Explorer add gc and confirmed block notion

jormungandr/src/blockchain/multiverse.rs

@@ -1,4 +1,4 @@
-use crate::blockcfg::{ChainLength, HeaderHash, Ledger, Multiverse as MultiverseData};
+use crate::blockcfg::{ChainLength, HeaderHash, Multiverse as MultiverseData};
 use chain_impl_mockchain::multiverse;
 use std::sync::Arc;
 use tokio::sync::RwLock;
@@ -43,12 +43,9 @@ impl<T: Clone> Multiverse<T> {
     }
 }
 
-impl Multiverse<Ledger> {
+impl<T> Multiverse<T> {
     /// run the garbage collection of the multiverse
     ///
-    /// TODO: this function is only working for the `Ledger` at the moment
-    ///       we need to generalize the `chain_impl_mockchain` to handle
-    ///       the garbage collection for any `T`
     pub async fn gc(&self, depth: u32) {
         let mut guard = self.inner.write().await;
         guard.gc(depth)

jormungandr/src/explorer/graphql/mod.rs

@@ -190,6 +190,10 @@ impl Block {
             });
         Ok(treasury)
     }
+
+    pub async fn is_confirmed(&self, context: &Context) -> bool {
+        context.db.is_block_confirmed(&self.hash).await
+    }
 }
 
 struct BftLeader {
@@ -698,6 +702,14 @@ impl Status {
         latest_block(context).await.map(|b| Block::from(&b))
     }
 
+    pub async fn epoch_stability_depth(&self, context: &Context) -> String {
+        context
+            .db
+            .blockchain_config
+            .epoch_stability_depth
+            .to_string()
+    }
+
     pub fn fee_settings(&self, context: &Context) -> FeeSettings {
         let chain_impl_mockchain::fee::LinearFee {
             constant,

jormungandr/src/explorer/mod.rs

@@ -29,8 +29,11 @@ use chain_impl_mockchain::fee::LinearFee;
 use chain_impl_mockchain::multiverse;
 use futures::prelude::*;
 use std::convert::Infallible;
-use std::sync::Arc;
-use tokio::sync::RwLock;
+use std::sync::{
+    atomic::{AtomicU32, Ordering},
+    Arc,
+};
+use tokio::sync::{Mutex, RwLock};
 
 #[derive(Clone)]
 pub struct Explorer {
@@ -53,6 +56,12 @@ pub struct ExplorerDB {
     pub blockchain_config: BlockchainConfig,
     blockchain: Blockchain,
     blockchain_tip: blockchain::Tip,
+    stable_store: StableIndex,
+}
+
+#[derive(Clone)]
+pub struct StableIndex {
+    confirmed_block_chain_length: Arc<AtomicU32>,
 }
 
 #[derive(Clone)]
@@ -62,6 +71,7 @@ pub struct BlockchainConfig {
     discrimination: Discrimination,
     consensus_version: ConsensusVersion,
     fees: LinearFee,
+    epoch_stability_depth: u32,
 }
 
 /// Inmutable data structure used to represent the explorer's state at a given Block
@@ -104,35 +114,42 @@ impl Explorer {
         }
     }
 
