Re: PATCH/s: RM#1387 - Bad handling of missing connection database server

Hi

Can you re-base please? The nodes patch no longer applies.

Ignoring that conflict though, the first test I did was to restart the app
server when connected to a database. I then (after it restarted) to open
the Schemas node in that database; nothing happened at all in the client,
but on the server I saw:

2016-08-19 16:59:16,321: INFO werkzeug: 127.0.0.1 - - [19/Aug/2016
16:59:16] "GET /browser/schema/nodes/1/1/219759/ HTTP/1.1" 500 -
Traceback (most recent call last):
File
"/Users/dpage/.virtualenvs/pgadmin4/lib/python2.7/site-packages/flask/app.py",
line 2000, in __call__
return self.wsgi_app(environ, start_response)
File
"/Users/dpage/.virtualenvs/pgadmin4/lib/python2.7/site-packages/flask/app.py",
line 1991, in wsgi_app
response = self.make_response(self.handle_exception(e))
File
"/Users/dpage/.virtualenvs/pgadmin4/lib/python2.7/site-packages/flask/app.py",
line 1567, in handle_exception
reraise(exc_type, exc_value, tb)
File
"/Users/dpage/.virtualenvs/pgadmin4/lib/python2.7/site-packages/flask/app.py",
line 1988, in wsgi_app
response = self.full_dispatch_request()
File
"/Users/dpage/.virtualenvs/pgadmin4/lib/python2.7/site-packages/flask/app.py",
line 1641, in full_dispatch_request
rv = self.handle_user_exception(e)
File
"/Users/dpage/.virtualenvs/pgadmin4/lib/python2.7/site-packages/flask/app.py",
line 1544, in handle_user_exception
reraise(exc_type, exc_value, tb)
File
"/Users/dpage/.virtualenvs/pgadmin4/lib/python2.7/site-packages/flask/app.py",
line 1639, in full_dispatch_request
rv = self.dispatch_request()
File
"/Users/dpage/.virtualenvs/pgadmin4/lib/python2.7/site-packages/flask/app.py",
line 1625, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File
"/Users/dpage/.virtualenvs/pgadmin4/lib/python2.7/site-packages/flask/views.py",
line 84, in view
return self.dispatch_request(*args, **kwargs)
File "/Users/dpage/git/pgadmin4/web/pgadmin/browser/utils.py", line 235,
in dispatch_request
return method(*args, **kwargs)
File
"/Users/dpage/git/pgadmin4/web/pgadmin/browser/server_groups/servers/databases/schemas/__init__.py",
line 129, in wrap
self.conn = self.manager.connection(did=kwargs['did'])
File
"/Users/dpage/git/pgadmin4/web/pgadmin/utils/driver/psycopg2/__init__.py",
line 1330, in connection
raise Exception(msg_active_conn)

I realise it could well be caused by the conflict when applying the nodes
patch, but just in case it's not... :-)

On Fri, Aug 19, 2016 at 12:25 PM, Ashesh Vashi <
ashesh(dot)vashi(at)enterprisedb(dot)com> wrote:

> Hi Dave/Team,
>
> I have attached three patches targeting specific area of work.
>
> -> *backend_connection_status_management*
> * Takes care of the connection status in the psycopg2 driver. And, when
> the connection is lost, it throws a exception with 503 http status message,
> and connection lost information in it.
> * Contains a change to allow to the flask application to propagate the
> exceptions even in the release mode.
> * Modification for utilising the existing password (while reconnection, if
> not disconnected explicitly).
> * Introduced a new ajax response message 'service_unavailable' (http
> status code: 503), which suggests temporary service unavailable.
>
> *-> manage_client_connect_lost*
> * It handles the connection lost for different operations at client
> (browser) side.
> * Using the events to handle this situation.
>
> *-> remove_connection_status_check*
> * We're currently return precondition_required (HTTP status code: 428) for
> the same, but - there is no consistent message/information available to
> identify it reliably as the server connection lost error (client side
> changes takes care of this situation, but - this patch is recommended for
> the whole change to work properly). This patch removes the connection
> status check from the individual nodes.
>
>
> TODO:
> * Browser tree - node expansion
> - When there is an error occurred during expanding the aci-tree node, it
> does not let the client handle the issue based on the status code, and
> error message, as it does not expose/share the error details with us. We
> will have to hack the aci-tree for the same.
>
> * Query Editor
> - Slick grid changes are in progress, hence - I did not touch the code for
> it, as it will lead to rework for either one of us (me, or Murtuza). I will
> take care of it as soon as the slick grid changes will be committed.
>
> --
>
> Thanks & Regards,
>
> Ashesh Vashi
> EnterpriseDB INDIA: Enterprise PostgreSQL Company
> <http://www.enterprisedb.com>
>
>
> *http://www.linkedin.com/in/asheshvashi*
> <http://www.linkedin.com/in/asheshvashi>
>

--
Dave Page
Blog: http://pgsnake.blogspot.com
Twitter: @pgsnake

EnterpriseDB UK: http://www.enterprisedb.com
The Enterprise PostgreSQL Company