Optimized by not reading the entire log file into memory

python-logs/parselogs.py

@@ -10,15 +10,16 @@ def main():
 
     input_file = sys.argv[1]
 
-    with open(input_file, "r") as f:
-        # Read log file
-        lines = f.readlines()
-
     # keep track of both the total number of authentication failures and the number of failures from each IP address
     auth_failures = {}
     total = 0
 
-    for line in lines:
+    with open(input_file, "r") as f:
+        # Read log file
+        for line in f:
+            # check for auth failure in line
+            # NOTE: This is a rudimentary check, and will not work for all log formats. This was chosen for the log file provided.
+            # as an example, it will not work when the failure arises from PAM, as those logs are formatted differently
             if "authentication failure" in line:
                 # add failure
                 total += 1