brokerd: escape container errors in the log; prefix and quote two messages

Implemented-By: OpenCode session (model recorded in docs/implementer-log.md)

crates/brokerd/src/config.rs

@@ -176,7 +176,7 @@ impl Config {
         }
         if let Some(runner) = &config.runner {
             let where_image = format!(
-                "[runner] image is {}; it must be named by digest: <name>@sha256:<64 hex digits>",
+                "[runner] image is {:?}; it must be named by digest: <name>@sha256:<64 hex digits>",
                 runner.image
             );
             let (name, hex) = match runner.image.rsplit_once("@sha256:") {
@@ -198,7 +198,7 @@ impl Config {
                 return Err(ConfigError::Invalid(
                     path.to_path_buf(),
                     format!(
-                        "[runner] memory is {}; it must be a number and one of b, k, m, g",
+                        "[runner] memory is {:?}; it must be a number and one of b, k, m, g",
                         runner.memory
                     ),
                 ));

crates/brokerd/src/container.rs

@@ -214,16 +214,20 @@ impl Podman {
                     truncated,
                 }),
                 Some(2) => {
-                    (self.log)(err);
+                    (self.log)(&format!("brokerd: {name}: the tool could not run: {err:?}"));
                     Err(RunError::Failed(COULD_NOT_RUN.to_string()))
                 }
                 Some(125..=127) => {
-                    (self.log)(&format!("{err}\n{RUNBOOK}"));
+                    (self.log)(&format!(
+                        "brokerd: podman could not start {name}: {err:?}\n{RUNBOOK}"
+                    ));
                     Err(RunError::Unavailable(CANNOT_START.to_string()))
                 }
                 Some(137) => Err(RunError::Failed(KILLED.to_string())),
                 _ => {
-                    (self.log)(&format!("brokerd: container {name} exited {status}\n{err}"));
+                    (self.log)(&format!(
+                        "brokerd: container {name} exited {status}: {err:?}"
+                    ));
                     Err(RunError::Failed(UNEXPECTED.to_string()))
                 }
             },
@@ -302,7 +306,7 @@ impl Podman {
             Ok(output) => {
                 let stderr = String::from_utf8_lossy(&output.stderr).into_owned();
                 (self.log)(&format!(
-                    "brokerd: podman could not start {name}-egress: {stderr}\n{RUNBOOK}"
+                    "brokerd: podman could not start {name}-egress: {stderr:?}\n{RUNBOOK}"
                 ));
                 return Err(RunError::Unavailable(CANNOT_START.to_string()));
             }

crates/brokerd/src/main.rs

@@ -97,7 +97,7 @@ fn main() -> ExitCode {
         broker_path.display(),
         admin_path.display()
     );
-    eprintln!("{runtime_notice}");
+    eprintln!("brokerd: {runtime_notice}");
 
