backends/bitcoind/blockchain_processor.py

   1 from json import dumps, loads
   2 import leveldb, urllib
   3 import deserialize
   4 import ast, time, threading, hashlib
   5 from Queue import Queue
   6 import traceback, sys, os
   7
   8
   9
  10 Hash = lambda x: hashlib.sha256(hashlib.sha256(x).digest()).digest()
  11 hash_encode = lambda x: x[::-1].encode('hex')
  12 hash_decode = lambda x: x.decode('hex')[::-1]
  13
  14
  15
  16 def rev_hex(s):
  17     return s.decode('hex')[::-1].encode('hex')
  18
  19
  20 def int_to_hex(i, length=1):
  21     s = hex(i)[2:].rstrip('L')
  22     s = "0"*(2*length - len(s)) + s
  23     return rev_hex(s)
  24
  25 def header_to_string(res):
  26     pbh = res.get('prev_block_hash')
  27     if pbh is None: pbh = '0'*64
  28     s = int_to_hex(res.get('version'),4) \
  29         + rev_hex(pbh) \
  30         + rev_hex(res.get('merkle_root')) \
  31         + int_to_hex(int(res.get('timestamp')),4) \
  32         + int_to_hex(int(res.get('bits')),4) \
  33         + int_to_hex(int(res.get('nonce')),4)
  34     return s
  35
  36 def header_from_string( s):
  37     hex_to_int = lambda s: eval('0x' + s[::-1].encode('hex'))
  38     h = {}
  39     h['version'] = hex_to_int(s[0:4])
  40     h['prev_block_hash'] = hash_encode(s[4:36])
  41     h['merkle_root'] = hash_encode(s[36:68])
  42     h['timestamp'] = hex_to_int(s[68:72])
  43     h['bits'] = hex_to_int(s[72:76])
  44     h['nonce'] = hex_to_int(s[76:80])
  45     return h
  46
  47
  48
  49
  50 from processor import Processor, print_log
  51
  52 class BlockchainProcessor(Processor):
  53
  54     def __init__(self, config, shared):
  55         Processor.__init__(self)
  56
  57         self.shared = shared
  58         self.up_to_date = False
  59         self.watched_addresses = []
  60         self.history_cache = {}
  61         self.chunk_cache = {}
  62         self.cache_lock = threading.Lock()
  63         self.headers_data = ''
  64
  65         self.mempool_addresses = {}
  66         self.mempool_hist = {}
  67         self.mempool_hashes = []
  68         self.mempool_lock = threading.Lock()
  69
  70         self.address_queue = Queue()
  71         self.dbpath = config.get('leveldb', 'path')
  72
  73         self.dblock = threading.Lock()
  74         try:
  75             self.db = leveldb.LevelDB(self.dbpath)
  76         except:
  77             traceback.print_exc(file=sys.stdout)
  78             self.shared.stop()
  79
  80         self.bitcoind_url = 'http://%s:%s@%s:%s/' % (
  81             config.get('bitcoind','user'),
  82             config.get('bitcoind','password'),
  83             config.get('bitcoind','host'),
  84             config.get('bitcoind','port'))
  85
  86         self.height = 0
  87         self.sent_height = 0
  88         self.sent_header = None
  89
  90
  91         try:
  92             hist = self.deserialize(self.db.Get('0'))
  93             hh, self.height, _ = hist[0]
  94             self.block_hashes = [hh]
  95             print_log( "hist", hist )
  96         except:
  97             #traceback.print_exc(file=sys.stdout)
  98             print_log('initializing database')
  99             self.height = 0
 100             self.block_hashes = [ '000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f' ]
 101
 102         # catch_up headers
 103         self.init_headers(self.height)
 104
 105         threading.Timer(0, lambda: self.catch_up(sync=False)).start()
 106         while not shared.stopped() and not self.up_to_date:
 107             try:
 108                 time.sleep(1)
 109             except:
 110                 print "keyboard interrupt: stopping threads"
 111                 shared.stop()
 112                 sys.exit(0)
 113
 114         print "blockchain is up to date."
