refactor: dependency injection instead of package globals (#57)

* refactor: export Settings type, Setup returns value

* refactor: resolver.Setup takes explicit Settings struct

* refactor: GetHeadersWithoutTrustedHeaders takes explicit header params

* refactor: server constructors take narrow config

* refactor: Router struct with handler methods, remove geoSvc global

* refactor: wire DI through main, remove setting.App references

* refactor: remove App global, use returned Settings

* refactor: update router tests for DI

* chore: fix lint issues — rename ServerTimeouts to Timeouts, fix shadowed variables

router/setup_test.go

@@ -47,11 +47,14 @@ const (
 	domain            = "dns.example.com"
 )
 
+var rt *Router
+
 func TestMain(m *testing.M) {
 	app = gin.Default()
 	app.TrustedPlatform = trustedHeader
 	svc, _ := service.NewGeo(context.Background(), "../test/GeoIP2-City-Test.mmdb", "../test/GeoLite2-ASN-Test.mmdb")
-	Setup(app, svc)
+	rt = NewRouter(svc, trustedHeader, "", "", false)
+	Setup(app, rt)
 
 	os.Exit(m.Run())
 }