无法从 Azure 事件中心写入 CosmosDB

Question

I'm working on an Azure Function(2.x) which is triggered by events coming from an Event Hub and writes the received data to a CosmosDB instance. Before I deploy it, I'd like to test it locally and reading the event works flawlessly. However, when I try to write to CosmosDB this error shows up:

"System.Private.CoreLib: Exception while executing function: Functions.EventHubTrigger. Microsoft.Azure.DocumentDB.Core: Message: {"Errors":["One of the specified inputs is invalid"]}"

The database instance was created using the Azure Portal and I added a couple of dummy entries, all of which works fine. What am I doing wrong?

function.json :

{
  "scriptFile": "__init__.py",
  "bindings": [
    {
      "type": "eventHubTrigger",
      "name": "event",
      "direction": "in",
      "eventHubName": "event-hub-name",
      "connection": "event-hub-connection",
      "cardinality": "many",
      "consumerGroup": "$Default"
    },
    {
      "type": "cosmosDB",
      "direction": "out",
      "name": "doc",
      "databaseName": "database-name",
      "collectionName": "test",
      "createIfNotExists": "true",
      "connectionStringSetting": "CosmosDBConnectionString"
    }
  ]
}

local.settings.json :

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "storage-key",
    "CosmosDBConnectionString": "AccountEndpoint=document-db-endpoint;AccountKey=account-key;",
    "FUNCTIONS_WORKER_RUNTIME": "python",
    "event-hub-connection": "Endpoint=sb://endpoint-name;SharedAccessKeyName=shared-access-key-name;SharedAccessKey=shared-access-key" 
  }
}

host.json :

{
  "version": "2.0",
  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle",
    "version": "[1.*, 2.0.0)"
  }
}

__init__.py :

import logging, json

import azure.functions as func


def main(event: func.EventHubEvent, doc: func.Out[func.Document]):

    event_data = event.get_body().decode("utf-8")
    logging.info('Python EventHub trigger processed an event: %s', event_data)

    # json object for testing the DB write operation
    temp = {}
    temp["id"] = 1
    temp["category"] = "feedback"
    temp = json.dumps(temp)

    doc.set(func.Document.from_json(temp))
    logging.info("CosmosDB updated!; Value: ", temp)

Answer 1

That error is a HTTP 400, BadRequest. Meaning that something in the payload is not correctly formed JSON or some of your attributes is invalid.

I see your id is a number, but in the REST contract, it's a string. Reference: https://docs.microsoft.com/rest/api/cosmos-db/create-a-document#body

Can you change the id to a string?