record whether webhook events had actions taken, idempotency flag

_migrations/2022-09-17-053418_stripe_webhook_event_logs/up.sql

@@ -33,8 +33,12 @@ CREATE TABLE stripe_webhook_event_logs (
 
   -- ========== INTERNAL SYSTEM METADATA ==========
 
-  -- Whether we handled the event
-  event_was_handled BOOLEAN NOT NULL DEFAULT FALSE,
+  -- Whether we handled the event with any sort of action
+  action_was_taken BOOLEAN NOT NULL DEFAULT FALSE,
+
+  -- Whether we should ignore any future retries by Stripe replaying the event.
+  -- This helps us treat events with idempotency.
+  should_ignore_retry BOOLEAN NOT NULL DEFAULT FALSE,
 
   -- Some event types may attach a user token
   maybe_user_token VARCHAR(32) DEFAULT NULL,

crates/component_subsystem/billing/src/stripe/http_endpoints/stripe_webhook_handler.rs

@@ -98,7 +98,8 @@ pub async fn stripe_webhook_handler(
     maybe_user_token: None,
     maybe_event_entity_id: None,
     maybe_stripe_customer_id: None,
-    event_was_handled: false
+    action_was_taken: false,
+    should_ignore_retry: false,
   };
 
   // NB:
@@ -298,7 +299,8 @@ pub async fn stripe_webhook_handler(
     stripe_event_created_at,
     stripe_is_production,
     maybe_user_token: webhook_summary.maybe_user_token,
-    event_was_handled: webhook_summary.event_was_handled,
+    action_was_taken: webhook_summary.action_was_taken,
+    should_ignore_retry: webhook_summary.should_ignore_retry,
   };
 
   query.insert(&mysql_pool)

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/charge/charge_succeeded_handler.rs

@@ -26,6 +26,7 @@ pub fn charge_succeeded_handler(charge: &Charge) -> Result<StripeWebhookSummary,
     maybe_user_token: maybe_user_token,
     maybe_event_entity_id: Some(charge_id),
     maybe_stripe_customer_id: maybe_stripe_customer_id,
-    event_was_handled: false,
+    action_was_taken: false,
+    should_ignore_retry: false,
   })
 }

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/checkout_session/checkout_session_completed_handler.rs

@@ -28,6 +28,7 @@ pub fn checkout_session_completed_handler(checkout_session: CheckoutSession) ->
     maybe_user_token: maybe_user_token,
     maybe_event_entity_id: Some(stripe_checkout_id),
     maybe_stripe_customer_id: maybe_stripe_customer_id,
-    event_was_handled: false,
+    action_was_taken: false,
+    should_ignore_retry: false,
   })
 }

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/customer/customer_created_handler.rs

@@ -20,6 +20,7 @@ pub fn customer_created_handler(customer: &Customer) -> Result<StripeWebhookSumm
     maybe_user_token: maybe_user_token,
     maybe_event_entity_id: Some(customer_id.clone()),
     maybe_stripe_customer_id: Some(customer_id.clone()),
-    event_was_handled: false,
+    action_was_taken: false,
+    should_ignore_retry: false,
   })
 }

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/customer/customer_deleted_handler.rs

@@ -19,6 +19,7 @@ pub fn customer_deleted_handler(customer: &Customer) -> Result<StripeWebhookSumm
     maybe_user_token: maybe_user_token,
     maybe_event_entity_id: Some(customer_id.clone()),
     maybe_stripe_customer_id: Some(customer_id.clone()),
-    event_was_handled: false,
+    action_was_taken: false,
+    should_ignore_retry: false,
   })
 }

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/customer/customer_updated_handler.rs

@@ -19,6 +19,7 @@ pub fn customer_updated_handler(customer: &Customer) -> Result<StripeWebhookSumm
     maybe_user_token: maybe_user_token,
     maybe_event_entity_id: Some(customer_id.clone()),
     maybe_stripe_customer_id: Some(customer_id.clone()),
-    event_was_handled: false,
+    action_was_taken: false,
+    should_ignore_retry: false,
   })
 }

