[BUG] Service Bus Session ID is not available to Function code

Read azure/functions/servicebus.py around lines 274-275 first and compare how session-enabled messages populate msg.session_id with the nested metadata workaround. Reproduce the Service Bus session queue example, then verify that msg.session_id exposes the SessionId while existing message metadata behavior remains intact.

Investigative information

Please provide the following:

IcM: 283549053 has an impacted function app with relevant detail

Repro steps

1. Create a Function App that triggers off a Service bus session enabled queue.

Provide the steps required to reproduce the problem:

Expected behavior

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Actual behavior

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Known workarounds

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Fetch the session id from the nested field in the message:
msg.metadata["MessageSession"]["SessionId"]

Contents of the requirements.txt file:

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N/A

Related information

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• Bindings used: Service Bus

def main(msg: func.ServiceBusMessage):
    logging.info('Python ServiceBus queue trigger processed message: %s',
                 msg.get_body().decode('utf-8'))
    logging.info('Python msg.session_id - : %s', msg.metadata["MessageSession"]["SessionId"])
    logging.info('Python msg.session_id1 - : %s', msg.session_id)

Output

[2022-02-09T00:36:58.242Z] Python msg.session_id - : {12229E1-B37B-4D29-AA0A-E367906C206E}
[2022-02-09T00:36:58.242Z] Python msg.session_id1 - : None

The location where library sets session_id.

curl -H "Authorization: SharedAccessSignature sr=SERVICE_BUS.servicebus.windows.net%2FINPUT_QUEUE&sig=XXXXXX&se=YYY&skn=RootManageSharedAccessKey"  \
  -H 'BrokerProperties: {"SessionId": "{12229E1-B37B-4D29-AA0A-E367906C206E}"}' \
  -H "Content-Type: application/json" \
  -d "HelloWorld" \
  -X POST -i "https://servicebus-test-vameru.servicebus.windows.net/myinputqueue/messages\?timeout\=60"

HTTP/1.1 201 Created
Transfer-Encoding: chunked
Content-Type: application/xml; charset=utf-8
Server: Microsoft-HTTPAPI/2.0
Strict-Transport-Security: max-age=31536000
Date: Wed, 09 Feb 2022 00:36:57 GMT

The Complete Metadata

{
    "UserProperties": {},
    "DeliveryCount": 1,
    "LockToken": "fc949e24-410f-4a78-853b-7b8ce125cb99",
    "MessageSession": {
        "LockedUntilUtc": "2022-02-08T22: 30: 52.33697Z",
        "SessionId": "{17729E1-B37B-4D29-AA0A-E367906C206E}",
        "RegisteredPlugins": [],
        "ReceiveMode": 0,
        "PrefetchCount": 0,
        "LastPeekedSequenceNumber": 0,
        "Path": "myinputqueue",
        "OperationTimeout": "00: 01: 00",
        "ServiceBusConnection": {
            "Endpoint": "sb://servicebus-test-vameru.servicebus.windows.net",
            "OperationTimeout": "00:01:00",
            "RetryPolicy": {
                "MinimalBackoff": "00:00:00",
                "MaximumBackoff": "00:00:30",
                "DeltaBackoff": "00:00:03",
                "MaxRetryCount": 5,
                "IsServerBusy": False,
                "ServerBusyExceptionMessage": None
            },
            "TransportType": 0,
            "TokenProvider": {},
            "IsClosedOrClosing": False
        },
        "IsClosedOrClosing": False,
        "OwnsConnection": False,
        "ClientId": "MessageSession27myinputqueue_{17729E1-B37B-4D29-AA0A-E367906C206E}",
        "RetryPolicy": {
            "MinimalBackoff": "00:00:00",
            "MaximumBackoff": "00:00:30",
            "DeltaBackoff": "00:00:03",
            "MaxRetryCount": 5,
            "IsServerBusy": False,
            "ServerBusyExceptionMessage": None
        }
    },
    "ContentType": "application/json",
    "SequenceNumber": 13,
    "MessageReceiver": {
        "LockedUntilUtc": "2022-02-08T22:30:52.33697Z",
        "SessionId": "{17729E1-B37B-4D29-AA0A-E367906C206E}",
        "RegisteredPlugins": [],
        "ReceiveMode": 0,
        "PrefetchCount": 0,
        "LastPeekedSequenceNumber": 0,
        "Path": "myinputqueue",
        "OperationTimeout": "00:01:00",
        "ServiceBusConnection": {
            "Endpoint": "sb://servicebus-test-vameru.servicebus.windows.net",
            "OperationTimeout": "00:01:00",
            "RetryPolicy": {
                "MinimalBackoff": "00:00:00",
                "MaximumBackoff": "00:00:30",
                "DeltaBackoff": "00:00:03",
                "MaxRetryCount": 5,
                "IsServerBusy": False,
                "ServerBusyExceptionMessage": None
            },
            "TransportType": 0,
            "TokenProvider": {},
            "IsClosedOrClosing": False
        },
        "IsClosedOrClosing": False,
        "OwnsConnection": False,
        "ClientId": "MessageSession27myinputqueue_{17729E1-B37B-4D29-AA0A-E367906C206E}",
        "RetryPolicy": {
            "MinimalBackoff": "00:00:00",
            "MaximumBackoff": "00:00:30",
            "DeltaBackoff": "00:00:03",
            "MaxRetryCount": 5,
            "IsServerBusy": False,
            "ServerBusyExceptionMessage": None
        }
    },
    "EnqueuedTimeUtc": "2022-02-08T22:22:19.292Z",
    "ExpiresAtUtc": "2022-02-22T22:22:19.292Z",
    "MessageId": "806c77a2924441fe855697d39647e096"
}