Sausage spike: host (broker, supervisors, commit-on-close fs, cargo actor, console), agent actor, examples

examples/fetch/Cargo.toml

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+[package]
+name = "fetch"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+serde_json = "1"
+wstd = "0.6"

examples/fetch/src/main.rs

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+//! Fetches URLs over HTTP(S) and writes the body to /public/fetch/<n>.
+//! Reads stdin and runs requests at the same time: while a fetch runs,
+//! `ping` still answers at once.
+use serde_json::{Value, json};
+use std::cell::RefCell;
+use std::rc::Rc;
+use wstd::http::{Body, Client, Request};
+use wstd::io::{AsyncRead, AsyncWrite};
+
+type Out = Rc<RefCell<Vec<String>>>;
+
+async fn flush(out: &Out) {
+    let lines: Vec<String> = out.borrow_mut().drain(..).collect();
+    let mut stdout = wstd::io::stdout();
+    for l in lines {
+        let _ = stdout.write_all(format!("{l}\n").as_bytes()).await;
+    }
+    let _ = stdout.flush().await;
+}
+
+async fn fetch(n: u64, msg: Value, out: Out) {
+    let url = msg["body"]["url"].as_str().unwrap_or_default().to_string();
+    let started = wstd::time::Instant::now();
+    let result = async {
+        let req = Request::get(&url).body(Body::empty()).map_err(|e| e.to_string())?;
+        let resp = Client::new().send(req).await.map_err(|e| format!("{e:?}"))?;
+        let status = resp.status().as_u16();
+        let bytes = resp.into_body().contents().await.map_err(|e| format!("{e:?}"))?.to_vec();
+        std::fs::create_dir_all("/public/fetch").map_err(|e| e.to_string())?;
+        let path = format!("/public/fetch/{n}");
+        std::fs::write(&path, &bytes).map_err(|e| e.to_string())?;
+        Ok::<_, String>((status, bytes.len(), path))
+    }
+    .await;
+    let ms = started.elapsed().as_millis();
+    let body = match result {
+        Ok((status, size, path)) => {
+            let id = std::env::var("SAUSAGE_ACTOR").unwrap_or("fetch".into());
+            json!({"type": "fetched", "status": status, "bytes": size, "path": path.replacen("/public", &format!("/actor/{id}/public"), 1), "ms": ms})
+        }
+        Err(e) => json!({"type": "error", "reason": e, "ms": ms}),
+    };
+    out.borrow_mut().push(json!({"to": msg["from"], "reply_to": msg["id"], "body": body}).to_string());
+    flush(&out).await;
+}
+
+fn main() {
+    wstd::runtime::block_on(async {
+        let out: Out = Rc::new(RefCell::new(Vec::new()));
+        let mut stdin = wstd::io::stdin();
+        let mut buf = Vec::new();
+        let mut chunk = vec![0u8; 8192];
+        let mut n = 0u64;
+        loop {
+            let Ok(len) = stdin.read(&mut chunk).await else { break };
+            if len == 0 {
+                break;
+            }
+            buf.extend_from_slice(&chunk[..len]);
+            while let Some(pos) = buf.iter().position(|b| *b == b'\n') {
+                let line: Vec<u8> = buf.drain(..=pos).collect();
+                let Ok(msg) = serde_json::from_slice::<Value>(&line) else { continue };
+                match msg["body"]["type"].as_str() {
+                    Some("shutdown") => return,
+                    Some("fetch") => {
+                        n += 1;
+                        wstd::runtime::spawn(fetch(n, msg, out.clone())).detach();
+                    }
+                    Some("ping") => {
+                        out.borrow_mut().push(json!({"to": msg["from"], "reply_to": msg["id"], "body": {"type": "pong"}}).to_string());
+                        flush(&out).await;
+                    }
+                    _ => {}
+                }
+            }
+        }
+    });
+}