feat: *pop_non_blocking()

springql-core/src/api/high_level_rs.rs

@@ -4,7 +4,10 @@
 
 use crate::{
     error::{Result, SpringError},
-    low_level_rs::{spring_command, spring_open, spring_pop, SpringConfig, SpringPipeline},
+    low_level_rs::{
+        spring_command, spring_open, spring_pop, spring_pop_non_blocking, SpringConfig,
+        SpringPipeline,
+    },
     stream_engine::{SinkRow, SpringValue, SqlValue},
 };
 
@@ -35,13 +38,32 @@ impl SpringPipelineHL {
 
     /// Pop a row from an in memory queue. This is a blocking function.
     ///
+    /// **Do not call this function from threads.**
+    /// If you need to pop from multiple in-memory queues using threads, use `spring_pop_non_blocking()`.
+    /// See: <https://github.com/SpringQL/SpringQL/issues/125>
+    ///
     /// # Failure
     ///
     /// - [SpringError::Unavailable](crate::error::SpringError::Unavailable) when:
     ///   - queue named `queue` does not exist.
     pub fn pop(&self, queue: &str) -> Result<SpringRowHL> {
         spring_pop(&self.0, queue).map(|row| SpringRowHL(row.0))
     }
+
+    /// Pop a row from an in memory queue. This is a non-blocking function.
+    ///
+    /// # Returns
+    ///
+    /// - `Ok(Some)` when at least a row is in the queue.
+    /// - `None` when no row is in the queue.
+    ///
+    /// # Failure
+    ///
+    /// - [SpringError::Unavailable](crate::error::SpringError::Unavailable) when:
+    ///   - queue named `queue` does not exist.
+    pub fn pop_non_blocking(&self, queue: &str) -> Result<Option<SpringRowHL>> {
+        spring_pop_non_blocking(&self.0, queue).map(|opt_row| opt_row.map(|row| SpringRowHL(row.0)))
+    }
 }
 
 /// Row object from an in memory queue.

springql-core/src/api/low_level_rs.rs

@@ -9,7 +9,7 @@ mod spring_config;
 
 pub use spring_config::*;
 
-use std::sync::Once;
+use std::{sync::Once, thread, time::Duration};
 
 use crate::{
     error::{Result, SpringError},
@@ -89,14 +89,48 @@ pub fn spring_command(pipeline: &SpringPipeline, sql: &str) -> Result<()> {
 
 /// Pop a row from an in memory queue. This is a blocking function.
 ///
+/// **Do not call this function from threads.**
+/// If you need to pop from multiple in-memory queues using threads, use `spring_pop_non_blocking()`.
+/// See: <https://github.com/SpringQL/SpringQL/issues/125>
+///
 /// # Failure
 ///
 /// - [SpringError::Unavailable](crate::error::SpringError::Unavailable) when:
 ///   - queue named `queue` does not exist.
 pub fn spring_pop(pipeline: &SpringPipeline, queue: &str) -> Result<SpringRow> {
+    const SLEEP_MSECS: u64 = 10;
+
+    let mut engine = pipeline.engine.get()?;
+
+    loop {
+        if let Some(sink_row) =
+            engine.pop_in_memory_queue_non_blocking(QueueName::new(queue.to_string()))?
+        {
+            return Ok(SpringRow::from(sink_row));
+        } else {
+            thread::sleep(Duration::from_millis(SLEEP_MSECS));
+        }
+    }
+}
+
+/// Pop a row from an in memory queue. This is a non-blocking function.
+///
+/// # Returns
+///
+/// - `Ok(Some)` when at least a row is in the queue.
+/// - `None` when no row is in the queue.
+///
+/// # Failure
+///
+/// - [SpringError::Unavailable](crate::error::SpringError::Unavailable) when:
+///   - queue named `queue` does not exist.
+pub fn spring_pop_non_blocking(
+    pipeline: &SpringPipeline,
+    queue: &str,
+) -> Result<Option<SpringRow>> {
     let mut engine = pipeline.engine.get()?;
-    let sink_row = engine.pop_in_memory_queue(QueueName::new(queue.to_string()))?;
-    Ok(SpringRow::from(sink_row))
+    let sink_row = engine.pop_in_memory_queue_non_blocking(QueueName::new(queue.to_string()))?;
+    Ok(sink_row.map(SpringRow::from))
 }
 
