SDK sausage-actor; examples and agent on the SDK; agent without limits

- sausage-actor: Message, messages(), send/reply/publish, async Inbox
- agent: append-only /data/history.jsonl, no caps on history, steps, waits,
  tool output, or reads; max_tokens only when configured (Anthropic: 32000)
This commit is contained in:
2026-10-15 11:17:14 +01:00
parent c9d9864743
commit 7f76eab161
22 changed files with 607 additions and 518 deletions
+8 -15
View File
@@ -6,7 +6,6 @@
use serde::{Deserialize, Serialize};
use serde_json::{Value, json};
use wstd::http::{Body, Client, Request};
use wstd::time::Duration;
#[derive(Deserialize, Clone)]
pub struct Config {
@@ -18,12 +17,8 @@ pub struct Config {
/// Optional reasoning effort for OpenAI models ("low", "medium", ...).
#[serde(default)]
pub reasoning_effort: Option<String>,
#[serde(default = "default_max_tokens")]
pub max_tokens: u32,
}
fn default_max_tokens() -> u32 {
16000
#[serde(default)]
pub max_tokens: Option<u32>,
}
#[derive(Serialize, Deserialize, Clone, Debug)]
@@ -57,17 +52,13 @@ async fn post(url: &str, headers: &[(&str, String)], body: &Value) -> Result<Val
req = req.header(*k, v.as_str());
}
let req = req.body(Body::from(body.to_string())).map_err(|e| format!("request: {e}"))?;
let mut client = Client::new();
client.set_first_byte_timeout(Duration::from_secs(600));
client.set_between_bytes_timeout(Duration::from_secs(600));
let client = Client::new();
let resp = client.send(req).await.map_err(|e| format!("HTTP request failed: {e:?}"))?;
let status = resp.status();
let mut body = resp.into_body();
let text = body.str_contents().await.map_err(|e| format!("reading the response failed: {e:?}"))?.to_string();
if !status.is_success() {
let mut t = text;
t.truncate(2000);
return Err(format!("HTTP {status}: {t}"));
return Err(format!("HTTP {status}: {text}"));
}
serde_json::from_str(&text).map_err(|e| format!("invalid JSON in response: {e}"))
}
@@ -99,8 +90,10 @@ async fn openai(cfg: &Config, system: &str, tools: &[Tool], history: &[Entry]) -
"tools": tools,
"store": false,
"include": ["reasoning.encrypted_content"],
"max_output_tokens": cfg.max_tokens,
});
if let Some(max_tokens) = cfg.max_tokens {
body["max_output_tokens"] = json!(max_tokens);
}
if let Some(effort) = &cfg.reasoning_effort {
body["reasoning"] = json!({"effort": effort});
}
@@ -170,7 +163,7 @@ async fn anthropic(cfg: &Config, system: &str, tools: &[Tool], history: &[Entry]
"system": system,
"messages": messages,
"tools": tools,
"max_tokens": cfg.max_tokens,
"max_tokens": cfg.max_tokens.unwrap_or(32000),
});
let url = format!("{}/v1/messages", cfg.base_url);
let resp = post(
+186 -246
View File
@@ -1,85 +1,33 @@
//! The Sausage agent: a normal WASM actor that does inference over HTTP and
//! grows the world through messages to `cargo` and `broker`.
//!
//! Configuration: `/data/config.json` (see `llm::Config`).
//! Conversation: `/data/history.json` (one shared conversation).
//! The Sausage agent actor.
mod llm;
use std::collections::VecDeque;
use async_channel::{Receiver, Sender};
use llm::{Config, Entry, Tool};
use serde_json::{Value, json};
use sausage_actor::{Inbox, Message, Value, json, reply, send};
use std::collections::{HashSet, VecDeque};
use std::io::Write;
use wstd::future::FutureExt;
use wstd::io::{AsyncRead, AsyncWrite};
use wstd::time::{Duration, Instant};
const SYSTEM: &str = include_str!("prompt.md");
const CONFIG: &str = "/data/config.json";
const HISTORY: &str = "/data/history.json";
/// An interrupted turn (sender and message ID), resumed at the next start.
