I have a server written in Go that accesses an Oracle database. It works fine. However, there will be multiple instances running at different (currently 2) locations some of which do not need to access the database. (They get the same info passed on to them from their peer servers.)
I want the same executable running in all places but some will be configured to not use the database since they don't need it. The problem is that once I import the OCI package, its init() function is called which panics when it can't talk to the database.
Running GO 1.12.5 on Windows Server 2019.
I tried adding OCI.DLL to the same directory as the .EXE but it still panics.
import _ "github.com/mattn/go-oci8"
When I run on the server (without DB drivers) I get the error:
panic: OCIEnvCreate error
goroutine 1 [running]:
github.com/mattn/go-oci8.init.0()
D:/Golang/src/github.com/mattn/go-oci8/globals.go:160 +0x130
I want to avoid this panic when I don't need database access. I would prefer one .EXE without the mess of conditional builds.
Swap to the Go goracle driver which delays Oracle client library initialization until connections are opened precisely to handle your situation, where not all app users connect to Oracle DB.
As you said, adding the DLLs to the same directory as the exe solves your problem, so if you wanted a single file to still work you can have the exe copy all of the DLLs over when it starts, and even delete then when it is done if you want. This way, you can transfer the file to multiple locations, but there is most likely no way to keep it one file while running.