Make start chunk size optional and default to min chunk size unless s…

…pecified otherwise. Having 20 as the default negates the initial use of min chunk size which seems like a waste. I can see a potential usage for not wanting to use the min chunk size for a specific case of scanning a large number of blocks but seems unnecessary otherwise.

nucypher/utilities/events.py

@@ -301,14 +301,16 @@ def estimate_next_chunk_size(self, current_chunk_size: int, event_found_count: i
  current_chunk_size = min(self.max_scan_chunk_size, current_chunk_size)
  return int(current_chunk_size)
 
- def scan(self, start_block, end_block, start_chunk_size=20) -> Tuple[list, int]:
+ def scan(
+ self, start_block, end_block, start_chunk_size: Optional[int] = None
+ ) -> Tuple[list, int]:
  """Perform a scan for events.
 
  :param start_block: The first block included in the scan
 
  :param end_block: The last block included in the scan
 
- :param start_chunk_size: How many blocks we try to fetch over JSON-RPC on the first attempt
+ :param start_chunk_size: How many blocks we try to fetch over JSON-RPC on the first attempt; min chunk size if not specified
 
  :return: [All processed events, number of chunks used]
  """
@@ -321,7 +323,7 @@ def scan(self, start_block, end_block, start_chunk_size=20) -> Tuple[list, int]:
  current_block = start_block
 
  # Scan in chunks, commit between
- chunk_size = start_chunk_size
+ chunk_size = start_chunk_size or self.min_scan_chunk_size
  last_scan_duration = last_logs_found = 0
  total_chunks_scanned = 0
 

tests/unit/test_event_scanner.py

@@ -163,9 +163,7 @@ def test_scan_when_events_always_found(chunk_size):
  scanner, start_block, end_block
  )
 
- all_processed, total_chunks_scanned = scanner.scan(
- start_block, end_block, start_chunk_size=chunk_size
- )
+ all_processed, total_chunks_scanned = scanner.scan(start_block, end_block)
  assert total_chunks_scanned == len(expected_calls)
  assert scanner.scan_chunk_calls_made == expected_calls
  assert scanner.get_last_scanned_block() == end_block
@@ -197,9 +195,7 @@ def test_scan_when_events_never_found(chunk_size):
  scanner, start_block, end_block
  )
 
- all_processed, total_chunks_scanned = scanner.scan(
- start_block, end_block, start_chunk_size=chunk_size
- )
+ all_processed, total_chunks_scanned = scanner.scan(start_block, end_block)
 
  assert total_chunks_scanned == len(expected_calls)
  assert len(all_processed) == 0 # no events processed
@@ -239,9 +235,7 @@ def test_scan_when_events_never_found_super_large_chunk_sizes():
  scanner, start_block, end_block
  )
 
- all_processed, total_chunks_scanned = scanner.scan(
- start_block, end_block, start_chunk_size=min_chunk_size
- )
+ all_processed, total_chunks_scanned = scanner.scan(start_block, end_block)
 
  assert total_chunks_scanned == len(expected_calls)
  assert len(all_processed) == 0 # no events processed