Support a basic update callback system

.gitignore

@@ -2,3 +2,4 @@
 **/*.rs.bk
 Cargo.lock
 /*.rkv
+/query-history.txt

meilidb-core/Cargo.toml

@@ -5,6 +5,7 @@ authors = ["Clément Renault <clement@meilisearch.com>"]
 edition = "2018"
 
 [dependencies]
+arc-swap = "0.4.3"
 bincode = "1.1.4"
 byteorder = "1.3.2"
 crossbeam-channel = "0.3.9"

meilidb-core/examples/from_file.rs

@@ -5,14 +5,14 @@ use std::io::Write;
 use std::iter::FromIterator;
 use std::path::{Path, PathBuf};
 use std::time::{Instant, Duration};
-use std::{fs, io};
+use std::{fs, io, sync::mpsc};
 
 use rustyline::{Editor, Config};
 use serde::{Serialize, Deserialize};
 use structopt::StructOpt;
 use termcolor::{Color, ColorChoice, ColorSpec, StandardStream, WriteColor};
 
-use meilidb_core::{Highlight, Database};
+use meilidb_core::{Highlight, Database, UpdateResult, BoxUpdateFn};
 use meilidb_schema::SchemaAttr;
 
 const INDEX_NAME: &str = "default";
@@ -79,8 +79,10 @@ struct Document(HashMap<String, String>);
 fn index_command(command: IndexCommand, database: Database) -> Result<(), Box<dyn Error>> {
     let start = Instant::now();
 
+    let (sender, receiver) = mpsc::sync_channel(0);
+    let update_fn = move |update: UpdateResult| sender.send(update.update_id).unwrap();
+    let index = database.open_index(INDEX_NAME, Some(Box::new(update_fn)))?;
     let rkv = database.rkv.read().unwrap();
-    let index = database.open_index(INDEX_NAME)?;
 
     let schema = {
         let string = fs::read_to_string(&command.schema)?;
@@ -139,14 +141,9 @@ fn index_command(command: IndexCommand, database: Database) -> Result<(), Box<dy
         max_update_id = max_update_id.max(update_id);
     }
 
-    loop {
     println!("Waiting for update {}", max_update_id);
-
-        let reader = rkv.read().unwrap();
-        if let Some(_) = index.updates_results.update_result(&reader, max_update_id)? {
-            break
-        }
-        std::thread::sleep(std::time::Duration::from_secs(1));
+    for id in receiver {
+        if id == max_update_id { break }
     }
 
     println!("database created in {:.2?} at: {:?}", start.elapsed(), command.database_path);
@@ -253,7 +250,8 @@ fn crop_text(
 
 fn search_command(command: SearchCommand, database: Database) -> Result<(), Box<dyn Error>> {
     let rkv = database.rkv.read().unwrap();
-    let index = database.open_index(INDEX_NAME)?;
+    let update_fn = None as Option::<BoxUpdateFn>;
+    let index = database.open_index(INDEX_NAME, update_fn)?;
     let reader = rkv.read().unwrap();
 
     let schema = index.main.schema(&reader)?;

meilidb-core/src/database.rs

@@ -8,14 +8,23 @@ use log::{debug, error};
 
 use crate::{store, update, Index, MResult};
 
+pub type BoxUpdateFn = Box<dyn Fn(update::UpdateResult) + Send + Sync + 'static>;
+type ArcSwapFn = arc_swap::ArcSwapOption<BoxUpdateFn>;
+
 pub struct Database {
     pub rkv: Arc<RwLock<rkv::Rkv>>,
     main_store: rkv::SingleStore,
     indexes_store: rkv::SingleStore,
-    indexes: RwLock<HashMap<String, (Index, thread::JoinHandle<()>)>>,
+    indexes: RwLock<HashMap<String, (Index, Arc<ArcSwapFn>, thread::JoinHandle<()>)>>,
 }
 
-fn update_awaiter(receiver: Receiver<()>, rkv: Arc<RwLock<rkv::Rkv>>, index: Index) {
+fn update_awaiter(
+    receiver: Receiver<()>,
+    rkv: Arc<RwLock<rkv::Rkv>>,
+    update_fn: Arc<ArcSwapFn>,
+    index: Index,
+)
+{
     for () in receiver {
         // consume all updates in order (oldest first)
         loop {
@@ -29,7 +38,13 @@ fn update_awaiter(receiver: Receiver<()>, rkv: Arc<RwLock<rkv::Rkv>>, index: Ind
                 Err(e) => { error!("LMDB writer transaction begin failed: {}", e); break }
             };
 