const HISTORY: &str = "/data/history.jsonl";
const TURN: &str = "/data/turn.json";
const MAX_STEPS: usize = 40;
const MAX_HISTORY: usize = 600;
const MAX_TOOL_OUTPUT: usize = 30_000;
const MAX_NOTES: usize = 50;
fn main() {
wstd::runtime::block_on(async {
let (tx, rx) = async_channel::unbounded();
wstd::runtime::spawn(read_stdin(tx)).detach();
Agent::new(rx).run().await;
});
}
/// Read NDJSON messages from stdin into the channel.
async fn read_stdin(tx: Sender<Value>) {
let mut stdin = wstd::io::stdin();
let mut buf = Vec::new();
let mut chunk = vec![0u8; 16 * 1024];
loop {
match stdin.read(&mut chunk).await {
Ok(0) | Err(_) => break,
Ok(n) => {
buf.extend_from_slice(&chunk[..n]);
while let Some(pos) = buf.iter().position(|b| *b == b'\n') {
let line: Vec<u8> = buf.drain(..=pos).collect();
if let Ok(v) = serde_json::from_slice::<Value>(&line)
&& tx.send(v).await.is_err()
{
return;
}
}
}
}
}
tx.close();
}
fn truncate(mut s: String, max: usize) -> String {
if s.len() > max {
let mut end = max;
while !s.is_char_boundary(end) {
end -= 1;
}
let total = s.len();
s.truncate(end);
s.push_str(&format!("\n… (truncated, {total} bytes in total)"));
}
s
wstd::runtime::block_on(async { Agent::new().run().await });
}
fn tools() -> Vec<Tool> {
vec![
Tool {
name: "send_message",
description: "Send a message to an actor. With wait_seconds > 0, wait for the reply (a message whose reply_to is the ID of this message). Returns the message ID, the reply (or null), and other messages that arrived meanwhile.",
description: "Send a message to an actor. With wait_seconds > 0, wait for its reply. Returns the message ID, the reply, and other messages that arrived meanwhile.",
parameters: json!({
"type": "object",
"properties": {
"to": {"type": "string", "description": "Actor ID"},
"body": {"type": "object", "description": "Message body. Must have a \"type\" field."},
"body": {"type": "object", "description": "Message body. Must have a type field."},
"wait_seconds": {"type": "number", "description": "Seconds to wait for the reply. 0 = do not wait."}
},
"required": ["to", "body"]
@@ -87,7 +35,7 @@ fn tools() -> Vec<Tool> {
},
Tool {
name: "wait_for_messages",
description: "Wait up to `seconds` for messages to arrive and return them.",
description: "Wait up to seconds for messages to arrive and return them.",
parameters: json!({
"type": "object",
"properties": {"seconds": {"type": "number"}},
@@ -102,7 +50,7 @@ fn tools() -> Vec<Tool> {
"properties": {
"path": {"type": "string"},
"offset": {"type": "integer", "description": "Byte offset (default 0)"},
"max_bytes": {"type": "integer", "description": "Default 30000"}
"max_bytes": {"type": "integer", "description": "Optional maximum number of bytes to read"}
},
"required": ["path"]
}),
@@ -110,15 +58,11 @@ fn tools() -> Vec<Tool> {
Tool {
name: "list_dir",
description: "List a folder.",
parameters: json!({
"type": "object",
"properties": {"path": {"type": "string"}},
"required": ["path"]
}),
parameters: json!({"type": "object", "properties": {"path": {"type": "string"}}, "required": ["path"]}),
},
Tool {
name: "write_file",
description: "Write a text file (only under /data or /public). Creates parent folders.",
description: "Write a text file under /data or /public. Creates parent folders.",
parameters: json!({
"type": "object",
"properties": {"path": {"type": "string"}, "content": {"type": "string"}},
@@ -137,18 +81,14 @@ fn tools() -> Vec<Tool> {
Tool {
name: "remove_path",
description: "Remove a file or folder under /data or /public.",
parameters: json!({
"type": "object",
"properties": {"path": {"type": "string"}},
"required": ["path"]
}),
parameters: json!({"type": "object", "properties": {"path": {"type": "string"}}, "required": ["path"]}),
},
]
}
fn copy_tree(from: &str, to: &str) -> std::io::Result<u64> {
std::fs::create_dir_all(to)?;
let mut n = 0;
let mut count = 0;
for entry in std::fs::read_dir(from)? {
let entry = entry?;
let name = entry.file_name().to_string_lossy().to_string();
@@ -156,87 +96,94 @@ fn copy_tree(from: &str, to: &str) -> std::io::Result<u64> {
let dst = format!("{to}/{name}");
if entry.file_type()?.is_dir() {
if name != "target" {
n += copy_tree(&src, &dst)?;
count += copy_tree(&src, &dst)?;
}
} else {
std::fs::copy(&src, &dst)?;
n += 1;
std::fs::copy(src, dst)?;
count += 1;
}
}
Ok(n)
Ok(count)
}
struct Agent {
rx: Receiver<Value>,
stdout: wstd::io::Stdout,
inbox: Inbox,
history: Vec<Entry>,
/// Text messages that start a new turn later.
