Adjust start_sync_block to receive all the events

[loredanacirstea]

Currently, when trying to get all events fromBlock, some of them are missing and you need to set fromBlock = block_number - delta. We need to find a small enough delta in order to receive all the events, but big enough to work with warped chains.

Error example:

DEBUG:channel_manager:setting up channel manager, receiver=0xbB5AEb01acF5b75bc36eC01f5137Dd2728FbE983 channel_contract=0x74434527b8E6C8296506D61d0faF3D18c9e4649A 
INFO:blockchain:starting blockchain polling (interval 2s) 
DEBUG:blockchain:filtering for events u:2507630-2545243 c:2507630-2545242 @2545243 
DEBUG:blockchain:received unconfirmed ChannelCreated event (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2507921) 
INFO:channel_manager:unconfirmed channel event received (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block_number 2507921) 
DEBUG:blockchain:received unconfirmed ChannelCreated event (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2507952) 
INFO:channel_manager:unconfirmed channel event received (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block_number 2507952) 
DEBUG:blockchain:received unconfirmed ChannelCreated event (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2508285) 
INFO:channel_manager:unconfirmed channel event received (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block_number 2508285) 
DEBUG:blockchain:received unconfirmed ChannelCreated event (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2508297) 
INFO:channel_manager:unconfirmed channel event received (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block_number 2508297) 
DEBUG:blockchain:received unconfirmed ChannelCreated event (sender 0xbB5AEb01acF5b75bc36eC01f5137Dd2728FbE983, block number 2509129) 
INFO:channel_manager:unconfirmed channel event received (sender 0xbB5AEb01acF5b75bc36eC01f5137Dd2728FbE983, block_number 2509129) 
DEBUG:blockchain:received ChannelOpened event (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2507921) 
INFO:channel_manager:new channel opened (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2507921) 
DEBUG:blockchain:received ChannelOpened event (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2507952) 
INFO:channel_manager:new channel opened (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2507952) 
DEBUG:blockchain:received ChannelOpened event (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2508285) 
INFO:channel_manager:new channel opened (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2508285) 
DEBUG:blockchain:received ChannelOpened event (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2508297) 
INFO:channel_manager:new channel opened (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2508297) 
DEBUG:blockchain:received ChannelOpened event (sender 0xbB5AEb01acF5b75bc36eC01f5137Dd2728FbE983, block number 2509129) 
INFO:channel_manager:new channel opened (sender 0xbB5AEb01acF5b75bc36eC01f5137Dd2728FbE983, block number 2509129) 
DEBUG:blockchain:received top up event (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2508297, deposit 3000000000000000000) 
INFO:channel_manager:Registering unconfirmed deposit top up (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2508297, added 3000000000000000000) 
DEBUG:blockchain:received top up event (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2508297, added deposit 3000000000000000000) 
INFO:channel_manager:Registering deposit top up (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2508297, added deposit 3000000000000000000) 
DEBUG:blockchain:received ChannelSettled event (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2507900) 
INFO:channel_manager:Forgetting settled channel (sender 0x103eddCA006c3776Fc1a9eD5D26aA5b96f206b6E, block number 2507900) 
Traceback (most recent call last):
  File "/Users/loredana/ETH/kondron/env/lib/python3.6/site-packages/gevent/greenlet.py", line 536, in run
    result = self._run(*self.args, **self.kwargs)
  File "/Users/loredana/ETH/kondron/env/lib/python3.6/site-packages/microraiden/channel_manager/blockchain.py", line 54, in _run
    self._update()
  File "/Users/loredana/ETH/kondron/env/lib/python3.6/site-packages/microraiden/channel_manager/blockchain.py", line 233, in _update
    self.cm.event_channel_settled(sender, open_block_number)
  File "/Users/loredana/ETH/kondron/env/lib/python3.6/site-packages/microraiden/channel_manager/manager.py", line 202, in event_channel_settled
    self.state.del_channel(sender, open_block_number)
  File "/Users/loredana/ETH/kondron/env/lib/python3.6/site-packages/microraiden/channel_manager/state.py", line 363, in del_channel
    assert self.channel_exists(sender, open_block_number)
AssertionError
Mon Jan 29 13:12:51 2018 <Blockchain at 0x10b031af8> failed with AssertionError

[LefterisJP]

As discussed this really sounds like a geth bug. It really should be reported upstream.