From 2e5a36e53869f558d5fdebd964e711be0e4189d4 Mon Sep 17 00:00:00 2001
From: Molly Struve <mollylbs@gmail.com>
Date: Wed, 15 Jan 2020 12:33:14 -0500
Subject: [PATCH] Log DB Table sizes in a Sidekiq Worker (#5518)

---
 .../metrics/record_db_table_counts_worker.rb     | 15 +++++++++++++++
 lib/tasks/fetch.rake                             |  7 +------
 .../record_db_table_counts_worker_spec.rb        | 16 ++++++++++++++++
 3 files changed, 32 insertions(+), 6 deletions(-)
 create mode 100644 app/workers/metrics/record_db_table_counts_worker.rb
 create mode 100644 spec/workers/metrics/record_db_table_counts_worker_spec.rb

diff --git a/app/workers/metrics/record_db_table_counts_worker.rb b/app/workers/metrics/record_db_table_counts_worker.rb
new file mode 100644
index 000000000..569745402
--- /dev/null
+++ b/app/workers/metrics/record_db_table_counts_worker.rb
@@ -0,0 +1,15 @@
+module Metrics
+  class RecordDbTableCountsWorker
+    include Sidekiq::Worker
+    sidekiq_options queue: :low_priority, retry: 10
+
+    def perform
+      models = [User, Article, Organization, Comment, Podcast, ClassifiedListing, PageView]
+      models.each do |model|
+        estimate = model.estimated_count
+        Rails.logger.info("db_table_size", table_info: { table_name: model.table_name, table_size: estimate })
+        DataDogStatsClient.gauge("postgres.db_table_size", estimate, tags: { table_name: model.table_name })
+      end
+    end
+  end
+end
diff --git a/lib/tasks/fetch.rake b/lib/tasks/fetch.rake
index f2af0e882..f8d0a78de 100644
--- a/lib/tasks/fetch.rake
+++ b/lib/tasks/fetch.rake
@@ -113,12 +113,7 @@ task fix_credits_count_cache: :environment do
 end
 
 task record_db_table_counts: :environment do
-  models = [User, Article, Organization, Comment, Podcast, ClassifiedListing, PageView]
-  models.each do |model|
-    estimate = model.estimated_count
-    Rails.logger.info("db_table_size", table_info: { table_name: model.table_name, table_size: estimate })
-    DataDogStatsClient.gauge("postgres.db_table_size", estimate, tags: { table_name: model.table_name })
-  end
+  RecordDbTableCountsWorker.perform_async
 end
 
 task log_worker_queue_stats: :environment do
diff --git a/spec/workers/metrics/record_db_table_counts_worker_spec.rb b/spec/workers/metrics/record_db_table_counts_worker_spec.rb
new file mode 100644
index 000000000..474a2b178
--- /dev/null
+++ b/spec/workers/metrics/record_db_table_counts_worker_spec.rb
@@ -0,0 +1,16 @@
+require "rails_helper"
+
+RSpec.describe Metrics::RecordDbTableCountsWorker, type: :worker do
+  include_examples "#enqueues_on_correct_queue", "low_priority", 1
+
+  describe "#perform" do
+    it "logs estimated counts in Datadog" do
+      allow(DataDogStatsClient).to receive(:gauge)
+      described_class.new.perform
+
+      expect(
+        DataDogStatsClient,
+      ).to have_received(:gauge).with("postgres.db_table_size", 0, Hash).at_least(1)
+    end
+  end
+end