# Background Tasks - `BackgroundTasks`

You can declare a parameter in a *path operation function* or dependency function with the type `BackgroundTasks`, and then you can use it to schedule the execution of background tasks after the response is sent.

You can import it directly from `fastapi`:

```python
from fastapi import BackgroundTasks
```

        public void scheduledTask(@CronExpression String schedule) {
            // Method for testing parameter annotation
        }
    }

    private static class TestConstructor {
        private final String schedule;

        public TestConstructor(@CronExpression String schedule) {
            this.schedule = schedule;
        }

        public String getSchedule() {

        .build();

    final long startNanos = System.nanoTime();
    final Call call = client.newCall(request);

    // Schedule a job to cancel the call in 1 second.
    executor.schedule(() -> {
      System.out.printf("%.2f Canceling call.%n", (System.nanoTime() - startNanos) / 1e9f);
      call.cancel();

version: 2
updates:
  - package-ecosystem: "github-actions"
    directory: "/"
    schedule:
      interval: "daily"
    labels:
      - "@dev-productivity"
      - "a:chore"
      - "in:building-gradle"
  - package-ecosystem: "gradle"
    open-pull-requests-limit: 0
    directory: "/"
    schedule:
      interval: "daily"
    labels:
      - "@dev-productivity"
      - "a:chore"

        this.listeners = new ConcurrentHashMap<>();
        this.scheduler = Executors.newScheduledThreadPool(2);
        this.rpcClient = new WitnessRpcClient(witnessServer, context);
        
        // Schedule periodic tasks
        schedulePeriodicTasks();
    }
    
    private void schedulePeriodicTasks() {
        // Heartbeat monitoring
        scheduler.scheduleAtFixedRate(this::checkHeartbeats, 30, 30, TimeUnit.SECONDS);

  }

  @Override
  public ListenableScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
    Preconditions.checkNotNull(command, "command must not be null");
    Preconditions.checkNotNull(unit, "unit must not be null!");
    return schedule(callable(command), delay, unit);
  }

  @Override
  public <V> ListenableScheduledFuture<V> schedule(
      Callable<V> callable, long delay, TimeUnit unit) {

  }

  @Override
  public ListenableScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
    Preconditions.checkNotNull(command, "command must not be null");
    Preconditions.checkNotNull(unit, "unit must not be null!");
    return schedule(callable(command), delay, unit);
  }

  @Override
  public <V> ListenableScheduledFuture<V> schedule(
      Callable<V> callable, long delay, TimeUnit unit) {

    addressStates[address]?.scheduleOpener()
  }

  fun scheduleCloser() {
    cleanupQueue.schedule(cleanupTask)
  }

  /**
   * Ensure enough connections open to [address] to satisfy its [ConnectionPool.AddressPolicy].
   * If there are already enough connections, we're done.
   * If not, we create one and then schedule the task to run again immediately.
   */
  private fun openConnections(state: AddressState): Long {

   * This counter prevents an ABA issue where a thread may successfully schedule the worker, the
   * worker runs and exhausts the queue, another thread enqueues a task and fails to schedule the
   * worker, and then the first thread's call to delegate.execute() returns. Without this counter,
   * it would observe the QUEUING state and set it to QUEUED, and the worker would never be
   * scheduled again for future submissions.
   */
  @GuardedBy("queue")

name: 'Lock Threads'

on:
  schedule:
    - cron: '0 0 * * *'
  workflow_dispatch:

permissions:
  issues: write

concurrency:
  group: lock

jobs:
  action:
    runs-on: ubuntu-latest
    steps:
      - uses: dessant/lock-threads@v3
        with:
          github-token: ${{ github.token }}
          issue-inactive-days: '365'
          exclude-any-issue-labels: 'do-not-close'