chore(p2p_service): clean up processing of p2p req/res protocol (#2124)

## Linked Issues/PRs
<!-- List of related issues/PRs -->
- #2112
- #2121

## Description
<!-- List of detailed changes -->
Cleans up the impl for `TaskRequest` by breaking the processing into
digestable but extendable functions

## Checklist
- [x] Breaking changes are clearly marked as such in the PR description
and changelog
- [x] New behavior is reflected in tests
- [x] [The specification](https://github.com/FuelLabs/fuel-specs/)
matches the implemented behavior (link update PR if changes are needed)

### Before requesting review
- [x] I have reviewed the code myself
- [x] I have created follow-up issues caused by this PR and linked them
here

### After merging, notify other teams

[Add or remove entries as needed]

- [ ] [Rust SDK](https://github.com/FuelLabs/fuels-rs/)
- [ ] [Sway compiler](https://github.com/FuelLabs/sway/)
- [ ] [Platform
documentation](https://github.com/FuelLabs/devrel-requests/issues/new?assignees=&labels=new+request&projects=&template=NEW-REQUEST.yml&title=%5BRequest%5D%3A+)
(for out-of-organization contributors, the person merging the PR will do
this)
- [ ] Someone else?

---------

Co-authored-by: Green Baneling <XgreenX9999@gmail.com>

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - [2113](https://github.com/FuelLabs/fuel-core/pull/2113): Modify the way the gas price service and shared algo is initialized to have some default value based on best guess instead of `None`, and initialize service before graphql.
 - [2112](https://github.com/FuelLabs/fuel-core/pull/2112): Alter the way the sealed blocks are fetched with a given height.
 - [2115](https://github.com/FuelLabs/fuel-core/pull/2115): Add test for `SignMode` `is_available` method.
+- [2124](https://github.com/FuelLabs/fuel-core/pull/2124): Generalize the way p2p req/res protocol handles requests.
 
 ### Added
 - [2119](https://github.com/FuelLabs/fuel-core/pull/2119): GraphQL query fields for retrieving information about upgrades.

crates/fuel-core/src/database/sealed_block.rs

@@ -81,14 +81,11 @@ impl OnChainIterableKeyValueView {
     pub fn get_sealed_block_headers(
         &self,
         block_height_range: Range<u32>,
-    ) -> StorageResult<Vec<SealedBlockHeader>> {
+    ) -> StorageResult<Option<Vec<SealedBlockHeader>>> {
         let headers = block_height_range
             .map(BlockHeight::from)
             .map(|height| self.get_sealed_block_header(&height))
-            .collect::<StorageResult<Vec<_>>>()?
-            .into_iter()
-            .flatten()
-            .collect();
+            .collect::<StorageResult<Option<Vec<_>>>>()?;
         Ok(headers)
     }
 

crates/fuel-core/src/service/adapters/p2p.rs

@@ -20,7 +20,7 @@ impl P2pDb for OnChainIterableKeyValueView {
     fn get_sealed_headers(
         &self,
         block_height_range: Range<u32>,
-    ) -> StorageResult<Vec<SealedBlockHeader>> {
+    ) -> StorageResult<Option<Vec<SealedBlockHeader>>> {
         self.get_sealed_block_headers(block_height_range)
     }
 

crates/services/p2p/src/ports.rs

@@ -14,7 +14,7 @@ pub trait P2pDb: Send + Sync {
     fn get_sealed_headers(
         &self,
         block_height_range: Range<u32>,
-    ) -> StorageResult<Vec<SealedBlockHeader>>;
+    ) -> StorageResult<Option<Vec<SealedBlockHeader>>>;
 
     fn get_transactions(
         &self,

crates/services/p2p/src/service.rs

@@ -432,116 +432,109 @@ where
         request_message: RequestMessage,
         request_id: InboundRequestId,
     ) -> anyhow::Result<()> {
+        match request_message {
+            RequestMessage::Transactions(range) => {
+                self.handle_transactions_request(range, request_id)
+            }
+            RequestMessage::SealedHeaders(range) => {
+                self.handle_sealed_headers_request(range, request_id)
+            }
+        }
+    }
+
+    fn handle_request<DbLookUpFn, ResponseSenderFn, TaskRequestFn, R>(
+        &mut self,
+        range: Range<u32>,
+        request_id: InboundRequestId,
+        response_sender: ResponseSenderFn,
+        db_lookup: DbLookUpFn,
+        task_request: TaskRequestFn,
+    ) -> anyhow::Result<()>
+    where
+        DbLookUpFn:
+            Fn(&V::LatestView, Range<u32>) -> anyhow::Result<Option<R>> + Send + 'static,
+        ResponseSenderFn: Fn(Option<R>) -> ResponseMessage + Send + 'static,
+        TaskRequestFn: Fn(Option<R>, InboundRequestId) -> TaskRequest + Send + 'static,
+        R: Send + 'static,
+    {
         let instant = Instant::now();
         let timeout = self.response_timeout;
         let response_channel = self.request_sender.clone();
+        // For now, we only process requests that are smaller than the max_blocks_per_request
+        // If there are other types of data we send over p2p req/res protocol, then this needs
+        // to be generalized
         let max_len = self.max_headers_per_request;
 
