Retrieving connection/parameter values from environment unreliable in Azure Logic Apps Standard?

Question

I have trouble fetching values (using the @appsetting() expression) from environment variables to parameters.json and connections.json in Azure Logic Apps Standard. I ran into an issue with the SQL trigger when relying on this approach. Is this normal?

STEPS TO REPRODUCE

1. Create a test database with a test table - adding the necessary permissions for a logic app instance to said database (must be able to read and create tables)
2. Configure the SQL database name and server name into environment variables
3. Specify a SQL connection in the connections.json. Something like:

{
  "serviceProviderConnections": {
    "sql": {
      "parameterValues": {
        "serverName": "@appsetting('test_sql_server_name')",
        "databaseName": "@appsetting('test_sql_db_name')",
        "authProvider": {
          "Type": "ManagedServiceIdentity"
        }
      },
      "serviceProvider": {
        "id": "/serviceProviders/sql"
      },
      "displayName": "Test-SQL"
    }
  }
}

4. Add a SQL 'When a row if modified' in-app trigger to a workflow
5. Insert/update row in the test table

EXPECTED RESULTS

• The SQL trigger fires normally

ACTUAL RESULTS

• The SQL trigger does not fire. Furthermore, there is no indication of an error anywhere

PS. There is a limitation in the V2 telemetry when a trigger fails. This seems like an additional oversight. Switching to the V1 telemetry does reveal an exception and an "Access denied" error. But rather than a permissions problem, it looks like the trigger is unable to expand the @appsetting() expression. The trigger (+ creating the necessary tracking tables in the az_func schema) does work when typing the literal server and database names into parameterValues instead.

Answer 1

Hi @Veli-Jussi Raitila

I think what you're looking for is Parameters, see Create parameters for workflow inputs - Azure Logic Apps | Microsoft Learn. Create the parameter and reference that parameter in your connector. Using the JSON above, you would replace @appsetting('test_sql_server_name') with @parameters('test_sql_server_name').

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EDIT 23 Oct 2024 The product team has discovered a bug that prevented usage of @appsetting('<setting name>'). It was isolated to the SQL MI/AAD trigger where it wasn't resolving correctly. The fix is pending and will be deployed (no ETA) soon.