In V8 or above, if the class definition is as per latest api, i.e (models.Model)

then use the below like syntax, no need to import any date-related files.

date_action = fields.Datetime('Date current action', required=False, readonly=False, select=True
                                , default=lambda self: fields.datetime.now())

The reason I can figure out is, all the models start loading as soon as the server restart. For the default fields, while using datetime.now(), it takes the time as soon as the server restart and gets treated like a constant afterward. To overcome this, we can use either of the two methods given below:-

Method 1: Using a lambda function "lambda self: fields.datetime.now()"

In the new API, you can define the field as 

fields.datetime('Date current action', default=lambda self: fields.datetime.now(), required=False, readonly=False, select=True)

Method 2: Using "fields.Datetime.now"

fields.datetime('Date current action', default=fields.Datetime.now, required=False, readonly=False, select=True)

I preferred Method 2 over Method 1 as it seemed more promising and is already used in ERP base code.

Note: Please take care of the DateTime spelling (case-sensitive) in both the methods.

Hope this helps.

For v8/v9: You have not defined the field correctly, not using a CAPITAL for Datetime:

'date_action': fields.Datetime('Date current action', required=False, readonly=False, select=True),

For v7: You are mixing the API functions.

Try:

from openerp.osv import fields, osv
from openerp.tools import DEFAULT_SERVER_DATE_FORMAT

date.today().strftime(DEFAULT_SERVER_DATE_FORMAT)

\Stack\ overflow\ link\ \,\ answer\ \#4\ solved\ the\ issue\ \\\

\
Just remove () from fields.Datetime.now()

to be:

fields.Datetime.now

For finding current time use below code.

import time

local = time.asctime(time.localtime())

print "Current time is : ",local