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/customer_subscription/customer_subscription_created_handler.rs

@@ -27,7 +27,8 @@ pub async fn customer_subscription_created_handler(
     maybe_user_token: summary.user_token.clone(),
     maybe_event_entity_id: Some(summary.stripe_subscription_id.clone()),
     maybe_stripe_customer_id: Some(summary.stripe_customer_id.clone()),
-    event_was_handled: false,
+    action_was_taken: false,
+    should_ignore_retry: false,
   };
 
   // NB: It's possible to receive events out of order.
@@ -40,6 +41,7 @@ pub async fn customer_subscription_created_handler(
       })?;
 
   if maybe_existing_subscription.is_some() {
+    result.should_ignore_retry = true;
     return Ok(result);
   }
 
@@ -70,6 +72,8 @@ pub async fn customer_subscription_created_handler(
         StripeWebhookError::ServerError
       })?;
 
-  result.event_was_handled = true;
+  result.action_was_taken = true;
+  result.should_ignore_retry = true;
+
   Ok(result)
 }

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/customer_subscription/customer_subscription_deleted_handler.rs

@@ -21,6 +21,7 @@ pub async fn customer_subscription_deleted_handler(
     maybe_user_token: summary.user_token,
     maybe_event_entity_id: Some(summary.stripe_subscription_id),
     maybe_stripe_customer_id: Some(summary.stripe_customer_id),
-    event_was_handled: false,
+    action_was_taken: false,
+    should_ignore_retry: false,
   })
 }

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/customer_subscription/customer_subscription_updated_handler.rs

@@ -21,8 +21,10 @@ pub async fn customer_subscription_updated_handler(
         StripeWebhookError::ServerError // NB: This was probably *our* fault.
       })?;
 
+  let mut should_process_update = true;
 
-  let mut skip_update = false;
+  let mut action_was_taken = false;
+  let mut should_ignore_retry = false;
 
   // NB: It's possible to receive events out of order.
   let maybe_existing_subscription = get_subscription_by_stripe_id(&summary.stripe_subscription_id, &mysql_pool)
@@ -36,7 +38,8 @@ pub async fn customer_subscription_updated_handler(
     match existing_subscription.maybe_stripe_subscription_status {
       Some(StripeSubscriptionStatus::Canceled) => {
         // NB: This is a terminal status and the subscription cannot be updated any further.
-        skip_update = true;
+        should_process_update = false;
+        should_ignore_retry = true;
       }
       _ => {}
     }
@@ -44,7 +47,7 @@ pub async fn customer_subscription_updated_handler(
 
   // TODO: record cancel_at (future_cancel_at), canceled_at, ended_at (if subscription ended, when it ended), start_date
 
-  if !skip_update {
+  if should_process_update {
     let upsert = UpsertSubscriptionByStripeId {
       stripe_subscription_id: &summary.stripe_subscription_id,
       maybe_user_token: summary.user_token.as_deref(),
@@ -69,12 +72,16 @@ pub async fn customer_subscription_updated_handler(
           error!("Mysql error: {:?}", err);
           StripeWebhookError::ServerError
         })?;
+
+    action_was_taken = true;
+    should_ignore_retry = true;
   }
 
   Ok(StripeWebhookSummary {
     maybe_user_token: summary.user_token,
     maybe_event_entity_id: Some(summary.stripe_subscription_id),
     maybe_stripe_customer_id: Some(summary.stripe_customer_id),
-    event_was_handled: true,
+    action_was_taken,
+    should_ignore_retry,
   })
 }

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/invoice/invoice_paid_handler.rs

@@ -78,7 +78,8 @@ pub fn invoice_paid_handler(invoice: &Invoice) -> Result<StripeWebhookSummary, S
     maybe_user_token: None,
     maybe_event_entity_id: None,
     maybe_stripe_customer_id: None,
-    event_was_handled: false
+    action_was_taken: false,
+    should_ignore_retry: false,
   })
 }
 