 115
 116         threading.Timer(10, self.main_iteration).start()
 117
 118
 119
 120     def bitcoind(self, method, params=[]):
 121         postdata = dumps({"method": method, 'params': params, 'id':'jsonrpc'})
 122         respdata = urllib.urlopen(self.bitcoind_url, postdata).read()
 123         r = loads(respdata)
 124         if r['error'] != None:
 125             raise BaseException(r['error'])
 126         return r.get('result')
 127
 128
 129     def serialize(self, h):
 130         s = ''
 131         for txid, txpos, height in h:
 132             s += txid + int_to_hex(txpos, 4) + int_to_hex(height, 4)
 133         return s.decode('hex')
 134
 135
 136     def deserialize(self, s):
 137         h = []
 138         while s:
 139             txid = s[0:32].encode('hex')
 140             txpos = int( rev_hex( s[32:36].encode('hex') ), 16 )
 141             height = int( rev_hex( s[36:40].encode('hex') ), 16 )
 142             h.append( ( txid, txpos, height ) )
 143             s = s[40:]
 144         return h
 145
 146
 147     def block2header(self, b):
 148         return {"block_height":b.get('height'), "version":b.get('version'), "prev_block_hash":b.get('previousblockhash'),
 149                 "merkle_root":b.get('merkleroot'), "timestamp":b.get('time'), "bits":int(b.get('bits'),16), "nonce":b.get('nonce')}
 150
 151
 152     def get_header(self, height):
 153         block_hash = self.bitcoind('getblockhash', [height])
 154         b = self.bitcoind('getblock', [block_hash])
 155         return self.block2header(b)
 156
 157
 158     def init_headers(self, db_height):
 159         self.chunk_cache = {}
 160         self.headers_filename = os.path.join( self.dbpath, 'blockchain_headers')
 161
 162         height = 0
 163         if os.path.exists(self.headers_filename):
 164             height = os.path.getsize(self.headers_filename)/80
 165
 166         if height:
 167             prev_header = self.read_header(height -1)
 168             prev_hash = self.hash_header(prev_header)
 169         else:
 170             open(self.headers_filename,'wb').close()
 171             prev_hash = None
 172
 173         if height != db_height:
 174             print_log( "catching up missing headers:", height, db_height)
 175
 176         s = ''
 177         try:
 178             for i in range(height, db_height):
 179                 header = self.get_header(i)
 180                 assert prev_hash == header.get('prev_block_hash')
 181                 self.write_header(header, sync=False)
 182                 prev_hash = self.hash_header(header)
 183                 if i%1000==0: print_log("headers file:",i)
 184         except KeyboardInterrupt:
 185             self.flush_headers()
 186             sys.exit()
 187
 188         self.flush_headers()
 189
 190
 191     def hash_header(self, header):
 192         return rev_hex(Hash(header_to_string(header).decode('hex')).encode('hex'))
 193
 194
 195     def read_header(self, block_height):
 196         if os.path.exists(self.headers_filename):
 197             f = open(self.headers_filename,'rb')
 198             f.seek(block_height*80)
 199             h = f.read(80)
 200             f.close()
 201             if len(h) == 80:
 202                 h = header_from_string(h)
 203                 return h
 204
 205
 206     def read_chunk(self, index):
 207         f = open(self.headers_filename,'rb')
 208         f.seek(index*2016*80)
 209         chunk = f.read(2016*80)
 210         f.close()
 211         return chunk.encode('hex')
 212
 213
 214     def write_header(self, header, sync=True):
 215         if not self.headers_data:
 216             self.headers_offset = header.get('block_height')
 217         self.headers_data += header_to_string(header).decode('hex')
 218         if sync or len(self.headers_data) > 40*100:
 219             self.flush_headers()
 220
 221     def pop_header(self):
 222         # we need to do this only if we have not flushed
 223         if self.headers_data:
 224             self.headers_data = self.headers_data[:-40]
 225
 226     def flush_headers(self):
 227         if not self.headers_data: return
 228         f = open(self.headers_filename,'rb+')
 229         f.seek(self.headers_offset*80)
 230         f.write(self.headers_data)
 231         f.close()
 232         self.headers_data = ''
 233
 234
 235     def get_chunk(self, i):
 236         # store them on disk; store the current chunk in memory
 237         chunk = self.chunk_cache.get(i)
 238         if not chunk:
 239             chunk = self.read_chunk(i)
 240             self.chunk_cache[i] = chunk
 241         return chunk
 242
 243
 244     def get_transaction(self, txid, block_height=-1, is_coinbase = False):
 245         raw_tx = self.bitcoind('getrawtransaction', [txid, 0, block_height])
 246         vds = deserialize.BCDataStream()
 247         vds.write(raw_tx.decode('hex'))
 248         out = deserialize.parse_Transaction(vds, is_coinbase)
 249         return out
 250
 251
 252     def get_history(self, addr, cache_only=False):
 253         with self.cache_lock: hist = self.history_cache.get( addr )
 254         if hist is not None: return hist
 255         if cache_only: return -1
 256
 257         with self.dblock:
 258             try:
 259                 hist = self.deserialize(self.db.Get(addr))
 260                 is_known = True
 261             except:
 262                 hist = []
 263                 is_known = False
 264
 265         # should not be necessary
 266         hist.sort( key=lambda tup: tup[1])
 267         # check uniqueness too...
