Finish rename Oplog.Oplog

Author: dbmurphy

mongodb_consistent_backup/Oplog/Oplog.py

@@ -0,0 +1,49 @@
+import os
+import logging
+
+from gzip import GzipFile
+# Skip bson in requirements , pymongo provides
+# noinspection PyPackageRequirements
+from bson import decode_file_iter
+
+
+class Oplog:
+    def __init__(self, oplog_file, dump_gzip=False):
+        self.oplog_file = oplog_file
+        self.dump_gzip  = dump_gzip
+
+        self._count    = 0
+        self._first_ts = None
+        self._last_ts  = None
+
+        self.read()
+
+    def read(self):
+        if os.path.isfile(self.oplog_file):
+            try:
+                logging.debug("Reading oplog file %s" % self.oplog_file)
+
+                if self.dump_gzip:
+                    oplog = GzipFile(self.oplog_file)
+                else:
+                    oplog = open(self.oplog_file)
+
+                for change in decode_file_iter(oplog):
+                    if 'ts' in change:
+                        self._last_ts = change['ts']
+                    if self._first_ts is None and self._last_ts is not None:
+                        self._first_ts = self._last_ts
+                    self._count += 1
+                oplog.close()
+            except Exception, e:
+                logging.fatal("Error reading oplog file %s! Error: %s" % (self.oplog_file, e))
+                raise e
+
+    def count(self):
+        return self._count
+
+    def first_ts(self):
+        return self._first_ts
+
+    def last_ts(self):
+        return self._last_ts