursday, September 05, 2013 04:21:03 PM Mike Latimer
wrote:
> This patch adds the following startup options:
> 
>   -v | --verbose
>         Enables verbose messages logging
>   -vv
>         Verbose messages, plus sets LIBGUESTFS_TRACE=1
>   -vvv
>         Verbose messages, plus sets LIBGUESTFS_TRACE=1 and
> LIBGUESTFS_DEBUG=1
> $output_name); };
I should have mentioned that I prefer this '-vvv' syntax (similar to
LVM),
rather than the '-v -v -v' type of syntax. However, if this second
format is
preferred, it would be easy to change to the GetOpt 'v+' type of syntax.
(Of
course, the value of all of this logging is still subjective.)

-Mike