 /// Get an integer column.

springql-core/src/stream_engine.rs

@@ -83,15 +83,21 @@ impl StreamEngine {
         self.autonomous_executor.notify_pipeline_update(pipeline)
     }
 
-    /// Blocking call
+    /// # Returns
+    ///
+    /// - `Ok(Some)` when at least a row is in the queue.
+    /// - `None` when no row is in the queue.
     ///
     /// # Failure
     ///
     /// - [SpringError::Unavailable](crate::error::SpringError::Unavailable) when:
     ///   - queue named `queue_name` does not exist.
-    pub(crate) fn pop_in_memory_queue(&mut self, queue_name: QueueName) -> Result<SinkRow> {
+    pub(crate) fn pop_in_memory_queue_non_blocking(
+        &mut self,
+        queue_name: QueueName,
+    ) -> Result<Option<SinkRow>> {
         let q = InMemoryQueueRepository::instance().get(&queue_name)?;
-        let row = q.pop();
+        let row = q.pop_non_blocking();
         Ok(row)
     }
 }

springql-core/src/stream_engine/in_memory_queue_repository/in_memory_queue.rs

@@ -3,30 +3,22 @@
 use std::{
     collections::VecDeque,
     sync::{Mutex, MutexGuard},
-    thread,
-    time::Duration,
 };
 
 use crate::stream_engine::autonomous_executor::row::foreign_row::sink_row::SinkRow;
 
-const SLEEP_MSECS: u64 = 10;
-
 #[derive(Debug, Default)]
 pub(in crate::stream_engine) struct InMemoryQueue(
     Mutex<VecDeque<SinkRow>>, // TODO faster (lock-free?) queue
 );
 
 impl InMemoryQueue {
-    /// Blocking call    
-    pub(in crate::stream_engine) fn pop(&self) -> SinkRow {
-        loop {
-            let r = self.lock().pop_front();
-            if let Some(r) = r {
-                return r;
-            } else {
-                thread::sleep(Duration::from_millis(SLEEP_MSECS));
-            }
-        }
+    /// # Returns
+    ///
+    /// - `Ok(Some)` when at least a row is in the queue.
+    /// - `None` when no row is in the queue.
+    pub(in crate::stream_engine) fn pop_non_blocking(&self) -> Option<SinkRow> {
+        self.lock().pop_front()
     }
 
     pub(in crate::stream_engine) fn push(&self, row: SinkRow) {

springql-core/tests/e2e_high_level_rs.rs

@@ -251,3 +251,88 @@ fn test_e2e_pop_from_in_memory_queue() {
         assert_eq!(row.get_not_null_by_index::<i32>(1).unwrap(), amount);
     }
 }
+
+#[test]
+fn test_e2e_pop_non_blocking_from_in_memory_queue() {
+    setup_test_logger();
+
+    let queue_name = "queue_trade_nb"; // FIXME using the same name as in test_e2e_pop_from_in_memory_queue causes panic
+    let ts = "2021-11-04 23:02:52.123456789";
+    let ticker = "ORCL";
+    let amount = 20;
+
+    let json_oracle = json!({
+        "ts": ts,
+        "ticker": ticker,
+        "amount": amount,
+    });
+    let trade_times = 5;
+
+    let test_source = ForeignSource::new().unwrap();
+
+    let ddls = vec![
+        "
+        CREATE SOURCE STREAM source_trade (
+          ts TIMESTAMP NOT NULL ROWTIME,    
+          ticker TEXT NOT NULL,
+          amount INTEGER NOT NULL
+        );
+        "
+        .to_string(),
+        "
+        CREATE SINK STREAM sink_trade (
+          ts TIMESTAMP NOT NULL,    
+          amount INTEGER NOT NULL
+        );
+        "
+        .to_string(),
+        "
+        CREATE PUMP pu_projection AS
+          INSERT INTO sink_trade (ts, amount)
+          SELECT STREAM source_trade.ts, source_trade.amount FROM source_trade;
+        "
+        .to_string(),
+        format!(
+            "
+      CREATE SINK WRITER queue_sink_trade FOR sink_trade
+        TYPE IN_MEMORY_QUEUE OPTIONS (
+          NAME '{queue_name}'
+      );
+      ",
+            queue_name = queue_name,
+        ),
+        format!(
+            "
+        CREATE SOURCE READER tcp_trade FOR source_trade
+          TYPE NET_CLIENT OPTIONS (
+            PROTOCOL 'TCP',
+            REMOTE_HOST '{remote_host}',
+            REMOTE_PORT '{remote_port}'
+          );
+        ",
+            remote_host = test_source.host_ip(),
+            remote_port = test_source.port()
+        ),
+    ];
+
+    let pipeline = apply_ddls(&ddls, SpringConfig::default());
+    test_source.start(ForeignSourceInput::new_fifo_batch(
+        (0..trade_times)
+            .into_iter()
+            .map(|_| json_oracle.clone())
+            .collect(),
+    ));
+
+    for _ in 0..trade_times {
+        loop {
+            match pipeline.pop_non_blocking(queue_name).unwrap() {
+                Some(row) => {
+                    assert_eq!(row.get_not_null_by_index::<String>(0).unwrap(), ts);
+                    assert_eq!(row.get_not_null_by_index::<i32>(1).unwrap(), amount);
+                    break;
+                }
+                None => {}
+            }
+        }
+    }
+}

