fix(webhook): provide acknowledgment for webhooks with unsupported event types (#1815)

crates/router/src/core/errors/utils.rs

@@ -1,3 +1,5 @@
+use common_utils::errors::CustomResult;
+
 use crate::{core::errors, logger};
 
 pub trait StorageErrorExt<T, E> {
@@ -55,6 +57,13 @@ pub trait ConnectorErrorExt<T> {
     #[cfg(feature = "payouts")]
     #[track_caller]
     fn to_payout_failed_response(self) -> error_stack::Result<T, errors::ApiErrorResponse>;
+
+    // Validates if the result, is Ok(..) or WebhookEventTypeNotFound all the other error variants
+    // are cascaded while these two event types are handled via `Option`
+    #[track_caller]
+    fn allow_webhook_event_type_not_found(
+        self,
+    ) -> error_stack::Result<Option<T>, errors::ConnectorError>;
 }
 
 impl<T> ConnectorErrorExt<T> for error_stack::Result<T, errors::ConnectorError> {
@@ -230,4 +239,14 @@ impl<T> ConnectorErrorExt<T> for error_stack::Result<T, errors::ConnectorError>
             err.change_context(error)
         })
     }
+
+    fn allow_webhook_event_type_not_found(self) -> CustomResult<Option<T>, errors::ConnectorError> {
+        match self {
+            Ok(event_type) => Ok(Some(event_type)),
+            Err(error) => match error.current_context() {
+                errors::ConnectorError::WebhookEventTypeNotFound => Ok(None),
+                _ => Err(error),
+            },
+        }
+    }
 }

crates/router/src/core/metrics.rs

@@ -39,3 +39,7 @@ counter_metric!(WEBHOOK_SOURCE_VERIFIED_COUNT, GLOBAL_METER);
 counter_metric!(WEBHOOK_OUTGOING_COUNT, GLOBAL_METER);
 counter_metric!(WEBHOOK_OUTGOING_RECEIVED_COUNT, GLOBAL_METER);
 counter_metric!(WEBHOOK_OUTGOING_NOT_RECEIVED_COUNT, GLOBAL_METER);
+counter_metric!(
+    WEBHOOK_EVENT_TYPE_IDENTIFICATION_FAILURE_COUNT,
+    GLOBAL_METER
+);

crates/router/src/core/webhooks.rs

@@ -10,7 +10,7 @@ use super::{errors::StorageErrorExt, metrics};
 use crate::{
     consts,
     core::{
-        errors::{self, CustomResult, RouterResponse},
+        errors::{self, ConnectorErrorExt, CustomResult, RouterResponse},
         payments, refunds,
     },
     logger,
@@ -672,10 +672,35 @@ pub async fn webhooks_core<W: types::OutgoingWebhookType>(
 
     request_details.body = &decoded_body;
 
-    let event_type = connector
+    let event_type = match connector
         .get_webhook_event_type(&request_details)
+        .allow_webhook_event_type_not_found()
         .switch()
-        .attach_printable("Could not find event type in incoming webhook body")?;
+        .attach_printable("Could not find event type in incoming webhook body")?
+    {
+        Some(event_type) => event_type,
+        // Early return allows us to acknowledge the webhooks that we do not support
+        None => {
+            logger::error!(
+                webhook_payload =? request_details.body,
+                "Failed while identifying the event type",
+            );
+
+            metrics::WEBHOOK_EVENT_TYPE_IDENTIFICATION_FAILURE_COUNT.add(
+                &metrics::CONTEXT,
+                1,
+                &[
+                    metrics::KeyValue::new(MERCHANT_ID, merchant_account.merchant_id.clone()),
+                    metrics::KeyValue::new("connector", connector_name.to_string()),
+                ],
+            );
+
+            return connector
+                .get_webhook_api_response(&request_details)
+                .switch()
+                .attach_printable("Failed while early return in case of event type parsing");
+        }
+    };
 
     let process_webhook_further = utils::lookup_webhook_event(
         &*state.store,