Crate graphile_worker

Expand description

§Graphile Worker RS

A powerful PostgreSQL-backed job queue for Rust applications, based on Graphile Worker. This is a complete Rust rewrite that offers excellent performance, reliability, and a convenient API.

§Overview

Graphile Worker RS allows you to run jobs (such as sending emails, performing calculations, generating PDFs) in the background, so your HTTP responses and application code remain fast and responsive. It’s ideal for any PostgreSQL-backed Rust application.

Key highlights:

High performance: Uses PostgreSQL’s SKIP LOCKED for efficient job fetching
Low latency: Typically under 3ms from task schedule to execution using LISTEN/NOTIFY
Reliable: Automatically retries failed jobs with exponential backoff
Flexible: Supports scheduled jobs, task queues, cron-like recurring tasks, and more
Type-safe: Uses Rust’s type system to ensure job payloads match their handlers

§Differences from Node.js version

This port is mostly compatible with the original Graphile Worker, meaning you can run it side by side with the Node.js version. The key differences are:

No support for batch jobs yet (create an issue if you need this feature)
In the Node.js version, each process has its own worker_id. In the Rust version, there is only one worker_id, and jobs are processed in your async runtime thread

§Installation

Add the library to your project:

cargo add graphile_worker

§Getting Started

§1. Define a Task

A task consists of a struct that implements the TaskHandler trait. Each task has:

A struct with Serialize/Deserialize for the payload
A unique identifier string
An async run method that contains the task’s logic

use serde::{Deserialize, Serialize};
use graphile_worker::{WorkerContext, TaskHandler, IntoTaskHandlerResult};

#[derive(Deserialize, Serialize)]
struct SendEmail {
    to: String,
    subject: String,
    body: String,
}

impl TaskHandler for SendEmail {
    const IDENTIFIER: &'static str = "send_email";

    async fn run(self, _ctx: WorkerContext) -> impl IntoTaskHandlerResult {
        println!("Sending email to {} with subject '{}'", self.to, self.subject);
        // Email sending logic would go here
        Ok::<(), String>(())
    }
}

§2. Configure and Run the Worker

Set up the worker with your configuration options and run it:

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create a PostgreSQL connection pool
    let pg_pool = sqlx::postgres::PgPoolOptions::new()
        .max_connections(5)
        .connect("postgres://postgres:password@localhost/mydb")
        .await?;

    // Initialize and run the worker
    graphile_worker::WorkerOptions::default()
        .concurrency(5)                 // Process up to 5 jobs concurrently
        .schema("graphile_worker")      // Use this PostgreSQL schema
        .define_job::<SendEmail>()      // Register the task handler
        .pg_pool(pg_pool)               // Provide the database connection
        .init()                         // Initialize the worker
        .await?
        .run()                          // Start processing jobs
        .await?;

    Ok(())
}

§3. Schedule Jobs

§Option A: Schedule a job via SQL

Connect to your database and run the following SQL:

SELECT graphile_worker.add_job(
    'send_email',
    json_build_object(
        'to', 'user@example.com',
        'subject', 'Welcome to our app!',
        'body', 'Thanks for signing up.'
    )
);

§Option B: Schedule a job from Rust

// Get a WorkerUtils instance to manage jobs
let utils = worker.create_utils();

// Type-safe method (recommended):
utils.add_job(
    SendEmail {
        to: "user@example.com".to_string(),
        subject: "Welcome to our app!".to_string(),
        body: "Thanks for signing up.".to_string(),
    },
    Default::default(), // Use default job options
).await?;

// Or use the raw method when type isn't available:
utils.add_raw_job(
    "send_email",
    serde_json::json!({
        "to": "user@example.com",
        "subject": "Welcome to our app!",
        "body": "Thanks for signing up."
    }),
    Default::default(),
).await?;

§Advanced Features

§Shared Application State

You can provide shared state to all your tasks using extensions:

use serde::{Deserialize, Serialize};
use graphile_worker::{WorkerContext, TaskHandler, IntoTaskHandlerResult};
use std::sync::{Arc, atomic::{AtomicUsize, Ordering::SeqCst}};

