1 files changed, 41 insertions, 8 deletions

diff --git a/app/workers/check_gcp_project_billing_worker.rb b/app/workers/check_gcp_project_billing_worker.rb
index 5466ccdda59..363f81590ab 100644
--- a/app/workers/check_gcp_project_billing_worker.rb
+++ b/app/workers/check_gcp_project_billing_worker.rb
@@ -7,6 +7,7 @@ class CheckGcpProjectBillingWorker
   LEASE_TIMEOUT = 3.seconds.to_i
   SESSION_KEY_TIMEOUT = 5.minutes
   BILLING_TIMEOUT = 1.hour
+  BILLING_CHANGED_LABELS = { state_transition: nil }.freeze
 
   def self.get_session_token(token_key)
     Gitlab::Redis::SharedState.with do |redis|
@@ -22,8 +23,11 @@ class CheckGcpProjectBillingWorker
     end
   end
 
-  def self.redis_shared_state_key_for(token)
-    "gitlab:gcp:#{Digest::SHA1.hexdigest(token)}:billing_enabled"
+  def self.get_billing_state(token)
+    Gitlab::Redis::SharedState.with do |redis|
+      value = redis.get(redis_shared_state_key_for(token))
+      ActiveRecord::Type::Boolean.new.type_cast_from_user(value)
+    end
   end
 
   def perform(token_key)
@@ -33,12 +37,9 @@ class CheckGcpProjectBillingWorker
     return unless token
     return unless try_obtain_lease_for(token)
 
-    billing_enabled_projects = CheckGcpProjectBillingService.new.execute(token)
-    Gitlab::Redis::SharedState.with do |redis|
-      redis.set(self.class.redis_shared_state_key_for(token),
-        !billing_enabled_projects.empty?,
-        ex: BILLING_TIMEOUT)
-    end
+    billing_enabled_state = !CheckGcpProjectBillingService.new.execute(token).empty?
+    update_billing_change_counter(self.class.get_billing_state(token), billing_enabled_state)
+    self.class.set_billing_state(token, billing_enabled_state)
   end
 
   private
@@ -51,9 +52,41 @@ class CheckGcpProjectBillingWorker
     "gitlab:gcp:session:#{token_key}"
   end
 
+  def self.redis_shared_state_key_for(token)
+    "gitlab:gcp:#{Digest::SHA1.hexdigest(token)}:billing_enabled"
+  end
+
+  def self.set_billing_state(token, value)
+    Gitlab::Redis::SharedState.with do |redis|
+      redis.set(redis_shared_state_key_for(token), value, ex: BILLING_TIMEOUT)
+    end
+  end
+
   def try_obtain_lease_for(token)
     Gitlab::ExclusiveLease
       .new("check_gcp_project_billing_worker:#{token.hash}", timeout: LEASE_TIMEOUT)
       .try_obtain
   end
+
+  def billing_changed_counter
+    @billing_changed_counter ||= Gitlab::Metrics.counter(
+      :gcp_billing_change_count,
+      "Counts the number of times a GCP project changed billing_enabled state from false to true",
+      BILLING_CHANGED_LABELS
+    )
+  end
+
+  def state_transition(previous_state, current_state)
+    if previous_state.nil? && !current_state
+      'no_billing'
+    elsif previous_state.nil? && current_state
+      'with_billing'
+    elsif !previous_state && current_state
+      'billing_configured'
+    end
+  end
+
+  def update_billing_change_counter(previous_state, current_state)
+    billing_changed_counter.increment(state_transition: state_transition(previous_state, current_state))
+  end
 end