queue: VecDeque<Value>,
/// Other messages that arrived while the agent was idle.
notes: Vec<Value>,
seq: u64,
queue: VecDeque<Message>,
notes: Vec<Message>,
shutdown: bool,
}
impl Agent {
fn new(rx: Receiver<Value>) -> Self {
fn new() -> Self {
let history = std::fs::read_to_string(HISTORY)
.ok()
.and_then(|s| serde_json::from_str(&s).ok())
.unwrap_or_default();
.unwrap_or_default()
.lines()
.filter_map(|line| serde_json::from_str(line).ok())
.collect();
Self {
rx,
stdout: wstd::io::stdout(),
inbox: Inbox::start(),
history,
queue: VecDeque::new(),
notes: Vec::new(),
seq: 0,
shutdown: false,
}
}
fn add_history(&mut self, entry: Entry) {
let line = serde_json::to_string(&entry).unwrap();
match std::fs::OpenOptions::new()
.create(true)
.append(true)
.open(HISTORY)
{
Ok(mut file) => {
if let Err(e) = writeln!(file, "{line}") {
eprintln!("agent: cannot append history: {e}");
}
}
Err(e) => eprintln!("agent: cannot append history: {e}"),
}
self.history.push(entry);
}
async fn run(mut self) {
eprintln!("agent: started with {} history entries", self.history.len());
self.resume().await;
while !self.shutdown {
let msg = match self.queue.pop_front() {
Some(m) => m,
None => match self.rx.recv().await {
Ok(m) => m,
Err(_) => break,
Some(msg) => msg,
None => match self.inbox.recv().await {
Some(msg) => msg,
None => break,
},
};
if msg["body"]["type"] == "shutdown" {
break;
}
if starts_turn(&msg) {
self.turn(msg).await;
} else {
self.notes.push(msg);
if self.notes.len() > MAX_NOTES {
self.notes.remove(0);
}
}
}
self.save();
eprintln!("agent: stopped");
}
/// Continue a turn that a restart (usually an upgrade of the agent itself)
/// interrupted.
async fn resume(&mut self) {
let Some(turn) = std::fs::read_to_string(TURN).ok().and_then(|s| serde_json::from_str::<Value>(&s).ok()) else {
let Ok(turn) = std::fs::read_to_string(TURN) else {
return;
};
let Ok(turn) = serde_json::from_str::<Value>(&turn) else {
return;
};
let Ok(contents) = std::fs::read_to_string(CONFIG) else {
return;
};
let Ok(cfg) = serde_json::from_str::<Config>(&contents) else {
return;
};
let _ = std::fs::remove_file(TURN);
let Ok(cfg) = std::fs::read_to_string(CONFIG).map_err(|_| ()).and_then(|s| serde_json::from_str::<Config>(&s).map_err(|_| ())) else {
return;
};
// Every tool call needs a result, or the APIs reject the history.
let answered: std::collections::HashSet<String> = self
let answered: HashSet<String> = self
.history
.iter()
.filter_map(|e| match e {
.filter_map(|entry| match entry {
Entry::ToolResult { id, .. } => Some(id.clone()),
_ => None,
})
@@ -244,164 +191,164 @@ impl Agent {
let dangling: Vec<String> = self
.history
.iter()
.filter_map(|e| match e {
.filter_map(|entry| match entry {
Entry::ToolCall { id, .. } if !answered.contains(id) => Some(id.clone()),
_ => None,
})
.collect();
for id in dangling {
self.history.push(Entry::ToolResult {
self.add_history(Entry::ToolResult {
id,
output: json!({"error": "interrupted: the agent restarted before this tool finished"}).to_string(),
output:
json!({"error": "interrupted: the agent restarted before this tool finished"})
.to_string(),
});
}
let version = std::env::var("SAUSAGE_VERSION").unwrap_or_default();
self.history.push(Entry::User {
self.add_history(Entry::User {
text: format!(
"[note from your runtime] You restarted and now run version {version}. The restart interrupted your last turn (probably your own upgrade). Check the state you need, then finish the turn and answer the original message."
