Remove tokio as a dependency

Closes SUR-102

lib/Cargo.toml

@@ -7,7 +7,7 @@ authors = ["Tobie Morgan Hitchcock <tobie@surrealdb.com>"]
 
 [features]
 default = ["parallel", "kv-tikv", "kv-echodb", "kv-yokudb"]
-parallel = ["tokio"]
+parallel = []
 kv-tikv = ["tikv"]
 kv-echodb = ["echodb"]
 kv-indxdb = ["indxdb"]
@@ -47,7 +47,6 @@ sha2 = "0.10.2"
 slug = "0.1.4"
 thiserror = "1.0.31"
 tikv = { version = "0.1.0", package = "tikv-client", optional = true }
-tokio = { version = "1.18.1", features = ["sync"], optional = true }
 url = "2.2.2"
 utf-8 = "0.7.6"
 uuid = { version = "1.0.0", features = ["serde", "v4"] }

lib/src/err/mod.rs

@@ -7,9 +7,6 @@ use storekey::decode::Error as DecodeError;
 use storekey::encode::Error as EncodeError;
 use thiserror::Error;
 
-#[cfg(feature = "parallel")]
-use tokio::sync::mpsc::error::SendError as TokioError;
-
 /// An error originating from the SurrealDB client library.
 #[derive(Error, Debug)]
 pub enum Error {
@@ -252,15 +249,14 @@ impl From<tikv::Error> for Error {
 	}
 }
 
-#[cfg(feature = "parallel")]
-impl From<TokioError<bytes::Bytes>> for Error {
-	fn from(e: TokioError<bytes::Bytes>) -> Error {
+impl From<channel::RecvError> for Error {
+	fn from(e: channel::RecvError) -> Error {
 		Error::Channel(e.to_string())
 	}
 }
 
-impl From<channel::RecvError> for Error {
-	fn from(e: channel::RecvError) -> Error {
+impl From<channel::SendError<bytes::Bytes>> for Error {
+	fn from(e: channel::SendError<bytes::Bytes>) -> Error {
 		Error::Channel(e.to_string())
 	}
 }

lib/src/exe/mod.rs

@@ -0,0 +1,17 @@
+use executor::{Executor, Task};
+use once_cell::sync::Lazy;
+use std::future::Future;
+use std::panic::catch_unwind;
+
+pub fn spawn<T: Send + 'static>(future: impl Future<Output = T> + Send + 'static) -> Task<T> {
+	static GLOBAL: Lazy<Executor<'_>> = Lazy::new(|| {
+		std::thread::spawn(|| {
+			catch_unwind(|| {
+				futures::executor::block_on(GLOBAL.run(futures::future::pending::<()>()))
+			})
+			.ok();
+		});
+		Executor::new()
+	});
+	GLOBAL.spawn(future)
+}

lib/src/kvs/ds.rs

@@ -12,7 +12,7 @@ use crate::sql;
 use crate::sql::query::Query;
 use crate::sql::thing::Thing;
 use bytes::Bytes;
-use tokio::sync::mpsc::Sender;
+use channel::Receiver;
 
 /// The underlying datastore instance which stores the dataset.
 pub struct Datastore {
@@ -199,9 +199,13 @@ impl Datastore {
 	}
 
 	/// Performs a full database export as SQL
-	pub async fn export(&self, ns: String, db: String, chn: Sender<Bytes>) -> Result<(), Error> {
+	pub async fn export(&self, ns: String, db: String) -> Result<Receiver<Bytes>, Error> {
 		// Start a new transaction
 		let mut txn = self.transaction(false, false).await?;
+		// Create a new channel
+		let (chn, rcv) = channel::bounded(10);
+		// Spawn the export
+		crate::exe::spawn(async move {
 			// Output OPTIONS
 			{
 				chn.send(output!("-- ------------------------------")).await?;
@@ -341,7 +345,8 @@ impl Datastore {
 									let v: crate::sql::value::Value = (&v).into();
 									let t = Thing::from((k.tb, k.id));
 									// Write record
-								chn.send(output!(format!("UPDATE {} CONTENT {};", t, v))).await?;
+									chn.send(output!(format!("UPDATE {} CONTENT {};", t, v)))
+										.await?;
 								}
 								continue;
 							}
@@ -357,8 +362,13 @@ impl Datastore {
 					chn.send(output!("COMMIT TRANSACTION;")).await?;
 					chn.send(output!("")).await?;
 				}
-		}
-		// Everything fine
-		Ok(())
+			};
+			// Everything exported
+			Ok::<(), Error>(())
+			// Task done
+		})
+		.detach();
+		// Send back the receiver
+		Ok(rcv)
 	}
 }

lib/src/lib.rs

@@ -19,12 +19,15 @@ mod ctx;
 mod dbs;
 mod doc;
 mod err;
+mod exe;
 mod fnc;
 mod key;
 mod kvs;
 
+// SQL
 pub mod sql;
 
+// Exports
 pub use dbs::Auth;
 pub use dbs::Response;
 pub use dbs::Session;
@@ -33,3 +36,6 @@ pub use kvs::Datastore;
 pub use kvs::Key;
 pub use kvs::Transaction;
 pub use kvs::Val;
+
+// Re-exports
+pub use channel::Receiver;

src/net/export.rs

@@ -25,19 +25,23 @@ async fn handler(session: Session) -> Result<impl warp::Reply, warp::Rejection>
 			let dbv = session.db.clone().unwrap();
 			// Create a chunked response
 			let (mut chn, bdy) = Body::channel();
-			// Initiate a new async channel
-			let (snd, mut rcv) = tokio::sync::mpsc::channel(100);
 			// Spawn a new database export
-			tokio::spawn(db.export(nsv, dbv, snd));
+			match db.export(nsv, dbv).await {
+				Ok(rcv) => {
 					// Process all processed values
 					tokio::spawn(async move {
-				while let Some(v) = rcv.recv().await {
+						while let Ok(v) = rcv.recv().await {
 							let _ = chn.send_data(v).await;
 						}
 					});
 					// Return the chunked body
 					Ok(warp::reply::Response::new(bdy))
 				}
+				// There was en error with the export
+				_ => Err(warp::reject::custom(Error::InvalidAuth)),
+			}
+		}
+		// There was an error with permissions
 		_ => Err(warp::reject::custom(Error::InvalidAuth)),
 	}
 }