 268
 269         # add memory pool
 270         with self.mempool_lock:
 271             for txid in self.mempool_hist.get(addr,[]):
 272                 hist.append((txid, 0, 0))
 273
 274         hist = map(lambda x: {'tx_hash':x[0], 'height':x[2]}, hist)
 275         # add something to distinguish between unused and empty addresses
 276         if hist == [] and is_known: hist = ['*']
 277
 278         with self.cache_lock: self.history_cache[addr] = hist
 279         return hist
 280
 281
 282     def get_status(self, addr, cache_only=False):
 283         tx_points = self.get_history(addr, cache_only)
 284         if cache_only and tx_points == -1: return -1
 285
 286         if not tx_points: return None
 287         if tx_points == ['*']: return '*'
 288         status = ''
 289         for tx in tx_points:
 290             status += tx.get('tx_hash') + ':%d:' % tx.get('height')
 291         return hashlib.sha256( status ).digest().encode('hex')
 292
 293
 294     def get_merkle(self, tx_hash, height):
 295
 296         block_hash = self.bitcoind('getblockhash', [height])
 297         b = self.bitcoind('getblock', [block_hash])
 298         tx_list = b.get('tx')
 299         tx_pos = tx_list.index(tx_hash)
 300
 301         merkle = map(hash_decode, tx_list)
 302         target_hash = hash_decode(tx_hash)
 303         s = []
 304         while len(merkle) != 1:
 305             if len(merkle)%2: merkle.append( merkle[-1] )
 306             n = []
 307             while merkle:
 308                 new_hash = Hash( merkle[0] + merkle[1] )
 309                 if merkle[0] == target_hash:
 310                     s.append( hash_encode( merkle[1]))
 311                     target_hash = new_hash
 312                 elif merkle[1] == target_hash:
 313                     s.append( hash_encode( merkle[0]))
 314                     target_hash = new_hash
 315                 n.append( new_hash )
 316                 merkle = merkle[2:]
 317             merkle = n
 318
 319         return {"block_height":height, "merkle":s, "pos":tx_pos}
 320
 321
 322     def add_to_batch(self, addr, tx_hash, tx_pos, tx_height):
 323
 324         # we do it chronologically, so nothing wrong can happen...
 325         s = (tx_hash + int_to_hex(tx_pos, 4) + int_to_hex(tx_height, 4)).decode('hex')
 326         self.batch_list[addr] += s
 327
 328         # backlink
 329         txo = (tx_hash + int_to_hex(tx_pos, 4)).decode('hex')
 330         self.batch_txio[txo] = addr
 331
 332
 333     def remove_from_batch(self, tx_hash, tx_pos):
 334
 335         txi = (tx_hash + int_to_hex(tx_pos, 4)).decode('hex')
 336         try:
 337             addr = self.batch_txio[txi]
 338         except:
 339             #raise BaseException(tx_hash, tx_pos)
 340             print "WARNING: cannot find address for", (tx_hash, tx_pos)
 341             return
 342
 343         serialized_hist = self.batch_list[addr]
 344
 345         l = len(serialized_hist)/40
 346         for i in range(l):
 347             if serialized_hist[40*i:40*i+36] == txi:
 348                 serialized_hist = serialized_hist[0:40*i] + serialized_hist[40*(i+1):]
 349                 break
 350         else:
 351             raise BaseException("prevout not found", addr, hist, tx_hash, tx_pos)
 352         self.batch_list[addr] = serialized_hist
 353
 354
 355     def deserialize_block(self, block):
 356         txlist = block.get('tx')
 357         tx_hashes = []  # ordered txids
 358         txdict = {}     # deserialized tx
 359         is_coinbase = True
 360         for raw_tx in txlist:
 361             tx_hash = hash_encode(Hash(raw_tx.decode('hex')))
 362             tx_hashes.append(tx_hash)
 363             vds = deserialize.BCDataStream()
 364             vds.write(raw_tx.decode('hex'))
 365             tx = deserialize.parse_Transaction(vds, is_coinbase)
 366             txdict[tx_hash] = tx
 367             is_coinbase = False
 368         return tx_hashes, txdict
 369
 370
 371     def import_block(self, block, block_hash, block_height, sync, revert=False):
 372
 373         self.batch_list = {}  # address -> history
 374         self.batch_txio = {}  # transaction i/o -> address
