title: Avoiding Go panic when Oracle Database client libraries not found
body: <p>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.)</p>
  
  <p>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.</p>
  
  <p>Running GO 1.12.5 on Windows Server 2019.</p>
  
  <p>I tried adding OCI.DLL to the same directory as the .EXE but it still panics.</p>
  
  <pre><code>import _ "github.com/mattn/go-oci8"
  </code></pre>
  
  <p>When I run on the server (without DB drivers) I get the error:</p>
  
  <pre><code>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
  </code></pre>
  
  <p>I want to avoid this panic when I don't need database access. I would prefer one .EXE without the mess of conditional builds.</p>