" '<client_name_here>' has no attribute '_lock' " when trying to run sample that uses installed client

isaiahT · Oct 11th 2017

I have created a custom Python OpenDXL client using the bootstrapper (which I found here: OpenDXL Bootstrap Application.). The intention is to use this client to send requests to a service on the DXL fabric and get a response. To test it, I modified the built-in sample that comes with bootstrap-generated files.

When I run my code using python -m P2InternalClient <config-directory> I don't have any problems and everything works perfectly fine. However, I want to use this as an installed library that can have a client that extends the P2InternalClient to use as a normal DXL client.

I used the bootstrap distribution script to create a .whl and install it using PIP without any problem. However, when I try to use the modified sample code to import the installed module, I get this error:

[IMG:https://i.imgur.com/GCGunXQ.png]

I have no idea what this is referring to with the _lock attribute.

Client Code:

If it helps, I've included a version of the client class that can cause the issue (see below)

Python

import logging
from dxlbootstrap.app import Application
from eventhandlers import *
# Configure local logger
logger = logging.getLogger(__name__)
class P2InternalClient(Application):
"""
The "P2 Internal Client" application class.
"""
def __init__(self, config_dir):
"""
Constructor parameters:
:param config_dir: The location of the configuration files for the
application
"""
super(P2InternalClient, self).__init__(config_dir, "opendxl-p2.config")
@property
def client(self):
"""
The DXL client used by the application to communicate with the DXL
fabric
"""
return self._dxl_client
@property
def config(self):
"""
The application configuration (as read from the "opendxl-p2.config" file)
"""
return self._config
def on_run(self):
"""
Invoked when the application has started running.
"""
logger.info("On 'run' callback.")
def on_load_configuration(self, config):
"""
Invoked after the application-specific configuration has been loaded
This callback provides the opportunity for the application to parse
additional configuration properties.
:param config: The application configuration
"""
logger.info("On 'load configuration' callback.")
def on_dxl_connect(self):
"""
Invoked after the client associated with the application has connected
to the DXL fabric.
"""
logger.info("On 'DXL connect' callback.")
def on_register_event_handlers(self):
"""
Invoked when event handlers should be registered with the application
"""
# Register event callback 'p2internalclient_handler'
logger.info("Registering event callback: {0}".format("p2internalclient_handler"))
self.add_event_callback("/p2/request/msgv1/#", P2InternalRequestsCallback(self), True)

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Sample Code:

And once the library is installed, here is the sample code that causes the error.

Python: basic_sample.py

import os
import sys
from dxlclient.client_config import DxlClientConfig
from dxlclient.client import DxlClient
from dxlclient.message import Message, Event, Request
from dxlbootstrap.util import MessageUtils
# Import common logging and configuration
sys.path.append(os.path.dirname(os.path.abspath(__file__)) + "/..")
from common import *
from opendxlp2 import P2InternalClient
# Configure local logger
logging.getLogger().setLevel(logging.ERROR)
logger = logging.getLogger(__name__)
# Create DXL configuration from file
config = DxlClientConfig.create_dxl_config_from_file(CONFIG_FILE)
# Create the client
with DxlClient(config) as client:
# Connect to the fabric
client.connect()
p2client = P2InternalClient(client)
logger.info("Connected to DXL fabric.")
# Send event that will trigger event callback 'p2internalclient_handler'
evt = Event("/p2/request/msgv1/#")
MessageUtils.encode_payload(evt, "p2internalclient_handler event payload")
client.send_event(evt)

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I'm pretty stumped on this, does anyone have any idea what the problem is?

ncolter · Oct 11th 2017

It looks like you are trying to use an application generated by OpenDXL Bootstrap's application-template generation function, rather than a client based on the client-template. This is apparent for two reasons: the name of your client file is app.py, which is the default name of the client file created by the application template, and this error in your output:

TypeError: object of type 'DxlClient' has no len()

This is a result of the difference in the __init__ used for OpenDXL Bootstrap application templates and client templates.

In the application template, the __init__ for your client will look like this:

Python: open-dxlbootstrap-python/dxlbootstrap/app.py

def __init__(self, config_dir, app_config_file_name):
"""
Constructs the application
:param config_dir: The directory containing the application configuration files
:param app_config_file_name: The name of the application-specific configuration file
"""

In the client template, it will look like this:

Python: opendxl-bootstrap-python/dxlbootstrap/client.py

def __init__(self, dxl_client):
"""
Constructor parameters:
:param dxl_client: The DXL client to use for communication with the fabric
"""

As you can see, the constructor in the application template does not take in a DxlClient as an argument, and is instead attempting to use the DxlClient you passed it as a file path.

The Fix:
The simplest way to fix this issue would be to generate a new client template using the instructions found here: OpenDXL Bootstrap Tutorial Part 4: Create Client Wrapper.

" '<client_name_here>' has no attribute '_lock' " when trying to run sample that uses installed client

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