Task Module in Elixir
Task Module in Elixir[edit]
The Task module is an essential part of the Elixir programming language. It provides a powerful and efficient way to manage concurrent computations and handle asynchronous operations. With the Task module, developers can easily create and manage lightweight processes, called tasks, to execute code asynchronously.
Creating Tasks[edit]
To create a new task, the `Task.start/1` function is used. It takes a single argument, which is a function that will be executed by the task. The function can be defined inline or as a named function.
Syntax: ```elixir {:ok, task} = Task.start(function_name, args) ```
Example: ```elixir {:ok, task} = Task.start(fn -> IO.puts("Hello, World!") end) ```
Task Monitoring[edit]
The Task module provides several functions to monitor the state of a task. These functions allow you to check if a task is running, completed, or terminated abnormally.
- `Task.await/2`: Suspends the calling process until the task completes and returns its result. - `Task.yield/2`: Takes a task and waits for it to complete, but does not return any result. - `Task.status/2`: Returns the current status of a task, which can be `:running`, `:completed`, or `:exit`. - `Task.is_alive/1`: Returns `true` if the task is still running, otherwise `false`.
Example: ```elixir task = Task.start(fn -> :timer.sleep(5000) end) IO.puts("Task running? #{Task.is_alive(task)}") Task.await(task) IO.puts("Task running? #{Task.is_alive(task)}") ```
Handling Task Failures[edit]
When a task encounters an error or raises an exception, it can be important to handle these failures gracefully. The Task module provides functions to handle such scenarios.
- `Task.async/3`: Similar to `Task.start/1`, but returns a task that traps exit signals. This means that if the task fails, it won't crash the parent process. - `Task.await/2`: Takes an additional timeout argument, allowing you to specify a maximum time to wait for the task to complete. If the timeout is reached before the task completes, a `Task.TimeoutError` is raised.
Example: ```elixir {:ok, task} = Task.async(fn ->
raise "Something went wrong!"
end)
Task.await(task, 1000) ```
Task Parallelism[edit]
The Task module also enables parallel execution of tasks. This is particularly useful when you have multiple independent tasks that can be executed concurrently.
- `Task.async_stream/3`: Executes a given function in parallel for a given enumerable collection. This function returns a stream that produces the results as they become available.
Example: ```elixir 1..10 |> Task.async_stream(fn x -> x * x end) |> Enum.to_list() ```