Prior to this fix, in the production rails console we ran the following:
```ruby
Articles::Feeds::WeightedQueryStrategy
.new(user: nil, page: 1, tags: nil)
.featured_story_and_default_home_feed(user_signed_in: false)
```
The result was: `[nil, []]`. Which in the
[StoriesController#assign_feed_stories][1] is where we have the
following:
```ruby
@featured_story, @stories = feed
.featured_story_and_default_home_feed(
user_signed_in: user_signed_in?)
```
In Blazer, I ran the following query at 2021-12-02 Thu 20:41 EST:
```sql
SELECT * FROM articles
WHERE featured = true
AND published = true
AND published_at > (NOW() - interval '7 days')
AND published_at < NOW()
AND main_image IS NOT NULL
```
So the logic of filtering with `only_featured` resulted in the
`@featured_story` being `nil`. Which then cascaded into the logic for
determining the remainder of the results.
For further discussion see the inline comments and specs that I wrote.
In addition to the above, I'm also reusing
`Articles::Feeds::FindFeaturedStory`
Prior to this commit, the `Articles::Feeds::WeightedQueryStrategy` first
grabbed the featured story, then grabbed the remaining articles. This
is different than the implementation of the
`Articles::Feeds::LargeForemExperimental` in which we first grab all the
articles then claim one as the featured.
In the WeightedQueryStrategy, the articles would not include the
featured. However, in the LargeForemExperimental it would. This
results in upstream logic in [app/javascript/articles/Feed.jsx][2]
going through and removing one of the articles.
[1]:c1a3ba99eb/app/controllers/stories_controller.rb (L237-L271)
[2]:c1a3ba99eb/app/javascript/articles/Feed.jsx (L57-L63)
* Fixing logic error for feed
Prior to this change, we were forcing features into the feed.
* Adding spec to help ensure parameter match
Prior to this commit, but before I had merged changes into main, the I
had implemented `alias default_home_feed call`. However, this broke the
interface assumed in the feeds controller.
* Limiting feed queries
Prior to this commit, we were joining on all comments. With this
change, we're limiting the comments to reflect the same time period as
our article limit.
Hopefully this further improves the performance of the query.
* Removing unintentional puts statement
* AB Test for Feed Strategy
Adding the plumbing for performing AB Tests on the feed strategy.
You can add the environment variable `AB_TEST_SERVICE_FEED_STRATEGY` to
specify the field test to run.
For example, from the forem application home directory you can run the
following to force a strategy for all users:
```console
AB_TEST_SERVICE_FEED_STRATEGY=original bin/start
```
Forcing the strategy can significantly help with quality assurance testing.
* Adding configurable weighted feed strategy
I wrote about this exploration on [DEV.to][1]. This particular
implementation provides significant configuration options for A/B
testing.
At it's core this `Articles::Feeds::WeightedQueryStrategy` provides a
means to query articles that are relevant to the user. The
configuration helps us test and refine those values.
Further more this implementation introduces the idea of some common
interfaces for feed strategies. I'm not happy with the naming
convention but we can work to change that.
This even hints at a mechanism for administrators to configure.
Related to forem/rfcs#314, as I work towards understanding the feed
algorithm. And #15180
[1]:https://dev.to/jeremyf/practicing-postgresql-and-postulating-improvements-5m
* Renaming AbTestService to AbExperiment
I'm loath to end any production class's filename with "test". I don't
want minitest or rspec coming along and attempting to "test" that file.
In addition, I find that Experiment better describes the concept.
Also, per conversations with Michael K, we favor nouns objects to go
in app/models and verb objects to go in app/services. That's a great
separation.
* Factoring AbExperiment into a Controller concern
I wish this could be a stand-alone module but the implementation of
field test has cases that require controller context.
* Sanitizing configurable weighted strategy cases
* Minor refactoring of coding structure
* Renaming parameter for clarity
* Renaming variable to avoid confusion
Prior to the commit, `env` is a controller variable. The injected `env`
variable didn't collide, but did create just a bit of confusion.
With this change, I'm trying to disentangle from that variable.
* Factoring AbExperiment away from mixin concern
Per discussion with Michael K, we both agree that we do not like
controller concern mixins. They can quickly complicate the legibility
of any given codebase.
This refactor provides a common and simplified interface for a Plain Old
Ruby Object (PORO) that accounts for the implementation considerations
of the underlying "field_test" controller method.
* Adding Datadog.tracer.trace around feed actions
* Adding featured_article_factor
Prior to this commit, there was no consideration for how moderators
engage with an article. This is a first nudge towards that effort.
* Removing spec
Add a spec that says yes or no we're feature testing something seems
fragile. Namely, why are we wanting to assert that as a truism.
* Helping ensure we're "tracing" the same things
From the code comment:
> Hey, why the to_a you say? Because the
> LargeForemExperimental has already done this. But the
> weighted strategy has not. I also don't want to alter the
> weighted query implementation as it returns a lovely
> ActiveRecord::Relation. So this is a concession.
* Addressing parameters for tracing function
* For weight feed query only count positive tags
A user assigns explicit points to the tags that they do or do not want
to see. This change treats the negative explicit_points as an indicator
that they don't want to see the tag.
* Adding weighted factor for privileged user reactions
* Updating comments to better clarify
* Adding additional constraint for published_at
* Updating documentation and adding logger
* Adding documentation concerning method call
* Upping logging level for experiments
See conversations in https://github.com/forem/forem/pull/15240
* Adding group by clauses to appease postgres configs
* Injecting relevant scoring method's joins
Prior to this commit, we included all of the joins regardless of the
scoring methods chosen. With this commit, we only inject joins that are
used with the commit.
What this would allow us to do is to then have some pre-cooked scoring
methods but not turn them on. Or to turn off the more expensive scoring
methods.
* Adding feature flag for feed strategy experiment
