Reversed event stream

backend/moonstreamapi/data.py

@@ -1,13 +1,12 @@
 """
 Pydantic schemas for the Moonstream HTTP API
 """
+from datetime import datetime
 from enum import Enum
-from typing import List, Optional, Dict, Any, Union
+from typing import Any, Dict, List, Optional, Union
 from uuid import UUID
 
-
 from pydantic import BaseModel, Field
-from datetime import datetime
 
 USER_ONBOARDING_STATE = "onboarding_state"
 
@@ -154,6 +153,7 @@ class StreamBoundary(BaseModel):
     end_time: Optional[int] = None
     include_start: bool = False
     include_end: bool = False
+    reversed_time: bool = False
 
 
 class Event(BaseModel):

backend/moonstreamapi/providers/__init__.py

@@ -24,17 +24,17 @@ if the order does not matter and you would rather emphasize speed. Only availabl
 lists of events. (Default: True)
 """
 
-from concurrent.futures import Future, ThreadPoolExecutor
 import logging
+from concurrent.futures import Future, ThreadPoolExecutor
 from typing import Any, Dict, List, Optional, Tuple
 
 from bugout.app import Bugout
 from bugout.data import BugoutResource
 from sqlalchemy.orm import Session
 
-from . import bugout, ethereum_blockchain
 from .. import data
 from ..stream_queries import StreamQuery
+from . import bugout, ethereum_blockchain
 
 logger = logging.getLogger(__name__)
 logger.setLevel(logging.WARN)
@@ -107,9 +107,15 @@ def get_events(
             else:
                 raise ReceivingEventsException(e)
 
+    stream_boundary = [boundary for boundary, _ in results.values()][0]
     events = [event for _, event_list in results.values() for event in event_list]
     if sort_events:
-        events.sort(key=lambda event: event.event_timestamp, reverse=True)
+        # If stream_boundary time was reversed, so do not reverse by timestamp,
+        # it is already in correct oreder
+        events.sort(
+            key=lambda event: event.event_timestamp,
+            reverse=not stream_boundary.reversed_time,
+        )
 
     return (stream_boundary, events)
 

backend/moonstreamapi/providers/ethereum_blockchain.py

@@ -1,25 +1,18 @@
-from dataclasses import dataclass, field
 import logging
-from typing import cast, Dict, Any, List, Optional, Tuple
+from dataclasses import dataclass, field
+from typing import Any, Dict, List, Optional, Tuple, cast
 
 from bugout.app import Bugout
 from bugout.data import BugoutResource
-
+from moonstreamdb.models import EthereumBlock, EthereumLabel, EthereumTransaction
-from moonstreamdb.models import (
+from sqlalchemy import and_, or_, text
-    EthereumBlock,
+from sqlalchemy.orm import Query, Session
-    EthereumTransaction,
-    EthereumLabel,
-)
-from sqlalchemy import or_, and_, text
-from sqlalchemy.orm import Session, Query
 from sqlalchemy.sql.functions import user
 
-
 from .. import data
 from ..stream_boundaries import validate_stream_boundary
 from ..stream_queries import StreamQuery
 
-
 logger = logging.getLogger(__name__)
 logger.setLevel(logging.WARN)
 
@@ -59,7 +52,9 @@ def validate_subscription(
     return True, errors
 
 
-def stream_boundary_validator(stream_boundary: data.StreamBoundary) -> None:
+def stream_boundary_validator(
+    stream_boundary: data.StreamBoundary,
+) -> data.StreamBoundary:
     """
     Stream boundary validator for the ethereum_blockchain event provider.
 
