Bare sausage creates ./world if needed and runs it (default app)

- cli: the subcommand is optional; without one, sausage runs ./world and
  runs init first when ./world is not a world yet (test: cli/tests/cli.rs).
  So `nix run git+https://gitea.surma.technology/surma/sausage` works.
- flake: .#loop without a folder runs bare sausage.
- README: mention the bare command and the bare loop.

.gitea/workflows/ci.yml

@@ -1,4 +1,4 @@
-# Runs on the Nix runner on nexus (label `nixos`, host executor).
+# Runs on a self-hosted Nix runner (label `nixos`, host executor).
 name: ci
 on: [push, pull_request]
 

PROTOCOL.md

@@ -109,7 +109,7 @@ Any request can be answered with `{"type": "fs_error", "errno": "no-entry"}`.
 
 Requests to `broker`. The answer is a message whose `reply_to` is the ID of
 the request: the request's `type` in past tense (`spawned`, `upgraded`,
-`rolled_back`, `stopped`, `started`, `subscribed`, `unsubscribed`,
+`rolled_back`, `stopped`, `started`, `removed`, `subscribed`, `unsubscribed`,
 `tapping`, `untapped`, `scanned`, `exiting`), or `{"type": "error", "reason": "..."}`.
 
 | `type` | Fields | Effect |
@@ -118,6 +118,7 @@ the request: the request's `type` in past tense (`spawned`, `upgraded`,
 | `upgrade` | `actor`, `wasm`, `source`?, `built_by`? | test, then swap the version |
 | `rollback` | `actor`, `version` | go back to an older version |
 | `stop`, `start` | `actor` | stop or start an actor |
+| `remove` | `actor` | stop the actor (normal shutdown), then delete its whole folder `/actor/<id>/` (all versions, `data/`, `public/`, logs); answer `{"type": "removed", "actor"}`. Messages to it are then undeliverable, and the ID can be spawned again. An unknown actor or a native one (`broker`, `console`, `cargo`, `fs`) is an `error` |
 | `subscribe`, `unsubscribe` | `actor` | receive (or not) what `actor` publishes |
 | `tap`, `untap` | | receive (or not) a copy of every message the broker routes |
 | `scan` | | boot new or changed `actor.wasm` files |

README.md

@@ -10,28 +10,43 @@ change its own code.
 
 ## Start
 
-You need [Nix](https://nixos.org/download) with flakes.
+You need [Nix](https://nixos.org/download) with flakes, and an API token for
+an LLM (OpenAI Responses or Anthropic Messages API). No clone needed:
 
 ```sh
-nix run -- init     # creates ./world and builds the agent (a few minutes)
-nix run -- run      # starts the world and a console
+nix run git+https://gitea.surma.technology/surma/sausage
+```
+
+This creates a world in `./world` the first time (it builds the agent, which
+takes a few minutes), then starts it with a console. Later runs start the
+existing world. The two steps on their own:
+
+```sh
+nix run git+https://gitea.surma.technology/surma/sausage -- init   # creates ./world and builds the agent
+nix run git+https://gitea.surma.technology/surma/sausage -- run    # starts the world and a console
 ```
 
 `init` asks for the API shape (`openai-responses` or `anthropic-messages`),
 the base URL, the model, and the token. It reads `SAUSAGE_API`,
 `SAUSAGE_BASE_URL`, `SAUSAGE_MODEL`, and `SAUSAGE_API_TOKEN` first. The
 values go to `world/actor/agent/data/config.json`. Both commands take another
-folder as an argument, for example `nix run -- run my-world`.
+folder as an argument, for example `... -- run my-world`.
 
 To keep a world on the newest version, run it in a loop:
 
 ```sh
-nix run .#loop -- my-world            # or .#loop-internal (Gitea on the LAN)
+nix run git+https://gitea.surma.technology/surma/sausage#loop               # ./world, created if needed
+nix run git+https://gitea.surma.technology/surma/sausage#loop -- my-world   # an existing world
 ```
 
-The loop runs `nix run --refresh git+ssh://…/surma/sausage -- run my-world`.
+The loop runs `nix run --refresh git+https://gitea.surma.technology/surma/sausage -- run my-world`.
 When the host crashes or an actor sends `@broker {"type":"exit"}`, the loop
-fetches the newest commit and starts it again. `/quit` ends the loop.
+fetches the newest commit and starts it again. `/quit` ends the loop. Set
+`SAUSAGE_FLAKE` to run another flake URL instead, for example your fork.
+
+From a clone (`git clone https://gitea.surma.technology/surma/sausage`), the
+same commands are `nix run`, `nix run -- init`, `nix run -- run` and
+`nix run .#loop`.
 
