BunBun-Worker

bunbun-worker is a panic-safe multithreaded job-runner server/client library for rust. It supports RPC and regular (non-rpc) calls. As of right now only rabbitmq is supported but gRPC will be added too.

❗ Disclaimer
This crate is still under development, meaning api's may change on every commit...

Introduction

bunbun-worker was made to provide a way for microservices written in rust to communicate to each other by dispatching jobs that may return data and those who don't.

Rpc

Remote procedure call, as it's name says is a message that can be sent to a remote microservice to be processed and the result to be returned. In bunbun-worker it's implemented by the following example:

sequenceDiagram
    ServiceA->>+ServiceB: Hey, could you do this job for me?
    Note right of ServiceB: ServiceB does the job
    ServiceB->>+ServiceA: Sure, here is the data result

1. ServiceA creates a callback queue that the response shall be sent to.
2. ServiceA sends a json job message to an already declared queue on a rabbitmq server.
3. ServiceB is listening on that queue for messages and spawns a new thread for each received.
4. Once ServiceB has finished the work, using the received messages header it responds to the callback queue with the correlation-id.

Non-rpc

In bunbun-worker regular jobs are called non-rpc jobs, indicating that the response is not awaited.

Installation

Get directly from crates.io

[dependencies]
bunbun-worker = { version = "0.1.0" }

or get it directly from source

[dependencies]
bunbun-worker = { git = "https://git.4o1x5.dev/4o1x5/bunbun-worker", branch = "master" }

Usage

Here is a basic implementation of an RPC job in bunbun-worker

// server

// First let's create a state that will be used inside a job.
// Imagine this holding a database connection, some context that may need to be changed. Anything really
#[derive(Clone, Debug)]
pub struct State {
    pub something: String,
}

/// Second, let's create a job, with field that can be serialized/deserialized into JSON
/// This is what the server will receive from a client and will do the job based on these properties
#[derive(Deserialize, Serialize, Clone, Debug)]
pub struct EmailJob {
    send_to: String,
    contents: String,
}
// We also create a result for it, since it's an RPC job
#[derive(Deserialize, Serialize, Clone, Debug, PartialEq)]
pub struct EmailJobResult {
    contents: String,
}
// And an error type so know if the other end errored out, what to do.
#[derive(Deserialize, Serialize, Clone, Debug)]
pub enum EmailJobResultError {
    Errored,
}

/// After all this we implement a Jobrunner/Taskrunner to the type, so when the listener receives it, it can run this piece of code.
impl RPCServerTask for EmailJob {
    type ErroredResult = EmailJobResultError;
    type Result = EmailJobResult;
    type State = State;
    fn run(
        self,
        state: Self::State,
    ) -> futures::prelude::future::BoxFuture<'static, Result<Self::Result, Self::ErroredResult>>
    {
        Box::pin(async move {
            tracing::info!("Sent email to {}", self.send_to);
            tokio::time::sleep(Duration::from_secs(2)).await;
            return Ok(EmailJobResult {
                contents: self.contents.clone(),
            });
        })
    }
}
// Finally, we can define an async main function to run the listener in.
#[tokio::main]
async fn main(){
    // Define a listener, with a hard-limit of 100 jobs at once.
    let mut listener =
        BunBunWorker::new(env::var("AMQP_SERVER_URL").unwrap(), 100.into()).await;
    // Add the defined sturct to the worker
    listener
        .add_rpc_consumer::<EmailJob>(
            "email-emailjob-v1.0.0", // queue name
            "emailjob", // consumer tag
            State {
                something: "test".into(), // putting our state into a Arc<Mutex<S>> for thread safety
            },
        )
        .await;
    tracing::debug!("Starting listener");
    // Starting the listener
    listener.start_all_listeners().await;
}

Instal futures_util for the client

cargo add futures_util

// client

// Define the same structs we did. These are DTO's after all..
#[derive(Deserialize, Serialize, Clone, Debug)]
pub struct EmailJob {
    send_to: String,
    contents: String,
}
#[derive(Deserialize, Serialize, Clone, Debug, PartialEq)]
pub struct EmailJobResult {
    contents: String,
}
#[derive(Deserialize, Serialize, Clone, Debug)]
pub enum EmailJobResultError {
    Errored,
}
// Now we implement the clientside task for it. This reduces generics when defining the calling..
impl RPCClientTask for EmailJob {
    type ErroredResult = EmailJobResultError;
    type Result = EmailJobResult;
}

#[tokio::main]
async fn main(){
// Define a client
  let mut client = BunBunClient::new(env::var("AMQP_SERVER_URL").unwrap().as_str())
      .await
      .unwrap();
  // Make a call
  let result = client
      .rpc_call::<EmailJob>(
            // Define the job
          EmailJob {
              send_to: "someone".into(),
              contents: "something".into(),
          },
          "email-emailjob-v1.0.0", // the queue name
      )
      .await
      .unwrap();
}

Limitations

1. Currently some unwrap()'s are called inside the code and may results in panics (not in the job-runner).
2. No TLS support
3. No settings, and very limited API
4. The rabbitmq RPC logic is very basic with no message-versioning (aside using different queue names (see usage) )

Bugs department

Since the code is hosted on a private git instance (as of right now) any bugs shall be discussed in 4o1x5's project room.

License

Licensed under GNU AFFERO GENERAL PUBLIC LICENSE

Contribution

Currently this library does not accept any contributors, as it's hosted on a private git server.

Credits

This package was made with the help of-

• This readme template you are reading right now
• Lapin, an extensive easy to use rabbitmq client