 375
 376         inputs_to_read = []
 377         addr_to_read = []
 378
 379         # deserialize transactions
 380         t0 = time.time()
 381         tx_hashes, txdict = self.deserialize_block(block)
 382
 383         # read addresses of tx inputs
 384         t00 = time.time()
 385         for tx in txdict.values():
 386             for x in tx.get('inputs'):
 387                 txi = (x.get('prevout_hash') + int_to_hex(x.get('prevout_n'), 4)).decode('hex')
 388                 inputs_to_read.append(txi)
 389
 390         inputs_to_read.sort()
 391         for txi in inputs_to_read:
 392             try:
 393                 addr = self.db.Get(txi)
 394             except:
 395                 # the input could come from the same block
 396                 continue
 397             self.batch_txio[txi] = addr
 398             addr_to_read.append(addr)
 399
 400         # read histories of addresses
 401         for txid, tx in txdict.items():
 402             for x in tx.get('outputs'):
 403                 addr_to_read.append(x.get('address'))
 404
 405         addr_to_read.sort()
 406         for addr in addr_to_read:
 407             try:
 408                 self.batch_list[addr] = self.db.Get(addr)
 409             except:
 410                 self.batch_list[addr] = ''
 411
 412         # process
 413         t1 = time.time()
 414
 415         for txid in tx_hashes: # must be ordered
 416             tx = txdict[txid]
 417             if not revert:
 418                 for x in tx.get('inputs'):
 419                     self.remove_from_batch( x.get('prevout_hash'), x.get('prevout_n'))
 420                 for x in tx.get('outputs'):
 421                     self.add_to_batch( x.get('address'), txid, x.get('index'), block_height)
 422             else:
 423                 for x in tx.get('outputs'):
 424                     self.remove_from_batch( x.get('prevout_hash'), x.get('prevout_n'))
 425                 for x in tx.get('inputs'):
 426                     self.add_to_batch( x.get('address'), txid, x.get('index'), block_height)
 427
 428         # write
 429         max_len = 0
 430         max_addr = ''
 431         t2 = time.time()
 432
 433         batch = leveldb.WriteBatch()
 434         for addr, serialized_hist in self.batch_list.items():
 435             batch.Put(addr, serialized_hist)
 436             l = len(serialized_hist)
 437             if l > max_len:
 438                 max_len = l
 439                 max_addr = addr
 440
 441         for txio, addr in self.batch_txio.items():
 442             batch.Put(txio, addr)
 443         # delete spent inputs
 444         for txi in inputs_to_read:
 445             batch.Delete(txi)
 446         batch.Put('0', self.serialize( [(block_hash, block_height, 0)] ) )
 447
 448         # actual write
 449         self.db.Write(batch, sync = sync)
 450
 451         t3 = time.time()
 452         if t3 - t0 > 10:
 453             print_log("block", block_height,
 454                       "parse:%0.2f "%(t00 - t0),
 455                       "read:%0.2f "%(t1 - t00),
 456                       "proc:%.2f "%(t2-t1),
 457                       "write:%.2f "%(t3-t2),
 458                       "max:", max_len, max_addr)
 459
 460         for addr in self.batch_list.keys(): self.invalidate_cache(addr)
 461
 462
 463
 464     def add_request(self, request):
 465         # see if we can get if from cache. if not, add to queue
 466         if self.process( request, cache_only = True) == -1:
 467             self.queue.put(request)
 468
 469
 470
 471     def process(self, request, cache_only = False):
 472         #print "abe process", request
 473
 474         message_id = request['id']
 475         method = request['method']
 476         params = request.get('params',[])
 477         result = None
 478         error = None
 479
 480         if method == 'blockchain.numblocks.subscribe':
 481             result = self.height
 482
 483         elif method == 'blockchain.headers.subscribe':
 484             result = self.header
 485
 486         elif method == 'blockchain.address.subscribe':
 487             try:
 488                 address = params[0]
