gistfile1.diff

--- oak-purge-master-logs.py    2011-12-06 08:48:48.328557390 -0800
+++ oak-purge-master-logs.nibble.py     2011-12-06 10:31:16.237144233 -0800
@@ -23,6 +23,7 @@
 from optparse import OptionParser
 import ConfigParser
 import os.path
+import time
 
 def parse_options():
     parser = OptionParser()
@@ -42,6 +43,8 @@
     parser.add_option("--sentinel", dest="sentinel", default="/tmp/oak-purge-master-logs.sentinel", help="Sentinel file: exit if the file exists")
     parser.add_option("--print-only", action="store_true", dest="print_only", help="Do not execute. Only print statement")
     parser.add_option("-v", "--verbose", dest="verbose", action="store_true", help="Print user friendly messages")
+    parser.add_option("-N", "--nibble", action="store_true", dest="nibble", help="Nibble one log at a time")
+    parser.add_option("-d", "--delay", dest="delay", type="float", default="1.0", help="Delay between each log file when nibbling")
     return parser.parse_args()
 
 def verbose(message):
@@ -192,24 +195,62 @@
     slaves_master_log_files.sort()
     return slaves_master_log_files
 
-def purge_master_logs_to(master_log_file):
+def purge_to(purge_target):
+    """
+    Wrapper around actual purge commands; decides whether to nibble or purge all at once.
+    """
+    if(options.nibble):
+        nibble_master_logs_to(purge_target)
+    else:
+        purge_master_logs_to(purge_target)
+
+def purge_master_logs_to(purge_target):
     """
     Execute the PARGE MASTER LOGS TO statement, given a log name
     """
-    query = "PURGE MASTER LOGS TO '%s'" % master_log_file
+    query = "PURGE MASTER LOGS TO '%s'" % purge_target
     if(options.print_only):
         print query
         return
 
-    verbose("Will purge master logs to %s" % desired_master_logs[0])
+    verbose("Will purge master logs to %s" % purge_target)
     purge_cursor = None
     try:
         try:
             purge_cursor = master_connection.cursor()
             purge_cursor.execute(query)
-            verbose("Successfuly purged master logs to %s" % master_log_file)
+            verbose("Successfuly purged master logs to %s" % purge_target)
         except:
-            print_error("Failed purging master logs to %s" % master_log_file)
+            print_error("Failed purging master logs to %s" % purge_target)
+    finally:
+        if purge_cursor:
+            purge_cursor.close()
+
+def nibble_master_logs_to(purge_target):
+    """
+    Execute the PARGE MASTER LOGS TO statement, one log file at a time, up to the named log file
+    """
+
+    verbose("Will purge master logs, one file at a time, to %s, sleeping %f sec between each purge" % (purge_target, options.delay))
+    purge_cursor = None
+    try:
+        purge_cursor = master_connection.cursor()
+        try:
+           for next_log in master_logs[1:]:
+                query = "PURGE MASTER LOGS TO '%s'" % next_log
+                if(options.print_only):
+                    print query
+                    if(options.delay): time.sleep(options.delay)
+                else:
+                    purge_cursor.execute(query)
+                    verbose("Successfuly purged master logs to %s" % next_log)
+                    if(options.delay): time.sleep(options.delay)
+                if(next_log == purge_target): 
+                   break
+        except Exception as e:
+           print_error("Failed purging master logs, error: %s" % e)
+        else:
+            verbose("Finished purging master logs")
     finally:
         if purge_cursor:
             purge_cursor.close()
@@ -218,7 +259,7 @@
     """
     Purge master logs up to options.retain_logs. This is the desired behavior.
     """
-    purge_master_logs_to(desired_master_logs[0])
+    purge_to(desired_master_logs[0])
 
 def purge_master_logs_on_delaying_slaves():
     """
@@ -227,13 +268,13 @@
     """
     if options.pro_master and options.pro_slaves:
         master_log_to_purge_to = min(desired_master_logs[0], max_slave_master_log_file)
-        purge_master_logs_to(master_log_to_purge_to)
+        purge_to(master_log_to_purge_to)
     elif options.pro_master and not options.pro_slaves:
-        purge_master_logs_to(desired_master_logs[0])
+        purge_to(desired_master_logs[0])
     else:
         # Not pro-master
         # Play safe: the only safe thing to do is to purge to the min_slave_master_log_file.
-        purge_master_logs_to(min_slave_master_log_file)
+        purge_to(min_slave_master_log_file)
         if options.pro_slaves:
             pass
         else:
@@ -247,9 +288,9 @@
     if options.pro_master:
         if options.pro_slaves:
             master_log_to_purge_to = min(desired_master_logs[0], max_slave_master_log_file)
-            purge_master_logs_to(master_log_to_purge_to)
+            purge_to(master_log_to_purge_to)
         else:
-            purge_master_logs_to(desired_master_logs[0])
+            purge_to(desired_master_logs[0])
     else:
         # Not pro-master
         print_error("Some slaves are missing. Have not purged anything. Specify --pro-master (possibly with --pro-slaves) to force purging.")