@@ -68,9 +63,10 @@ def stream_boundary_validator(stream_boundary: data.StreamBoundary) -> None:
     Raises an error for invalid stream boundaries, else returns None.
     """
     valid_period_seconds = 2 * 60 * 60
-    validate_stream_boundary(
+    _, stream_boundary = validate_stream_boundary(
         stream_boundary, valid_period_seconds, raise_when_invalid=True
     )
+    return stream_boundary
 
 
 @dataclass
@@ -298,7 +294,7 @@ def get_events(
 
     If the query does not require any data from this provider, returns None.
     """
-    stream_boundary_validator(stream_boundary)
+    stream_boundary = stream_boundary_validator(stream_boundary)
 
     parsed_filters = parse_filters(query, user_subscriptions)
     if parsed_filters is None:

backend/moonstreamapi/stream_boundaries.py

@@ -2,6 +2,7 @@
 Utilities to work with stream boundaries.
 """
 import time
+from typing import Tuple
 
 from .data import StreamBoundary
 
@@ -16,7 +17,7 @@ def validate_stream_boundary(
     stream_boundary: StreamBoundary,
     time_difference_seconds: int,
     raise_when_invalid: bool = False,
-) -> bool:
+) -> Tuple[bool, StreamBoundary]:
     """
     This function can be used by event providers to check if a stream boundary is valid according to their
     requirements.
@@ -33,6 +34,16 @@ def validate_stream_boundary(
                 f"Stream boundary start and end times must not differ by more than {time_difference_seconds} seconds:\n{stream_boundary.json()}"
             )
         else:
-            return False
+            return False, stream_boundary
 
-    return True
+    # If required reversed time stream of events
+    if start_time > end_time:
+        include_start = stream_boundary.include_start
+        include_end = stream_boundary.include_end
+        stream_boundary.start_time = end_time
+        stream_boundary.end_time = start_time
+        stream_boundary.include_start = include_end
+        stream_boundary.include_end = include_start
+        stream_boundary.reversed_time = True
+
+    return True, stream_boundary

backend/moonstreamapi/test_stream_boundaries.py

@@ -3,8 +3,8 @@ Tests for stream boundary utilities.
 """
 import unittest
 
-from .data import StreamBoundary
 from . import stream_boundaries
+from .data import StreamBoundary
 
 
 class TestValidateStreamBoundary(unittest.TestCase):
@@ -12,45 +12,44 @@ class TestValidateStreamBoundary(unittest.TestCase):
         stream_boundary = StreamBoundary(
             start_time=1, end_time=5, include_start=True, include_end=True
         )
-        self.assertTrue(
+        valid, _ = stream_boundaries.validate_stream_boundary(
-            stream_boundaries.validate_stream_boundary(
+            stream_boundary, 10, raise_when_invalid=False
-                stream_boundary, 10, raise_when_invalid=False
-            )
         )
+        self.assertTrue(valid)
 
     def test_invalid_stream_boundary(self):
         stream_boundary = StreamBoundary(
             start_time=1, end_time=5, include_start=True, include_end=True
         )
-        self.assertFalse(
+        valid, _ = stream_boundaries.validate_stream_boundary(
-            stream_boundaries.validate_stream_boundary(
+            stream_boundary, 1, raise_when_invalid=False
-                stream_boundary, 1, raise_when_invalid=False
-            )
         )
+        self.assertFalse(valid)
 
     def test_invalid_stream_boundary_error(self):
         stream_boundary = StreamBoundary(
             start_time=1, end_time=5, include_start=True, include_end=True
         )
+        valid, _ = stream_boundaries.validate_stream_boundary(
+            stream_boundary, 1, raise_when_invalid=True
+        )
         with self.assertRaises(stream_boundaries.InvalidStreamBoundary):
-            stream_boundaries.validate_stream_boundary(
+            valid
-                stream_boundary, 1, raise_when_invalid=True
-            )
 
     def test_unconstrainted_invalid_stream_boundary(self):
         stream_boundary = StreamBoundary()
-        self.assertFalse(
+        valid, _ = stream_boundaries.validate_stream_boundary(
-            stream_boundaries.validate_stream_boundary(
+            stream_boundary, 1, raise_when_invalid=False
-                stream_boundary, 1, raise_when_invalid=False
-            )
         )
+        self.assertFalse(valid)
 
     def test_unconstrained_invalid_stream_boundary_error(self):
         stream_boundary = StreamBoundary()
+        valid, _ = stream_boundaries.validate_stream_boundary(
+            stream_boundary, 1, raise_when_invalid=True
+        )
         with self.assertRaises(stream_boundaries.InvalidStreamBoundary):
-            stream_boundaries.validate_stream_boundary(
+            valid
-                stream_boundary, 1, raise_when_invalid=True
-            )
 
 
 if __name__ == "__main__":