Sending an empty packet to the proxy causes it to dump its current cache contents, for debugging

os-dns.rkt

@@ -22,6 +22,10 @@
   (os-big-bang 'no-state
     (subscribe 'packet-reader
       (meta-message-handlers w
+	[(udp-packet source (== s) #"")
+	 (display "Debug dump packet received\n")
+	 (transition w
+	   (send-message `(debug-dump)))]
 	[(udp-packet source (== s) body)
 	 (transition w
 	   (send-message

proxy.rkt

@@ -145,6 +145,19 @@
     ;; TODO: consider deduping questions here too?
     (subscribe 'question-handler-factory
       (message-handlers zone
+	[`(debug-dump)
+	 (with-output-to-file "zone-proxy.dump"
+	   (lambda ()
+	     (display "----------------------------------------------------------------------\n")
+	     (display (seconds->date (current-seconds)))
+	     (newline)
+	     (for* ([(domain rrmap) zone] [(rr expiry) rrmap])
+	       (write (list rr expiry))
+	       (newline))
+	     (newline))
+	   #:mode 'text
+	   #:exists 'append)
+	 zone]
 	[(? question? q)
 	 (transition zone
 	   (spawn (question-handler zone q client-sock)))]