 In the console:
 

cli/src/broker.rs

@@ -1,7 +1,7 @@
 //! The broker: message routing, mailboxes, subscriptions, taps, the version
 //! store, and the requests to `broker` (spawn, upgrade, rollback, stop, start,
-//! subscribe, unsubscribe, tap, untap, scan, exit). `supervisor.rs` runs each
-//! WASM actor.
+//! remove, subscribe, unsubscribe, tap, untap, scan, exit). `supervisor.rs`
+//! runs each WASM actor.
 //!
 //! The broker accepts only `.wasm` files. It does not know any source language.
 //! The world folder is the source of truth: `scan` boots every
@@ -377,6 +377,35 @@ impl Broker {
         Ok(result)
     }
 
+    /// Stop an actor (normal shutdown) and delete its folder `actor/<id>/`.
+    /// Afterwards the ID is unknown: messages to it are undeliverable, and
+    /// it can be spawned again from scratch.
+    pub async fn remove_actor(&self, id: &str) -> Result<Value> {
+        if NATIVE.contains(&id) {
+            bail!("{id} is part of the host and cannot be removed");
+        }
+        if !world::valid_id(id) {
+            bail!("invalid actor ID {id:?}");
+        }
+        let lock = self.op_lock(id);
+        let _guard = lock.lock().await;
+        let dir = self.world.actor_dir(id);
+        if !self.is_supervised(id) && !dir.is_dir() {
+            bail!("no actor with ID {id}");
+        }
+        if self.is_supervised(id) {
+            self.control(id, |reply| Control::Shutdown { reply }).await?;
+        }
+        // Without its mailbox, messages to `id` are undeliverable.
+        self.controls.lock().unwrap().remove(id);
+        self.mailboxes.lock().unwrap().remove(id);
+        self.metas.lock().unwrap().remove(id);
+        if dir.exists() {
+            std::fs::remove_dir_all(&dir).with_context(|| format!("delete {}", dir.display()))?;
+        }
+        Ok(json!({"type": "removed", "actor": id}))
+    }
+
     /// Boot the actors in `actor/`. Called at start and on `scan`.
     ///
     /// - An `actor.wasm` equal to the installed version starts as is.
@@ -481,6 +510,7 @@ impl Broker {
             }
             "stop" => self.control(&actor()?, |reply| Control::Stop { reply }).await,
             "start" => self.control(&actor()?, |reply| Control::Start { reply }).await,
+            "remove" => self.remove_actor(&actor()?).await,
             "subscribe" | "unsubscribe" => {
                 let publisher = actor()?;
                 let on = ty == "subscribe";
@@ -506,7 +536,7 @@ impl Broker {
                 self.exit.notify_one();
                 Ok(json!({"type": "exiting"}))
             }
-            other => bail!("unknown broker request {other:?}. Known: spawn, upgrade, rollback, stop, start, subscribe, unsubscribe, tap, untap, scan, exit"),
+            other => bail!("unknown broker request {other:?}. Known: spawn, upgrade, rollback, stop, start, remove, subscribe, unsubscribe, tap, untap, scan, exit"),
         }
     }
 

cli/src/main.rs

@@ -12,11 +12,13 @@ use sausage::{Host, cargo_actor, console};
 /// The source of the agent actor. `init` builds it like any other actor.
 static AGENT_SOURCE: Dir<'_> = include_dir!("$CARGO_MANIFEST_DIR/../agent");
 
+// Without a command, `sausage` runs the world in `./world` and creates it
+// first (like `init`) if it does not exist yet.
 #[derive(Parser)]
 #[command(version, about)]
 struct Cli {
     #[command(subcommand)]
-    command: Cmd,
+    command: Option<Cmd>,
 }
 
