JSONRPCReorganisationMonitor
Documentation for eth_defi.event_reader.reorganisation_monitor.JSONRPCReorganisationMonitor Python class.
- class JSONRPCReorganisationMonitor
Bases:
eth_defi.event_reader.reorganisation_monitor.ReorganisationMonitorWatch blockchain for reorgs using eth_getBlockByNumber JSON-RPC API.
Use expensive eth_getBlockByNumber call to download block hash and timestamp from Ethereum compatible node
Attributes summary
check_depthHow many blocks we replay from the blockchain to detect any chain organisations
last_block_readLast block served by
update_chain()in the duty cyclemax_cycle_triesHow many times we try to re-read data from the blockchain in the case of reorganisation.
reorg_wait_secondsHow long we allow our node to catch up in the case there has been a change in the chain tip.
Methods summary
__init__(web3, **kwargs)add_block(record)Add new block to header tracking.
check_block_reorg(block_number, block_hash)Check that newly read block matches our record.
fetch_block_data(start_block, end_block)Read the new block headers.
figure_reorganisation_and_new_blocks([max_range])Compare the local block database against the live data from chain.
get_block_by_number(block_number)Get block header data for a specific block number from our memory buffer.
get_block_timestamp(block_number)Return UNIX UTC timestamp of a block.
get_block_timestamp_as_pandas(block_number)Return UNIX UTC timestamp of a block.
Get last block number
Get the number of the last block served by update_chain().
has_data()Do we have any data available yet.
load_initial_block_headers([block_count, ...])Get the initial block buffer filled up.
load_pandas(df)Load block header data from Pandas data frame.
restore(block_map)Restore the chain state from a saved data.
skip_to_block(block_number)Skip scanning initial chain and directly start from a certain block.
to_pandas([partition_size])Convert the data to Pandas DataFrame format for storing.
truncate(latest_good_block)Delete data after a block number because chain reorg happened.
Update the internal memory buffer of block headers from the blockchain node.
- __init__(web3, **kwargs)
- Parameters
web3 (web3.main.Web3) –
- get_last_block_live()
Get last block number
- fetch_block_data(start_block, end_block)
Read the new block headers.
- Parameters
start_block – The first block where to read (inclusive)
end_block – The block where to read (inclusive)
- Return type
- add_block(record)
Add new block to header tracking.
Blocks must be added in order.
- Parameters
- check_block_reorg(block_number, block_hash)
Check that newly read block matches our record.
Called during the event reader
Event reader gets the block number and hash with the event
We have initial block_map in memory, previously buffered in
We check if any of the blocks in the block map have different values on our event produces -> in this case we know there has been a chain reorganisation
If we do not have records, ignore.
- Raises
ChainReorganisationDetected – When any if the block data in our internal buffer does not match those provided by events.
- Parameters
- Return type
- figure_reorganisation_and_new_blocks(max_range=1000000)
Compare the local block database against the live data from chain.
Spot the differences in (block number, block header) tuples and determine a chain reorg.
- Parameters
Abort if we need to scan more than this amount of blocks.
This is because giving too long block range to scan is likely to take forever on non-graphql nodes.
Set None to ignore.
- Raises
ChainReorganisationDetected – When any if the block data in our internal buffer does not match those provided by events.
- get_block_by_number(block_number)
Get block header data for a specific block number from our memory buffer.
- Parameters
block_number (int) –
- Return type
- get_block_timestamp(block_number)
Return UNIX UTC timestamp of a block.
- get_block_timestamp_as_pandas(block_number)
Return UNIX UTC timestamp of a block.
- Parameters
block_number (int) –
- Return type
- get_last_block_read()
Get the number of the last block served by update_chain().
- Return type
- has_data()
Do we have any data available yet.
- Return type
- load_initial_block_headers(block_count=None, start_block=None, tqdm=None, save_callable=None)
Get the initial block buffer filled up.
You can call this during the application start up, or when you start the chain. This interface is designed to keep the application on hold until new blocks have been served.
- Parameters
How many latest block to load
Give start_block or block_count.
What is the first block to read.
Give start_block or block_count.
tqdm (Optional[Type[tqdm.std.tqdm]]) – To display a progress bar
save_callable (Optional[Callable]) –
Save after every block.
Called after every block.
TODO: Hack. Design a better interface.
- Returns
The initial block range to start to work with
- Return type
- load_pandas(df)
Load block header data from Pandas data frame.
- Parameters
df (pandas.DataFrame) – Pandas DataFrame exported with
to_pandas().
- restore(block_map)
Restore the chain state from a saved data.
- Parameters
block_map (dict) – Block number -> Block header dictionary
- skip_to_block(block_number)
Skip scanning initial chain and directly start from a certain block.
- Parameters
block_number (int) –
- to_pandas(partition_size=0)
Convert the data to Pandas DataFrame format for storing.
- Parameters
partition_size (int) –
To partition the outgoing data.
Set 0 to ignore.
- Return type
- truncate(latest_good_block)
Delete data after a block number because chain reorg happened.
- Parameters
latest_good_block (int) – Delete all data starting after this block (exclusive)
- update_chain()
Update the internal memory buffer of block headers from the blockchain node.
Do several attempt to read data (as a fork can cause other forks can cause fork)
Give up after some time if we detect the chain to be in a doom loop
- Returns
What block range the consumer application should read.
What we think about the chain state.
- Return type
eth_defi.event_reader.reorganisation_monitor.ChainReorganisationResolution