*
 * Most applications should share a process-wide [TaskRunner] and use queues for per-client work.
 */
class TaskRunner(
  val backend: Backend,
  internal val logger: Logger = TaskRunner.logger,
) {
  val lock: ReentrantLock = ReentrantLock()
  val condition: Condition = lock.newCondition()

  private var nextQueueName = 10000
  private var coordinatorWaiting = false

    if (assertionsEnabled && taskRunner.lock.isHeldByCurrentThread) {
      throw AssertionError("Thread ${Thread.currentThread().name} MUST NOT hold lock on $this")
    }
  }

  val logger = Logger.getLogger("TaskFaker." + instance++)

  /** Though this executor service may hold many threads, they are not executed concurrently. */
  private val tasksExecutor = Executors.newCachedThreadPool(threadFactory("TaskFaker"))

The client will get a **500 Internal Server Error** for that request, but the application will continue working for the next requests instead of just crashing completely.

### Bigger Errors - Crashes

Nevertheless, there might be cases where we write some code that **crashes the entire application** making Uvicorn and Python crash. 💥

 * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
 */

package org.jetbrains.kotlin.analysis.api.descriptors.components

import com.intellij.openapi.diagnostic.Logger
import org.jetbrains.kotlin.analysis.api.components.*
import org.jetbrains.kotlin.analysis.api.descriptors.KtFe10AnalysisSession
import org.jetbrains.kotlin.analysis.api.descriptors.components.base.Fe10KtAnalysisSessionComponent

COPY ./requirements.txt /app/requirements.txt

RUN pip install --no-cache-dir --upgrade -r /app/requirements.txt

COPY ./app /app
```

### Bigger Applications

If you followed the section about creating [Bigger Applications with Multiple Files](../tutorial/bigger-applications.md){.internal-link target=_blank}, your `Dockerfile` might instead look like:

```Dockerfile hl_lines="7"

And the `items_per_user` would keep its default value of `50`.

## Settings in another module

You could put those settings in another module file as you saw in [Bigger Applications - Multiple Files](../tutorial/bigger-applications.md){.internal-link target=_blank}.

For example, you could have a file `config.py` with:

```Python
{!../../../docs_src/settings/app01/config.py!}
```

import org.junit.jupiter.api.extension.RegisterExtension

class TaskRunnerTest {
  private val taskFaker = TaskFaker()

  @RegisterExtension @JvmField
  val testLogHandler = TestLogHandler(taskFaker.logger)

  private val taskRunner = taskFaker.taskRunner
  private val log = mutableListOf<String>()
  private val redQueue = taskRunner.newQueue()
  private val blueQueue = taskRunner.newQueue()