Add stats extension based on Redis (#186)

README.rst

@@ -73,6 +73,9 @@ Use the following settings in your project:
   # Ensure all spiders share same duplicates filter through redis.
   DUPEFILTER_CLASS = "scrapy_redis.dupefilter.RFPDupeFilter"
 
+  # Enables stats shared based on Redis
+  STATS_CLASS = "scrapy_redis.stats.RedisStatsCollector"
+
   # Default requests serializer is pickle, but it can be changed to any module
   # with loads and dumps functions. Note that pickle is not compatible between
   # python versions.

src/scrapy_redis/defaults.py

@@ -6,6 +6,8 @@
 
 PIPELINE_KEY = '%(spider)s:items'
 
+STATS_KEY = '%(spider)s:stats'
+
 REDIS_CLS = redis.StrictRedis
 REDIS_ENCODING = 'utf-8'
 # Sane connection defaults.
@@ -20,7 +22,7 @@
 SCHEDULER_QUEUE_CLASS = 'scrapy_redis.queue.PriorityQueue'
 SCHEDULER_DUPEFILTER_KEY = '%(spider)s:dupefilter'
 SCHEDULER_DUPEFILTER_CLASS = 'scrapy_redis.dupefilter.RFPDupeFilter'
-
+SCHEDULER_PERSIST = False
 START_URLS_KEY = '%(name)s:start_urls'
 START_URLS_AS_SET = False
 START_URLS_AS_ZSET = False

src/scrapy_redis/stats.py

@@ -0,0 +1,78 @@
+from scrapy.statscollectors import StatsCollector
+from .connection import from_settings as redis_from_settings
+from .defaults import STATS_KEY, SCHEDULER_PERSIST
+
+
+class RedisStatsCollector(StatsCollector):
+    """
+    Stats Collector based on Redis
+    """
+
+    def __init__(self, crawler, spider=None):
+        super().__init__(crawler)
+        self.server = redis_from_settings(crawler.settings)
+        self.spider = spider
+        self.spider_name = spider.name if spider else crawler.spidercls.name
+        self.stats_key = crawler.settings.get('STATS_KEY', STATS_KEY)
+        self.persist = crawler.settings.get(
+            'SCHEDULER_PERSIST', SCHEDULER_PERSIST)
+
+    def _get_key(self, spider=None):
+        """Return the hash name of stats"""
+        if spider:
+            self.stats_key % {'spider': spider.name}
+        if self.spider:
+            return self.stats_key % {'spider': self.spider.name}
+        return self.stats_key % {'spider': self.spider_name or 'scrapy'}
+
+    @classmethod
+    def from_crawler(cls, crawler):
+        return cls(crawler)
+
+    def get_value(self, key, default=None, spider=None):
+        """Return the value of hash stats"""
+        if self.server.hexists(self._get_key(spider), key):
+            return int(self.server.hget(self._get_key(spider), key))
+        else:
+            return default
+
+    def get_stats(self, spider=None):
+        """Return the all of the values of hash stats"""
+        return self.server.hgetall(self._get_key(spider))
+
+    def set_value(self, key, value, spider=None):
+        """Set the value according to hash key of stats"""
+        self.server.hset(self._get_key(spider), key, value)
+
+    def set_stats(self, stats, spider=None):
+        """Set all the hash stats"""
+        self.server.hmset(self._get_key(spider), stats)
+
+    def inc_value(self, key, count=1, start=0, spider=None):
+        """Set increment of value according to key"""
+        if not self.server.hexists(self._get_key(spider), key):
+            self.set_value(key, start)
+        self.server.hincrby(self._get_key(spider), key, count)
+
+    def max_value(self, key, value, spider=None):
+        """Set max value between current and new value"""
+        self.set_value(key, max(self.get_value(key, value), value))
+
+    def min_value(self, key, value, spider=None):
+        """Set min value between current and new value"""
+        self.set_value(key, min(self.get_value(key, value), value))
+
+    def clear_stats(self, spider=None):
+        """Clarn all the hash stats"""
+        self.server.delete(self._get_key(spider))
+
+    def open_spider(self, spider):
+        """Set spider to self"""
+        if spider:
+            self.spider = spider
+
+    def close_spider(self, spider, reason):
+        """Clear spider and clear stats"""
+        self.spider = None
+        if not self.persist:
+            self.clear_stats(spider)