Hands-On Microservices with Rust

Utility methods

Let's add the process_message method, which processes incoming Delivery items:

impl<T: QueueHandler> QueueActor<T> {     fn process_message(         &self,         item: Delivery,         _: &mut Context<Self>,     ) -> Result<Option<(ShortString, T::Outgoing)>, Error> {         let corr_id = item             .properties             .correlation_id()             .to_owned()             .ok_or_else(|| format_err!("Message has no address for the response"))?;         let incoming = serde_json::from_slice(&item.data)?;         let outgoing = self.handler.handle(&corr_id, incoming)?;         if let Some(outgoing) = outgoing {             Ok(Some((corr_id, outgoing)))         } else {             Ok(None)         }     } }

First, we have to get a unique ID associated with a message. If you remember, we used the UUID in this case. We stored it in the correlation ID field of the message. ...