blockchain sandbox: UTXO chain, p2p mining, attacker node

p2p/events.go

@@ -0,0 +1,24 @@
+package p2p
+
+import "time"
+
+type Event struct {
+	Type      string `json:"type"`       // "block_accept", "block_reject", "block_mine"
+	Node      string `json:"node"`       // short ID
+	BlockHash string `json:"block_hash"` // first 8 chars
+	Height    int    `json:"height"`
+	From      string `json:"from"` // who sent it (short ID), empty if mined
+	Ts        int64  `json:"ts"`   // unix ms
+	TxCount   int    `json:"tx_count"`
+}
+
+// Global event stream. Buffered so nodes never block.
+var Events = make(chan Event, 1000)
+
+func emit(e Event) {
+	e.Ts = time.Now().UnixMilli()
+	select {
+	case Events <- e:
+	default: // drop if nobody listens
+	}
+}