https://github.com/Azure/azure-webjobs-sdk-script/wiki/Retrieving-information-about-the-currently-running-function describes a EXECUTION_CONTEXT_FUNCTIONDIRECTORY
environment variable. But it's not available for F# functions. Also Microsoft.Azure.WebJobs.ExecutionContext
doesn't provide a FunctionDirectory property.
This sample function confirms that the property does exist:
let Run(req: HttpRequestMessage, log: TraceWriter, context: ExecutionContext) =
log.Info context.FunctionDirectory
req.CreateResponse(HttpStatusCode.OK, "Hello")
(tested in the portal on v1 runtime)