Add flag to watch for proposer builds (#10)

README.md

@@ -35,5 +35,6 @@ Options:
 - `--continue` (bool): Whether to restart the chain from a previous run if the output folder is not empty. It defaults to `false`.
 - `--use-bin-path` (bool): Whether to use the binaries from the local path instead of downloading them. It defaults to `false`.
 - `--genesis-delay` (int): The delay in seconds before the genesis block is created. It is used to account for the delay between the creation of the artifacts and the running of the services. It defaults to `5` seconds.
+- `--watch-payloads` (bool): If enabled, it logs whenever a builder builds a valid block through the relay. It defaults to `false`.
 
 Unless the `--continue` flag is set, the playground will delete the output directory and start a new chain from scratch on every run.

main.go

@@ -8,7 +8,9 @@ import (
 	"encoding/json"
 	"fmt"
 	"html/template"
+	"io"
 	"math/big"
+	"net/http"
 	"os"
 	"os/exec"
 	"os/signal"
@@ -49,6 +51,7 @@ var continueFlag bool
 var useBinPathFlag bool
 var validateFlag bool
 var genesisDelayFlag uint64
+var watchPayloadsFlag bool
 
 var rootCmd = &cobra.Command{
 	Use:   "playground",
@@ -153,6 +156,7 @@ func main() {
 	rootCmd.Flags().BoolVar(&continueFlag, "continue", false, "")
 	rootCmd.Flags().BoolVar(&useBinPathFlag, "use-bin-path", false, "")
 	rootCmd.Flags().Uint64Var(&genesisDelayFlag, "genesis-delay", 5, "")
+	rootCmd.Flags().BoolVar(&watchPayloadsFlag, "watch-payloads", false, "")
 
 	downloadArtifactsCmd.Flags().BoolVar(&validateFlag, "validate", false, "")
 	validateCmd.Flags().Uint64Var(&numBlocksValidate, "num-blocks", 5, "")
@@ -207,6 +211,10 @@ func runIt() error {
 		return err
 	}
 
+	if watchPayloadsFlag {
+		go watchProposerPayloads()
+	}
+
 	sig := make(chan os.Signal, 1)
 	signal.Notify(sig, os.Interrupt)
 
@@ -781,3 +789,48 @@ func getHomeDir() (string, error) {
 
 	return customHomeDir, nil
 }
+
+func watchProposerPayloads() {
+	// This is not the most efficient solution since we are querying the endpoint for the full list of payloads
+	// every 2 seconds. It should be fine for the kind of workloads expected to run.
+
+	lastSlot := uint64(0)
+
+	for {
+		time.Sleep(2 * time.Second)
+
+		vals, err := getProposerPayloadDelivered()
+		if err != nil {
+			fmt.Println("Error getting proposer payloads:", err)
+			continue
+		}
+
+		for _, val := range vals {
+			if val.Slot <= lastSlot {
+				continue
+			}
+
+			fmt.Printf("Block Proposed: Slot: %d, Builder: %s, Block: %d\n", val.Slot, val.BuilderPubkey, val.BlockNumber)
+			lastSlot = val.Slot
+		}
+	}
+}
+
+func getProposerPayloadDelivered() ([]*mevRCommon.BidTraceV2JSON, error) {
+	resp, err := http.Get("http://localhost:5555/relay/v1/data/bidtraces/proposer_payload_delivered")
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	data, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	var payloadDeliveredList []*mevRCommon.BidTraceV2JSON
+	if err := json.Unmarshal(data, &payloadDeliveredList); err != nil {
+		return nil, err
+	}
+	return payloadDeliveredList, nil
+}