Operational Intelligence - MongoDB Applied Design Patterns - page 64

Log an event

Logging an event such as a page request (i.e., “hit”) is the main “write” activity for your sys-
tem. To maximize performance, you'll be doing in-place updates with the upsert=True to
create documents if they haven't been created yet. Consider the following example:

from from datetime datetime import import datetime , time

def def log_hit ( db , dt_utc , site , page ):

# Update daily stats doc
id_daily = dt_utc . strftime ( '%Y%m %d /' ) + site + page
hour = dt_utc . hour
minute = dt_utc . minute

# Get a datetime that only includes date info
d = datetime . combine ( dt_utc . date (), time . min )
query = {
'_id' : id_daily ,
'metadata' : { 'date' : d , 'site' : site , 'page' : page } }
update = { '$inc' : {
'hourly. %d ' % ( hour ,): 1 ,
'minute. %d . %d ' % ( hour , minute ): 1 } }
db . stats . daily . update ( query , update , upsert = True )

# Update monthly stats document
id_monthly = dt_utc . strftime ( '%Y%m/' ) + site + page
day_of_month = dt_utc . day
query = {
'_id' : id_monthly ,
'metadata' : {
'date' : d . replace ( day = 1 ),
'site' : site ,
'page' : page } }
update = { '$inc' : {
'daily. %d ' % day_of_month : 1 } }
db . stats . monthly . update ( query , update , upsert = True )

The upsert operation (i.e., upsert=True ) performs an update if the document exists, and an
insert if the document does not exist.