Multiprocessing of Scrapy Spiders in Parallel Processes

Question

There as several similar questions that I have already read on Stack Overflow. Unfortunately, I lost links of all of them, because my browsing history got deleted unexpectedly.

All of the above questions, couldn't help me. Either, some of them have used CELERY or some of them SCRAPYD, and I want to use the MULTIPROCESSISNG Library. Also, the Scrapy Official Documentation shows how to run multiple spiders on a SINGLE PROCESS, not on MULTIPLE PROCESSES.

None of them couldn't help me, and hence I decided to ask this question.

After several try's, I came up with this code.

My Output-:

Enter a product to search for: apple
2015-06-27 14:34:15 [scrapy] INFO: Scrapy 1.0.0 started (bot: scrapybot)
2015-06-27 14:34:15 [scrapy] INFO: Scrapy 1.0.0 started (bot: scrapybot)
2015-06-27 14:34:15 [scrapy] INFO: Optional features available: ssl, http11
2015-06-27 14:34:15 [scrapy] INFO: Optional features available: ssl, http11
2015-06-27 14:34:15 [scrapy] INFO: Overridden settings: {}
2015-06-27 14:34:15 [scrapy] INFO: Overridden settings: {}
2015-06-27 14:34:15 [scrapy] INFO: Enabled extensions: CloseSpider, TelnetConsole, LogStats, CoreStats, SpiderState
2015-06-27 14:34:15 [scrapy] INFO: Enabled extensions: CloseSpider, TelnetConsole, LogStats, CoreStats, SpiderState
2015-06-27 14:34:15 [scrapy] INFO: Enabled downloader middlewares: HttpAuthMiddleware, DownloadTimeoutMiddleware, UserAgentMiddleware, RetryMiddleware, DefaultHeadersMiddleware, MetaRefreshMiddleware, HttpCompressionMiddleware, RedirectMiddleware, CookiesMiddleware, ChunkedTransferMiddleware, DownloaderStats
2015-06-27 14:34:15 [scrapy] INFO: Enabled spider middlewares: HttpErrorMiddleware, OffsiteMiddleware, RefererMiddleware, UrlLengthMiddleware, DepthMiddleware
2015-06-27 14:34:15 [scrapy] INFO: Enabled item pipelines: 
2015-06-27 14:34:15 [scrapy] INFO: Spider opened
2015-06-27 14:34:15 [scrapy] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2015-06-27 14:34:15 [scrapy] DEBUG: Telnet console listening on 127.0.0.1:6023
2015-06-27 14:34:15 [scrapy] INFO: Enabled downloader middlewares: HttpAuthMiddleware, DownloadTimeoutMiddleware, UserAgentMiddleware, RetryMiddleware, DefaultHeadersMiddleware, MetaRefreshMiddleware, HttpCompressionMiddleware, RedirectMiddleware, CookiesMiddleware, ChunkedTransferMiddleware, DownloaderStats
2015-06-27 14:34:15 [scrapy] INFO: Enabled spider middlewares: HttpErrorMiddleware, OffsiteMiddleware, RefererMiddleware, UrlLengthMiddleware, DepthMiddleware
2015-06-27 14:34:15 [scrapy] INFO: Enabled item pipelines: 
2015-06-27 14:34:15 [scrapy] INFO: Spider opened
2015-06-27 14:34:15 [scrapy] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2015-06-27 14:34:15 [scrapy] DEBUG: Telnet console listening on 127.0.0.1:6024
2015-06-27 14:34:15 [twisted] ERROR: Unhandled Error
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/twisted/python/log.py", line 88, in callWithLogger
    return callWithContext({"system": lp}, func, *args, **kw)
  File "/usr/lib/python2.7/dist-packages/twisted/python/log.py", line 73, in callWithContext
    return context.call({ILogContext: newCtx}, func, *args, **kw)
  File "/usr/lib/python2.7/dist-packages/twisted/python/context.py", line 118, in callWithContext
    return self.currentContext().callWithContext(ctx, func, *args, **kw)
  File "/usr/lib/python2.7/dist-packages/twisted/python/context.py", line 81, in callWithContext
    return func(*args,**kw)
--- <exception caught here> ---
  File "/usr/lib/python2.7/dist-packages/twisted/internet/posixbase.py", line 619, in _doReadOrWrite
    why = selectable.doWrite()
  File "/usr/lib/python2.7/dist-packages/twisted/internet/base.py", line 1117, in doWrite
    "doWrite called on a %s" % reflect.qual(self.__class__))
exceptions.RuntimeError: doWrite called on a twisted.internet.tcp.Port

