feat(internal): add Thoth client and simple ASN checker

Signed-off-by: Xe Iaso <me@xeiaso.net>

internal/thoth/asnchecker_test.go

@@ -0,0 +1,59 @@
+package thoth
+
+import (
+	"fmt"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestASNChecker(t *testing.T) {
+	cli := loadSecrets(t)
+
+	asnc := &ASNChecker{
+		iptoasn: cli.iptoasn,
+		asns: map[int]struct{}{
+			13335: struct{}{},
+		},
+		hash: "foobar",
+	}
+
+	for _, cs := range []struct {
+		ipAddress string
+		wantMatch bool
+		wantError bool
+	}{
+		{
+			ipAddress: "1.1.1.1",
+			wantMatch: true,
+			wantError: false,
+		},
+		{
+			ipAddress: "8.8.8.8",
+			wantMatch: false,
+			wantError: false,
+		},
+		{
+			ipAddress: "taco",
+			wantMatch: false,
+			wantError: true,
+		},
+	} {
+		t.Run(fmt.Sprintf("%v", cs), func(t *testing.T) {
+			req := httptest.NewRequest("GET", "/", nil)
+			req.Header.Set("X-Real-Ip", cs.ipAddress)
+
+			match, err := asnc.Check(req)
+
+			if match != cs.wantMatch {
+				t.Errorf("Wanted match: %v, got: %v", cs.wantMatch, match)
+			}
+
+			switch {
+			case err != nil && !cs.wantError:
+				t.Errorf("Did not want error but got: %v", err)
+			case err == nil && cs.wantError:
+				t.Error("Wanted error but got none")
+			}
+		})
+	}
+}