Merge branch '43460-track-projects-a-user-contributed-to' into 'master'

Keep track of projects a user interacted with

Closes #43460

See merge request gitlab-org/gitlab-ce!17327

2 files changed, 67 insertions, 0 deletions

diff --git a/app/models/event.rb b/app/models/event.rb
index be0fc7efa9a..17a198d52c7 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -65,6 +65,7 @@ class Event < ActiveRecord::Base
   # Callbacks
   after_create :reset_project_activity
   after_create :set_last_repository_updated_at, if: :push?
+  after_create :track_user_interacted_projects
 
   # Scopes
   scope :recent, -> { reorder(id: :desc) }
@@ -389,4 +390,11 @@ class Event < ActiveRecord::Base
     Project.unscoped.where(id: project_id)
       .update_all(last_repository_updated_at: created_at)
   end
+
+  def track_user_interacted_projects
+    # Note the call to .available? is due to earlier migrations
+    # that would otherwise conflict with the call to .track
+    # (because the table does not exist yet).
+    UserInteractedProject.track(self) if UserInteractedProject.available?
+  end
 end
diff --git a/app/models/user_interacted_project.rb b/app/models/user_interacted_project.rb
new file mode 100644
index 00000000000..dd55a6acb79
--- /dev/null
+++ b/app/models/user_interacted_project.rb
@@ -0,0 +1,59 @@
+class UserInteractedProject < ActiveRecord::Base
+  belongs_to :user
+  belongs_to :project
+
+  validates :project_id, presence: true
+  validates :user_id, presence: true
+
+  CACHE_EXPIRY_TIME = 1.day
+
+  # Schema version required for this model
+  REQUIRED_SCHEMA_VERSION = 20180223120443
+
+  class << self
+    def track(event)
+      # For events without a project, we simply don't care.
+      # An example of this is the creation of a snippet (which
+      # is not related to any project).
+      return unless event.project_id
+
+      attributes = {
+        project_id: event.project_id,
+        user_id: event.author_id
+      }
+
+      cached_exists?(attributes) do
+        transaction(requires_new: true) do
+          begin
+            where(attributes).select(1).first || create!(attributes)
+            true # not caching the whole record here for now
+          rescue ActiveRecord::RecordNotUnique
+            # Note, above queries are not atomic and prone
+            # to race conditions (similar like #find_or_create!).
+            # In the case where we hit this, the record we want
+            # already exists - shortcut and return.
+            true
+          end
+        end
+      end
+    end
+
+    # Check if we can safely call .track (table exists)
+    def available?
+      @available_flag ||= ActiveRecord::Migrator.current_version >= REQUIRED_SCHEMA_VERSION # rubocop:disable Gitlab/PredicateMemoization
+    end
+
+    # Flushes cached information about schema
+    def reset_column_information
+      @available_flag = nil
+      super
+    end
+
+    private
+
+    def cached_exists?(project_id:, user_id:, &block)
+      cache_key = "user_interacted_projects:#{project_id}:#{user_id}"
+      Rails.cache.fetch(cache_key, expires_in: CACHE_EXPIRY_TIME, &block)
+    end
+  end
+end