Add simple example for rsdos reading

examples/rsdos-example.py

@@ -0,0 +1,35 @@
+# Example code that uses the AvroRsdosReader extension class to count
+# DOS attacks via a perDos callback method
+
+import sys
+from pyavro_stardust.rsdos import AvroRsdosReader, RsdosAttribute, \
+       AvroRsdos
+
+count = 0
+attack_pkts = 0
+
+def perDosCallback(rsdos, userarg):
+    global count, attack_pkts
+
+    count += 1
+    dos = rsdos.asDict()
+    attack_pkts += dos['packet_count']
+
+    # Ideally, we'd do things with the other fields in 'dos' as well,
+    # but this is just intended to be a very simple example
+
+def run():
+    # sys.argv[1] must be a valid wandio path -- e.g. a swift URL or
+    # a path to a file on disk
+    reader = AvroRsdosReader(sys.argv[1])
+    reader.start()
+
+    # This will read all of the attack records and call `perDosCallback` on
+    # each one
+    reader.perAvroRecord(perDosCallback)
+    reader.close()
+
+    # Display our final results
+    print("Attacks", count, "   Packets:", attack_pkts)
+
+run()