[ovs-dev] [PATCH V6] Add Passive TCP connection to IDL.

[Ben Pfaff]

That's not how the Python version of the IDL is meant to be used.
SchemaHelper operates on the schema that the client *wants*, not on the
schema that the database server *has*.  That's why it reads the schema
from a local disk file by default.  If Neutron does something else then
it should probably be changed.

On Mon, Feb 29, 2016 at 08:06:33AM +0000, Ofer Ben-Yacov wrote:
> Take a loot at the contractor of IDL:
> 
> ...
> def __init__(self, remote, schema):
> ...
> 
> 
> You can see that it gets schema as a parameter, which is actually
> SchemaHelper object:
> 
> ...
> assert isinstance(schema, SchemaHelper)
> ...
> 
> 
> This object holds the schema in a json string (schema_json) until you will
> call its register_columns function which will build the tables.
> 
> You can see that the IDL, when first built, is getting the schema which
> means that the OVSDB server was already connected beforehand to get it.
> 
> If you should like to know how this is done, you can look at Neutron's
> idlutils.py file and check the get_schema_helper() function.
> 
> You can see that it gets the schema name as a parameter, connects to the
> OVSDB, get the schema, close the connection and
> return SchemaHelper object to be used for the above.
> 
> 
> Note that after this patch will be committed, I'm going to send a patch to
> Neutron to add another function similar to get_schema_helper() with the
> the deference that it will get stream (open connection to the OVSDB server)
> as a parameter and get the schema from the server without closing it when
> done.
> 
> Ofer.
> 
> 
> 
> 
> 
> 
> 
> 
> ‫בתאריך שבת, 27 בפבר׳ 2016 ב-3:13 מאת ‪Ben Pfaff‬‏ <‪blp at ovn.org‬‏>:‬
> 
> > On Wed, Feb 24, 2016 at 08:39:02AM +0000, Ofer Ben-Yacov wrote:
> > > The current implementation IDL is:
> > > 1. connects to the OVSDB
> > > 2. get the schema and
> > > 3. disconnect
> > > 4. connect again to work with the OVSDB server.
> >
> > I don't understand--where do you see that behavior?  I can't spot it
> > anywhere.  The code I see in python/ovs/db/idl.py doesn't seem to do
> > anything like it.
> >