     match started.run() {
         Ok(()) => ExitCode::SUCCESS,

crates/brokerd/tests/container_log.rs

@@ -0,0 +1,128 @@
+//! What a tool or Podman writes on standard error reaches `brokerd`'s log escaped, one entry per
+//! event: it cannot start a line of its own or forge a runbook pointer (M3b review finding 5).
+//! Do not edit.
+
+#[path = "support/build.rs"]
+mod build;
+#[path = "support/fake_podman.rs"]
+mod fake_podman;
+
+use brokerd::container::{CANNOT_START, COULD_NOT_RUN, Podman, UNEXPECTED};
+use brokerd::policy::{Outcome, SessionState, decide};
+use brokerd::runner::run;
+use build::{fetch, grant, now, read, set};
+use fake_podman::{Fake, Lines, serial};
+use proto::{Mode, ToolRequest, ToolResponse};
+
+const FORGED: &str = "real line\nbrokerd: forged\nsee docs/runbook.md#grants-invalid";
+
+fn call(fake: &Fake, req: ToolRequest, grants: Vec<build::Build>, log: &Lines) -> ToolResponse {
+    let podman = Podman::new(fake.runner(""), fake.dir.join("egress"), log.sink());
+    let decision = match decide(req, &set(grants), SessionState::default(), now()) {
+        Outcome::Allowed(d) => d,
+        other => panic!("not allowed: {other:?}"),
+    };
+    run(decision, &podman)
+}
+
+/// No entry holds the forged text as lines of its own; the one that carries it has it escaped.
+fn escaped(log: &Lines) {
+    let entries = log.0.lock().unwrap().clone();
+    for entry in &entries {
+        assert!(!entry.contains("\nbrokerd: forged"), "raw: {entry:?}");
+        assert!(
+            !entry.contains("\nsee docs/runbook.md#grants-invalid"),
+            "raw: {entry:?}"
+        );
+    }
+    assert!(
+        entries
+            .iter()
+            .any(|e| e.contains(r"real line\nbrokerd: forged")),
+        "the error is still logged, escaped: {entries:?}"
+    );
+}
+
+fn notes() -> Vec<build::Build> {
+    vec![grant("notes", "read_file", Mode::Auto).paths(&["/n"])]
+}
+
+#[test]
+fn a_tool_that_could_not_run() {
+    let _s = serial();
+    let fake = Fake::new(
+        "log-2",
+        &format!("cat > /dev/null; printf '{FORGED}' >&2; exit 2"),
+    );
+    let log = Lines::default();
+    assert_eq!(
+        call(&fake, read("/n/a"), notes(), &log),
+        ToolResponse::Failed {
+            message: COULD_NOT_RUN.to_string()
+        }
+    );
+    escaped(&log);
+}
+
+#[test]
+fn a_container_podman_could_not_start_keeps_its_one_real_pointer() {
+    let _s = serial();
+    let fake = Fake::new(
+        "log-125",
+        &format!("cat > /dev/null; printf '{FORGED}' >&2; exit 125"),
+    );
+    let log = Lines::default();
+    assert_eq!(
+        call(&fake, read("/n/a"), notes(), &log),
+        ToolResponse::Failed {
+            message: CANNOT_START.to_string()
+        }
+    );
+    escaped(&log);
+    let entries = log.0.lock().unwrap().clone();
+    assert!(
+        entries
+            .iter()
+            .any(|e| e.ends_with("\nsee docs/runbook.md#runner-unavailable")),
+        "{entries:?}"
+    );
+}
+
+#[test]
+fn an_unexpected_ending() {
+    let _s = serial();
+    let fake = Fake::new(
+        "log-3",
+        &format!("cat > /dev/null; printf '{FORGED}' >&2; exit 3"),
+    );
+    let log = Lines::default();
+    assert_eq!(
+        call(&fake, read("/n/a"), notes(), &log),
+        ToolResponse::Failed {
+            message: UNEXPECTED.to_string()
+        }
+    );
+    escaped(&log);
+}
+
+#[test]
+fn a_proxy_podman_could_not_start() {
+    let _s = serial();
+    let body =
+        format!("if [ \"$2\" = -d ]; then printf '{FORGED}' >&2; exit 125; fi; cat > /dev/null");
+    let fake = Fake::new("log-egress", &body);
+    let log = Lines::default();
+    let got = call(
+        &fake,
+        fetch("https://example.com/"),
+        vec![grant("web", "http_fetch", Mode::Auto).hosts(&["example.com"])],
+        &log,
+    );
+    assert_eq!(
+        got,
+        ToolResponse::Failed {
+            message: CANNOT_START.to_string()
+        }
+    );
+    escaped(&log);
+}