-    pub async fn start(&mut self, info: TokioServiceInfo, messages: MessageQueue<ExplorerMsg>) {
+    pub async fn start(&self, info: TokioServiceInfo, messages: MessageQueue<ExplorerMsg>) {
+        let tip_candidate: Arc<Mutex<Option<HeaderHash>>> = Arc::new(Mutex::new(None));
+
         messages
-            .for_each(|input| async {
+            .for_each(|input| {
+                let explorer_db = self.db.clone();
+                let tip_candidate = Arc::clone(&tip_candidate);
                 match input {
                     ExplorerMsg::NewBlock(block) => {
-                        let explorer_db = self.db.clone();
-                        let logger = info.logger().clone();
-                        info.spawn_fallible("apply block", async move {
-                            explorer_db
-                                .apply_block(block)
-                                .map(move |result| match result {
-                                    // XXX: There is no garbage collection now, so the GCRoot is not used
-                                    Ok(_gc_root) => Ok(()),
-                                    Err(err) => {
-                                        error!(logger, "Explorer error: {}", err);
-                                        Err(())
-                                    }
-                                })
-                                .await
+                        info.spawn_fallible::<_, Error>("apply block to explorer", async move {
+                            let _state_ref = explorer_db.apply_block(block.clone()).await?;
+
+                            let mut guard = tip_candidate.lock().await;
+                            if guard.map(|hash| hash == block.header.id()).unwrap_or(false) {
+                                let hash = guard.take().unwrap();
+                                explorer_db.set_tip(hash).await;
+                            }
+
+                            Ok(())
                         });
                     }
                     ExplorerMsg::NewTip(hash) => {
-                        let explorer_db = self.db.clone();
-                        info.spawn(
-                            "apply block",
-                            async move { explorer_db.set_tip(hash).await },
-                        );
+                        info.spawn_fallible::<_, Error>("apply block to explorer", async move {
+                            let successful = explorer_db.set_tip(hash).await;
+
+                            if !successful {
+                                let mut guard = tip_candidate.lock().await;
+                                guard.replace(hash);
+                            }
+
+                            Ok(())
+                        });
                     }
-                }
+                };
+
+                futures::future::ready(())
             })
             .await;
     }
@@ -197,24 +214,27 @@ impl ExplorerDB {
 
         let block0_id = block0.id();
 
-        let bootstraped_db = ExplorerDB {
-            multiverse,
-            longest_chain_tip: Tip::new(block0.header.id()),
-            blockchain_config,
-            blockchain: blockchain.clone(),
-            blockchain_tip,
-        };
-
         let maybe_head = blockchain.storage().get_tag(MAIN_BRANCH_TAG)?;
-        let stream = match maybe_head {
-            Some(head) => blockchain.storage().stream_from_to(block0_id, head)?,
+        let (stream, hash) = match maybe_head {
+            Some(head) => (blockchain.storage().stream_from_to(block0_id, head)?, head),
             None => {
                 return Err(Error::from(ErrorKind::BootstrapError(
                     "Couldn't read the HEAD tag from storage".to_owned(),
                 )))
             }
         };
 
+        let bootstraped_db = ExplorerDB {
+            multiverse,
+            longest_chain_tip: Tip::new(hash),
+            blockchain_config,
+            blockchain: blockchain.clone(),
+            blockchain_tip,
+            stable_store: StableIndex {
+                confirmed_block_chain_length: Arc::new(AtomicU32::default()),
+            },
+        };
+
         let db = stream
             .map_err(Error::from)
             .try_fold(bootstraped_db, |db, block| async move {
@@ -311,11 +331,6 @@ impl ExplorerDB {
         Ok(state_ref)
     }
 
-    pub async fn set_tip(&self, hash: HeaderHash) {
-        let mut guard = self.longest_chain_tip.0.write().await;
-        *guard = hash;
-    }
-
     pub async fn get_latest_block_hash(&self) -> HeaderHash {
         self.longest_chain_tip.get_block_id().await
     }
@@ -328,6 +343,45 @@ impl ExplorerDB {
         .await
     }
 
