This commit moves the logic for crawler rate limits out of the application controller and into the request tracker middleware. The reason for this move is to apply rate limits to all crawler requests instead of just the requests that make it to the application controller. Some requests are served early from the middleware stack without reaching the Rails app for performance reasons (e.g. `AnonymousCache`) which results in crawlers getting 200 responses even though they've reached their limits and should be getting 429 responses.
Internal topic: t/128810.
This can happen for various reasons including rate limiting and middleware bugs. This should resolve the warning we're seeing in the logs
```
RequestTracker.get_data failed : NoMethodError : undefined method `[]' for nil:NilClass
```
Our 'page_view_crawler' / 'page_view_anon' metrics are based purely on the User Agent sent by clients. This means that 'badly behaved' bots which are imitating real user agents are counted towards 'anon' page views.
This commit introduces a new method of tracking visitors. When an initial HTML request is made, we assume it is a 'non-browser' request (i.e. a bot). Then, once the JS application has booted, we notify the server to count it as a 'browser' request. This reliance on a JavaScript-capable browser matches up more closely to dedicated analytics systems like Google Analytics.
Existing data collection and graphs are unchanged. Data collected via the new technique is available in a new 'experimental' report.
Why this change?
This is a follow up to e8f7b62752.
Tracking of GC stats didn't really belong in the `MethodProfiler` class
so we want to extract that concern into its own class.
As part of this PR, the `track_gc_stat_per_request` site setting has
also been renamed to `instrument_gc_stat_per_request`.
This method is a huge footgun in production, since it calls
the Redis KEYS command. From the Redis documentation at
https://redis.io/commands/keys/:
> Warning: consider KEYS as a command that should only be used in
production environments with extreme care. It may ruin performance when
it is executed against large databases. This command is intended for
debugging and special operations, such as changing your keyspace layout.
Don't use KEYS in your regular application code.
Since we were only using `delete_prefixed` in specs (now that we
removed the usage in production in 24ec06ff85)
we can remove this and instead rely on `use_redis_snapshotting` on the
particular tests that need this kind of clearing functionality.
This amends it so our cached counting reliant specs run in synchronize mode
When running async there are situations where data is left over in the table
after a transactional test. This means that repeat runs of the test suite
fail.
Adds stats for API and user API requests similar to regular page views.
This comes with a new report to visualize API requests per day like the
consolidated page views one.
`TestLogger` was responsible for some flaky specs runs:
```
Error during failsafe response: undefined method `debug' for #<TestLogger:0x0000556c4b942cf0 @warnings=1>
Did you mean? debugger
```
This commit also cleans up other uses of `FakeLogger`
It's very easy to forget to add `require 'rails_helper'` at the top of every core/plugin spec file, and omissions can cause some very confusing/sporadic errors.
By setting this flag in `.rspec`, we can remove the need for `require 'rails_helper'` entirely.
Previously cached counting made redis calls in main thread and performed
the flush in main thread.
This could lead to pathological states in extreme heavy load.
This refactor reduces load and cleans up the interface