crates/brokerd/tests/notices.rs

@@ -0,0 +1,80 @@
+//! Two small texts from the M3b review: every line `brokerd serve` prints about its runtime starts
+//! with `brokerd:`, and a bad `[runner]` value is quoted in its error. Do not edit.
+
+#[path = "support/fake_podman.rs"]
+mod fake_podman;
+
+use std::io::Read;
+use std::os::unix::net::UnixStream;
+use std::process::{Command, Stdio};
+use std::time::{Duration, Instant};
+
+use brokerd::config::{Config, ConfigError};
+use fake_podman::{Fake, IMAGE, serial};
+
+#[test]
+fn the_runtime_notice_starts_with_brokerd() {
+    let _s = serial();
+    let fake = Fake::new("notice", "exit 0");
+    let home = fake.dir.join("home");
+    std::fs::create_dir_all(home.join("grants")).unwrap();
+    let config = fake.dir.join("brokerd.toml");
+    std::fs::write(
+        &config,
+        format!(
+            "[paths]\nhome = \"{0}\"\ngrants = \"{0}/grants\"\n[runner]\npodman = \"{1}\"\nimage = \"{IMAGE}\"\n",
+            home.display(),
+            fake.script.display()
+        ),
+    )
+    .unwrap();
+    let mut child = Command::new(env!("CARGO_BIN_EXE_brokerd"))
+        .args(["serve", "--config"])
+        .arg(&config)
+        .stderr(Stdio::piped())
+        .spawn()
+        .unwrap();
+    let until = Instant::now() + Duration::from_secs(10);
+    while UnixStream::connect(home.join("run/loop-broker/broker.sock")).is_err() {
+        assert!(Instant::now() < until, "brokerd never listened");
+        std::thread::sleep(Duration::from_millis(20));
+    }
+    std::thread::sleep(Duration::from_millis(100));
+    child.kill().unwrap();
+    child.wait().unwrap();
+    let mut printed = String::new();
+    child
+        .stderr
+        .take()
+        .unwrap()
+        .read_to_string(&mut printed)
+        .unwrap();
+    assert!(
+        printed
+            .lines()
+            .any(|l| l == format!("brokerd: tools run in containers from {IMAGE}")),
+        "{printed}"
+    );
+}
+
+#[test]
+fn a_bad_runner_value_is_quoted() {
+    let dir = std::env::temp_dir().join(format!("bx-notice-cfg-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    let cases = [
+        ("image = \"not by digest\"", "\"not by digest\""),
+        (
+            &*format!("image = \"{IMAGE}\"\nmemory = \"lots\""),
+            "\"lots\"",
+        ),
+    ];
+    for (n, (body, quoted)) in cases.iter().enumerate() {
+        let path = dir.join(format!("q{n}.toml"));
+        std::fs::write(&path, format!("[runner]\n{body}\n")).unwrap();
+        match Config::load(&path) {
+            Err(ConfigError::Invalid(_, why)) => assert!(why.contains(quoted), "{why}"),
+            other => panic!("{body}: {other:?}"),
+        }
+    }
+    let _ = std::fs::remove_dir_all(&dir);
+}

docs/implementer-log.md

@@ -6,6 +6,7 @@ reviewer adds findings under "Reviews" once per milestone.
 
