## Running on Startup { #running-on-startup }

In most cases, when you create a web API, you want it to be **always running**, uninterrupted, so that your clients can always access it. This is of course, unless you have a specific reason why you want it to run only in certain situations, but most of the time you want it constantly running and **available**.

### In a Remote Server { #in-a-remote-server }

  }

  private static <T extends @Nullable Object> List<Predicate<? super T>> asList(
      Predicate<? super T> first, Predicate<? super T> second) {
    // TODO(kevinb): understand why we still get a warning despite @SafeVarargs!
    return Arrays.<Predicate<? super T>>asList(first, second);
  }

  private static <T> List<T> defensiveCopy(T... array) {
    return defensiveCopy(Arrays.asList(array));

<a href="https://x.com/compose/tweet?text=I'm loving @fastapi because... https://github.com/fastapi/fastapi" class="external-link" target="_blank">Tweet about **FastAPI**</a> and let me and others know why you like it. 🎉

I love to hear about how **FastAPI** is being used, what you have liked in it, in which project/company are you using it, etc.

## Vote for FastAPI { #vote-for-fastapi }

    DelayingIdentityLoader(AtomicBoolean shouldWait, CountDownLatch delayLatch) {
      this.shouldWait = shouldWait;
      this.delayLatch = delayLatch;
    }

    @CanIgnoreReturnValue // Sure, why not?
    @Override
    public T load(T key) throws InterruptedException {
      if (shouldWait.get()) {
        delayLatch.await();
      }
      return key;
    }
  }

                                // MNG-2123: if the previous node was not a range, then it wouldn't have any available
                                // versions. We just clobbered the selected version above. (why? I have no idea.)
                                // So since we are here and this is ranges we must go figure out the version (for a
                                // third time...)

    // This lock protects the task so we can ensure that none of the template methods (startUp,
    // shutDown or runOneIteration) run concurrently with one another.
    // TODO(lukes): why don't we use ListenableFuture to sequence things? Then we could drop the
    // lock.
    private final ReentrantLock lock = new ReentrantLock();

    @WeakOuter
    final class Task implements Runnable {

     * outputs users get when calling this with <Foo> and calling it with <@Nullable Foo>. The only
     * difference is that calling it with <Foo> won't work when an input Future has a @Nullable
     * type. So why even make that error possible by giving callers the choice?
     *
     * On the other hand, the current signature is consistent with the similar allAsList method. And

     * `numHashFunctions/bitSize`. So, after n insertions, expected bitCount is `bitSize * (1 - (1 -
     * numHashFunctions/bitSize)^n)`. Solving that for n, and approximating `ln x` as `x - 1` when x
     * is close to 1 (why?), gives the following formula.
     */
    double fractionOfBitsSet = (double) bitCount / bitSize;
    return DoubleMath.roundToLong(
        -Math.log1p(-fractionOfBitsSet) * bitSize / numHashFunctions, RoundingMode.HALF_UP);

Это особенно заметно при использовании `docker compose`. См. раздел FAQ Docker Compose с техническими подробностями: <a href="https://docs.docker.com/compose/faq/#why-do-my-services-take-10-seconds-to-recreate-or-stop" class="external-link" target="_blank">Почему мои сервисы пересоздаются или останавливаются 10 секунд?</a>.

#### Структура директорий { #directory-structure }

    // This lock protects the task so we can ensure that none of the template methods (startUp,
    // shutDown or runOneIteration) run concurrently with one another.
    // TODO(lukes): why don't we use ListenableFuture to sequence things? Then we could drop the
    // lock.
    private final ReentrantLock lock = new ReentrantLock();

    @WeakOuter
    final class Task implements Runnable {