Rust SDK

Ferrite applications depend on ferrite-app. The SDK exposes only the runtime and capabilities available to constrained application code.

Application entry point

#![forbid(unsafe_code)]

use std::io;
use ferrite_app::{app_main, AppContext, FerriteApp};

struct Worker;

impl FerriteApp for Worker {
    async fn run(ctx: AppContext) -> io::Result<()> {
        let mut jobs = ctx.queue("jobs")?;
        loop {
            let Some(lease) = jobs.poll_wait(1_000).await? else { continue };
            // Apply an idempotent effect before acknowledging the lease.
            jobs.ack(lease.token).await?;
        }
    }
}

fn main() { app_main::<Worker>() }

The handle passed to ctx.queue("jobs") must exist as a Queue binding in ferrite.json. A missing or mismatched handle returns an error.

Service handles

SDK call	Use it for
ctx.store("name")	Linearizable key-value reads, writes, deletes, and compare-and-swap.
ctx.ape("name")	Guarded multi-key transactions.
ctx.queue("name")	Durable leased work, delayed delivery, acknowledgements, and retries.
ctx.log("name")	Ordered append and offset reads.
ctx.topics("name")	Named ordered streams within one binding.
ctx.blob("name")	Content-addressed object reads and writes.
ctx.egress("name")	Outbound HTTP to declared destination prefixes.

Ingress and replies

API routes publish an IngressRequest to the bound Queue. Decode the request, apply the effect, publish an IngressReply to req.reply_to, and acknowledge only after the reply publish succeeds.

use ferrite_app::{serde_json, AppContext, IngressReply, IngressRequest};

let request: IngressRequest = serde_json::from_slice(&lease.payload)?;
let reply = IngressReply {
    correlation_id: request.correlation_id.clone(),
    status: 200,
    headers: vec![("content-type".into(), "application/json".into())],
    body: br#"{"ok":true}"#.to_vec(),
};
let mut replies = ctx.reply_to_queue(&request.reply_to).await?;
replies.publish(&serde_json::to_vec(&reply)?).await?;
requests.ack(lease.token).await?;

Platform utilities

Use ctx.clock() and ctx.now_ms() for injected time, ctx.entropy() for cryptographic randomness, ctx.secret("name") for a declared secret, and ferrite_app::rt for spawning, channels, sleep, interval, and timeout. The SDK also provides JSON, tracing, password and action-token primitives, HMAC and constant-time helpers, and safe response-cookie construction.

Continue with App Manifest to bind services or Functions for lifecycle and scaling.