),
});
eprintln!("agent: resuming an interrupted turn");
self.steps(&cfg, turn["from"].clone(), turn["id"].clone()).await;
let message = Message {
id: turn["id"].as_str().unwrap_or_default().to_string(),
from: turn["from"].as_str().unwrap_or_default().to_string(),
reply_to: None,
body: Value::Null,
};
self.steps(&cfg, &message).await;
}
fn save(&mut self) {
if self.history.len() > MAX_HISTORY {
let start = self.history.len() - MAX_HISTORY;
let cut = (start..self.history.len())
.find(|i| matches!(self.history[*i], Entry::User { .. }))
.unwrap_or(start);
self.history.drain(..cut);
}
if let Ok(s) = serde_json::to_string(&self.history)
&& let Err(e) = std::fs::write(HISTORY, s)
async fn turn(&mut self, message: Message) {
let cfg = match std::fs::read_to_string(CONFIG)
.map_err(|e| e.to_string())
.and_then(|contents| serde_json::from_str(&contents).map_err(|e| e.to_string()))
{
eprintln!("agent: cannot save history: {e}");
}
}
async fn emit(&mut self, msg: Value) {
let mut line = msg.to_string();
line.push('\n');
if self.stdout.write_all(line.as_bytes()).await.is_err() || self.stdout.flush().await.is_err() {
eprintln!("agent: cannot write to stdout");
}
}
async fn reply(&mut self, to: &Value, reply_to: &Value, text: String) {
self.emit(json!({"to": to, "reply_to": reply_to, "body": {"type": "text", "text": text}})).await;
}
/// Sort a message that arrived during a turn.
fn stash(&mut self, m: Value, others: &mut Vec<Value>) {
if m["body"]["type"] == "shutdown" {
self.shutdown = true;
} else if starts_turn(&m) {
others.push(json!({"queued_for_a_later_turn": true, "message": m}));
self.queue.push_back(m);
} else {
others.push(m);
}
}
async fn turn(&mut self, msg: Value) {
let from = msg["from"].clone();
let id = msg["id"].clone();
let cfg: Config = match std::fs::read_to_string(CONFIG).map_err(|e| e.to_string()).and_then(|s| serde_json::from_str(&s).map_err(|e| e.to_string())) {
Ok(c) => c,
Ok(cfg) => cfg,
Err(e) => {
self.reply(&from, &id, format!("I am not configured: cannot read {CONFIG}: {e}")).await;
let _ = reply(
&message,
json!({"type": "text", "text": format!("I am not configured: cannot read {CONFIG}: {e}")}),
);
return;
}
};
let mut text = format!(
"Message {} from {}:\n{}",
id.as_str().unwrap_or("?"),
from.as_str().unwrap_or("?"),
msg["body"]["text"].as_str().unwrap_or("")
message.id,
message.from,
message.body["text"].as_str().unwrap_or("")
);
if !self.notes.is_empty() {
let notes: Vec<String> = self.notes.drain(..).map(|n| n.to_string()).collect();
text = format!("Messages that arrived while you were idle:\n{}\n\n{text}", notes.join("\n"));
let notes = self
.notes
.drain(..)
.map(|note| serde_json::to_string(&note).unwrap())
.collect::<Vec<_>>()
.join("\n");
text = format!("Messages that arrived while you were idle:\n{notes}\n\n{text}");
}
self.history.push(Entry::User { text });
self.steps(&cfg, from, id).await;
self.add_history(Entry::User { text });
self.steps(&cfg, &message).await;
}
/// Run inference and tools until the model answers. If a shutdown
/// interrupts the turn, remember it in TURN so the next start resumes it.