-        match request_message {
-            RequestMessage::Transactions(range) => {
-                if range.len() > max_len {
-                    tracing::error!(
-                        requested_length = range.len(),
-                        max_len,
-                        "Requested range of blocks is too big"
-                    );
-                    let response = None;
-                    let _ = self.p2p_service.send_response_msg(
-                        request_id,
-                        ResponseMessage::Transactions(response),
-                    );
-                    return Ok(())
-                }
-
-                let view = self.view_provider.latest_view()?;
-                let result = self.database_processor.spawn(move || {
-                    if instant.elapsed() > timeout {
-                        tracing::warn!("Get transactions request timed out");
-                        return;
-                    }
+        if range.len() > max_len {
+            tracing::error!(
+                requested_length = range.len(),
+                max_len,
+                "Requested range is too big"
+            );
+            // TODO: Return helpful error message to requester. https://github.com/FuelLabs/fuel-core/issues/1311
+            let response = None;
+            let _ = self
+                .p2p_service
+                .send_response_msg(request_id, response_sender(response));
+            return Ok(());
+        }
 
-                    let response = view
-                        .get_transactions(range.clone())
-                        .trace_err(
-                            format!(
-                                "Failed to get transactions for the range {:?}",
-                                range
-                            )
-                            .as_str(),
-                        )
-                        .ok()
-                        .flatten();
-
-                    let _ = response_channel
-                        .try_send(TaskRequest::DatabaseTransactionsLookUp {
-                            response,
-                            request_id,
-                        })
-                        .trace_err(
-                            "Failed to send transactions response to the request channel",
-                        );
-                });
-
-                if result.is_err() {
-                    let _ = self.p2p_service.send_response_msg(
-                        request_id,
-                        ResponseMessage::Transactions(None),
-                    );
-                }
+        let view = self.view_provider.latest_view()?;
+        let result = self.database_processor.spawn(move || {
+            if instant.elapsed() > timeout {
+                tracing::warn!("Request timed out");
+                return;
             }
-            RequestMessage::SealedHeaders(range) => {
-                if range.len() > max_len {
-                    tracing::error!(
-                        requested_length = range.len(),
-                        max_len,
-                        "Requested range of sealed headers is too big"
-                    ); // TODO: Return helpful error message to requester. https://github.com/FuelLabs/fuel-core/issues/1311
-                    let response = None;
-                    let _ = self.p2p_service.send_response_msg(
-                        request_id,
-                        ResponseMessage::SealedHeaders(response),
-                    );
-                    return Ok(())
-                }
 
-                let view = self.view_provider.latest_view()?;
-                let result = self.database_processor.spawn(move || {
-                    if instant.elapsed() > timeout {
-                        tracing::warn!("Get headers request timed out");
-                        return;
-                    }
+            let response = db_lookup(&view, range.clone()).ok().flatten();
 
-                    let response = view
-                        .get_sealed_headers(range.clone())
-                        .trace_err(
-                            format!(
-                                "Failed to get sealed headers for the range {:?}",
-                                range
-                            )
-                            .as_str(),
-                        )
-                        .ok();
-
-                    let _ = response_channel
-                        .try_send(TaskRequest::DatabaseHeaderLookUp {
-                            response,
-                            request_id,
-                        })
-                        .trace_err(
-                            "Failed to send headers response to the request channel",
-                        );
-                });
-
-                if result.is_err() {
-                    let _ = self.p2p_service.send_response_msg(
-                        request_id,
-                        ResponseMessage::SealedHeaders(None),
-                    );
-                }
-            }
+            let _ = response_channel
+                .try_send(task_request(response, request_id))
+                .trace_err("Failed to send response to the request channel");
+        });
+
+        if result.is_err() {
+            let _ = self
+                .p2p_service
+                .send_response_msg(request_id, response_sender(None));
         }
+
         Ok(())
     }
+
+    fn handle_transactions_request(
+        &mut self,
+        range: Range<u32>,
+        request_id: InboundRequestId,
+    ) -> anyhow::Result<()> {
+        self.handle_request(
+            range,
+            request_id,
+            ResponseMessage::Transactions,
+            |view, range| view.get_transactions(range).map_err(anyhow::Error::from),
+            |response, request_id| TaskRequest::DatabaseTransactionsLookUp {
+                response,
+                request_id,
+            },
+        )
+    }
+
+    fn handle_sealed_headers_request(
+        &mut self,
+        range: Range<u32>,
+        request_id: InboundRequestId,
+    ) -> anyhow::Result<()> {
+        self.handle_request(
+            range,
+            request_id,
+            ResponseMessage::SealedHeaders,
+            |view, range| view.get_sealed_headers(range).map_err(anyhow::Error::from),
+            |response, request_id| TaskRequest::DatabaseHeaderLookUp {
+                response,
+                request_id,
+            },
+        )
+    }
 }
 
 fn convert_peer_id(peer_id: &PeerId) -> anyhow::Result<FuelPeerId> {
@@ -995,7 +988,7 @@ pub mod tests {
         fn get_sealed_headers(
             &self,
             _block_height_range: Range<u32>,
-        ) -> StorageResult<Vec<SealedBlockHeader>> {
+        ) -> StorageResult<Option<Vec<SealedBlockHeader>>> {
             unimplemented!()
         }
 
@@ -1111,7 +1104,7 @@ pub mod tests {
         fn get_sealed_headers(
             &self,
             _block_height_range: Range<u32>,
-        ) -> StorageResult<Vec<SealedBlockHeader>> {
+        ) -> StorageResult<Option<Vec<SealedBlockHeader>>> {
             todo!()
         }