signet/miner: add --prefer-gbt-cli option

contrib/signet/miner

@@ -375,6 +375,11 @@ def do_generate(args):
 
     ultimate_target = nbits_to_target(int(args.nbits,16))
 
+    if args.prefer_gbt_cli is not None:
+        gbtcli = lambda *a, input=b"", **kwargs: bitcoin_cli(args.prefer_gbt_cli.split(" "), list(a), input=input, **kwargs)
+    else:
+        gbtcli = None
+
     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)
 
@@ -421,6 +426,23 @@ def do_generate(args):
         # mine and submit
         mined_blocks += 1
         done = False
+
+        if gbtcli is not None:
+            # gbt via prefered bcli
+            tmpl = gen.gbt(gbtcli, bci["bestblockhash"], now)
+            if tmpl is not None:
+                logging.debug("Prefered GBT template: %s", tmpl)
+
+                # mine block
+                logging.debug("Mining block delta=%s start=%s mine=%s", seconds_to_hms(gen.mine_time-bestheader["time"]), gen.mine_time, gen.is_mine)
+                block = gen.mine(args.bcli, args.grind_cmd, tmpl, reward_spk)
+                if block is not None:
+                    r = args.bcli("-stdin", "submitblock", input=block.serialize().hex().encode('utf8'))
+                    if r is None or r == "":
+                        done = True
+                    else:
+                        logging.warning("submitblock based on prefered template returned %r" % (r,))
+
         if not done:
             # gbt
             tmpl = gen.gbt(args.bcli, bci["bestblockhash"], now)
@@ -519,6 +541,7 @@ 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("--prefer-gbt-cli", default=None, type=str, help="Alternative bitcoin-cli invocation for getblocktemplate (optional)")
 
     calibrate = cmds.add_parser("calibrate", help="Calibrate difficulty")
     calibrate.set_defaults(fn=do_calibrate)