Unhandled Error
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/twisted/python/log.py", line 88, in callWithLogger
    return callWithContext({"system": lp}, func, *args, **kw)
  File "/usr/lib/python2.7/dist-packages/twisted/python/log.py", line 73, in callWithContext
    return context.call({ILogContext: newCtx}, func, *args, **kw)
  File "/usr/lib/python2.7/dist-packages/twisted/python/context.py", line 118, in callWithContext
    return self.currentContext().callWithContext(ctx, func, *args, **kw)
  File "/usr/lib/python2.7/dist-packages/twisted/python/context.py", line 81, in callWithContext
    return func(*args,**kw)
--- <exception caught here> ---
  File "/usr/lib/python2.7/dist-packages/twisted/internet/posixbase.py", line 619, in _doReadOrWrite
    why = selectable.doWrite()
  File "/usr/lib/python2.7/dist-packages/twisted/internet/base.py", line 1117, in doWrite
    "doWrite called on a %s" % reflect.qual(self.__class__))
exceptions.RuntimeError: doWrite called on a twisted.internet.tcp.Port
2015-06-27 14:34:16 [twisted] ERROR: Unhandled Error
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/twisted/python/log.py", line 88, in callWithLogger
    return callWithContext({"system": lp}, func, *args, **kw)
  File "/usr/lib/python2.7/dist-packages/twisted/python/log.py", line 73, in callWithContext
    return context.call({ILogContext: newCtx}, func, *args, **kw)
  File "/usr/lib/python2.7/dist-packages/twisted/python/context.py", line 118, in callWithContext
    return self.currentContext().callWithContext(ctx, func, *args, **kw)
  File "/usr/lib/python2.7/dist-packages/twisted/python/context.py", line 81, in callWithContext
    return func(*args,**kw)
--- <exception caught here> ---
  File "/usr/lib/python2.7/dist-packages/twisted/internet/posixbase.py", line 619, in _doReadOrWrite
    why = selectable.doWrite()
  File "/usr/lib/python2.7/dist-packages/twisted/internet/base.py", line 1117, in doWrite
    "doWrite called on a %s" % reflect.qual(self.__class__))
exceptions.RuntimeError: doWrite called on a twisted.internet.tcp.Port

