api: retry conflicts as a workaround

This is a workaround for comment creation / updates conflicting with the `loom`
service that indexes threads objects concurrently. We will be fixing
this properly in the backend, but as a workaround we will retry
conflicts for now.

Author: mcobzarenco

api/src/retry.rs

@@ -60,7 +60,7 @@ impl Retrier {
             }
 
             match send_request() {
-                Ok(response) if response.status().is_server_error() => {
+                Ok(response) if should_retry(response) => {
                     warn_and_sleep!(format!("{} for {}", response.status(), response.url()))
                 }
                 Err(error) if error.is_timeout() => warn_and_sleep!(error),
@@ -74,6 +74,11 @@ impl Retrier {
     }
 }
 
+fn should_retry(response: &Response) -> bool {
+    // TODO(mcobzarenco): we retry conflicts because these can be generated by `loom`
+    response.status().is_server_error() || response.status() == StatusCode::CONFLICT
+}
+
 #[cfg(test)]
 mod tests {
     use super::{Retrier, RetryConfig, RetryStrategy};