p2p/simulations/adapters: fix websocket log line parsing in exec adapter (#16667)

1 files changed, 51 insertions, 0 deletions

diff --git a/p2p/simulations/adapters/ws.go b/p2p/simulations/adapters/ws.go
new file mode 100644
index 000000000..979a21709
--- /dev/null
+++ b/p2p/simulations/adapters/ws.go
@@ -0,0 +1,51 @@
+package adapters
+
+import (
+	"bufio"
+	"errors"
+	"io"
+	"regexp"
+	"strings"
+	"time"
+)
+
+// wsAddrPattern is a regex used to read the WebSocket address from the node's
+// log
+var wsAddrPattern = regexp.MustCompile(`ws://[\d.:]+`)
+
+func matchWSAddr(str string) (string, bool) {
+	if !strings.Contains(str, "WebSocket endpoint opened") {
+		return "", false
+	}
+
+	return wsAddrPattern.FindString(str), true
+}
+
+// findWSAddr scans through reader r, looking for the log entry with
+// WebSocket address information.
+func findWSAddr(r io.Reader, timeout time.Duration) (string, error) {
+	ch := make(chan string)
+
+	go func() {
+		s := bufio.NewScanner(r)
+		for s.Scan() {
+			addr, ok := matchWSAddr(s.Text())
+			if ok {
+				ch <- addr
+			}
+		}
+		close(ch)
+	}()
+
+	var wsAddr string
+	select {
+	case wsAddr = <-ch:
+		if wsAddr == "" {
+			return "", errors.New("empty result")
+		}
+	case <-time.After(timeout):
+		return "", errors.New("timed out")
+	}
+
+	return wsAddr, nil
+}