async fn steps(&mut self, cfg: &Config, from: Value, id: Value) {
async fn steps(&mut self, cfg: &Config, message: &Message) {
let tools = tools();
let cfg = cfg.clone();
for _ in 0..MAX_STEPS {
let started = Instant::now();
let result = llm::complete(&cfg, SYSTEM, &tools, &self.history).await;
let entries = match result {
Ok(e) => e,
loop {
let entries = match llm::complete(cfg, SYSTEM, &tools, &self.history).await {
Ok(entries) => entries,
Err(e) => {
eprintln!("agent: inference failed: {e}");
self.history.push(Entry::Assistant { text: format!("(inference failed: {e})") });
self.save();
self.reply(&from, &id, format!("Inference failed: {e}")).await;
self.add_history(Entry::Assistant {
text: format!("(inference failed: {e})"),
});
let _ = reply(
message,
json!({"type": "text", "text": format!("Inference failed: {e}")}),
);
return;
}
};
eprintln!("agent: inference took {:?}", started.elapsed());
let calls: Vec<(String, String, String)> = entries
.iter()
.filter_map(|e| match e {
Entry::ToolCall { id, name, arguments } => Some((id.clone(), name.clone(), arguments.clone())),
.filter_map(|entry| match entry {
Entry::ToolCall {
id,
name,
arguments,
} => Some((id.clone(), name.clone(), arguments.clone())),
_ => None,
})
.collect();
let answer: Vec<String> = entries
.iter()
.filter_map(|e| match e {
.filter_map(|entry| match entry {
Entry::Assistant { text } => Some(text.clone()),
_ => None,
})
.collect();
self.history.extend(entries);
for entry in entries {
self.add_history(entry);
}
if calls.is_empty() {
self.save();
let answer = if answer.is_empty() { "(no answer)".to_string() } else { answer.join("\n\n") };
self.reply(&from, &id, answer).await;
let answer = if answer.is_empty() {
"(no answer)".to_string()
} else {
answer.join("\n\n")
};
let _ = reply(message, json!({"type": "text", "text": answer}));
return;
}
for (call_id, name, args) in calls {
for (id, name, args) in calls {
let output = self.tool(&name, &args).await;
self.history.push(Entry::ToolResult { id: call_id, output: truncate(output.to_string(), MAX_TOOL_OUTPUT) });
self.add_history(Entry::ToolResult {
id,
output: output.to_string(),
});
}
self.save();
if self.shutdown {
let _ = std::fs::write(TURN, json!({"from": from, "id": id}).to_string());
eprintln!("agent: turn interrupted by shutdown; it resumes after the restart");
let _ = std::fs::write(
TURN,
json!({"from": message.from, "id": message.id}).to_string(),
);
return;
}
}
self.reply(&from, &id, format!("I stopped after {MAX_STEPS} steps. Tell me to continue if you want.")).await;
}
fn stash(&mut self, message: Message, others: &mut Vec<Value>) {
if starts_turn(&message) {
others.push(json!({"queued_for_a_later_turn": true, "message": message}));
self.queue.push_back(message);
} else {
others.push(serde_json::to_value(message).unwrap());
}
}
async fn tool(&mut self, name: &str, args: &str) -> Value {
let a: Value = match serde_json::from_str(args) {
Ok(v) => v,
Ok(value) => value,
Err(e) => return json!({"error": format!("arguments are not valid JSON: {e}")}),
};
let path = |k: &str| a[k].as_str().unwrap_or_default().to_string();
let path = |key: &str| a[key].as_str().unwrap_or_default().to_string();
let err = |e: std::io::Error| json!({"error": e.to_string()});
match name {
"send_message" => self.send_message(&a).await,
"wait_for_messages" => {
let secs = a["seconds"].as_f64().unwrap_or(10.0).clamp(0.0, 900.0);
let seconds = a["seconds"].as_f64().unwrap_or(10.0).max(0.0);
let mut others = Vec::new();
match self.rx.recv().timeout(Duration::from_secs_f64(secs)).await {
Ok(Ok(m)) => {
self.stash(m, &mut others);
while let Ok(m) = self.rx.try_recv() {
self.stash(m, &mut others);
match self
.inbox
.recv()
.timeout(Duration::from_secs_f64(seconds))
.await
{
Ok(Some(message)) => {
self.stash(message, &mut others);
while let Some(message) = self.inbox.try_recv() {
self.stash(message, &mut others);
}
}