Unhandled Error
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/twisted/python/log.py", line 88, in callWithLogger
    return callWithContext({"system": lp}, func, *args, **kw)
  File "/usr/lib/python2.7/dist-packages/twisted/python/log.py", line 73, in callWithContext
    return context.call({ILogContext: newCtx}, func, *args, **kw)
  File "/usr/lib/python2.7/dist-packages/twisted/python/context.py", line 118, in callWithContext
    return self.currentContext().callWithContext(ctx, func, *args, **kw)
  File "/usr/lib/python2.7/dist-packages/twisted/python/context.py", line 81, in callWithContext
    return func(*args,**kw)
--- <exception caught here> ---
  File "/usr/lib/python2.7/dist-packages/twisted/internet/posixbase.py", line 619, in _doReadOrWrite
    why = selectable.doWrite()
  File "/usr/lib/python2.7/dist-packages/twisted/internet/base.py", line 1117, in doWrite
    "doWrite called on a %s" % reflect.qual(self.__class__))
exceptions.RuntimeError: doWrite called on a twisted.internet.tcp.Port
2015-06-27 14:34:17 [scrapy] DEBUG: Crawled (200) <GET http://bigbasket.com/ps/?q=apple> (referer: None)
hello, world
Current second: 17
Current microsecond: 546862
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 170', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/10000007_18-fresho-apple-washington.jpg', 'product_link': 'http://bigbasket.com/pd/10000007/fresho-apple-washington-1-kg/', 'productname': 'Apple - Washington', 'current_price': 'Rs. 170'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 199', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/10000003_7-fresho-apple-fuji.jpg', 'product_link': 'http://bigbasket.com/pd/10000003/fresho-apple-fuji-1-kg/', 'productname': 'Apple - Fuji', 'current_price': 'Rs. 199'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 229', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/10000005_16-fresho-apple-royal-gala.jpg', 'product_link': 'http://bigbasket.com/pd/10000005/fresho-apple-royal-gala-1-kg/', 'productname': 'Apple - Royal Gala', 'current_price': 'Rs. 229'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 156.75', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/205988_2-american-garden-vinegar-apple-cider.jpg', 'product_link': 'http://bigbasket.com/pd/205988/american-garden-vinegar-apple-cider-473-ml-bottle/', 'productname': 'Vinegar - Apple Cider', 'current_price': 'Rs. 156.75'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 151', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/10000397_7-fresho-apple-green.jpg', 'product_link': 'http://bigbasket.com/pd/10000397/fresho-apple-green-500-gm/', 'productname': 'Apple - Green', 'current_price': 'Rs. 151'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 114', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/229785_5-tropicana-100-juice-apple.jpg', 'product_link': 'http://bigbasket.com/pd/229785/tropicana-100-juice-apple-1-ltr-tetra/', 'productname': '100% Juice - Apple', 'current_price': 'Rs. 114'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 266', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/40015763_1-mylife-vinegar-apple-cider.jpg', 'product_link': 'http://bigbasket.com/pd/40015763/mylife-vinegar-apple-cider-300-ml/', 'productname': 'Vinegar - Apple Cider', 'current_price': 'Rs. 266'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 175', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/40015525_1-fresho-apple-chilli.jpg', 'product_link': 'http://bigbasket.com/pd/40015525/fresho-apple-chilli-1-kg/', 'productname': 'Apple - Chilli', 'current_price': 'Rs. 175'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 94.05', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/229791_3-tropicana-juice-apple.jpg', 'product_link': 'http://bigbasket.com/pd/229791/tropicana-juice-apple-1-ltr-tetra/', 'productname': 'Juice - Apple', 'current_price': 'Rs. 94.05'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 93', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/40015526_1-fresho-apple-chilli.jpg', 'product_link': 'http://bigbasket.com/pd/40015526/fresho-apple-chilli-500-gm/', 'productname': 'Apple - Chilli', 'current_price': 'Rs. 93'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 94.05', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/265854_2-real-fruit-power-juice-apple.jpg', 'product_link': 'http://bigbasket.com/pd/265854/real-fruit-power-juice-apple-1-ltr-carton/', 'productname': 'Fruit Power Juice - Apple', 'current_price': 'Rs. 94.05'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 143.10', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/252445_3-biotique-shampoo-and-conditioner-bio-green-apple.jpg', 'product_link': 'http://bigbasket.com/pd/252445/biotique-shampoo-and-conditioner-bio-green-apple-190-ml/', 'productname': 'Shampoo and Conditioner - Bio Green...', 'current_price': 'Rs. 143.10'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 250', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/30006470_1-fresho-apple-fuji-premium.jpg', 'product_link': 