feat: add runtime provider debugging capability

GNUmakefile

@@ -21,6 +21,10 @@ tools:
 build: fmtcheck
 	go install
 
+debug: fmtcheck
+	go build -gcflags="all=-N -l" -trimpath -o terraform-provider-azuread
+	dlv exec --listen=:51000 --headless=true --api-version=2 --accept-multiclient --continue terraform-provider-azuread -- -debug
+
 fumpt:
 	@echo "==> Fixing source code with gofmt..."
 	# This logic should match the search logic in scripts/gofmtcheck.sh

README.md

@@ -102,6 +102,18 @@ $ $GOPATH/bin/terraform-provider-azuread
 ...
 ```
 
+To compile the provider for attached debugging run `make debug`. 
+
+```sh
+$ make debug
+...
+Provider started. To attach Terraform CLI, set the TF_REATTACH_PROVIDERS environment variable with the following:
+    TF_REATTACH_PROVIDERS='{"registry.terraform.io/hashicorp/azuread":{"Protocol":"grpc","ProtocolVersion":5,"Pid":16227,"Test":true,"Addr":{"Network":"unix","String":"/var/folders/dy/r91ps1bx7fscm_v64qbwd0nh0000gn/T/plugin1540622971"}}}'
+```
+
+See the [documentation](https://developer.hashicorp.com/terraform/plugin/debugging#starting-a-provider-in-debug-mode) for attaching a debugger.
+
+
 In order to test the provider, you can simply run `make test`.
 
 ```sh

main.go

@@ -4,11 +4,22 @@
 package main
 
 import (
+	"flag"
+
 	"github.com/hashicorp/terraform-plugin-sdk/v2/plugin"
 )
 
 func main() {
-	plugin.Serve(&plugin.ServeOpts{
+	var debug bool
+
+	flag.BoolVar(&debug, "debug", false, "set to true to run the provider with support for debuggers like delve")
+	flag.Parse()
+
+	opts := &plugin.ServeOpts{
+		Debug:        debug,
+		ProviderAddr: "registry.terraform.io/hashicorp/azuread",
 		ProviderFunc: Provider,
-	})
+	}
+
+	plugin.Serve(opts)
 }