middleware/auto: add (#333)

Add auto-load middleware that automatically picks up zones.

Every X seconds it will scan for new zones.
Add tests and documentation.

Make 'make test' use -race.

middleware/auto/setup_test.go

@@ -0,0 +1,81 @@
+package auto
+
+import (
+	"testing"
+
+	"github.com/mholt/caddy"
+)
+
+func TestAutoParse(t *testing.T) {
+	tests := []struct {
+		inputFileRules    string
+		shouldErr         bool
+		expectedDirectory string
+		expectedTempl     string
+		expectedRe        string
+		expectedTo        string
+	}{
+		{
+			`auto example.org {
+				directory /tmp
+				transfer to 127.0.0.1
+			}`,
+			false, "/tmp", "${1}", `db\.(.*)`, "127.0.0.1:53",
+		},
+		{
+			`auto {
+				directory /tmp
+			}`,
+			false, "/tmp", "${1}", `db\.(.*)`, "",
+		},
+		{
+			`auto {
+				directory /tmp (.*) bliep
+			}`,
+			false, "/tmp", "bliep", `(.*)`, "",
+		},
+		// errors
+		{
+			`auto example.org {
+				directory
+			}`,
+			true, "", "${1}", `db\.(.*)`, "",
+		},
+		{
+			`auto example.org {
+				directory /tmp * {1}
+			}`,
+			true, "", "${1}", ``, "",
+		},
+		{
+			`auto example.org {
+				directory /tmp .* {1}
+			}`,
+			true, "", "${1}", ``, "",
+		},
+	}
+
+	for i, test := range tests {
+		c := caddy.NewTestController("dns", test.inputFileRules)
+		a, err := autoParse(c)
+
+		if err == nil && test.shouldErr {
+			t.Fatalf("Test %d expected errors, but got no error", i)
+		} else if err != nil && !test.shouldErr {
+			t.Fatalf("Test %d expected no errors, but got '%v'", i, err)
+		} else if !test.shouldErr {
+			if a.loader.directory != test.expectedDirectory {
+				t.Fatalf("Test %d expected %v, got %v", i, test.expectedDirectory, a.loader.directory)
+			}
+			if a.loader.template != test.expectedTempl {
+				t.Fatalf("Test %d expected %v, got %v", i, test.expectedTempl, a.loader.template)
+			}
+			if a.loader.re.String() != test.expectedRe {
+				t.Fatalf("Test %d expected %v, got %v", i, test.expectedRe, a.loader.re)
+			}
+			if test.expectedTo != "" && a.loader.transferTo[0] != test.expectedTo {
+				t.Fatalf("Test %d expected %v, got %v", i, test.expectedTo, a.loader.transferTo[0])
+			}
+		}
+	}
+}