Crate background_jobs[−][src]
Expand description
Background Jobs
This crate provides tooling required to run some processes asynchronously from a usually synchronous application. The standard example of this is Web Services, where certain things need to be processed, but processing them while a user is waiting for their browser to respond might not be the best experience.
Usage
Add Background Jobs to your project
[dependencies]
actix = "0.8"
background-jobs = "0.6.0"
anyhow = "1.0"
futures = "0.1"
serde = { version = "1.0", features = ["derive"] }
To get started with Background Jobs, first you should define a job.
Jobs are a combination of the data required to perform an operation, and the logic of that
operation. They implment the Job
, serde::Serialize
, and serde::DeserializeOwned
.
use anyhow::Error;
use background_jobs::Job;
use futures::future::{ok, Ready};
#[derive(Clone, Debug, serde::Deserialize, serde::Serialize)]
pub struct MyJob {
some_usize: usize,
other_usize: usize,
}
impl MyJob {
pub fn new(some_usize: usize, other_usize: usize) -> Self {
MyJob {
some_usize,
other_usize,
}
}
}
impl Job for MyJob {
type State = ();
type Future = Ready<Result<(), Error>>;
const NAME: &'static str = "MyJob";
fn run(self, _: Self::State) -> Self::Future {
println!("args: {:?}", self);
ok(())
}
}
The run method for a job takes an additional argument, which is the state the job expects to use. The state for all jobs defined in an application must be the same. By default, the state is an empty tuple, but it’s likely you’ll want to pass in some Actix address, or something else.
Let’s re-define the job to care about some application state.
use anyhow::Error;
use background_jobs::Job;
use futures::future::{ok, Ready};
#[derive(Clone, Debug)]
pub struct MyState {
pub app_name: String,
}
impl MyState {
pub fn new(app_name: &str) -> Self {
MyState {
app_name: app_name.to_owned(),
}
}
}
impl Job for MyJob {
type State = MyState;
type Future = Ready<Result<(), Error>>;
const NAME: &'static str = "MyJob";
fn run(self, state: Self::State) -> Self::Future {
info!("{}: args, {:?}", state.app_name, self);
ok(())
}
}
Running jobs
By default, this crate ships with the background-jobs-actix
feature enabled. This uses the
background-jobs-actix
crate to spin up a Server and Workers, and provides a mechanism for
spawning new jobs.
background-jobs-actix
on it’s own doesn’t have a mechanism for storing worker state. This
can be implemented manually by implementing the Storage
trait from background-jobs-core
, or the provided in-memory store can be used.
With that out of the way, back to the examples:
Main
use anyhow::Error;
use background_jobs::{ServerConfig, memory_storage::Storage, WorkerConfig};
#[actix_rt::main]
async fn main() -> Result<(), Error> {
// Set up our Storage
let storage = Storage::new();
// Start the application server. This guards access to to the jobs store
let queue_handle = ServerConfig::new(storage).start();
// Configure and start our workers
WorkerConfig::new(move || MyState::new("My App"))
.register::<MyJob>()
.set_processor_count(DEFAULT_QUEUE, 16)
.start(queue_handle.clone());
// Queue our jobs
queue_handle.queue(MyJob::new(1, 2))?;
queue_handle.queue(MyJob::new(3, 4))?;
queue_handle.queue(MyJob::new(5, 6))?;
// Block on Actix
actix_rt::signal::ctrl_c().await?;
Ok(())
}
Complete Example
For the complete example project, see the examples folder
Bringing your own server/worker implementation
If you want to create your own jobs processor based on this idea, you can depend on the
background-jobs-core
crate, which provides the Job trait, as well as some
other useful types for implementing a jobs processor and job store.
Modules
Useful types and methods for developing Storage and Processor implementations.
A default, in-memory implementation of a storage mechanism
Structs
A time-based overview of job completion and failures
A handle to the job server, used for queuing new jobs
Statistics about the jobs processor
Worker Configuration
Enums
Different styles for retrying jobs
How many times a job should be retried before giving up
Traits
The ActixJob trait defines parameters pertaining to an instance of background job
The Job trait defines parameters pertaining to an instance of background job
Functions
Create a new Server
Create a new server in the provided Arbiter
Create a new server in the provided ArbiterHandle