springql-core/tests/e2e_low_level_rs.rs

@@ -252,6 +252,91 @@ fn test_e2e_pop_from_in_memory_queue() {
     }
 }
 
+#[test]
+fn test_e2e_pop_non_blocking_from_in_memory_queue() {
+    setup_test_logger();
+
+    let queue_name = "queue_trade_nb"; // FIXME using the same name as in test_e2e_pop_from_in_memory_queue causes panic
+    let ts = "2021-11-04 23:02:52.123456789";
+    let ticker = "ORCL";
+    let amount = 20;
+
+    let json_oracle = json!({
+        "ts": ts,
+        "ticker": ticker,
+        "amount": amount,
+    });
+    let trade_times = 5;
+
+    let test_source = ForeignSource::new().unwrap();
+
+    let ddls = vec![
+        "
+        CREATE SOURCE STREAM source_trade (
+          ts TIMESTAMP NOT NULL ROWTIME,    
+          ticker TEXT NOT NULL,
+          amount INTEGER NOT NULL
+        );
+        "
+        .to_string(),
+        "
+        CREATE SINK STREAM sink_trade (
+          ts TIMESTAMP NOT NULL,    
+          amount INTEGER NOT NULL
+        );
+        "
+        .to_string(),
+        "
+        CREATE PUMP pu_projection AS
+          INSERT INTO sink_trade (ts, amount)
+          SELECT STREAM source_trade.ts, source_trade.amount FROM source_trade;
+        "
+        .to_string(),
+        format!(
+            "
+      CREATE SINK WRITER queue_sink_trade FOR sink_trade
+        TYPE IN_MEMORY_QUEUE OPTIONS (
+          NAME '{queue_name}'
+      );
+      ",
+            queue_name = queue_name,
+        ),
+        format!(
+            "
+        CREATE SOURCE READER tcp_trade FOR source_trade
+          TYPE NET_CLIENT OPTIONS (
+            PROTOCOL 'TCP',
+            REMOTE_HOST '{remote_host}',
+            REMOTE_PORT '{remote_port}'
+          );
+        ",
+            remote_host = test_source.host_ip(),
+            remote_port = test_source.port()
+        ),
+    ];
+
+    let pipeline = apply_ddls_low_level(&ddls, spring_config_default());
+    test_source.start(ForeignSourceInput::new_fifo_batch(
+        (0..trade_times)
+            .into_iter()
+            .map(|_| json_oracle.clone())
+            .collect(),
+    ));
+
+    for _ in 0..trade_times {
+        loop {
+            match spring_pop_non_blocking(&pipeline, queue_name).unwrap() {
+                Some(row) => {
+                    assert_eq!(spring_column_text(&row, 0).unwrap(), ts);
+                    assert_eq!(spring_column_i32(&row, 1).unwrap(), amount);
+                    break;
+                }
+                None => {}
+            }
+        }
+    }
+}
+
 #[test]
 fn test_e2e_spring_column_apis() {
     setup_test_logger();