Ok(Err(_)) => self.shutdown = true,
Ok(None) => self.shutdown = true,
Err(_) => {}
}
json!({"messages": others})
@@ -411,8 +358,9 @@ impl Agent {
match std::fs::read(&p) {
Ok(bytes) => {
let offset = (a["offset"].as_u64().unwrap_or(0) as usize).min(bytes.len());
let max = a["max_bytes"].as_u64().unwrap_or(30_000) as usize;
let end = (offset + max).min(bytes.len());
let end = a["max_bytes"].as_u64().map_or(bytes.len(), |max| {
offset.saturating_add(max as usize).min(bytes.len())
});
json!({
"path": p, "size": bytes.len(), "offset": offset,
"content": String::from_utf8_lossy(&bytes[offset..end]),
@@ -425,12 +373,11 @@ impl Agent {
"list_dir" => match std::fs::read_dir(path("path")) {
Ok(rd) => {
let mut entries: Vec<Value> = rd
.filter_map(|e| e.ok())
.take(500)
.map(|e| {
let meta = e.metadata().ok();
.filter_map(|entry| entry.ok())
.map(|entry| {
let meta = entry.metadata().ok();
json!({
"name": e.file_name().to_string_lossy(),
"name": entry.file_name().to_string_lossy(),
"type": if meta.as_ref().is_some_and(|m| m.is_dir()) { "dir" } else { "file" },
"size": meta.map(|m| m.len()),
})
@@ -452,13 +399,17 @@ impl Agent {
}
}
"copy_dir" => match copy_tree(&path("from"), &path("to")) {
Ok(n) => json!({"copied_files": n}),
Ok(count) => json!({"copied_files": count}),
Err(e) => err(e),
},
"remove_path" => {
let p = path("path");
let r = if std::path::Path::new(&p).is_dir() { std::fs::remove_dir_all(&p) } else { std::fs::remove_file(&p) };
match r {
let result = if std::path::Path::new(&p).is_dir() {
std::fs::remove_dir_all(&p)
} else {
std::fs::remove_file(&p)
};
match result {
Ok(()) => json!({"removed": p}),
Err(e) => err(e),
}
@@ -467,34 +418,32 @@ impl Agent {
}
}
async fn send_message(&mut self, a: &Value) -> Value {
let Some(to) = a["to"].as_str() else { return json!({"error": "missing \"to\""}) };
if !a["body"].is_object() {
async fn send_message(&mut self, args: &Value) -> Value {
let Some(to) = args["to"].as_str() else {
return json!({"error": "missing \"to\""});
};
if !args["body"].is_object() {
return json!({"error": "\"body\" must be a JSON object"});
}
self.seq += 1;
let own = format!("a{}-{}", wstd_now_ms(), self.seq);
let full = format!("agent/{own}");
self.emit(json!({"to": to, "id": own, "body": a["body"]})).await;
let wait = a["wait_seconds"].as_f64().unwrap_or(0.0).clamp(0.0, 900.0);
let id = send(to, args["body"].clone());
let wait = args["wait_seconds"].as_f64().unwrap_or(0.0).max(0.0);
let mut reply = Value::Null;
let mut others = Vec::new();
if wait > 0.0 {
let deadline = Instant::now() + Duration::from_secs_f64(wait);
loop {
match self.rx.recv().timeout(deadline).await {
Ok(Ok(m)) => {
if m["reply_to"] == full.as_str() {
reply = m;
break;
}
self.stash(m, &mut others);
match self.inbox.recv().timeout(deadline).await {
Ok(Some(message)) if message.reply_to.as_deref() == Some(&id) => {
reply = serde_json::to_value(message).unwrap();
break;
}
Ok(Some(message)) => {
self.stash(message, &mut others);
if self.shutdown {
break;
}
}
Ok(Err(_)) => {
// stdin closed: the broker stops us.
Ok(None) => {
self.shutdown = true;
break;
}
@@ -502,19 +451,10 @@ impl Agent {
}
}
}
json!({"id": full, "reply": reply, "waited": wait > 0.0, "other_messages": others})
json!({"id": id, "reply": reply, "waited": wait > 0.0, "other_messages": others})
}
}
/// A text message that is not a reply starts a turn. Replies never do, so
/// two actors cannot keep the agent in an endless conversation.
fn starts_turn(m: &Value) -> bool {
m["body"]["type"] == "text" && m.get("reply_to").is_none_or(Value::is_null)
}
fn wstd_now_ms() -> u64 {
std::time::SystemTime::now()
.duration_since(std::time::UNIX_EPOCH)
.map(|d| d.as_millis() as u64)
.unwrap_or(0)
fn starts_turn(message: &Message) -> bool {
message.kind() == "text" && message.reply_to.is_none()
}
+47 -63
View File
@@ -1,80 +1,64 @@
You are the agent of a Sausage world. Your actor ID is `agent`.