 489                 result = self.get_status(address, cache_only)
 490                 self.watch_address(address)
 491             except BaseException, e:
 492                 error = str(e) + ': ' + address
 493                 print_log( "error:", error )
 494
 495         elif method == 'blockchain.address.subscribe2':
 496             try:
 497                 address = params[0]
 498                 result = self.get_status(address, cache_only)
 499                 self.watch_address(address)
 500             except BaseException, e:
 501                 error = str(e) + ': ' + address
 502                 print_log( "error:", error )
 503
 504         elif method == 'blockchain.address.get_history2':
 505             try:
 506                 address = params[0]
 507                 result = self.get_history( address, cache_only )
 508             except BaseException, e:
 509                 error = str(e) + ': ' + address
 510                 print_log( "error:", error )
 511
 512         elif method == 'blockchain.block.get_header':
 513             if cache_only:
 514                 result = -1
 515             else:
 516                 try:
 517                     height = params[0]
 518                     result = self.get_header( height )
 519                 except BaseException, e:
 520                     error = str(e) + ': %d'% height
 521                     print_log( "error:", error )
 522
 523         elif method == 'blockchain.block.get_chunk':
 524             if cache_only:
 525                 result = -1
 526             else:
 527                 try:
 528                     index = params[0]
 529                     result = self.get_chunk( index )
 530                 except BaseException, e:
 531                     error = str(e) + ': %d'% index
 532                     print_log( "error:", error)
 533
 534         elif method == 'blockchain.transaction.broadcast':
 535             txo = self.bitcoind('sendrawtransaction', params)
 536             print_log( "sent tx:", txo )
 537             result = txo
 538
 539         elif method == 'blockchain.transaction.get_merkle':
 540             if cache_only:
 541                 result = -1
 542             else:
 543                 try:
 544                     tx_hash = params[0]
 545                     tx_height = params[1]
 546                     result = self.get_merkle(tx_hash, tx_height)
 547                 except BaseException, e:
 548                     error = str(e) + ': ' + tx_hash
 549                     print_log( "error:", error )
 550
 551         elif method == 'blockchain.transaction.get':
 552             try:
 553                 tx_hash = params[0]
 554                 height = params[1]
 555                 result = self.bitcoind('getrawtransaction', [tx_hash, 0, height] )
 556             except BaseException, e:
 557                 error = str(e) + ': ' + tx_hash
 558                 print_log( "error:", error )
 559
 560         else:
 561             error = "unknown method:%s"%method
 562
 563         if cache_only and result == -1: return -1
 564
 565         if error:
 566             response = { 'id':message_id, 'error':error }
 567             self.push_response(response)
 568         elif result != '':
 569             response = { 'id':message_id, 'result':result }
 570             self.push_response(response)
 571
 572
 573     def watch_address(self, addr):
 574         if addr not in self.watched_addresses:
 575             self.watched_addresses.append(addr)
 576
 577
 578
 579     def last_hash(self):
 580         return self.block_hashes[-1]
 581
 582
 583     def catch_up(self, sync = True):
 584         t1 = time.time()
 585
 586         while not self.shared.stopped():
 587
 588             # are we done yet?
 589             info = self.bitcoind('getinfo')
 590             bitcoind_height = info.get('blocks')
 591             bitcoind_block_hash = self.bitcoind('getblockhash', [bitcoind_height])
 592             if self.last_hash() == bitcoind_block_hash:
 593                 self.up_to_date = True
 594                 break
 595
 596             # not done..
