Cannot Connect to Azure SQL when deploying to Shinyapps.io - r

Question

I have built an R shiny app/dashboard which runs perfectly on my local Windows 10 machine. I am now ready to deploy it to the web. I have chosen to do this using Shinapps.io. The app deploys, but immediately disconnects when trying to access it. Checking the log file yields this error:
Error : nanodbc/nanodbc.cpp:1021: 00000: [FreeTDS][SQL Server]Unable
to connect: Adaptive Server is unavailable or does not exist
[FreeTDS][SQL Server]Unable to connect to data source [FreeTDS][SQL
Server]Unknown host machine name.
My current implementation for connecting to the database is as follows:
conn_args <- config::get("dataconnection")
is_local<-Sys.getenv('SHINY_PORT')==""
message(paste("is_local: ", is_local))
if(is_local){
con <- odbc::dbConnect(odbc::odbc(),
Driver = "ODBC Driver 13 for SQL Server",
Server = conn_args$server,
Database = conn_args$database,
Uid = conn_args$uid,
PWD = conn_args$pwd,
Port = conn_args$port,
TrustServerCertificate="no")
} else {
#con <- RODBC::odbcDriverConnect("Driver=FreeTDS;TDS_Version=7.2;Server=tcp:#######;Port=1433;Database=######;Uid=######;Pwd=#######;Encrypt=yes;TrustServerCertificate=no;Connection Timeout=30")
#con <- RODBC::odbcDriverConnect("Driver=FreeTDS;TDS_Version-7.2;Server=tcp:#######,1433;Database=###########;Uid=######;Pwd=######;Encrypt=yes;TrustServerCertificate=no;Connection Timeout=30;")
con <- odbc::dbConnect(
odbc::odbc(),
Driver = "FreeTDS",
Server = conn_args$server,
Database = conn_args$database,
UID = conn_args$uid,
PWD = conn_args$pwd,
Port = 1433,
TrustServerCertificate="no",
TDS_Version = 7.4
)
}
As ShinyApps.io runs a Linux instance, I'm using FreeTDS as the driver on deployment. I have adjusted the TDS_Version with 7.0, 7.1, 7.2, 7.4, 8.0, and 9.0, as well as removing that parameter completely. Initally I tried using "SQLServer" as the driver name as per the Shinyapps.io documentation suggestion but that failed, too. I even tried using the RODBC package instead of odbc, but that went nowhere either.
I have set my Azure firewall to let in all necessary IP addresses. I even briefly opened the firewall completely, but that did not yield different results.
I have checked every thread and tutorial I can find, including:
Cannot connect to Microsoft Azure from shinyapps.io
Connecting Azure SQL databse to shinyapps.io
https://groups.google.com/g/shinyapps-users/c/hs4bQHsk9JU
https://docs.rstudio.com/shinyapps.io/applications.html#accessing-databases-with-odbc
Besides the arguments passed to the driver parameter(s), my connection arguments remain the same for local and web deployment. What am I missing? Is Azure SQL simply not compatible with Shinyapps.io?

Answer 1

Found the answer here: https://community.rstudio.com/t/unable-to-connect-to-azure-sql-database-in-shinyapps-io/45723
In the Azure portal, the ODBC connection string formats the server name like so: Server=tcp:servername.database.windows.net
Although this works locally, shinyapps.io does not like that format. I simply had to remove "tcp:" prefix from the server name, and the connection went through: Server=servername.database.windows.net
I also changed my driver to "SQLServer", although "FreeTDS" is still a viable option. If you use "FreeTDS", ensure that you have this extra parameter: TDS_Version=7.2