[web2py] Re: Error in trunk opening PostgreSQL database
Thanks, it is easy to see how the default parameter gets changed with that example since the binding passes back outside the function through the return value, gets assigned to another variable and then the container contents modified through that assignment.
[web2py] Re: Error in trunk opening PostgreSQL database
Additional information:
I added a print to the front end of DAL.__init__ and was surprised to find
driver_args was set to {'check_same_thread': False} but I did not set it in
my db = DAL() class constructor call.
So here is the issue. I start up the development environment on Linux with a
terminal command python web2py.py sitting in the correct web2py directory.
Because I have Tcl/TK installed on the system it comes up, solicits an admin
password and then I start the server.
This in turn brings up a browser window running the welcome application. The
welcome application as written uses SQLLite as the database and since it is
default installed in Python = 2.5 I have the driver and a connection
succeeds. The SQLLite adapter does use this driver_args parameter and if it
is not set forces it to the value I am seeing.
Somehow driver_args gets stored globally and becomes the default for all
other adapter calls to __init__ on any other driver as well.
To test this theory I commented out the db=DAL(...) line in db.py in the
welcome application and restarted the server. This caused the welcome app to
crash during the TclTk solicited start of the welcome app when the browser
is opened but at least the DAL did not get initialized using the SQLLite
database.
Now I am able to run my own application and the driver_args = {} which would
be correct for the PostgreSQL adapter.
Hope that helps isolate it a little better.
Ron
[web2py] Re: Error in trunk opening PostgreSQL database
You must be using trunk. I think this is a bug in trunk but not
stable. Thanks for reporting it.
Massimo
On Mar 3, 2:02 pm, ron_m ron.mco...@gmail.com wrote:
Additional information:
I added a print to the front end of DAL.__init__ and was surprised to find
driver_args was set to {'check_same_thread': False} but I did not set it in
my db = DAL() class constructor call.
So here is the issue. I start up the development environment on Linux with a
terminal command python web2py.py sitting in the correct web2py directory.
Because I have Tcl/TK installed on the system it comes up, solicits an admin
password and then I start the server.
This in turn brings up a browser window running the welcome application. The
welcome application as written uses SQLLite as the database and since it is
default installed in Python = 2.5 I have the driver and a connection
succeeds. The SQLLite adapter does use this driver_args parameter and if it
is not set forces it to the value I am seeing.
Somehow driver_args gets stored globally and becomes the default for all
other adapter calls to __init__ on any other driver as well.
To test this theory I commented out the db=DAL(...) line in db.py in the
welcome application and restarted the server. This caused the welcome app to
crash during the TclTk solicited start of the welcome app when the browser
is opened but at least the DAL did not get initialized using the SQLLite
database.
Now I am able to run my own application and the driver_args = {} which would
be correct for the PostgreSQL adapter.
Hope that helps isolate it a little better.
Ron
[web2py] Re: Error in trunk opening PostgreSQL database
I just downloaded the nightly build, unpacked it, copied over my application and get the same problem. I don't have a problem with 1.92.1. I don't normally use trunk but test it once in a while to see what is coming. :-) Ron
[web2py] Re: Error in trunk opening PostgreSQL database
please try change line in dal
args =
(self,uri,pool_size,folder,db_codec,credential_decoder,driver_args)
to
args =
(self,uri,pool_size,folder,db_codec,credential_decoder,driver_args or
{})
On Mar 3, 4:07 pm, ron_m ron.mco...@gmail.com wrote:
I just downloaded the nightly build, unpacked it, copied over my application
and get the same problem.
I don't have a problem with 1.92.1. I don't normally use trunk but test it
once in a while to see what is coming. :-)
Ron
[web2py] Re: Error in trunk opening PostgreSQL database
Wow that fixed it. You are a Python Ninja :-)
I would sure like to know what the mechanism was that caused driver_args to
bleed from SQLLite to the other adapters even though it is defaulted it to
an empty dict on the class initializer. I also printed driver_args as the
first line of code in DAL.__init__() and it had the value left over from
SQLLite so how driver_args or {} produces {} when there is a value in
driver_args.
But you are very busy so if you don't have time no problem.
[web2py] Re: Error in trunk opening PostgreSQL database
class DAL:
def __init__(self,...,driver_args={})
so because this is defined in a module, every time driver_args is not
passed it is set to {}, the same {}. If one app changes, the default
changes for all apps. It is kind of counter intuitive but it works
that way.
It is very dangerous to set a default in a function to a list of
dictionary, because if somewhere downstream the object changed for one
instance, it changes the default for all future instances.
Massimo
On Mar 3, 5:12 pm, ron_m ron.mco...@gmail.com wrote:
Wow that fixed it. You are a Python Ninja :-)
I would sure like to know what the mechanism was that caused driver_args to
bleed from SQLLite to the other adapters even though it is defaulted it to
an empty dict on the class initializer. I also printed driver_args as the
first line of code in DAL.__init__() and it had the value left over from
SQLLite so how driver_args or {} produces {} when there is a value in
driver_args.
But you are very busy so if you don't have time no problem.
[web2py] Re: Error in trunk opening PostgreSQL database
Ah Ok, I was trying to reproduce with a simple program containing a couple of classes with a main all in one file but it did not exhibit the problem behaviour. So having the classes in a module is part of the recipe and lists and dicts are passed around as object references to the container leaving the contents open to modification.
[web2py] Re: Error in trunk opening PostgreSQL database
def f(a={}): return a
...
x=f()
x[1]=1
print x
{1: 1}
y=f()
print y
{1: 1}
On Mar 3, 5:49 pm, ron_m ron.mco...@gmail.com wrote:
Ah Ok, I was trying to reproduce with a simple program containing a couple
of classes with a main all in one file but it did not exhibit the problem
behaviour. So having the classes in a module is part of the recipe and lists
and dicts are passed around as object references to the container leaving
the contents open to modification.