 | Task | Date | Status | Gate runs | First gate | Deviations | Notes | Model |
 |---|---|---|---|---|---|---|---|
+| M3b/16-brokerd-log-escaping | 2026-09-23 | done | 1 | pass | none | Escaped the container's standard error before logging it (M3b review finding 5) and prefixed/quoted three small texts (finding 7). `container.rs` `answer`: exit 2 logs `brokerd: {name}: the tool could not run: {err:?}` instead of the raw stderr; exit 125..=127 logs `brokerd: podman could not start {name}: {err:?}\n{RUNBOOK}` (was `{err}\n{RUNBOOK}`); the `_` arm logs `brokerd: container {name} exited {status}: {err:?}` (the trailing `\n{err}` moved inside the debug format). `start_egress`: the proxy's `podman run -d` failure now logs `{stderr:?}`. `main.rs`: the runtime notice prints `brokerd: {runtime_notice}`. `config.rs`: the image and memory `[runner]` errors use `{:?}` so the bad value is quoted. Copied `tests/container_log.rs` and `tests/notices.rs`; 4, 2, 2 and 7 passed; `make gate` prints `gate: ok` first run. | ? |
 | M3b/15-brokerd-pipes-grace | 2026-09-23 | done | 1 | pass | none | Fixed the two M3b review findings in `pipes.rs`. Added `pub const GRACE: Duration = Duration::from_secs(2)`; replaced the `JoinHandle`-holding `Io` with one holding `Option<Receiver<(Vec<u8>, bool)>>` for stdout/stderr and added the `Finished { out, truncated, err, open }` struct. `Io::start` now returns `std::io::Result<Io>`: the stdin writer is started with `Builder::new().spawn(...)` and its handle dropped (never joined, a spawn error returned with `?`); a new private `reader(pipe, cap) -> io::Result<Receiver<...>>` starts one detached reader per pipe and returns a spawn error, used for both stdout (`cap`) and stderr (`err_cap`). `Io::finish(grace)` sets one `until = Instant::now() + grace` and calls a private `collect(rx, until)` per receiver: `recv_timeout(until.saturating_duration_since(now))` → `Ok` keeps bytes, `Timeout` sets `open`, `Disconnected` (panicked reader) counts closed; `open` is `stdout_open || stderr_open`. `read_capped` unchanged in behavior, now `cap.saturating_sub(kept.len())` and `chunk.get(..take).unwrap_or_default()` (no indexing, no wrapping subtraction). `container.rs`: added `pub const OUTPUT_OPEN` after `TIMED_OUT`, `use crate::pipes::{GRACE, Io}`, and replaced the `run_container` tail with the task's `Io::start` match (on spawn error, `podman kill`/`rm -f`, `child.kill()`/`wait()`, log + `Unavailable(CANNOT_START)`), then `io.finish(GRACE)` and the `done.open && status.is_some()` check returning `Failed(OUTPUT_OPEN)` (a timed-out call, `status` None, still answers `TIMED_OUT`). All `std::thread::spawn` gone from `crates/brokerd/src/`. Copied `tests/container_grace.rs`; 4 passed in ~4.4s, container 11, container_egress 6, all five runs; `make gate` prints `gate: ok` first run. | ? |
 | M3b/14-brokerd-pipes-module | 2026-09-23 | done | 1 | pass | none | Pure move: cut `struct Io`, `impl Io { start, finish }`, and `fn read_capped` from `container.rs` and pasted them into `crates/brokerd/src/pipes.rs` with bodies unchanged and `pub(crate)` visibility; `Io::start` now calls `crate::container::STDERR_KEPT` (the constant stays in `container.rs` since the tests import it). Added the module doc comment and the `use std::io::{Read, Write}`, `use std::process::Child`, `use std::thread::JoinHandle` lines. `lib.rs` gained `pub mod pipes;` between `ledger` and `podman`. `container.rs` gained `use crate::pipes::Io;` and lost the `Read, Write` and `JoinHandle` imports the compiler reported unused; nothing else changed. `cargo fmt --all` reflowed the `STDERR_KEPT` call line in `start` to wrap. `cargo check`/clippy clean; container 11, container_egress 6, serve_runner 2 pass; `grep "struct Io\|fn read_capped" container.rs` prints nothing and `container.rs` is 350 lines. `make gate` prints `gate: ok` on the first run. | ? |
 | M3b/13-brokerd-serve-runner | 2026-09-23 | done | 1 | pass | none | The `Podman` runtime was already written in task 12 (`crates/brokerd/src/container.rs`), so this task only wired it into `serve`. In `main.rs`: after the config loads, added `let log: Arc<dyn Fn(&str) + Send + Sync> = Arc::new(|line| eprintln!("{line}"))`; chose the runtime and its notice with a match on `&cfg.runner` — `Some(runner)` captures `runner.image` first then `Box::new(Podman::new(runner.clone(), cfg.egress_dir(), Arc::clone(&log)))` with notice `tools run in containers from {image}`; `None` → `Box::new(Refusing)` with notice `no [runner] section: every tool call is refused`. Passed `runtime` and `log` to `serve::start` (its signature needed no change — it already took `Box<dyn Runtime>` and `Arc<dyn Fn(&str)+Send+Sync>`), and printed the notice with `eprintln!` after the `serving tools on … and approvals on …` line. Added `use brokerd::container::Podman` and `Runtime` to the imports. Copied `tests/serve_runner.rs`; the 2 new tests plus the 9 serve tests pass; `make gate` prints `gate: ok` on the first run. | ? |