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/invoice/invoice_payment_failed.rs

@@ -26,6 +26,7 @@ pub fn invoice_payment_failed_handler(invoice: &Invoice) -> Result<StripeWebhook
     maybe_user_token: maybe_user_token,
     maybe_event_entity_id: Some(invoice_id),
     maybe_stripe_customer_id: maybe_stripe_customer_id,
-    event_was_handled: false,
+    action_was_taken: false,
+    should_ignore_retry: false,
   })
 }

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/invoice/invoice_payment_succeeded_handler.rs

@@ -26,6 +26,7 @@ pub fn invoice_payment_succeeded_handler(invoice: &Invoice) -> Result<StripeWebh
     maybe_user_token: maybe_user_token,
     maybe_event_entity_id: Some(invoice_id),
     maybe_stripe_customer_id: maybe_stripe_customer_id,
-    event_was_handled: false,
+    action_was_taken: false,
+    should_ignore_retry: false,
   })
 }

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/invoice/invoice_updated_handler.rs

@@ -31,6 +31,7 @@ pub fn invoice_updated_handler(invoice: &Invoice) -> Result<StripeWebhookSummary
     maybe_user_token: maybe_user_token,
     maybe_event_entity_id: Some(invoice_id),
     maybe_stripe_customer_id: maybe_stripe_customer_id,
-    event_was_handled: false,
+    action_was_taken: false,
+    should_ignore_retry: false,
   })
 }

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/payment_intent/payment_intent_succeeded_handler.rs

@@ -26,6 +26,7 @@ pub fn payment_intent_succeeded_handler(payment_intent: &PaymentIntent) -> Resul
     maybe_user_token: maybe_user_token,
     maybe_event_entity_id: Some(payment_intent_id),
     maybe_stripe_customer_id: maybe_stripe_customer_id,
-    event_was_handled: false,
+    action_was_taken: false,
+    should_ignore_retry: false,
   })
 }

crates/component_subsystem/billing/src/stripe/webhook_event_handlers/stripe_webhook_summary.rs

@@ -11,7 +11,11 @@ pub struct StripeWebhookSummary {
   /// This is the stripe customer ID, if it was associated with the event.
   pub maybe_stripe_customer_id: Option<String>,
 
-  /// Whether we took action in response to the webhook.
-  /// Not all event types have handlers yet.
-  pub event_was_handled: bool,
+  /// Whether we took any sort of action in response to the webhook.
+  /// Not all event types have handlers yet, and even so, sometimes we may choose to do nothing.
+  pub action_was_taken: bool,
+
+  /// Whether any retries should be dropped.
+  /// This helps us handle event with idempotency in the event Stripe replays them (and it can!)
+  pub should_ignore_retry: bool,
 }

crates/lib/database_queries/src/queries/billing/stripe/insert_stripe_webhook_event_log.rs

@@ -13,7 +13,8 @@ pub struct InsertStripeWebhookEventLog {
   pub stripe_event_created_at: NaiveDateTime,
   pub stripe_is_production: bool,
   pub maybe_user_token: Option<String>,
-  pub event_was_handled: bool,
+  pub action_was_taken: bool,
+  pub should_ignore_retry: bool,
 }
 
 impl InsertStripeWebhookEventLog {
@@ -31,7 +32,8 @@ SET
   stripe_event_created_at = ?,
   stripe_is_production = ?,
   maybe_user_token = ?,
-  event_was_handled = ?
+  action_was_taken = ?,
+  should_ignore_retry = ?
         "#,
       &self.stripe_event_id,
       &self.stripe_event_type,
@@ -40,7 +42,8 @@ SET
       &self.stripe_event_created_at,
       self.stripe_is_production,
       &self.maybe_user_token,
-      self.event_was_handled,
+      self.action_was_taken,
+      self.should_ignore_retry,
     );
 
     let query_result = query.execute(mysql_pool).await;