How to pass Parameters to Azure functions

Question

I have Azure timer function to copy data from my on premises database to Azure managed database. Currently I have hard coded the table names in the function.

Could the parameters be passed as a input to the function instead if hardcoding it ?

public static void Run([TimerTrigger("0 */1 * * * *")]TimerInfo myTimer, TraceWriter log) {
            string srcConnection = @"on premises connecting string";
            string destConnection = @"Azure managed instance connection string";

            string srcTable = "SourceTableName"; //am trying to make this as parameter
            string destTable = "DestinationTableName"; //am trying to make this as parameter
            string tmpTable = "select top 0 * into #DestTable from " + destTable;

            using(SqlConnection
                        srcConn = new SqlConnection(srcConnection),
                        destConn = new SqlConnection(destConnection)
                    ) {
                using(SqlCommand
                        srcGetCmd = new SqlCommand(srcTable, srcConn)
                    ) {
                    srcConn.Open();

                    destConn.Open();

                    SqlCommand cmd = new SqlCommand(tmpTable, destConn);
                    cmd.CommandTimeout = 180;
                    cmd.ExecuteNonQuery();
                    log.Info($"Temp table generated at: {DateTime.Now}");

                    SqlDataReader reader = srcGetCmd.ExecuteReader();
                    log.Info($"Source data loaded at: {DateTime.Now}");

                    using(SqlBulkCopy bulk = new SqlBulkCopy(destConn)) {
                        bulk.DestinationTableName = "#DestTable";
                        bulk.WriteToServer(reader);
                    }

                    string mergeSql = @"<sql logic to insert/Update/delete the data>";

                    cmd.CommandText = mergeSql;
                    cmd.CommandTimeout = 180;
                    cmd.ExecuteNonQuery();
                    log.Info($"Data update from temp table to destination at: {DateTime.Now}");

                    //Execute the command to drop temp table
                    cmd = new SqlCommand("drop table #DestTable", destConn);
                    cmd.CommandTimeout = 180;
                    cmd.ExecuteNonQuery();
                    log.Info($"Drop temp table at: {DateTime.Now}");

                    srcConn.Close();
                    destConn.Close();
                }
            }
            log.Info($"C# Timer trigger function executed at: {DateTime.Now}");

        }

As you can see I have hardcoded the table names, could this be made as paramater ?

Answer 1

The easiest way is to add Application Settings with these names (e.g. "SourceTableName") and then get them from Environment:

string srcTable = Environment.GetEnvironmentVariable("SourceTableName");

To really make it a parameter you would need to create a custom binding, similar to what I did in Authoring a Custom Binding for Azure Functions. Might be a bit of overkill.