Refactor docs; Add 'ipng_source_tag', add udp listener for nginx-ipng-stats plugin

cmd/collector/udp_test.go

@@ -0,0 +1,67 @@
+package main
+
+import (
+	"context"
+	"net"
+	"testing"
+	"time"
+)
+
+func TestUDPListenerRoundTrip(t *testing.T) {
+	ch := make(chan LogRecord, 4)
+	ps := NewPromStore()
+
+	// Bind to an ephemeral port on loopback.
+	pc, err := net.ListenPacket("udp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("listen probe: %v", err)
+	}
+	addr := pc.LocalAddr().String()
+	pc.Close() // release; listener will re-bind
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	u := NewUDPListener(addr, 24, 48, ch)
+	u.SetProm(ps)
+	go u.Run(ctx)
+
+	// Dial the listener and send one valid and one malformed packet.
+	conn, err := net.Dial("udp", addr)
+	if err != nil {
+		t.Fatalf("dial: %v", err)
+	}
+	defer conn.Close()
+
+	// The listener is started asynchronously; retry for up to 1s.
+	good := "www.example.com\t1.2.3.4\tGET\t/\t200\t42\t0.010\t0\t12345\tdirect\t10.0.0.1\thttps"
+	bad := "not enough\tfields"
+	deadline := time.Now().Add(time.Second)
+	for time.Now().Before(deadline) {
+		conn.Write([]byte(good))
+		conn.Write([]byte(bad))
+		select {
+		case rec := <-ch:
+			if rec.Website != "www.example.com" || rec.SourceTag != "direct" {
+				t.Fatalf("bad record: %+v", rec)
+			}
+			// Give the listener a moment to process the malformed packet too.
+			time.Sleep(50 * time.Millisecond)
+			ps.udpMu.Lock()
+			pkt, suc, con := ps.udpPacketsReceived, ps.udpLoglinesSuccess, ps.udpLoglinesConsumed
+			ps.udpMu.Unlock()
+			if pkt < 2 {
+				t.Errorf("udpPacketsReceived=%d, want >=2", pkt)
+			}
+			if suc < 1 {
+				t.Errorf("udpLoglinesSuccess=%d, want >=1", suc)
+			}
+			if con < 1 {
+				t.Errorf("udpLoglinesConsumed=%d, want >=1", con)
+			}
+			return
+		case <-time.After(50 * time.Millisecond):
+		}
+	}
+	t.Fatal("no record received within 1s")
+}