contrib: make block interval configurable in signet miner

contrib/signet/miner

@@ -223,11 +223,12 @@ def seconds_to_hms(s):
     return out
 
 class Generate:
-    INTERVAL = 600.0*2016/2015 # 10 minutes, adjusted for the off-by-one bug
 
 
     def __init__(self, multiminer=None, ultimate_target=None, poisson=False, max_interval=1800,
-                 standby_delay=0, backup_delay=0, set_block_time=None,
+                 standby_delay=0, backup_delay=0, set_block_time=None, 
+                 # 10 minutes, adjusted for the off-by-one bug
+                 block_interval=600.0*2016/2015, 
                  poolid=None):
         if multiminer is None:
             multiminer = (0, 1, 1)
@@ -239,6 +240,7 @@ class Generate:
         self.backup_delay = backup_delay
         self.set_block_time = set_block_time
         self.poolid = poolid
+        self.block_interval = block_interval
 
     def next_block_delta(self, last_nbits, last_hash):
         # strategy:
@@ -252,7 +254,7 @@ class Generate:
         retarget_factor = self.ultimate_target / current_target
         retarget_factor = max(0.25, min(retarget_factor, 4.0))
 
-        avg_interval = self.INTERVAL * retarget_factor
+        avg_interval = self.block_interval * retarget_factor
 
         if self.poisson:
             det_rand = int(last_hash[-8:], 16) * 2**-32
@@ -276,7 +278,7 @@ class Generate:
             self.action_time = now
             self.is_mine = True
         elif bestheader["height"] == 0:
-            time_delta = self.INTERVAL * 100 # plenty of time to mine 100 blocks
+            time_delta = self.block_interval * 100 # plenty of time to mine 100 blocks
             logging.info("Backdating time for first block to %d minutes ago" % (time_delta/60))
             self.mine_time = now - time_delta
             self.action_time = now
@@ -345,6 +347,9 @@ def do_generate(args):
     else:
         max_blocks = 1
 
+    if args.block_interval is not None:
+        logging.info("Using block interval %s", seconds_to_hms(args.block_interval))
+
     if args.set_block_time is not None and args.set_block_time < 0:
         args.set_block_time = time.time()
         logging.info("Treating negative block time as current time (%d)" % (args.set_block_time))
@@ -386,7 +391,8 @@ def do_generate(args):
     ultimate_target = nbits_to_target(int(args.nbits,16))
 
     gen = Generate(multiminer=my_blocks, ultimate_target=ultimate_target, poisson=args.poisson, max_interval=args.max_interval,
-                   standby_delay=args.standby_delay, backup_delay=args.backup_delay, set_block_time=args.set_block_time, poolid=poolid)
+                   standby_delay=args.standby_delay, backup_delay=args.backup_delay, set_block_time=args.set_block_time, poolid=poolid,
+                   block_interval=args.block_interval)
 
     mined_blocks = 0
     bestheader = {"hash": None}
@@ -529,6 +535,7 @@ def main():
     generate.add_argument("--backup-delay", default=300, type=int, help="Seconds to delay before mining blocks reserved for other miners (default=300)")
     generate.add_argument("--standby-delay", default=0, type=int, help="Seconds to delay before mining blocks (default=0)")
     generate.add_argument("--max-interval", default=1800, type=int, help="Maximum interblock interval (seconds)")
+    generate.add_argument("--block-interval", default=60*10, type=int, help="Consensus blocktime interval (seconds)")
 
     calibrate = cmds.add_parser("calibrate", help="Calibrate difficulty")
     calibrate.set_defaults(fn=do_calibrate)