'http://bigbasket.com/pd/30006470/fresho-apple-fuji-premium-1-kg/', 'productname': 'Apple Fuji Premium', 'current_price': 'Rs. 250'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 19', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/282654_2-real-fruit-power-juice-apple.jpg', 'product_link': 'http://bigbasket.com/pd/282654/real-fruit-power-juice-apple-200-ml-carton/', 'productname': 'Fruit Power Juice - Apple', 'current_price': 'Rs. 19'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 14.25', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/100535016_4-quaker-oats-strawberry-flavor-with-apple.jpg', 'product_link': 'http://bigbasket.com/pd/100535016/quaker-oats-strawberry-flavor-with-apple-40-gm-pouch/', 'productname': 'Oats - Strawberry Flavor with Apple', 'current_price': 'Rs. 14.25'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 12.60', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/265705_1-appy-apple-juice-drink-classic.jpg', 'product_link': 'http://bigbasket.com/pd/265705/appy-apple-juice-drink-classic-200-ml-carton/', 'productname': 'Apple Juice Drink - Classic', 'current_price': 'Rs. 12.60'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 19', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/40012961_2-candy-clouds-cotton-candy-orange-green-apple.jpg', 'product_link': 'http://bigbasket.com/pd/40012961/candy-clouds-cotton-candy-orange-green-apple-30-gm-cup/', 'productname': 'Cotton Candy - Orange & Green Apple', 'current_price': 'Rs. 19'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 96', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/229945_1-real-activ-juice-apple.jpg', 'product_link': 'http://bigbasket.com/pd/229945/real-activ-juice-apple-1-ltr-carton/', 'productname': 'Activ Juice - Apple', 'current_price': 'Rs. 96'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 23.75', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/286759_1-minute-maid-juice-apple.jpg', 'product_link': 'http://bigbasket.com/pd/286759/minute-maid-juice-apple-400-ml-bottle/', 'productname': 'Juice - Apple', 'current_price': 'Rs. 23.75'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://bigbasket.com/ps/?q=apple>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 85.50', 'imageurl': 'http://bigbasket.com/media/uploads/p/s/40020508_1-fresho-freshly-baked-apple-pie.jpg', 'product_link': 'http://bigbasket.com/pd/40020508/fresho-freshly-baked-apple-pie-100-gm-pouch/', 'productname': 'Freshly Baked - Apple Pie', 'current_price': 'Rs. 85.50'}
2015-06-27 14:34:17 [scrapy] INFO: Closing spider (finished)
2015-06-27 14:34:17 [scrapy] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 222,
 'downloader/request_count': 1,
 'downloader/request_method_count/GET': 1,
 'downloader/response_bytes': 54881,
 'downloader/response_count': 1,
 'downloader/response_status_count/200': 1,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2015, 6, 27, 9, 4, 17, 621449),
 'item_scraped_count': 20,
 'log_count/DEBUG': 22,
 'log_count/ERROR': 1,
 'log_count/INFO': 7,
 'response_received_count': 1,
 'scheduler/dequeued': 1,
 'scheduler/dequeued/memory': 1,
 'scheduler/enqueued': 1,
 'scheduler/enqueued/memory': 1,
 'start_time': datetime.datetime(2015, 6, 27, 9, 4, 15, 879467)}
2015-06-27 14:34:17 [scrapy] INFO: Spider closed (finished)
2015-06-27 14:34:17 [scrapy] DEBUG: Crawled (200) <GET http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0> (referer: None)
hello, world
Current second: 17
Current microsecond: 734324
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 31,800', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/178153.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-4-16-GB-Unlocked-Mobile-Phone-(Black)-pc-19326-97.aspx', 'productname': 'Apple iPhone 4 16 GB Unlocked Mobile Phone (Black)', 'current_price': 'Rs. 26,999'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': '', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/180356.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-5c-32-GB-GSM-Mobile-Phone-(White)-pc-20258-97.aspx', 'productname': 'Apple iPhone 5c 32 GB GSM Mobile Phone (White)', 'current_price': 'Rs. 53,500'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 53,500', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/180360.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-5s-16-GB-GSM-Mobile-Phone-(Grey)-pc-20262-97.aspx', 'productname': 'Apple iPhone 5s 16 GB GSM Mobile Phone (Grey)', 'current_price': 'Rs. 44,500'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 53,500', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/180362.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-5s-16-GB-GSM-Mobile-Phone-(Gold)-pc-20263-97.aspx', 'productname': 'Apple iPhone 5s 16 GB GSM Mobile Phone (Gold)', 'current_price': 'Rs. 44,500'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 53,500', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/180376.