scripts: debug tool to dump zone timers database

scripts/timerdb-info.py

+#!/usr/bin/env python3
+# vim: et ts=4 sw=4 sts=4
+#
+# Dump content of zone timers database in user readable format.
+#
+
+import datetime
+import lmdb
+import struct
+import sys
+
+class TimerDBInfo:
+    def __init__(self, path):
+        self._path = path
+
+    # the order is significant
+    TIMERS = [ "refresh", "expire", "flush" ]
+
+    @classmethod
+    def parse_dname(cls, dname):
+        labels = []
+        while dname[0] != 0:
+            llen = dname[0]
+            label = dname[1:llen+1].decode("utf-8")
+            dname = dname[llen+1:]
+            labels.append(label)
+        return ".".join(labels)
+
+    @classmethod
+    def parse_timers(cls, binary):
+        timers = {}
+        while len(binary) > 0:
+            chunk = binary[:9]
+            binary = binary[9:]
+            id, value = struct.unpack("!BQ", chunk)
+            if id > 0 and id <= len(cls.TIMERS):
+                timers[id - 1] = value
+        return timers
+
+    @classmethod
+    def format_date(cls, timestamp):
+        if timestamp == 0:
+            return "never"
+        else:
+            return datetime.datetime.fromtimestamp(timestamp).isoformat()
+
+    @classmethod
+    def format_line(cls, zone, timers):
+        parts = [zone]
+        for id, name in enumerate(cls.TIMERS):
+            parts.append("%s %s" % (name, cls.format_date(timers.get(id, 0))))
+        return " | ".join(parts)
+
+    def run(self):
+        with lmdb.open(self._path, readonly=True) as db:
+            with db.begin() as txn:
+                cursor = txn.cursor()
+                for key, value in cursor:
+                    zone = self.parse_dname(key)
+                    timers = self.parse_timers(value)
+                    print(self.format_line(zone, timers))
+
+if __name__ == "__main__":
+    if len(sys.argv) != 2:
+        print("usage: %s <timerdb-path>" % sys.argv[0], file=sys.stderr)
+        sys.exit(1)
+    path = sys.argv[1]
+    app = TimerDBInfo(path)
+    app.run()