75 lines
2.5 KiB
Python
75 lines
2.5 KiB
Python
# standard imports
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import logging
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# third-party imports
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from web3.exceptions import BlockNotFound
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from .error import LoopDone
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# local imports
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from .mined import MinedSyncer
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from .base import Syncer
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from cic_eth.db.models.base import SessionBase
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logg = logging.getLogger()
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class HistorySyncer(MinedSyncer):
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"""Implements the get method in Syncer for retrieving all blocks between last processed block before previous shutdown and block height at time of syncer start.
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:param bc_cache: Retrieves block cache cursors for chain head and latest processed block.
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:type bc_cache: Object implementing methods from cic_eth.sync.SyncerBackend
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:param mx: Maximum number of blocks to return in one call
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:type mx: int
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"""
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def __init__(self, bc_cache, mx=20):
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super(HistorySyncer, self).__init__(bc_cache)
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self.max = mx
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self.target = bc_cache.target()
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logg.info('History syncer target block number {}'.format(self.target))
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session_offset = self.bc_cache.get()
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self.block_offset = session_offset[0]
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self.tx_offset = session_offset[1]
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logg.info('History syncer starting at {}:{}'.format(session_offset[0], session_offset[1]))
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self.filter = []
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"""Implements Syncer.get
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BUG: Should also raise LoopDone when block array is empty after loop.
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:param w3: Web3 object
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:type w3: web3.Web3
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:raises LoopDone: If a block is not found.
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:return: Return a batch of blocks to process
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:rtype: list of str, 0x-hex
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"""
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def get(self, w3):
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sync_db = self.bc_cache
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height = self.bc_cache.get()
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logg.debug('height {}'.format(height))
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block_last = height[0]
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tx_last = height[1]
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if not self.running:
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raise LoopDone((block_last, tx_last))
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b = []
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block_target = block_last + self.max
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if block_target > self.target:
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block_target = self.target
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logg.debug('target {} last {} max {}'.format(block_target, block_last, self.max))
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for i in range(block_last, block_target):
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if i == self.target:
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logg.info('reached target {}, exiting'.format(i))
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self.running = False
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break
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bhash = w3.eth.getBlock(i).hash
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b.append(bhash)
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logg.debug('appending block {} {}'.format(i, bhash.hex()))
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if block_last == block_target:
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logg.info('aleady reached target {}, exiting'.format(self.target))
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self.running = False
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return b
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