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https://issues.apache.org/jira/browse/PROTON-2044?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16854965#comment-16854965
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Andrew Stitcher commented on PROTON-2044:
-----------------------------------------
It seems that you're trying to use the BlockingConnection when you really want
to just use a regular event style application - see the python example code for
how to use the event handling code.
But as you have observed if you want to use BlockingConnection you must use it
synchronously. It can be used in an application thread, but no other thread can
be using proton for the same connection at the same time. So it violates one of
protons threading rules to send messages in a different thread from the one
running the processing loop.
Another possibility is just to recognise the disconnect exception and reconnect
and send the message - as I said if you are connected to servicebus for long
enough without sending a message you will get disconnected anyway - so you have
to handle a case very like it anyway.
> Azure IoT Hub local-idle-timeout expired
> ----------------------------------------
>
> Key: PROTON-2044
> URL: https://issues.apache.org/jira/browse/PROTON-2044
> Project: Qpid Proton
> Issue Type: Bug
> Components: python-binding
> Affects Versions: proton-c-0.24.0
> Environment: Operating System: Windows
> Python: 3.6.4
> qpid-proton: 0.24.0
> Reporter: Andreas Fendt
> Priority: Major
>
> I'm using following python code to send messages to the devices
> (*/messages/devicebound*) which are connected to the *azure iot hub*:
> {code}
> import json
> from base64 import b64encode, b64decode
> from hashlib import sha256
> from hmac import HMAC
> from time import time
> from urllib.parse import quote_plus, urlencode
> from proton import ProtonException, Message
> from proton.utils import BlockingConnection
> class IotHub:
> def __init__(self):
> self._hostname = f"example-hub.azure-devices.net"
> self._username = f"[email protected]"
> self._blocking_connection = None
> self._sender = None
> self.connect()
> @staticmethod
> def generate_sas_token(uri: str, policy: str, key: str, expiry: float =
> None):
> if not expiry:
> expiry = time() + 3600 # Default to 1 hour.
> encoded_uri = quote_plus(uri)
> ttl = int(expiry)
> sign_key = f"{encoded_uri}\n{ttl}"
> signature = b64encode(HMAC(b64decode(key), sign_key.encode(),
> sha256).digest())
> result = {"sr": uri, "sig": signature, "se": str(ttl)}
> if policy:
> result["skn"] = policy
> return f"SharedAccessSignature {urlencode(result)}"
> def connect(self):
> # create credentials
> password = self.generate_sas_token(self._hostname,
> "iothubowner", "key",
> time() + 31557600) # ttl = 1 Year
> # establish connection
> self._blocking_connection =
> BlockingConnection(f"amqps://{self._hostname}", allowed_mechs="PLAIN",
> user=self._username,
> password=password,
> heartbeat=30)
> self._sender =
> self._blocking_connection.create_sender("/messages/devicebound")
> def send(self, message: dict, serial_number: str):
> message =
> Message(address="/devices/{serial_number}/messages/devicebound".format(serial_number=serial_number),
> body=bytes(json.dumps(message, separators=(",",
> ":")), "utf-8"))
> message.inferred = True # disable message encoding
> self._sender.send(message, timeout=20)
> {code}
> The problem is now that when I don't send any message for some seconds I get
> following exepction while sending a message:
> {code:java}
> Connection amqps://example-hub.azure-devices.net:amqps disconnected:
> Condition('amqp:resource-limit-exceeded', 'local-idle-timeout expired')
> {code}
> Whats the reason for that? How can I solve that?
> Thank you for help.
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