ruby 39 lines · 9 steps

Keeping a search index fresh in Rails

An Article model uses after_commit callbacks and a debounced job to keep an external search index in sync only when meaningful fields change.

Explained by highlit

Rails Intermediate callbacks background-jobs debounce search-indexing scopes

1class Article < ApplicationRecord
2  belongs_to :author
3  has_many :taggings, dependent: :destroy
4  has_many :tags, through: :taggings
5 
6  INDEX_DEBOUNCE = 5.minutes
7 
8  after_commit :schedule_search_reindex, on: %i[create update]
9  after_commit :remove_from_search_index, on: :destroy
10 
11  scope :pending_reindex, -> { where("indexed_at IS NULL OR indexed_at < updated_at") }
12 
13  def search_index_stale?
14    indexed_at.nil? || indexed_at < updated_at
15  end
16 
17  def mark_indexed!
18    update_column(:indexed_at, Time.current)
19  end
20 
21  private
22 
23  def schedule_search_reindex
24    return unless search_index_stale?
25    return unless saved_change_to_indexable_attributes?
26 
27    ReindexArticleJob
28      .set(wait: INDEX_DEBOUNCE)
29      .perform_later(id)
30  end
31 
32  def remove_from_search_index
33    RemoveFromSearchIndexJob.perform_later(self.class.name, id)
34  end
35 
36  def saved_change_to_indexable_attributes?
37    (saved_changes.keys & %w[title body summary published_at author_id]).any?
38  end
39end

01 / 01

STEP 01

Walkthrough

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Three takeaways

1after_commit runs jobs only after the transaction succeeds, so you never enqueue work for a rollback.
2Guarding reindexing behind a whitelist of changed columns avoids wasteful work on irrelevant updates.
3Debouncing job enqueues with a wait window collapses rapid edits into a single reindex.

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