 597             self.up_to_date = False
 598             block_hash = self.bitcoind('getblockhash', [self.height+1])
 599             block = self.bitcoind('getblock', [block_hash, 1])
 600
 601             if block.get('previousblockhash') == self.last_hash():
 602
 603                 self.import_block(block, block_hash, self.height+1, sync)
 604                 self.height = self.height + 1
 605                 self.write_header(self.block2header(block), sync)
 606
 607                 self.block_hashes.append(block_hash)
 608                 self.block_hashes = self.block_hashes[-10:]
 609
 610                 if (self.height+1)%100 == 0 and not sync:
 611                     t2 = time.time()
 612                     print_log( "catch_up: block %d (%.3fs)"%( self.height, t2 - t1 ) )
 613                     t1 = t2
 614
 615
 616             else:
 617                 # revert current block
 618                 print_log( "bc2: reorg", self.height, block.get('previousblockhash'), self.last_hash() )
 619                 block_hash = self.last_hash()
 620                 block = self.bitcoind('getblock', [block_hash, 1])
 621                 self.height = self.height -1
 622                 self.pop_header()
 623
 624                 self.block_hashes.remove(block_hash)
 625                 self.import_block(block, self.last_hash(), self.height, revert=True)
 626
 627
 628         self.header = self.block2header(self.bitcoind('getblock', [self.last_hash()]))
 629
 630
 631
 632
 633     def memorypool_update(self):
 634
 635         mempool_hashes = self.bitcoind('getrawmempool')
 636
 637         for tx_hash in mempool_hashes:
 638             if tx_hash in self.mempool_hashes: continue
 639
 640             tx = self.get_transaction(tx_hash)
 641             if not tx: continue
 642
 643             for x in tx.get('inputs'):
 644                 txi = (x.get('prevout_hash') + int_to_hex(x.get('prevout_n'), 4)).decode('hex')
 645                 try:
 646                     addr = self.db.Get(txi)
 647                 except:
 648                     continue
 649                 l = self.mempool_addresses.get(tx_hash, [])
 650                 if addr not in l:
 651                     l.append( addr )
 652                     self.mempool_addresses[tx_hash] = l
 653
 654             for x in tx.get('outputs'):
 655                 addr = x.get('address')
 656                 l = self.mempool_addresses.get(tx_hash, [])
 657                 if addr not in l:
 658                     l.append( addr )
 659                     self.mempool_addresses[tx_hash] = l
 660
 661             self.mempool_hashes.append(tx_hash)
 662
 663         # remove older entries from mempool_hashes
 664         self.mempool_hashes = mempool_hashes
 665
 666         # remove deprecated entries from mempool_addresses
 667         for tx_hash, addresses in self.mempool_addresses.items():
 668             if tx_hash not in self.mempool_hashes:
 669                 self.mempool_addresses.pop(tx_hash)
 670
 671         # rebuild histories
 672         with self.mempool_lock:
 673             self.mempool_hist = {}
 674             for tx_hash, addresses in self.mempool_addresses.items():
 675                 for addr in addresses:
 676                     h = self.mempool_hist.get(addr, [])
 677                     if tx_hash not in h:
 678                         h.append( tx_hash )
 679                         self.mempool_hist[addr] = h
 680                         self.invalidate_cache(addr)
 681
 682
 683
 684
 685     def invalidate_cache(self, address):
 686         with self.cache_lock:
 687             if self.history_cache.has_key(address):
 688                 print_log( "cache: invalidating", address )
 689                 self.history_cache.pop(address)
 690
 691
 692
 693     def main_iteration(self):
 694
 695         if self.shared.stopped():
 696             print_log( "blockchain processor terminating" )
 697             return
 698
 699         with self.dblock:
 700             t1 = time.time()
 701             self.catch_up()
 702             t2 = time.time()
 703
 704         self.memorypool_update()
 705         t3 = time.time()
 706         # print "mempool:", len(self.mempool_addresses), len(self.mempool_hist), "%.3fs"%(t3 - t2)
 707
 708
 709         if self.sent_height != self.height:
 710             self.sent_height = self.height
 711             self.push_response({ 'id': None, 'method':'blockchain.numblocks.subscribe', 'params':[self.height] })
 712
 713         if self.sent_header != self.header:
 714             print_log( "blockchain: %d (%.3fs)"%( self.height, t2 - t1 ) )
 715             self.sent_header = self.header
 716             self.push_response({ 'id': None, 'method':'blockchain.headers.subscribe', 'params':[self.header] })
 717
 718         while True:
 719             try:
 720                 addr = self.address_queue.get(False)
 721             except:
 722                 break
 723             if addr in self.watched_addresses:
 724                 status = self.get_status( addr )
 725                 self.push_response({ 'id': None, 'method':'blockchain.address.subscribe', 'params':[addr, status] })
 726
 727
 728         if not self.shared.stopped():
 729             threading.Timer(10, self.main_iteration).start()
 730         else:
 731             print_log( "blockchain processor terminating" )
 732
 733
 734
 735