make mapping alone print out existing mappings..

ui/fixtures/cmd.mapping.json

@@ -98,5 +98,10 @@
 	"special": "verify store object cnt",
 	"comment": "but didn't create an additional FileObject",
 	"count": 5
+},
+{
+	"title": "just mapping lists them",
+	"cmd": [ "mapping" ],
+	"stdout_re": "^efdb5d9c-d123-4b30-aaa8-45a9ea8f6053:/.*subdir/mapa <-> ceaa4862-dd00-41ba-9787-7480ec1b2679:/.*subdir/mapb\n$"
 }
 ]

ui/medashare/cli.py

@@ -53,7 +53,7 @@ import shutil
 import socket
 import sqlalchemy
 from sqlalchemy import create_engine, select, insert, func, delete
-from sqlalchemy.orm import sessionmaker
+from sqlalchemy.orm import sessionmaker, aliased
 import string
 import subprocess
 import sys
@@ -945,28 +945,36 @@ def printhost(host):
 
 @init_datastructs
 def cmd_mapping(options, persona, objstr, cache):
-	if options.mapping is not None:
-		parts = [ x.split(':', 1) for x in options.mapping ]
+	if options.mapping is None:
+		maps = objstr.get_by_type('mapping')
 
-		if len(parts[0]) == 1:
-			parts[0] = [ hostuuid(), parts[0][0] ]
+		maps = (' <-> '.join(i['mapping']) for i in maps)
 
-		if parts[0][0] == hostuuid():
-			parts[0][1] = str(pathlib.Path(parts[0][1]).resolve())
+		for i in maps:
+			print(i)
+		return
 
-		if parts[1][1][0] != '/':
-			print('ERROR: host path must be absolute, is %s.' %
-			    repr(parts[1][1][0]), file=sys.stderr)
-			sys.exit(1)
+	parts = [ x.split(':', 1) for x in options.mapping ]
 
-		try:
-			[ objstr.get_host(x[0]) for x in parts ]
-		except KeyError as e:
-			print('ERROR: Unable to find host %s' %
-			    str(e.args[0]), file=sys.stderr)
-			sys.exit(1)
+	if len(parts[0]) == 1:
+		parts[0] = [ hostuuid(), parts[0][0] ]
+
+	if parts[0][0] == hostuuid():
+		parts[0][1] = str(pathlib.Path(parts[0][1]).resolve())
+
+	if parts[1][1][0] != '/':
+		print('ERROR: host path must be absolute, is %s.' %
+		    repr(parts[1][1][0]), file=sys.stderr)
+		sys.exit(1)
+
+	try:
+		[ objstr.get_host(x[0]) for x in parts ]
+	except KeyError as e:
+		print('ERROR: Unable to find host %s' %
+		    str(e.args[0]), file=sys.stderr)
+		sys.exit(1)
 
-		m = persona.Mapping(mapping=[ ':'.join(x) for x in parts ])
+	m = persona.Mapping(mapping=[ ':'.join(x) for x in parts ])
 
 	objstr.loadobj(m)