fix shutdown test and add changelog entry

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 0.5.0 (2021-12-05)
+
+- Add graceful shutdown - [#14](https://github.com/ayrat555/fang/pull/14)
+
 ## 0.4.2 (2021-11-30)
 
 - Bump deps - [#13](https://github.com/ayrat555/fang/pull/13)

README.md

@@ -14,7 +14,7 @@ Background job processing library for Rust. It uses Postgres DB as a task queue.
 
 ```toml
 [dependencies]
-fang = "0.4.1"
+fang = "0.5"
 serde = { version = "1.0", features = ["derive"] }
 ```
 
@@ -96,6 +96,17 @@ use fang::WorkerPool;
 WorkerPool::new(10).start();
 ```
 
+Use `shutdown` to stop worker threads, they will try to finish in-progress tasks.
+
+```rust
+
+use fang::WorkerPool;
+
+worker_pool = WorkerPool::new(10).start().unwrap;
+
+worker_pool.shutdown()
+```
+
 Using a library like [signal-hook][signal-hook], it's possible to gracefully shutdown a worker. See the
 Simple Worker for an example implementation.
 

src/worker_pool.rs

@@ -270,9 +270,44 @@ mod job_pool_tests {
         }
     }
 
-    fn get_all_tasks(conn: &PgConnection) -> Vec<Task> {
+    #[derive(Serialize, Deserialize)]
+    struct ShutdownJob {
+        pub number: u16,
+        pub current_thread_name: String,
+    }
+
+    impl ShutdownJob {
+        pub fn new(number: u16) -> Self {
+            let handle = thread::current();
+            let current_thread_name = handle.name().unwrap().to_string();
+
+            Self {
+                number,
+                current_thread_name,
+            }
+        }
+    }
+
+    #[typetag::serde]
+    impl Runnable for ShutdownJob {
+        fn run(&self, connection: &PgConnection) -> Result<(), Error> {
+            thread::sleep(Duration::from_secs(3));
+
+            let new_job = MyJob::new(self.number + 1);
+
+            Queue::push_task_query(connection, &new_job).unwrap();
+
+            Ok(())
+        }
+
+        fn task_type(&self) -> String {
+            "shutdown_test".to_string()
+        }
+    }
+
+    fn get_all_tasks(conn: &PgConnection, job_type: &str) -> Vec<Task> {
         fang_tasks::table
-            .filter(fang_tasks::task_type.eq("worker_pool_test"))
+            .filter(fang_tasks::task_type.eq(job_type))
             .get_results::<Task>(conn)
             .unwrap()
     }
@@ -287,28 +322,25 @@ mod job_pool_tests {
         worker_params.set_retention_mode(RetentionMode::KeepAll);
         let mut job_pool = WorkerPool::new_with_params(2, worker_params);
 
-        queue.push_task(&MyJob::new(100)).unwrap();
-        queue.push_task(&MyJob::new(200)).unwrap();
+        queue.push_task(&ShutdownJob::new(100)).unwrap();
+        queue.push_task(&ShutdownJob::new(200)).unwrap();
 
         job_pool.start().unwrap();
         thread::sleep(Duration::from_secs(1));
         job_pool.shutdown().unwrap();
         thread::sleep(Duration::from_secs(5));
 
-        let tasks = get_all_tasks(&queue.connection);
-        // TODO - Replace with group_by when it's not nightly anymore
-        let new_tasks = tasks.iter().filter(|task| task.state == FangTaskState::New);
-        // let in_progress_tasks = tasks
-        //     .iter()
-        //     .filter(|task| task.state == FangTaskState::InProgress);
+        let tasks = get_all_tasks(&queue.connection, "shutdown_test");
+        let in_progress_tasks = tasks
+            .iter()
+            .filter(|task| task.state == FangTaskState::InProgress);
         let finished_tasks = tasks
             .iter()
             .filter(|task| task.state == FangTaskState::Finished);
 
         // Asserts first two tasks are allowed to finish, the tasks they spawn are not started
         // though. No tasks should be in progress after a graceful shutdown.
-        assert_eq!(new_tasks.count(), 2);
-        // assert_eq!(in_progress_tasks.count(), 0); // TODO - Can't verify because of dirty DB
+        assert_eq!(in_progress_tasks.count(), 0);
         assert_eq!(finished_tasks.count(), 2);
     }
 
@@ -328,7 +360,7 @@ mod job_pool_tests {
 
         thread::sleep(Duration::from_secs(100));
 
-        let tasks = get_all_tasks(&queue.connection);
+        let tasks = get_all_tasks(&queue.connection, "worker_pool_test");
 
         assert!(tasks.len() > 40);