Towards a full #6 in #17: output options for tarring

pymule/manageruns.py

 from PathType import PathType
+import argparse
 import os
 import shutil
 import subprocess
@@ -147,25 +148,31 @@ def create_backup_parser(subparsers):
     parser.add_argument('dir', type=PathType(
         type='dir', dash_ok=False
     ))
+    parser.add_argument(
+        '-o', type=argparse.FileType('wb'), help='output file'
+    )
 
     parser.set_defaults(func=backup_main)
 
 
 def backup_main(parsed):
-    tarfile = parsed.dir
-    if tarfile.endswith('/'):
-        tarfile = tarfile[:-1]
-    tarfile = tarfile + '.tar.gz'
-
-    with open(tarfile, 'wb') as fp:
-        pcompr = subprocess.Popen([
-            'gzip'
-        ], stdout=fp, stdin=subprocess.PIPE)
-
-        ptar = subprocess.Popen([
-            "tar", "cvf", '-', parsed.dir
-        ], stdout=pcompr.stdin)
-        ptar.wait()
-
-        pcompr.stdin.close()
-        pcompr.wait()
+    if parsed.o is None:
+        tarfile = parsed.dir
+        if tarfile.endswith('/'):
+            tarfile = tarfile[:-1]
+        tarfile = tarfile + '.tar.gz'
+        fp = open(tarfile, 'wb')
+    else:
+        fp = parsed.o
+
+    pcompr = subprocess.Popen([
+        'gzip'
+    ], stdout=fp, stdin=subprocess.PIPE)
+
+    ptar = subprocess.Popen([
+        "tar", "cvf", '-', parsed.dir
+    ], stdout=pcompr.stdin)
+    ptar.wait()
+
+    pcompr.stdin.close()
+    pcompr.wait()