 #[derive(Subcommand)]
@@ -112,7 +114,15 @@ async fn run(dir: PathBuf) -> Result<()> {
 #[tokio::main]
 async fn main() -> Result<()> {
     match Cli::parse().command {
-        Cmd::Init { dir } => init(dir).await,
-        Cmd::Run { dir } => run(dir).await,
+        Some(Cmd::Init { dir }) => init(dir).await,
+        Some(Cmd::Run { dir }) => run(dir).await,
+        None => {
+            let dir = PathBuf::from("world");
+            if !dir.join("actor").is_dir() {
+                println!("No world in ./world yet, creating it (same as `sausage init`).");
+                init(dir.clone()).await?;
+            }
+            run(dir).await
+        }
     }
 }

cli/tests/cli.rs

@@ -0,0 +1,41 @@
+//! Tests of the `sausage` command line.
+
+use std::path::PathBuf;
+use std::process::{Command, Stdio};
+use std::time::{SystemTime, UNIX_EPOCH};
+
+fn empty_dir(label: &str) -> PathBuf {
+    let nonce = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_nanos();
+    let dir = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .parent()
+        .unwrap()
+        .join("target/test-cli")
+        .join(format!("{label}-{}-{nonce}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    dir
+}
+
+/// Bare `sausage` (as in `nix run <flake>`) without a world starts `init`
+/// for ./world instead of printing a usage error.
+#[test]
+fn bare_command_without_a_world_starts_init() {
+    let dir = empty_dir("bare");
+    let output = Command::new(env!("CARGO_BIN_EXE_sausage"))
+        .current_dir(&dir)
+        .env_remove("SAUSAGE_API")
+        .env_remove("SAUSAGE_BASE_URL")
+        .env_remove("SAUSAGE_MODEL")
+        .env_remove("SAUSAGE_API_TOKEN")
+        .stdin(Stdio::null())
+        .output()
+        .unwrap();
+    let stdout = String::from_utf8_lossy(&output.stdout);
+    let stderr = String::from_utf8_lossy(&output.stderr);
+    // With no answers on stdin, init stops at the first required value.
+    assert!(!output.status.success(), "stdout:\n{stdout}\nstderr:\n{stderr}");
+    assert!(stdout.contains("No world in ./world yet"), "stdout:\n{stdout}\nstderr:\n{stderr}");
+    assert!(stderr.contains("SAUSAGE_BASE_URL"), "stdout:\n{stdout}\nstderr:\n{stderr}");
+    assert!(!stderr.contains("Usage:"), "stderr:\n{stderr}");
+    // It asks before it creates anything.
+    assert!(!dir.join("world").exists());
+}

cli/tests/host.rs

@@ -494,6 +494,62 @@ async fn explicit_rollback_keeps_current_data() {
     host.stop().await;
 }
 