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-5s-16-GB-GSM-Mobile-Phone-(Silver)-pc-20277-97.aspx', 'productname': 'Apple iPhone 5s 16 GB GSM Mobile Phone (Silver)', 'current_price': 'Rs. 44,500'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 31,500', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/180443.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-4S-8-GB-GSM-Mobile-Phone-(Black)-pc-20318-97.aspx', 'productname': 'Apple iPhone 4S 8 GB GSM Mobile Phone (Black)', 'current_price': 'Rs. 16,990'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 31,500', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/180444.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-4S-8-GB-GSM-Mobile-Phone-(White)-pc-20319-97.aspx', 'productname': 'Apple iPhone 4S 8 GB GSM Mobile Phone (White)', 'current_price': 'Rs. 16,990'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 53,500', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/185039.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-5S-16-GB-GSM-Mobile-Phone-(Gold)-pc-23555-97.aspx', 'productname': 'Apple iPhone 5S 16 GB GSM Mobile Phone (Gold)', 'current_price': 'Rs. 49,999'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 53,500', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/185802.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-6-16-GB-GSM-Mobile-Phone-(Silver)-pc-23996-97.aspx', 'productname': 'Apple iPhone 6 16 GB GSM Mobile Phone (Silver)', 'current_price': 'Rs. 52,500'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': '', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/185805.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-6-64-GB-GSM-Mobile-Phone-(Silver)-pc-23999-97.aspx', 'productname': 'Apple iPhone 6 64 GB GSM Mobile Phone (Silver)', 'current_price': 'Rs. 62,500'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': '', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/185808.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-6-128-GB-GSM-(Silver)-pc-24002-97.aspx', 'productname': 'Apple iPhone 6 128 GB GSM (Silver)', 'current_price': 'Rs. 71,500'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': '', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/185880.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-6-Plus-16-GB-GSM-(Space-Grey)-pc-24004-97.aspx', 'productname': 'Apple iPhone 6 Plus 16 GB GSM (Space Grey)', 'current_price': 'Rs. 62,500'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': '', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/185881.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-6-Plus-16-GB-GSM-(Silver)-pc-24005-97.aspx', 'productname': 'Apple iPhone 6 Plus 16 GB GSM (Silver)', 'current_price': 'Rs. 62,500'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': 'Rs. 56,000', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/189360.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-6-16-GB-(Gold)-pc-26002-97.aspx', 'productname': 'Apple iPhone 6 16 GB (Gold)', 'current_price': 'Rs. 53,499'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': '', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/189363.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-6-64-GB-(Gold)-pc-26005-97.aspx', 'productname': 'Apple iPhone 6 64 GB (Gold)', 'current_price': 'Rs. 65,000'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': '', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/189364.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-6-64-GB-(Grey)-pc-26006-97.aspx', 'productname': 'Apple iPhone 6 64 GB (Grey)', 'current_price': 'Rs. 65,000'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': '', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/189365.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-6-64-GB-(Silver)-pc-26007-97.aspx', 'productname': 'Apple iPhone 6 64 GB (Silver)', 'current_price': 'Rs. 65,000'}
2015-06-27 14:34:17 [scrapy] DEBUG: Scraped from <200 http://www.cromaretail.com/productsearch.aspx?txtSearch=apple&x=0&y=0>
{'outofstock_status': 'In Stock', 'offer': 'No additional offer available', 'mrp': '', 'imageurl': 'http://www.cromaretail.com/Images/Catalogue/Product/medium/189366.jpg', 'product_link': 'http://www.cromaretail.comApple-iPhone-6-128-GB-(Gold)-pc-26008-97.aspx', 'productname': 'Apple iPhone 6 128 GB (Gold)', 'current_price': 'Rs. 74,000'}
2015-06-27 14:34:17 [scrapy] INFO: Closing spider (finished)
2015-06-27 14:34:17 [scrapy] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 259,
 'downloader/request_count': 1,
 'downloader/request_method_count/GET': 1,
 'downloader/response_bytes': 16851,
 'downloader/response_count': 1,
 'downloader/response_status_count/200': 1,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2015, 6, 27, 9, 4, 17, 764861),
 'item_scraped_count': 18,
 'log_count/DEBUG': 20,
 'log_count/ERROR': 1,
 'log_count/INFO': 7,
 'response_received_count': 1,
 'scheduler/dequeued': 1,
 'scheduler/dequeued/memory': 1,
 'scheduler/enqueued': 1,
 'scheduler/enqueued/memory': 1,
 'start_time': datetime.datetime(2015, 6, 27, 9, 4, 15, 930386)}
2015-06-27 14:34:17 [scrapy] INFO: Spider closed (finished)
<Deferred at 0x7f02a29b7c68 current result: None>