// Define your shared state
#[derive(Clone, Debug)]
struct AppState {
    db_client: Arc<DatabaseClient>,
    api_key: String,
    counter: Arc<AtomicUsize>,
}

// Example database client (just for demonstration)
struct DatabaseClient;
impl DatabaseClient {
    fn new() -> Self { Self }
    async fn find_user(&self, _user_id: &str) -> Result<(), String> { Ok(()) }
}

#[derive(Deserialize, Serialize)]
struct ProcessUserTask {
    user_id: String,
}

impl TaskHandler for ProcessUserTask {
    const IDENTIFIER: &'static str = "process_user";

    async fn run(self, ctx: WorkerContext) -> impl IntoTaskHandlerResult {
        // Access the shared state in your task
        let app_state = ctx.get_ext::<AppState>().unwrap();
        let count = app_state.counter.fetch_add(1, SeqCst);
        
        // Use shared resources
        app_state.db_client.find_user(&self.user_id).await?;
        
        println!("Processed user {}, task count: {}", self.user_id, count);
        Ok::<(), String>(())
    }
}

// Add the extension when configuring the worker
let app_state = AppState {
    db_client: Arc::new(DatabaseClient::new()),
    api_key: "secret_key".to_string(),
    counter: Arc::new(AtomicUsize::new(0)),
};

graphile_worker::WorkerOptions::default()
    .add_extension(app_state)
    .define_job::<ProcessUserTask>()
    // ... other configuration
    .init()
    .await?;

§Scheduling Options

You can customize how and when jobs run with the JobSpec builder:

use graphile_worker::{JobSpecBuilder, JobKeyMode};
use chrono::Utc;

// Schedule a job to run after 5 minutes with high priority
let job_spec = JobSpecBuilder::new()
    .run_at(Utc::now() + chrono::Duration::minutes(5))
    .priority(10)
    .job_key("welcome_email_user_123")  // Unique identifier for deduplication
    .job_key_mode(JobKeyMode::Replace)  // Replace existing jobs with this key
    .max_attempts(5)                    // Max retry attempts (default is 25)
    .build();

utils.add_job(SendEmail { /* ... */ }, job_spec).await?;

§Job Queues

Jobs with the same queue name run in series (one after another) rather than in parallel:

// These jobs will run one after another, not concurrently
let spec1 = JobSpecBuilder::new()
    .queue_name("user_123_operations")
    .build();

let spec2 = JobSpecBuilder::new()
    .queue_name("user_123_operations")
    .build();

utils.add_job(UpdateProfile { /* ... */ }, spec1).await?;
utils.add_job(SendEmail { /* ... */ }, spec2).await?;

§Cron Jobs

You can schedule recurring jobs using crontab syntax:

// Run a task daily at 8:00 AM
let worker = WorkerOptions::default()
    .with_crontab("0 8 * * * send_daily_report")?
    .define_job::<SendDailyReport>()
    // ... other configuration
    .init()
    .await?;

§Job Management Utilities

The WorkerUtils class provides methods for managing jobs:

// Get a WorkerUtils instance
let utils = worker.create_utils();

// Remove a job by its key
utils.remove_job("job_key_123").await?;

// Mark jobs as completed
utils.complete_jobs(&[job_id1, job_id2]).await?;

// Permanently fail jobs with a reason
utils.permanently_fail_jobs(&[job_id3, job_id4], "Invalid data").await?;

// Reschedule jobs
let options = RescheduleJobOptions {
    run_at: Some(Utc::now() + chrono::Duration::minutes(60)),
    priority: Some(5),
    max_attempts: Some(3),
    ..Default::default()
};
utils.reschedule_jobs(&[job_id5, job_id6], options).await?;

// Run database cleanup tasks
utils.cleanup(&[
    CleanupTask::DeletePermenantlyFailedJobs,
    CleanupTask::GcTaskIdentifiers,
    CleanupTask::GcJobQueues,
]).await?;

