Cleaner shutdown (#12)

* Cleaner shutdown

* mark as bad just in case although im pretty sure we dont need it

* server session duration

* test clean shutdown

* ah

Author: levkk

.circleci/config.yml

@@ -25,7 +25,7 @@ jobs:
           key: cargo-lock-2-{{ checksum "Cargo.lock" }}
       - run:
           name: "Install dependencies"
-          command: "sudo apt-get update && sudo apt-get install -y postgresql-contrib-12 postgresql-client-12"
+          command: "sudo apt-get update && sudo apt-get install -y psmisc postgresql-contrib-12 postgresql-client-12"
       - run:
           name: "Build" 
           command: "cargo build"
@@ -47,4 +47,4 @@ jobs:
 workflows:
   build:
     jobs:
-      - build
+      - build

.circleci/run_tests.sh

@@ -26,3 +26,6 @@ psql -e -h 127.0.0.1 -p 6432 -f tests/sharding/query_routing_test_select.sql > /
 
 # Replica/primary selection & more sharding tests
 psql -e -h 127.0.0.1 -p 6432 -f tests/sharding/query_routing_test_primary_replica.sql > /dev/null
+
+# Attempt clean shut down
+killall pgcat -s SIGINT

src/main.rs

@@ -26,6 +26,7 @@ extern crate toml;
 
 use regex::Regex;
 use tokio::net::TcpListener;
+use tokio::signal;
 
 use std::collections::HashMap;
 use std::sync::{Arc, Mutex};
@@ -108,61 +109,72 @@ async fn main() {
 
     println!("> Waiting for clients...");
 
-    loop {
-        let pool = pool.clone();
-        let client_server_map = client_server_map.clone();
-        let server_info = server_info.clone();
-
-        let (socket, addr) = match listener.accept().await {
-            Ok((socket, addr)) => (socket, addr),
-            Err(err) => {
-                println!("> Listener: {:?}", err);
-                continue;
-            }
-        };
-
-        // Client goes to another thread, bye.
-        tokio::task::spawn(async move {
-            let start = chrono::offset::Utc::now().naive_utc();
-
-            println!(">> Client {:?} connected", addr);
-
-            match client::Client::startup(
-                socket,
-                client_server_map,
-                transaction_mode,
-                default_server_role,
-                server_info,
-            )
-            .await
-            {
-                Ok(mut client) => {
-                    println!(">> Client {:?} authenticated successfully!", addr);
-
-                    match client.handle(pool).await {
-                        Ok(()) => {
-                            let duration = chrono::offset::Utc::now().naive_utc() - start;
-
-                            println!(
-                                ">> Client {:?} disconnected, session duration: {}",
-                                addr,
-                                format_duration(&duration)
-                            );
-                        }
-
-                        Err(err) => {
-                            println!(">> Client disconnected with error: {:?}", err);
-                            client.release();
-                        }
-                    }
-                }
+    // Main app runs here.
+    tokio::task::spawn(async move {
+        loop {
+            let pool = pool.clone();
+            let client_server_map = client_server_map.clone();
+            let server_info = server_info.clone();
 
+            let (socket, addr) = match listener.accept().await {
+                Ok((socket, addr)) => (socket, addr),
                 Err(err) => {
-                    println!(">> Error: {:?}", err);
+                    println!("> Listener: {:?}", err);
+                    continue;
                 }
             };
-        });
-    }
+
+            // Client goes to another thread, bye.
+            tokio::task::spawn(async move {
+                let start = chrono::offset::Utc::now().naive_utc();
+
+                println!(">> Client {:?} connected", addr);
+
+                match client::Client::startup(
+                    socket,
+                    client_server_map,
+                    transaction_mode,
+                    default_server_role,
+                    server_info,
+                )
+                .await
+                {
+                    Ok(mut client) => {
+                        println!(">> Client {:?} authenticated successfully!", addr);
+
+                        match client.handle(pool).await {
+                            Ok(()) => {
+                                let duration = chrono::offset::Utc::now().naive_utc() - start;
+
+                                println!(
+                                    ">> Client {:?} disconnected, session duration: {}",
+                                    addr,
+                                    format_duration(&duration)
+                                );
+                            }
+
+                            Err(err) => {
+                                println!(">> Client disconnected with error: {:?}", err);
+                                client.release();
+                            }
+                        }
+                    }
+
+                    Err(err) => {
+                        println!(">> Error: {:?}", err);
+                    }
+                };
+            });
+        }
+    });
+
+    // Setup shut down sequence
+    match signal::ctrl_c().await {
+        Ok(()) => {}
+        Err(err) => {
+            eprintln!("Unable to listen for shutdown signal: {}", err);
+        }
+    };
 }
 
 /// Format chrono::Duration to be more human-friendly.

src/server.rs

@@ -49,7 +49,11 @@ pub struct Server {
     // Mapping of clients and servers used for query cancellation.
     client_server_map: ClientServerMap,
 
+    // Server role, e.g. primary or replica.
     role: Role,
+
+    // Server connected at
+    connected_at: chrono::naive::NaiveDateTime,
 }
 
 impl Server {
@@ -193,6 +197,7 @@ impl Server {
                         bad: false,
                         client_server_map: client_server_map,
                         role: role,
+                        connected_at: chrono::offset::Utc::now().naive_utc(),
                     });
                 }
 
@@ -417,3 +422,27 @@ impl Server {
         }
     }
 }
+
+impl Drop for Server {
+    // Try to do a clean shut down.
+    fn drop(&mut self) {
+        let mut bytes = BytesMut::with_capacity(4);
+        bytes.put_u8(b'X');
+        bytes.put_i32(4);
+
+        match self.write.try_write(&bytes) {
+            Ok(n) => (),
+            Err(_) => (),
+        };
+
+        self.bad = true;
+
+        let now = chrono::offset::Utc::now().naive_utc();
+        let duration = now - self.connected_at;
+
+        println!(
+            ">> Server connection closed, session duration: {}",
+            crate::format_duration(&duration)
+        );
+    }
+}