+    pub(self) async fn set_tip(&self, hash: HeaderHash) -> bool {
+        // the tip changes which means now a block is confirmed (at least after
+        // the initial epoch_stability_depth blocks).
+
+        let block = if let Some(state_ref) = self.multiverse.get_ref(hash).await {
+            let state = state_ref.state();
+            Arc::clone(state.blocks.lookup(&hash).unwrap())
+        } else {
+            return false;
+        };
+
+        if let Some(confirmed_block_chain_length) = block
+            .chain_length()
+            .nth_ancestor(self.blockchain_config.epoch_stability_depth)
+        {
+            debug_assert!(
+                ChainLength::from(
+                    self.stable_store
+                        .confirmed_block_chain_length
+                        .load(Ordering::Acquire)
+                ) <= block.chain_length()
+            );
+
+            self.stable_store
+                .confirmed_block_chain_length
+                .store(confirmed_block_chain_length.into(), Ordering::Release);
+
+            self.multiverse
+                .gc(self.blockchain_config.epoch_stability_depth)
+                .await;
+        }
+
+        let mut guard = self.longest_chain_tip.0.write().await;
+
+        *guard = hash;
+
+        true
+    }
+
     pub async fn get_epoch(&self, epoch: Epoch) -> Option<EpochData> {
         self.with_latest_state(move |state| state.epochs.lookup(&epoch).map(|e| e.as_ref().clone()))
             .await
@@ -397,6 +451,19 @@ impl ExplorerDB {
         .await
     }
 
+    pub async fn is_block_confirmed(&self, block_id: &HeaderHash) -> bool {
+        if let Some(block) = self.get_block(block_id).await {
+            let confirmed_block_chain_length: ChainLength = self
+                .stable_store
+                .confirmed_block_chain_length
+                .load(Ordering::Acquire)
+                .into();
+            block.chain_length <= confirmed_block_chain_length
+        } else {
+            false
+        }
+    }
+
     pub async fn get_stake_pool_blocks(
         &self,
         pool: &PoolId,
@@ -771,37 +838,36 @@ fn apply_block_to_vote_plans(
 
 impl BlockchainConfig {
     fn from_config_params(params: &ConfigParams) -> BlockchainConfig {
-        let discrimination = params
-            .iter()
-            .filter_map(|param| match param {
-                ConfigParam::Discrimination(discrimination) => Some(discrimination),
-                _ => None,
-            })
-            .next()
-            .expect("the discrimination to be present");
-
-        let consensus_version = params
-            .iter()
-            .filter_map(|param| match param {
-                ConfigParam::ConsensusVersion(version) => Some(version),
-                _ => None,
-            })
-            .next()
-            .expect("consensus version to be present");
-
-        let fees = params
-            .iter()
-            .filter_map(|param| match param {
-                ConfigParam::LinearFee(fee) => Some(fee),
-                _ => None,
-            })
-            .next()
-            .expect("fee is not in config params");
+        let mut discrimination: Option<Discrimination> = None;
+        let mut consensus_version: Option<ConsensusVersion> = None;
+        let mut fees: Option<LinearFee> = None;
+        let mut epoch_stability_depth: Option<u32> = None;
+
+        for p in params.iter() {
+            match p {
+                ConfigParam::Discrimination(d) => {
+                    discrimination.replace(*d);
+                }
+                ConfigParam::ConsensusVersion(v) => {
+                    consensus_version.replace(*v);
+                }
+                ConfigParam::LinearFee(fee) => {
+                    fees.replace(*fee);
+                }
+                ConfigParam::EpochStabilityDepth(d) => {
+                    epoch_stability_depth.replace(*d);
+                }
+                _ => (),
+            }
+        }
 
         BlockchainConfig {
-            discrimination: *discrimination,
-            consensus_version: *consensus_version,
-            fees: *fees,
+            discrimination: discrimination.expect("discrimination not found in initial params"),
+            consensus_version: consensus_version
+                .expect("consensus version not found in initial params"),
+            fees: fees.expect("fees not found in initial params"),
+            epoch_stability_depth: epoch_stability_depth
+                .expect("epoch stability depth not found in initial params"),
         }
     }
 }

jormungandr/src/main.rs

@@ -128,7 +128,7 @@ fn start_services(bootstrapped_node: BootstrappedNode) -> Result<(), start_up::E
                 .explorer_db
                 .expect("explorer db to be bootstrapped");
 
-            let mut explorer = explorer::Explorer::new(explorer_db);
+            let explorer = explorer::Explorer::new(explorer_db);
 
             // Context to give to the rest api
             let context = explorer.clone();