§Feature List

Flexible deployment: Run standalone or embedded in your application
Multi-language support: Use from Rust, SQL or alongside the Node.js version
Performance optimized:
- Low latency job execution (typically under 3ms)
- PostgreSQL LISTEN/NOTIFY for immediate job notifications
- SKIP LOCKED for efficient job fetching
Robust job processing:
- Parallel processing with customizable concurrency
- Serialized execution via named queues
- Automatic retries with exponential backoff
- Customizable retry counts (default: 25 attempts over ~3 days)
Scheduling features:
- Delayed execution with run_at
- Job prioritization
- Crontab-like recurring tasks
- Task deduplication via job_key
Type safety: End-to-end type checking of job payloads
Minimal overhead: Direct serialization of task payloads

§Requirements

PostgreSQL 12+
- Required for the generated always as (expression) feature
- May work with older versions but has not been tested

§Project Status

Production ready but the API may continue to evolve. If you encounter any issues or have feature requests, please open an issue on GitHub.

§Acknowledgments

This library is a Rust port of the excellent Graphile Worker by Benjie Gillam. If you find this library useful, please consider sponsoring Benjie’s work, as all the research and architecture design was done by him.

§License

MIT License - See LICENSE.md

§Graphile Worker RS

A PostgreSQL-backed job queue implementation for Rust applications. This crate is a Rust port of the Node.js Graphile Worker library.

§Architecture Overview

Graphile Worker uses PostgreSQL as its backend for job storage and coordination. The system consists of several key components:

Worker: Processes jobs from the queue using the specified concurrency.
WorkerUtils: Utility functions for job management (adding, removing, rescheduling, etc.).
TaskHandler: Trait that defines how specific job types are processed.
Job Specification: Configures job parameters like priority, retry behavior, and scheduling.
Migrations: Automatic schema management for the database tables.

§Database Schema

Graphile Worker manages its own database schema (default: graphile_worker). It automatically handles migrations and uses the following tables:

_private_jobs: Stores job data, state, and execution metadata
_private_tasks: Tracks registered task types
_private_job_queues: Manages job queue names for serialized job execution
_private_workers: Tracks active worker instances

§Module Structure

The crate is organized into the following modules:

Re-exports§

pub use builder::WorkerBuildError;
pub use builder::WorkerOptions;
pub use runner::Worker;
pub use worker_utils::WorkerUtils;
pub use crate::job_spec::*;

Modules§

builder: Configuration and initialization of worker instances
errors: Error types used throughout the crate
job_spec: Job specification and builder for configuring jobs
runner: Core worker implementation for running the job queue
sql: SQL query implementations for interacting with the database
streams: Job stream management for processing jobs
utils: General utility functions
worker_utils: Utility functions for job management

Structs§

DbJob: DbJob represents a job as stored in the database.
Job: Job extends DbJob with an additional task_identifier field.
WorkerContext: Context provided to task handlers when processing a job.

Traits§

IntoTaskHandlerResult: Trait for converting task handler return types into a standardized Result.
TaskHandler: Core trait for defining task handlers in Graphile Worker.

Functions§

parse_crontab: Parse a crontab definition into a Vec of crontab
run_task_from_worker_ctx: Internal function to execute a task handler from a worker context.

Crate graphile_workerCopy item path

§Graphile Worker RS

§Overview

§Differences from Node.js version

§Installation

§Getting Started

§1. Define a Task

§2. Configure and Run the Worker

§3. Schedule Jobs

§Option A: Schedule a job via SQL

§Option B: Schedule a job from Rust

§Advanced Features

§Shared Application State

§Scheduling Options

§Job Queues

§Cron Jobs

§Job Management Utilities

§Feature List

§Requirements

§Project Status

§Acknowledgments

§License

§Graphile Worker RS

§Architecture Overview

§Database Schema

§Module Structure

Re-exports§

Modules§

Structs§

Traits§

Functions§

Crate graphile_worker