When trying to identify the source of an issue or problem with your website, you will find yourself wanting to look at the server logs to try and find the root cause of your problem. This guide will help you with the CWP logging system and how to use it to get the information you need.
CWP uses Graylog as an internal logging collection and display dashboard. This tool has a lot of built in functionality that can be used for searching logs which you can find here. http://docs.graylog.org/en/2.4/pages/queries.html
CWP sends almost every server log into this system so you won’t just be dealing with PHP / SilverStripe logs, you will also be seeing infrastructure and system logs.
When searching through logs, it can often be a good idea to restrict your search based on a specific log type. This helps to remove all the non-related logs from your view and find the logs you are searching for a bit easier.
Useful log types
SilverStripe_log- SilverStripe Application logs
apache- Apache access logs
apache-error- Apache error logs
php- PHP error logs
postfix/error- Email error logs
postfix/bounce- Email bounce logs
Most of the time you will be searching through logs to trying and find the source of an error / problem you are having. Below are some tips on how to use Graylog’s search tool to help find your logs.
HTTP response codes
log_type:apache AND http_response:500
One easy way to find issues relating to your website may be via the response codes (e.g. Client has reported 500 errors on pages). You can filter requests to the webserver by response codes to help identify pages throwing errors.
Finding SilverStripe logs is as easy as defining the log_type filter to the defined log identifier for your codebase.
Excluding log types
NOT log_type:apache AND NOT log_type:cron
Sometimes you just want to search a time period of a reported fault for any errors / issues during that time frame. Doing this usually results in a lot of logs that are not required (e.g. postfix, apache, cron). You can use the Search filter to remove specific log types from a search.
Helpful search queries
Below is a list of useful search queries to get you started.
Long loading pages (requests longer than 10 seconds)
log_type:apache AND http_resp_usec:>10000000
Large assets / pages (requests larger than 1mb)
log_type:apache AND http_bytes:>1000000
Identifying 404s (missing pages / assets)
log_type:apache AND http_response:404
Filter requests made by IP
log_type:apache AND http_clientip:"x.x.x.x"
Filter requests made by User agent
log_type:apache AND http_agent:"Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)"