AZ204 Developer challenge on Module4 name: Chain Azure Functions together using input and output bindings

Question

When I was working on the Azure Function's

Module name: Chain Azure Functions together using input and output bindings

I got an error only after adding the output bindings.

Error message:

2024-05-02T16:44:00.267 [Error] Executed 'Functions.HttpTrigger3' (Failed, Id=3adfe2ef-2c11-411c-ab66-46371138cc42, Duration=10ms)Cosmos DB connection configuration 'CosmosDB' does not exist. Make sure that it is a defined App Setting.

To resolve it, In Function's environment variable, had only two values namely AccountEndpoint and AccountKey. But later I added 2 more values as well namely, Database value and containerId.

AccountEndpoint=https://<accountname>.documents.azure.com:443/;AccountKey=<key>;

Database=func-io-learn-db;containerId=Bookmarks;

After restarting the function, following was the error message,

New Error Message: 2024-05-02T17:37:01.582 [Error] Executed 'Functions.HttpTrigger3' (Failed, Id=6241cece-4917-4180-aa78-257c4427133b, Duration=10ms)Value cannot be null. (Parameter 'containerId')

Furthermore, following was function.json file:

{

"bindings": [

{

  "authLevel": "function",

  "type": "httpTrigger",

  "direction": "in",

  "name": "req",

  "methods": [

    "get",

    "post"

  ]

},

{

  "type": "http",

  "direction": "out",

  "name": "res"

},

{

  "name": "bookmark",

  "direction": "in",

  "type": "cosmosDB",

  "partitionKey": "{id}",

  "methods": [],

  "databaseName": "func-io-learn-db",

  "collectionName": "Bookmarks",

  "connectionStringSetting": "azcosmosdbaccount1_DOCUMENTDB",

  "id": "{id}"

},

{

  "name": "newbookmark",

  "direction": "out",

  "type": "cosmosDB",

  "partitionKey": "/id",

  "methods": [],

  "databaseName": "func-io-learn-db",

  "collectionName": "Bookmarks",

  "connectionStringSetting": "azcosmosdbaccount1_DOCUMENTDB"

},

{

  "name": "newmessage",

  "direction": "out",

  "type": "queue",

  "queueName": "bookmarks-post-process",

  "methods": [],

  "connection": "learn72620e65a50a4980b5_STORAGE"

}
```  ]

}

I went through the post and made the necessary changes. But the error message did not change. Any help would be greatly appreciated.

Answer 1

Hello rdp,

Thanks for reaching out in the Microsoft Q&A!

To resolve the error "Value cannot be null" for the parameter 'containerId' in your Azure Functions Cosmos DB output binding, ensure that you provide a valid value for the partitionKey parameter in the output binding configuration. In your function.json file, specify the partition key as below:

{
  "name": "newbookmark",
  "direction": "out",
  "type": "cosmosDB",
  "partitionKey": "/yourPartitionKeyField", // specify the partition key here
  "methods": [],
  "databaseName": "func-io-learn-db",
  "collectionName": "Bookmarks",
  "connectionStringSetting": "azcosmosdbaccount1_DOCUMENTDB"
}

Now you should be able to resolve the "Value cannot be null" error in your Azure Function.Don't forget to upvote! If you found this solution helpful, consider accepting it.