If you see my output correctly, initially some error comes and the program pauses just a bit before

2015-06-27 14:34:17 [scrapy] DEBUG: Crawled (200) <GET http://bigbasket.com/ps/?q=apple> (referer: None) 

- this line in my output, and then runs, but also produces an output.

I am not able to figure out the following 2 things:

• Why is that error coming? Why does the program pause over there (is it because that scrapy is crawling the pages, and so it is normal, or is it some problem?)? What changes I must do in my code in order to resolve it?
• If you see I am printing the current second, and current microsecond, to check when both of my function's get entered and start getting processed. I have done this, basically to check whether both of my functions are actually getting multiprocessed or not. I know that, even after using the Multiprocessing, there is a time lag of a few microseconds, and that is very well acceptable from my end. But, I ran this script several times, and sometimes I noticed a time lag of only a few microseconds (which I could well accept, but this case generally came when the sites returned only a few search results, so I don't know whether they actually got multiprocessed or not, because normally my functions independently execute in around 1.3 seconds and produce around 20 results.), and sometimes I notice a time lag of around 1 or 2 seconds also (that definitely says, that my functions haven't got multiprocessed, at least after reading about the time - around 1.3 seconds in which my functions execute independently - had they been on different python scripts). So, why is this time variation occurring? How do I check as to are my functions actually getting multiprocessed?

Please provide corrections in my code, and explanations to my 2 issues.

Please do help! Any answers, shall be well appreciated!

Thanks!

Answer 1

Scrapy is created with Twisted, and this framework already has its way of running multiple processes. There is nice question about this here. In your approach you are actually trying to marry two incompatible and competing libraries (Scrapy/Twisted + multiprocessing). This is probably not best idea, you can run into lots of problems with that.

If you would like to run Scrapy spiders in multiple processes it will much easier to just use Twisted. You could just read Twisted docs for spawnProcess and other calls and try to those tools for your goal. For example here's quick and dirty implementation that runs two spiders in two processes

from twisted.internet import defer, protocol, reactor
import os


class SpiderRunnerProtocol(protocol.ProcessProtocol):
    def __init__(self, d, inputt=None):
        self.deferred = d
        self.inputt = inputt
        self.output = ""
        self.err = ""

    def connectionMade(self):
        if self.inputt:
            self.transport.write(self.inputt)
        self.transport.closeStdin()

    def outReceived(self, data):
        self.output += data

    def processEnded(self, reason):
        print(reason.value)
        print(self.err)
        self.deferred.callback(self.output)

    def errReceived(self, data):
        self.err += data


def run_spider(cmd, *args, **kwargs):
    d = defer.Deferred()
    pipe = SpiderRunnerProtocol(d)
    args = [cmd] + list(args)
    env = os.environ.copy()
    x = reactor.spawnProcess(pipe, cmd, args, env=env)
    print(x.pid)
    print(x)
    return d


def print_out(result):
    print(result)

d = run_spider("scrapy", "crawl", "reddit")
d = run_spider("scrapy", "crawl", "dmoz")
d.addCallback(print_out)
d.addCallback(lambda _: reactor.stop())
reactor.run()

There's a nice blog post explaining usage of Twisted subprocesses here