swift-manage-shard-ranges analyze: accept incomplete shard data

swift-container-info does not currently include 'epoch' among the
shard range info that it outputs, which prevents shard data scraped
from that tool being read by the swift-manage-shard-ranges 'analyze'
command.  The 'epoch' key is not significant to the 'analyze' results
so it is safe to add a default value when it is missing.

Change-Id: I7be30c3247a53969a17fed63d0eba5ab4f4027e4

swift/cli/manage_shard_ranges.py

@@ -654,6 +654,10 @@ def repair_shard_ranges(broker, args):
 
 def analyze_shard_ranges(args):
     shard_data = _load_and_validate_shard_data(args, require_index=False)
+    for data in shard_data:
+        # allow for incomplete shard range data that may have been scraped from
+        # swift-container-info output
+        data.setdefault('epoch', None)
     shard_ranges = [ShardRange.from_dict(data) for data in shard_data]
     whole_sr = ShardRange('whole/namespace', 0)
     try:

test/unit/cli/test_manage_shard_ranges.py

@@ -1602,3 +1602,16 @@ class TestManageShardRanges(unittest.TestCase):
         self.assertEqual(
             ['Repairs necessary to remove overlapping shard ranges.'],
             out_lines[:1])
+
+        filtered_shard_json = [{k: v for k, v in sr.items() if k != 'epoch'}
+                               for sr in shard_json]
+        with open(shard_file, 'w') as fd:
+            json.dump(filtered_shard_json, fd)
+        out = StringIO()
+        err = StringIO()
+        with mock.patch('sys.stdout', out), mock.patch('sys.stderr', err):
+            ret = main([shard_file, 'analyze'])
+        self.assertEqual(0, ret)
+        self.assertEqual('', err.getvalue())
+        new_out_lines = out.getvalue().split('\n')
+        self.assertEqual(out_lines, new_out_lines)