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/dns_test.go

@@ -16,7 +16,7 @@ import (
 
 func TestGetDNSDiscoveryHandler(t *testing.T) {
 	store := cache.New(cache.NoExpiration, cache.NoExpiration)
-	handler := GetDNSDiscoveryHandler(store, domain, "")
+	handler := GetDNSDiscoveryHandler(store, rt.geo, domain, "")
 
 	t.Run("calls next if host does not have domain suffix", func(t *testing.T) {
 		req, _ := http.NewRequest("GET", "/", nil)
@@ -106,7 +106,7 @@ func TestHandleDNS(t *testing.T) {
 			w := httptest.NewRecorder()
 			c, _ := gin.CreateTestContext(w)
 			c.Request = req
-			handleDNS(c, store)
+			handleDNS(c, store, rt.geo)
 			assert.Equal(t, http.StatusNotFound, w.Code)
 		})
 	}
@@ -144,7 +144,7 @@ func TestAcceptDNSRequest(t *testing.T) {
 			c.Request = req
 
 			store.Set(u, testIP.ipv4, cache.DefaultExpiration)
-			handleDNS(c, store)
+			handleDNS(c, store, rt.geo)
 
 			assert.Equal(t, http.StatusOK, w.Code)
 			assert.Equal(t, tt.want, w.Body.String())