You are the `agent` actor in a Sausage world. Your actor ID is `agent`.
Sausage is a system of actors. Each actor is a WASI program (a `.wasm` file). Actors talk only through messages. People talk to you through other actors, for example `console` (a terminal) or later `matrix`. You help them by using actors, and by writing, testing, and upgrading actors. You can also change your own code.
Sausage is a system of actors. Each actor is a WASM program that sends JSON messages through a broker. Help people use actors, write new actors, and upgrade them when asked.
# Messages
## Messages and the SDK
Every message has a sender (`from`), an ID, an optional `reply_to` (the ID of the message it answers), and a JSON `body`. A body is an object with a `"type"` field. There is no request/response: a reply is a new message with `reply_to` set. Delivery is at most once.
Actors read one JSON message per line. Each message has `id`, `from`, optional `reply_to`, and `body`. The broker routes a message with `to`. Without `to`, the broker publishes it to subscribers. A reply is a new message with `reply_to` set to the original ID.
A WASM actor reads one JSON object per line on stdin:
`{"id":"m-17","from":"console","body":{...}}`
and writes one JSON object per line on stdout:
`{"to":"console","reply_to":"m-17","body":{...}}`
Without `"to"`, the broker publishes the message to the subscribers of the sender. An actor may set its own `"id"`. The broker then uses `"<sender>/<id>"`. stdout is only for messages. Logs go to stderr. The broker sends `{"type":"shutdown"}` before it stops an actor. EOF on stdin means "stop now".
Use `sausage-actor = "0.1"` in a Rust actor's `Cargo.toml`.
# Filesystem
Each actor sees:
- `/data`: private state, read-write. Only the actor itself sees it.
- `/public`: its public files, read-write.
- `/actor/<id>/public`: the public files of every actor, read-only.
- `/actor/<id>/source`: the source of the running version of every actor, read-only.
- `/actor/<id>/status.json` and `/actor/<id>/stderr.log`: state and stderr log of every actor.
`ls /actor` lists all actors. A write becomes visible to other actors only when the writer closes the file. Send large or binary data as a file path, not in a message.
# Built-in actors
`broker` (only accepts `.wasm` files, knows no source language):
- `{"type":"spawn","actor":"<new-id>","wasm":"<path>","source":"<folder>","built_by":"cargo"}`
- `{"type":"upgrade","actor":"<id>","wasm":"<path>","source":"<folder>","built_by":"cargo"}`
- `{"type":"rollback","actor":"<id>"}` (optional `"version"`)
- `{"type":"stop","actor":"<id>"}`, `{"type":"start","actor":"<id>"}`, `{"type":"remove","actor":"<id>"}` (archives, never deletes)
- `{"type":"subscribe","actor":"<id>"}`, `{"type":"unsubscribe","actor":"<id>"}`, `{"type":"list"}`
Before an upgrade or spawn, the broker tests the candidate on a copy of the actor's `/data` and `/public`, with no HTTP access. The tests are message transcripts in `<source>/tests/*.jsonl`. Each line is `{"send": <body>}` or `{"expect": <subset of the reply body>}` (optional `"to"`). Without test files, the candidate must start and stay up for 2 seconds. If a new version crashes 3 times within 30 seconds, the broker rolls it back automatically. The broker keeps the message that crashed an actor and delivers it again after the next upgrade.
`cargo` (built-in Rust compiler):
- `{"type":"build","source":"<folder with Cargo.toml>"}` → `{"type":"built","wasm":"/actor/cargo/public/builds/<n>/<name>.wasm",...}` or `{"type":"build_failed","errors":"..."}`. A build can take a minute. Wait up to 600 seconds for the reply.
# Writing an actor in Rust
1. Write the crate to `/public/drafts/<name>/`: `Cargo.toml`, `src/main.rs`, and `tests/*.jsonl`. Use `edition = "2024"`. Use `serde_json` for messages.
2. Send `build` to `cargo` with the folder path `/actor/agent/public/drafts/<name>` and wait for the reply. Fix compiler errors and build again.
3. Send `spawn` (new actor) or `upgrade` (existing actor) to `broker` with the `wasm` path from the build reply and the same `source` folder. Wait for the reply.
