15 releases (7 breaking)
0.8.1 | Nov 23, 2022 |
---|---|
0.7.0 | Aug 16, 2022 |
0.6.1 | Jul 18, 2022 |
0.5.0 | Mar 1, 2022 |
0.2.0 | Oct 24, 2021 |
#91 in WebAssembly
163 downloads per month
29KB
583 lines
wasmCloud Messaging Interface
This is the interface for the wasmcloud:messaging
contract. This contract is a very simple abstraction over the concept of a message broker. This contract does not have controls or knobs or settings for things like delivery guarantees (e.g. "at most once" vs "at least once"), persistence of messages, etc. Such details are the responsibility of individual providers.
Capability Provider Implementations
The following is a list of implementations of the wasmcloud:messaging
contract. Feel free to submit a PR adding your implementation if you have a community/open source version.
Name | Vendor | Description |
---|---|---|
NATS | wasmCloud | wasmCloud Messaging Provider for the NATS broker |
Example Usage (🦀 Rust)
Implementing the Messaging.HandleMessage
operation
use wasmbus_rpc::actor::prelude::*;
use wasmcloud_interface_logging::info;
use wasmcloud_interface_messaging::{MessageSubscriber, MessageSubscriberReceiver, SubMessage};
#[derive(Debug, Default, Actor, HealthResponder)]
#[services(Actor, MessageSubscriber)]
struct LogMessagingActor {}
#[async_trait]
impl MessageSubscriber for LogMessagingActor {
/// Handle a message received on a subscription
async fn handle_message(&self, _ctx: &Context, msg: &SubMessage) -> RpcResult<()> {
info!("Received message: {:?}", msg);
Ok(())
}
}
Sending a message via a wasmcloud:messaging
provider without expecting a reply
use wasmbus_rpc::actor::prelude::*;
use wasmcloud_interface_messaging::{Messaging, MessagingSender, PubMessage};
async fn publish_message(ctx: &Context, subject: &str, body: &[u8]) -> RpcResult<()> {
let provider = MessagingSender::new();
if let Err(e) = provider
.publish(
ctx,
&PubMessage {
body: body.to_vec(),
reply_to: None,
subject: subject.to_owned(),
},
)
.await
{
Err(format!("Could not publish message {}", e.to_string()).into())
} else {
Ok(())
}
}
Sending a message via a wasmcloud:messaging
provider, waiting one second for a reply
use wasmbus_rpc::actor::prelude::*;
use wasmcloud_interface_messaging::{Messaging, MessagingSender, RequestMessage};
async fn message_request(ctx: &Context, subject: &str, body: &[u8]) -> RpcResult<()> {
let provider = MessagingSender::new();
if let Err(e) = provider
.request(
ctx,
&RequestMessage {
body: body.to_vec(),
subject: subject.to_owned(),
timeout_ms: 1_000,
},
)
.await
{
Err(format!("Could not request message {}", e.to_string()).into())
} else {
Ok(())
}
}
Dependencies
~9–20MB
~405K SLoC