Count wiki page creation

This adds a counter to count page creation, which is reflected in the
usage-data we collect.

The number created is stored in Redis, avoiding DB access.

1 files changed, 32 insertions, 0 deletions

diff --git a/lib/gitlab/usage_data_counters/wiki_page_counter.rb b/lib/gitlab/usage_data_counters/wiki_page_counter.rb
new file mode 100644
index 00000000000..c8b59a3160c
--- /dev/null
+++ b/lib/gitlab/usage_data_counters/wiki_page_counter.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module Gitlab::UsageDataCounters
+  class WikiPageCounter
+    extend RedisCounter
+
+    KNOWN_EVENTS = %w[create update delete].map(&:freeze).freeze
+
+    UnknownEvent = Class.new(StandardError)
+
+    class << self
+      # Each event gets a unique Redis key
+      def redis_key(event)
+        raise UnknownEvent, event unless KNOWN_EVENTS.include?(event.to_s)
+
+        "USAGE_WIKI_PAGES_#{event}".upcase
+      end
+
+      def count(event)
+        increment(redis_key event)
+      end
+
+      def read(event)
+        total_count(redis_key event)
+      end
+
+      def totals
+        KNOWN_EVENTS.map { |e| ["wiki_pages_#{e}".to_sym, read(e)] }.to_h
+      end
+    end
+  end
+end