python-3.x azure-functions connection-string appsettings

How to access connection string with python

I have this local.settings.json in my local Azure function (Timer trigger)

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "",
    "FUNCTIONS_WORKER_RUNTIME": "python",
    .
    .
    .
  },
  "ConnectionStrings": {
    "sql_server": "valid connection string"
  }
}

I managed to access the connection string locally using: conn = os.environ["ConnectionStrings:sql_server"] and my code runs okay.

But, when I deploy I get 'Failure Exception: KeyError: 'sql_server' [...] getitem raise KeyError(key) from None'.

I tried to execute in portal changing that line to: conn = os.environ["sql_server"] But nothing changed.

Does anyone know how I can call this method on Azure Web?

Solution

Values stored under ConnectionStrings in local settings file needs to be added in connection string section of function app. I have added a test value of type SQLServer as shown below.

enter image description here

To access this values in function app, you need to add prefix based on the connection types. below are the prefixes for the different connection types. Refer MSDoc.

SQLServer: SQLCONNSTR_

MySQL: MYSQLCONNSTR_

SQLAzure: SQLAZURECONNSTR_

Custom: CUSTOMCONNSTR_

PostgreSQL: POSTGRESQLCONNSTR_

Notification Hub: NOTIFICATIONHUBCONNSTR_

Service Bus: SERVICEBUSCONNSTR_

Event Hub: EVENTHUBCONNSTR_

Document Db: DOCDBCONNSTR_

Redis Cache: REDISCACHECONNSTR_

As I have used SQLServer connection type, so SQLCONNSTR_ is to be amended along with the connection string name.
I am accessing the value using os.environ['SQLCONNSTR_test_sql_server_connectionString'] in code and able to get the expected value.

enter image description here

You need to use the prefix along with the connection string name based on its type in order to fetch the value in function app.