Adds a log line that is easy to parse with Cloudwatch filters to create a useful metric. To enable:
EXTENSIONS = {
'scrapy_demo_cloudwatch_log.DemoLogger': 100
}
Then you can use this filter expression: { $.eventType = "ScrapyCrawlSummary" }.
It creates the demo metric $.item_scraped_count.
The $.spider can be used as a dimension.
Source code in Github.