Fix sqlalchemy queue component partition_id

Author: jpbalarini

docs/source/topics/frontera-settings.rst

@@ -310,6 +310,15 @@ Default: ``5.0``
 (in progress + queued requests in that slot) / max allowed concurrent downloads per slot before slot is considered
 overused. This affects only Scrapy scheduler."
 
+.. setting:: QUEUE_HOSTNAME_PARTITIONING
+
+QUEUE_HOSTNAME_PARTITIONING
+--------------------
+
+Default: ``False``
+
+Wheter to use the hostname as a partitioning scheme or not (uses the fingerprint as default).
+
 .. setting:: REQUEST_MODEL
 
 REQUEST_MODEL

frontera/contrib/backends/sqlalchemy/__init__.py

@@ -58,7 +58,7 @@ def _init_db_worker(self, manager):
         self.check_and_create_tables(drop, clear_content, (metadata_m, queue_m))
         self._metadata = Metadata(self.session_cls, metadata_m,
                                   settings.get('SQLALCHEMYBACKEND_CACHE_SIZE'))
-        self._queue = Queue(self.session_cls, queue_m, settings.get('SPIDER_FEED_PARTITIONS'))
+        self._queue = Queue(self.session_cls, queue_m, settings)
 
     @classmethod
     def strategy_worker(cls, manager):

frontera/contrib/backends/sqlalchemy/components.py

@@ -148,12 +148,14 @@ def flush(self):
 
 
 class Queue(BaseQueue):
-    def __init__(self, session_cls, queue_cls, partitions, ordering='default'):
+    def __init__(self, session_cls, queue_cls, settings, ordering='default'):
+        partitions = settings.get('SPIDER_FEED_PARTITIONS')
         self.session = session_cls()
         self.queue_model = queue_cls
         self.logger = logging.getLogger("sqlalchemy.queue")
         self.partitions = [i for i in range(0, partitions)]
         self.partitioner = Crc32NamePartitioner(self.partitions)
+        self.hostname_partitioning = settings.get('QUEUE_HOSTNAME_PARTITIONING')
         self.ordering = ordering
 
     def frontier_stop(self):
@@ -202,7 +204,8 @@ def schedule(self, batch):
                     partition_id = self.partitions[0]
                     host_crc32 = 0
                 else:
-                    partition_id = self.partitioner.partition(hostname, self.partitions)
+                    partition_key = hostname if self.hostname_partitioning else to_native_str(fprint)
+                    partition_id = self.partitioner.partition(partition_key, self.partitions)
                     host_crc32 = get_crc32(hostname)
                 q = self.queue_model(fingerprint=to_native_str(fprint), score=score, url=request.url, meta=request.meta,
                                      headers=request.headers, cookies=request.cookies, method=to_native_str(request.method),

tests/contrib/backends/test_backends.py

@@ -1,6 +1,7 @@
 import pytest
 from frontera.core.components import States
 from frontera.core.models import Request
+from frontera import Settings
 from happybase import Connection
 from frontera.contrib.backends.hbase import HBaseState, HBaseQueue
 from frontera.contrib.backends.sqlalchemy import States as SQLAlchemyStates, Queue as SQLAlchemyQueue
@@ -88,11 +89,14 @@ def queue(request):
         return
 
     if request.param == "sqlalchemy":
+        settings = Settings()
+        settings.SPIDER_FEED_PARTITIONS = 2
+        settings.QUEUE_HOSTNAME_PARTITIONING = True
         engine = create_engine('sqlite:///:memory:', echo=False)
         session_cls = sessionmaker()
         session_cls.configure(bind=engine)
         QueueModel.__table__.create(bind=engine)
-        sqla_queue = SQLAlchemyQueue(session_cls, QueueModel, 2)
+        sqla_queue = SQLAlchemyQueue(session_cls, QueueModel, settings)
         yield sqla_queue
         sqla_queue.frontier_stop()
         engine.dispose()
@@ -114,4 +118,4 @@ def test_queue(queue):
     assert set([r.url for r in queue.get_next_requests(10, 0, min_requests=3, min_hosts=1,
                                                        max_requests_per_host=10)]) == set([r3.url])
     assert set([r.url for r in queue.get_next_requests(10, 1, min_requests=3, min_hosts=1,
-                                                       max_requests_per_host=10)]) == set([r1.url, r2.url])
+                                                       max_requests_per_host=10)]) == set([r1.url, r2.url])