Handle the inlcusive block range when filtering events.

nucypher/blockchain/eth/events.py

@@ -95,7 +95,7 @@ class ContractEventsThrottler:
                  **argument_filters):
         self.event_filter = agent.events[event_name]
         self.from_block = from_block
-        self.to_block = to_block if to_block else agent.blockchain.client.block_number
+        self.to_block = to_block if to_block is not None else agent.blockchain.client.block_number
         # validity check of block range
         if self.to_block < self.from_block:
             raise ValueError(f"Invalid events block range: to_block {self.to_block} must be greater than or equal "
@@ -107,12 +107,13 @@ class ContractEventsThrottler:
     def __iter__(self):
         current_from_block = self.from_block
         current_to_block = min(self.from_block + self.max_blocks_per_call, self.to_block)
-        while current_from_block < current_to_block:
+        while current_from_block <= current_to_block:
             for event_record in self.event_filter(from_block=current_from_block,
                                                   to_block=current_to_block,
                                                   **self.argument_filters):
                 yield event_record
-            current_from_block = current_to_block
+            # previous block range is inclusive hence the increment
+            current_from_block = current_to_block + 1
             # update the 'to block' to the lesser of either the next `max_blocks_per_call` blocks,
             # or the remainder of blocks
             current_to_block = min(current_from_block + self.max_blocks_per_call, self.to_block)

nucypher/utilities/prometheus/collector.py

@@ -299,7 +299,7 @@ class EventMetricsCollector(BaseMetricsCollector):
         self.contract_agent = contract_agent
 
         # this way we don't have to deal with 'latest' at all
-        self.filter_last_block_checked = self.contract_agent.blockchain.client.block_number
+        self.filter_current_from_block = self.contract_agent.blockchain.client.block_number
         self.filter_arguments = argument_filters
         self.event_args_config = event_args_config
 
@@ -311,9 +311,10 @@ class EventMetricsCollector(BaseMetricsCollector):
             self.metrics[metric_key] = metric_class(metric_name, metric_doc, registry=registry)
 
     def _collect_internal(self) -> None:
-        from_block = self.filter_last_block_checked
+        from_block = self.filter_current_from_block
         to_block = self.contract_agent.blockchain.client.block_number
-        if from_block == to_block:
+        if from_block >= to_block:
+            # we've already checked the latest block and waiting for a new block
             # nothing to see here
             return
 
@@ -325,8 +326,8 @@ class EventMetricsCollector(BaseMetricsCollector):
         for event_record in events_throttler:
             self._event_occurred(event_record.raw_event)
 
-        # update last block for the next round
-        self.filter_last_block_checked = to_block
+        # update last block checked for the next round - from/to block range is inclusive
+        self.filter_current_from_block = to_block + 1
 
     def _event_occurred(self, event) -> None:
         for arg_name in self.event_args_config:
@@ -374,6 +375,10 @@ class CommitmentMadeEventMetricsCollector(EventMetricsCollector):
             for event_record in events_throttler:
                 self._event_occurred(event_record.raw_event)
 
+            # update last block checked since we just looked for this event up to and including latest block
+            # block range is inclusive, hence the increment
+            self.filter_current_from_block = latest_block + 1
+
 
 class ReStakeEventMetricsCollector(EventMetricsCollector):
     """Collector for RestakeSet event."""

tests/unit/test_blockchain_events.py

@@ -0,0 +1,118 @@
+"""
+ This file is part of nucypher.
+
+ nucypher is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ nucypher is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with nucypher.  If not, see <https://www.gnu.org/licenses/>.
+"""
+
+from unittest.mock import Mock, MagicMock
+
+import pytest
+
+from nucypher.blockchain.eth.events import ContractEventsThrottler
+
+
+def test_contract_events_throttler_to_block_check():
+    event_name = 'TestEvent'
+    latest_block = 50
+    blockchain = MagicMock()
+    blockchain.client.block_number = latest_block
+    agent = Mock(events={event_name: Mock(return_value=[])}, blockchain=blockchain)
+
+    # from_block < to_block
+    throttler = ContractEventsThrottler(agent=agent, event_name=event_name, from_block=1, to_block=10)
+    assert throttler.from_block == 1
+    assert throttler.to_block == 10
+
+    # to_block < from_block
+    with pytest.raises(ValueError):
+        ContractEventsThrottler(agent=agent, event_name=event_name, from_block=10, to_block=8)
+
+    # to_block can be equal to from_block
+    throttler = ContractEventsThrottler(agent=agent, event_name=event_name, from_block=10, to_block=10)
+    assert throttler.from_block == 10
+    assert throttler.to_block == 10
+
+    # from_block and to_block value of zero allowed
+    throttler = ContractEventsThrottler(agent=agent, event_name=event_name, from_block=0, to_block=0)
+    assert throttler.from_block == 0
+    assert throttler.to_block == 0
+
+    #
+    # when to_block is not specified it defaults to latest block number
+    #
+
+    # latest block is lower than from_block
+    with pytest.raises(ValueError):
+        ContractEventsThrottler(agent=agent, event_name=event_name, from_block=latest_block + 1)
+
+    # latest block is equal to from_block
+    throttler = ContractEventsThrottler(agent=agent, event_name=event_name, from_block=latest_block)
+    assert throttler.from_block == latest_block
+    assert throttler.to_block == latest_block
+
+
+def test_contract_events_throttler_inclusive_block_ranges():
+    event_name = 'TestEvent'
+
+    #
+    # 1 block at a time
+    #
+    mock_method = Mock(return_value=[])
+    agent = Mock(events={event_name: mock_method})
+    events_throttler = ContractEventsThrottler(
+        agent=agent,
+        event_name=event_name,
+        from_block=0,
+        to_block=10,
+        max_blocks_per_call=1
+    )
+
+    for _ in events_throttler:
+        pass
+
+    # check calls to filter
+    # ranges used = (0, 1), (2, 3), (4, 5), (6, 7), (8, 9), (10, 10)
+    assert mock_method.call_count == 6
+    mock_method.assert_any_call(from_block=0, to_block=1)
+    mock_method.assert_any_call(from_block=2, to_block=3)
+    mock_method.assert_any_call(from_block=4, to_block=5)
+    mock_method.assert_any_call(from_block=6, to_block=7)
+    mock_method.assert_any_call(from_block=8, to_block=9)
+    mock_method.assert_any_call(from_block=10, to_block=10)
+
+    #
+    # 5 blocks at a time
+    #
+    mock_method = Mock(return_value=[])
+    agent = Mock(events={event_name: mock_method})
+    argument_filters = {'address': '0xdeadbeef'}
+    events_throttler = ContractEventsThrottler(
+        agent=agent,
+        event_name=event_name,
+        from_block=0,
+        to_block=21,
+        max_blocks_per_call=5,
+        **argument_filters
+    )
+
+    for _ in events_throttler:
+        pass
+
+    # check calls to filter
+    # ranges used = (0, 5), (6, 11), (12, 17) (18, 21)
+    assert mock_method.call_count == 4
+    mock_method.assert_any_call(**argument_filters, from_block=0, to_block=5)
+    mock_method.assert_any_call(**argument_filters, from_block=6, to_block=11)
+    mock_method.assert_any_call(**argument_filters, from_block=12, to_block=17)
+    mock_method.assert_any_call(**argument_filters, from_block=18, to_block=21)