Add ability to pack and combine with a previous baseprofile

For example, this is a good complement to unpack in a tethered environment:

unpack profile-v1 /root/scratch
#modify /root/scratch
pack /root/scratch profile-v2 -b profile-v1

imgutil/imgutil

@@ -636,6 +636,7 @@ def main():
     packp = sps.add_parser('pack', help='Pack a scratch directory to a diskless profile')
     packp.add_argument('scratchdir', help='Directory containing diskless root')
     packp.add_argument('profilename', help='The desired diskless OS profile name to pack the root into')
+    packp.add_argument('-b', '--baseprofile', help='Profile to copy extra info from, for example to make a new version of an existing profile, reference the previous one as baseprofile', default=None)
     capturep = sps.add_parser('capture', help='Capture an image for cloning from a running system')
     capturep.add_argument('node', help='Node to capture image from')
     capturep.add_argument('profilename', help='Profile name for captured image')
@@ -960,6 +961,25 @@ def unpack_image(args):
                     time.sleep(0.1)
 
 
+def recursecp(source, targ):
+    if os.path.islink(source):
+        if os.path.exists(targ):
+            return
+        linktarg = os.readlink(source)
+        os.symlink(linktarg, targ)
+    if os.path.isdir(source):
+        if not os.path.exists(targ):
+            os.mkdir(targ)
+        for entry in os.listdir(source):
+            srcentry = os.path.join(source, entry)
+            targentry = os.path.join(targ, entry)
+            recursecp(srcentry, targentry)
+    elif os.path.exists(targ):
+        return
+    else:
+        shutil.copy2(source, targ)
+
+
 def pack_image(args):
     outdir = args.profilename
     if '/' in outdir:
@@ -1008,28 +1028,36 @@ def pack_image(args):
     encrypt_image(tmploc, os.path.join(outdir, 'rootimg.sfs'), '{}/pending/rootimg.key'.format(privdir))
     os.remove(tmploc)
     with open(os.path.join(outdir, 'build-info'), 'w') as buildinfo:
-        buildinfo.write('Packed from {} on {}\n'.format(args.scratchdir, datetime.datetime.now().strftime('%Y-%m-%dT%H:%M')))
-    if distpath:
-        os.symlink(distpath, os.path.join(outdir, 'distribution'))
-    oshandler = fingerprint_host(args, args.scratchdir)
-    tryupdate = False
-    if oshandler:
-        prettyname = oshandler.osname
-        with open(os.path.join(args.scratchdir, 'etc/os-release')) as osr:
-            osrdata = osr.read().split('\n')
-            for line in osrdata:
-                if line.startswith('PRETTY_NAME="'):
-                    prettyname = line.replace(
-                        'PRETTY_NAME=', '').replace('"', '')
-        label = '{0} ({1})'.format(prettyname, 'Diskless Boot')
-        with open(os.path.join(outdir, 'profile.yaml'), 'w') as profiley:
-            profiley.write('label: {0}\nkernelargs: quiet # confluent_imagemethod=untethered|tethered # tethered is default when unspecified to save on memory, untethered will use more ram, but will not have any ongoing runtime root fs dependency on the http servers.\n'.format(label))
-        oscat = oshandler.oscategory
-        confdir = '/opt/confluent/lib/osdeploy/{}-diskless'.format(oscat)
-        os.symlink('{}/initramfs/addons.cpio'.format(confdir),
-            os.path.join(outdir, 'boot/initramfs/addons.cpio'))
-        if os.path.exists('{}/profiles/default'.format(confdir)):
-            copy_tree('{}/profiles/default'.format(confdir), outdir)
+        buildinfo.write('PACKEDFROM={}\nPACKDATE={}\n'.format(args.scratchdir, datetime.datetime.now().strftime('%Y-%m-%dT%H:%M')))
+        if args.baseprofile:
+            buildinfo.write('BASEPROFILE={}\n'.format(args.baseprofile))
+    if args.baseprofile:
+        if '/' not in args.baseprofile:
+            args.baseprofile = os.path.join('/var/lib/confluent/public/os', args.baseprofile)
+        recursecp(args.baseprofile, outdir)
+        tryupdate = True
+    else:
+        if distpath:
+            os.symlink(distpath, os.path.join(outdir, 'distribution'))
+        oshandler = fingerprint_host(args, args.scratchdir)
+        tryupdate = False
+        if oshandler:
+            prettyname = oshandler.osname
+            with open(os.path.join(args.scratchdir, 'etc/os-release')) as osr:
+                osrdata = osr.read().split('\n')
+                for line in osrdata:
+                    if line.startswith('PRETTY_NAME="'):
+                        prettyname = line.replace(
+                            'PRETTY_NAME=', '').replace('"', '')
+            label = '{0} ({1})'.format(prettyname, 'Diskless Boot')
+            with open(os.path.join(outdir, 'profile.yaml'), 'w') as profiley:
+                profiley.write('label: {0}\nkernelargs: quiet # confluent_imagemethod=untethered|tethered # tethered is default when unspecified to save on memory, untethered will use more ram, but will not have any ongoing runtime root fs dependency on the http servers.\n'.format(label))
+            oscat = oshandler.oscategory
+            confdir = '/opt/confluent/lib/osdeploy/{}-diskless'.format(oscat)
+            os.symlink('{}/initramfs/addons.cpio'.format(confdir),
+                os.path.join(outdir, 'boot/initramfs/addons.cpio'))
+            if os.path.exists('{}/profiles/default'.format(confdir)):
+                copy_tree('{}/profiles/default'.format(confdir), outdir)
             tryupdate = True
     try:
         pwd.getpwnam('confluent')