+#[tokio::test]
+async fn remove_shuts_an_actor_down_and_deletes_its_folder() {
+    let world = create_world("remove");
+    let wasm = toolbox_wasm().clone();
+    let (host, mut mailbox) = start(&world).await;
+    let source = passing_source(&world, "source");
+    spawn_type(&host, &mut mailbox, "doomed", &wasm, &source).await;
+    let write = json!({"type": "write", "path": "/data/state", "text": "x"});
+    ask_type(&host, &mut mailbox, "doomed", write, "ok").await;
+    ask_type(&host, &mut mailbox, "doomed", json!({"type": "arm-shutdown"}), "armed").await;
+
+    // Normal shutdown: the actor gets "shutdown" and its last message is routed.
+    let id = host.broker.send("console", Some("broker"), None, None, json!({"type": "remove", "actor": "doomed"}));
+    let (mut removed, mut last_words) = (false, false);
+    tokio::time::timeout(Duration::from_secs(10), async {
+        while !removed || !last_words {
+            let message = mailbox.recv().await.expect("console mailbox closed");
+            if message.reply_to.as_deref() == Some(id.as_str()) {
+                assert_eq!(message.body, json!({"type": "removed", "actor": "doomed"}));
+                removed = true;
+            } else if message.reply_to.as_deref() == Some("broker/shutdown") {
+                assert_eq!(message.body["type"], "shutdown-reply");
+                last_words = true;
+            }
+        }
+    })
+    .await
+    .expect("remove did not answer or did not shut the actor down");
+    assert!(!world.actor_dir("doomed").exists());
+
+    let gone = ask(&host, &mut mailbox, "doomed", json!({"type": "echo", "value": "hi"})).await;
+    assert_eq!(gone.body["type"], "undeliverable");
+    let again = request(&host, &mut mailbox, json!({"type": "remove", "actor": "doomed"})).await;
+    assert_eq!(again.body["type"], "error");
+    let broker = request(&host, &mut mailbox, json!({"type": "remove", "actor": "broker"})).await;
+    assert_eq!(broker.body["type"], "error");
+    assert!(world.actor_dir("broker").exists());
+
+    // The ID is free again: a new spawn starts at version 1 with empty data.
+    assert_eq!(spawn_type(&host, &mut mailbox, "doomed", &wasm, &source).await.body["version"], 1);
+    let read = json!({"type": "read", "path": "/data/state"});
+    ask_type(&host, &mut mailbox, "doomed", read, "error").await;
+    host.stop().await;
+}
+
+#[tokio::test]
+async fn unknown_broker_request_lists_the_known_ones() {
+    let world = create_world("unknown-request");
+    let (host, mut mailbox) = start(&world).await;
+    let unknown = request(&host, &mut mailbox, json!({"type": "frobnicate"})).await;
+    assert_eq!(unknown.body["type"], "error");
+    let reason = unknown.body["reason"].as_str().unwrap();
+    assert!(reason.contains("remove") && reason.contains("tap"), "{reason}");
+    host.stop().await;
+}
+
 #[tokio::test]
 async fn cargo_actor_builds_valid_crates_and_reports_compiler_errors() {
     let world = create_world("cargo-actor");

flake.nix

@@ -36,18 +36,19 @@
           meta.mainProgram = "sausage";
         };
         # `nix run .#loop -- <world>` runs the newest `sausage run <world>`
-        # from the Gitea repo, again and again: after a crash or a broker
+        # (without a folder: bare `sausage`, i.e. ./world, created if needed)
+        # from the public repo, again and again: after a crash or a broker
         # `exit` request it refreshes the flake and starts the host again,
         # so the world updates itself. `/quit` (exit code 0) ends the loop.
-        # `--internal` (or `.#loop-internal`) uses Gitea's SSH port on the LAN.
-        publicUrl = "git+ssh://containeruser@gitea.surma.technology:2222/surma/sausage";
-        internalUrl = "git+ssh://containeruser@10.0.0.2:2222/surma/sausage";
-        loop = name: url: pkgs.writeShellScriptBin name ''
-          url="${url}"
-          if [ "''${1:-}" = "--internal" ]; then url="${internalUrl}"; shift; fi
-          if [ $# -eq 0 ]; then set -- world; fi
+        # SAUSAGE_FLAKE overrides where it fetches from (any flake URL,
+        # e.g. a fork or a local checkout).
+        repoUrl = "git+https://gitea.surma.technology/surma/sausage";
+        loop = pkgs.writeShellScriptBin "sausage-loop" ''
+          url="''${SAUSAGE_FLAKE:-${repoUrl}}"
+          # No folder: bare `sausage` (creates ./world first if needed).
+          if [ $# -gt 0 ]; then set -- run "$@"; fi
           while true; do
-            nix run --refresh "$url#default" -- run "$@"
+            nix run --refresh "$url#default" -- "$@"
             code=$?
             if [ "$code" -eq 0 ]; then exit 0; fi
             echo "sausage-loop: sausage exited with $code, starting the newest version in 2 s …" >&2
@@ -72,8 +73,7 @@
         });
 
         apps.default = { type = "app"; program = "${sausage}/bin/sausage"; };
-        apps.loop = { type = "app"; program = "${loop "sausage-loop" publicUrl}/bin/sausage-loop"; };
-        apps.loop-internal = { type = "app"; program = "${loop "sausage-loop-internal" internalUrl}/bin/sausage-loop-internal"; };
+        apps.loop = { type = "app"; program = "${loop}/bin/sausage-loop"; };
 
         devShells.default = pkgs.mkShell {
           packages = [ rust pkgs.wasmtime pkgs.wasm-tools ];