4. Send a message to the new actor to check it.
A simple actor that only reacts to messages can block on stdin:
A simple actor reads messages with `messages()` and replies with `reply()`:
```rust
use serde_json::{json, Value};
use std::io::{BufRead, Write};
use sausage_actor::{json, messages, reply};
fn main() {
let mut out = std::io::stdout().lock();
for line in std::io::stdin().lock().lines() {
let Ok(line) = line else { break };
let Ok(msg) = serde_json::from_str::<Value>(&line) else { continue };
let body = &msg["body"];
let reply = match body["type"].as_str() {
Some("shutdown") => break,
Some("ping") => json!({"type": "pong"}),
_ => json!({"type": "error", "reason": "unknown message"}),
};
writeln!(out, "{}", json!({"to": msg["from"], "reply_to": msg["id"], "body": reply})).unwrap();
out.flush().unwrap();
for message in messages() {
if message.kind() == "ping" {
let _ = reply(&message, json!({"type": "pong"}));
}
}
}
```
An actor that needs HTTP or timers and must also read messages uses the async `wstd` crate (`wstd = "0.6"`): `#[wstd::main] async fn main()`, `wstd::io::stdin()` (`AsyncRead`), `wstd::io::stdout()` (`AsyncWrite`, `write_all`, `flush`), `wstd::http::{Client, Request, Body}` (`Client::new().send(Request::get(url).body(Body::empty())?).await?`, then `response.into_body().contents().await?`), `wstd::task::sleep(wstd::time::Duration::from_secs(n)).await`, and `wstd::runtime::spawn(future)`. Actors have outgoing HTTP and HTTPS only, no raw sockets. Threads are not available. Store state in `/data` so it survives restarts and upgrades. A new version must read the data format of the old version.
Use `Inbox` for an actor that needs HTTP or timers. Enable the SDK's `async` feature. Use `wstd` for HTTP:
# Changing yourself
```rust
use sausage_actor::{Inbox, json, reply};
use wstd::http::{Body, Client, Request};
Your own source is at `/actor/agent/source`. To change yourself, copy it to `/public/drafts/agent`, edit the copy, build it, and upgrade `agent`. The upgrade restarts you, and the conversation continues from `/data`. Be careful: if the new version cannot answer, the person must roll you back through the console. Change yourself only when the person asks for it.
fn main() {
wstd::runtime::block_on(async {
let inbox = Inbox::start();
while let Some(message) = inbox.recv().await {
if message.kind() != "fetch" {
continue;
}
let url = message.body["url"].as_str().unwrap();
let request = Request::get(url).body(Body::empty()).unwrap();
let response = Client::new().send(request).await.unwrap();
let text = response.into_body().str_contents().await.unwrap();
let _ = reply(&message, json!({"type": "fetched", "text": text.to_string()}));
}
});
}
```
# How to work
## Writing and testing actors
- Use tools to look at the real state before you claim anything. Read files instead of guessing.
- Keep answers short and concrete. Say what you changed and whether it worked.
- Your final text in a turn goes back to the person who wrote to you.
Write each Rust actor under `/public/drafts/<name>/`. Add `Cargo.toml`, `src/main.rs`, and tests under `tests/`.
The broker tests each `tests/*.json` file before an upgrade or spawn. Each file has a `steps` list. A step can have `send`, `expect`, `from`, and `to`. An expected body matches a subset of the reply body. Tests have no HTTP access.
Send `{"type":"build","source":"/actor/agent/public/drafts/<name>"}` to `cargo`. Then send `spawn` or `upgrade` to `broker` with the returned WASM path and the source folder. Check the actor with a message.
## Filesystem
Your private state lives under `/data`. Your public files live under `/public`. Other actors' `data/` directories are hidden.
The host will provide `/actor/<id>/` with `actor.wasm`, `actor.json`, `source/`, `public/`, `status.json`, and `stderr.log`. Each `versions/<n>/` contains `actor.wasm`, `source/`, and `meta.json`.
Keep state in `/data` so it survives restarts and upgrades. Read the old data format when you upgrade an actor.
Your source lives at `/actor/agent/source`. To change yourself, copy it to `/public/drafts/agent`, build it with `cargo`, and send an `upgrade` request to `broker`. The upgrade restarts you. Your turn resumes from `/data/turn.json`.