-            match update::update_task(&mut writer, index.clone(), None as Option::<fn(_)>) {
+            let update_fn = update_fn.load();
+            let update_fn: Option<&dyn Fn(update::UpdateResult)> = match *update_fn {
+                Some(ref f) => Some(f.as_ref()),
+                None => None,
+            };
+
+            match update::update_task(&mut writer, index.clone(), update_fn) {
                 Ok(true) => if let Err(e) = writer.commit() { error!("update transaction failed: {}", e) },
                 // no more updates to handle for now
                 Ok(false) => { debug!("no more updates"); writer.abort(); break },
@@ -78,15 +93,21 @@ impl Database {
 
             let (sender, receiver) = crossbeam_channel::bounded(100);
             let index = store::open(&rkv_read, &index_name, sender.clone())?;
+            let update_fn = Arc::new(ArcSwapFn::empty());
+
             let rkv_clone = rkv.clone();
             let index_clone = index.clone();
-            let handle = thread::spawn(move || update_awaiter(receiver, rkv_clone, index_clone));
+            let update_fn_clone = update_fn.clone();
+
+            let handle = thread::spawn(move || {
+                update_awaiter(receiver, rkv_clone, update_fn_clone, index_clone)
+            });
 
             // send an update notification to make sure that
             // possible previous boot updates are consumed
             sender.send(()).unwrap();
 
-            let result = indexes.insert(index_name, (index, handle));
+            let result = indexes.insert(index_name, (index, update_fn, handle));
             assert!(result.is_none(), "The index should not have been already open");
         }
 
@@ -95,12 +116,20 @@ impl Database {
         Ok(Database { rkv, main_store, indexes_store, indexes: RwLock::new(indexes) })
     }
 
-    pub fn open_index(&self, name: impl Into<String>) -> MResult<Index> {
+    pub fn open_index(
+        &self,
+        name: impl Into<String>,
+        update_fn: Option<BoxUpdateFn>,
+    ) -> MResult<Index>
+    {
         let indexes_lock = self.indexes.read().unwrap();
         let name = name.into();
 
         match indexes_lock.get(&name) {
-            Some((index, _)) => Ok(index.clone()),
+            Some((index, old_update_fn, _)) => {
+                old_update_fn.swap(update_fn.map(Arc::new));
+                Ok(index.clone())
+            },
             None => {
                 drop(indexes_lock);
 
@@ -117,8 +146,16 @@ impl Database {
                     indexes_write.entry(name).or_insert_with(|| {
                         let rkv_clone = self.rkv.clone();
                         let index_clone = index.clone();
-                        let handle = thread::spawn(move || update_awaiter(receiver, rkv_clone, index_clone));
-                        (index.clone(), handle)
+
+                        let update_fn = update_fn.map(Arc::new);
+                        let update_fn = Arc::new(ArcSwapFn::new(update_fn));
+                        let update_fn_clone = update_fn.clone();
+
+                        let handle = thread::spawn(move || {
+                            update_awaiter(receiver, rkv_clone, update_fn_clone, index_clone)
+                        });
+
+                        (index.clone(), update_fn, handle)
                     });
                 }
 

meilidb-core/src/lib.rs

@@ -15,13 +15,13 @@ pub mod raw_indexer;
 pub mod serde;
 pub mod store;
 
-pub use self::database::Database;
+pub use self::database::{Database, BoxUpdateFn};
 pub use self::error::{Error, MResult};
 pub use self::number::{Number, ParseNumberError};
 pub use self::ranked_map::RankedMap;
 pub use self::raw_document::RawDocument;
 pub use self::store::Index;
-pub use self::update::UpdateStatus;
+pub use self::update::{UpdateStatus, UpdateResult};
 
 use zerocopy::{AsBytes, FromBytes};
 use ::serde::{Serialize, Deserialize};

meilidb-core/src/query_builder.rs

@@ -296,10 +296,10 @@ mod tests {
     use sdset::SetBuf;
     use tempfile::TempDir;
 
+    use crate::automaton::normalize_str;
+    use crate::database::{Database, BoxUpdateFn};
     use crate::DocIndex;
     use crate::store::Index;
-    use crate::database::Database;
-    use crate::automaton::normalize_str;
 
     fn set_from_stream<'f, I, S>(stream: I) -> Set
     where
@@ -392,7 +392,8 @@ mod tests {
         fn from_iter<I: IntoIterator<Item=(&'a str, &'a [DocIndex])>>(iter: I) -> Self {
             let tempdir = TempDir::new().unwrap();
             let database = Database::open_or_create(&tempdir).unwrap();
-            let index = database.open_index("default").unwrap();
+            let update_fn = None as Option::<BoxUpdateFn>;
+            let index = database.open_index("default", update_fn).unwrap();
 
             let rkv = database.rkv.read().unwrap();
             let mut writer = rkv.write().unwrap();

meilidb-core/src/update/mod.rs

@@ -98,7 +98,7 @@ pub fn next_update_id(
 pub fn update_task(
     writer: &mut rkv::Writer,
     index: store::Index,
-    mut callback: Option<impl FnOnce(UpdateResult)>,
+    mut callback: Option<impl Fn(UpdateResult)>,
 ) -> MResult<bool>
 {
     let (update_id, update) = match index.updates.pop_front(writer)? {
@@ -111,6 +111,7 @@ pub fn update_task(
     let (update_type, result, duration) = match update {
         Update::SchemaUpdate(schema) => {
             let start = Instant::now();
+
             let update_type = UpdateType::SchemaUpdate { schema: schema.clone() };
             let result = apply_schema_update(writer, index.main, &schema);