transport config plane (ConfigPlane + /config routes, manifest.config), hull network/legacy-usenet/wait_ready calls, SDK 1.5.0

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "meta-feeder-sdk"
-version = "1.4.0"
+version = "1.5.0"
 edition = "2021"
 rust-version = "1.85"
 license = "MIT"
@@ -76,4 +76,5 @@ tokio-util = { version = "0.7", features = ["io"], optional = true }
 
 [dev-dependencies]
 tempfile = "3"
+tower = { version = "0.4", features = ["util"] }
 tokio = { version = "1.40", features = ["full", "test-util"] }

src/config_page.html

@@ -3,7 +3,7 @@
 <head>
 <meta charset="utf-8" />
 <meta name="viewport" content="width=device-width, initial-scale=1" />
-<title>feeder config</title>
+<title>plugin config</title>
 <style>
   :root { color-scheme: dark; }
   * { box-sizing: border-box; }
@@ -47,7 +47,7 @@
 </head>
 <body>
   <h1 id="title">Plugin configuration</h1>
-  <p class="sub">Secrets are write-only — set values are shown as “set”, never echoed back. Saving requires a feeder restart to take effect. Fields marked <span class="req">*</span> are required.</p>
+  <p class="sub">Secrets are write-only — set values are shown as “set”, never echoed back. Saving restarts the plugin to apply. Fields marked <span class="req">*</span> are required.</p>
   <div id="banner" class="banner"></div>
   <form id="form"></form>
   <div class="bar" id="bar" style="display:none">
@@ -220,14 +220,14 @@ async function save() {
     });
     if (!res.ok) {
       const detail = (await res.text().catch(() => "")).trim();
-      throw new Error(detail ? `the feeder rejected it (HTTP ${res.status}): ${detail}`
+      throw new Error(detail ? `the plugin rejected it (HTTP ${res.status}): ${detail}`
-                             : `the feeder returned HTTP ${res.status}`);
+                             : `the plugin returned HTTP ${res.status}`);
     }
     const j = await res.json().catch(() => ({}));
     if (j.reloading) {
       // The feeder is restarting itself (~2-3s) to apply the change. Poll it
       // back up, then refresh the form so secret pills reflect stored state.
-      banner("warn", "Saved — reloading the feeder to apply (~3 s)…");
+      banner("warn", "Saved — reloading the plugin to apply (~3 s)…");
       let tries = 6;
       const poll = async () => {
         try { await load(); banner("ok", "Reloaded — new config applied."); }
@@ -235,7 +235,7 @@ async function save() {
       };
       setTimeout(poll, 3000);
     } else {
-      if (j.restart_required) banner("warn", "Saved. Restart the feeder container for changes to take effect.");
+      if (j.restart_required) banner("warn", "Saved. Restart the plugin container for changes to take effect.");
       else banner("ok", "Saved.");
       // Re-fetch so secret pills reflect the new stored state.
       await load();
@@ -243,7 +243,7 @@ async function save() {
   } catch (e) {
     const msg = (e && e.message) ? e.message : String(e);
     const friendly = /Failed to fetch|NetworkError|load failed/i.test(msg)
-      ? "couldn't reach the feeder — it may be restarting; wait a moment and try again."
+      ? "couldn't reach the plugin — it may be restarting; wait a moment and try again."
       : msg;
     banner("err", "Could not save: " + friendly);
   } finally {

src/transport/config.rs

@@ -0,0 +1,347 @@
+//! A transport plugin's own settings — the "config plane".
+//!
+//! Same model as a feeder's (`crate::config`): the plugin declares a
+//! [`ConfigSchema`], keeps its values in `<state_dir>/config.json`, and serves a
+//! schema-driven page that meta-share's dashboard embeds through its plugin
+//! proxy (`/api/plugins/:name/ui/config`). Keys stay on the plugin; the hull
+//! carries no protocol-specific settings.
+//!
+//! Routes (mounted by [`serve`](super::serve) when
+//! [`TransportPlugin::config`](super::plugin::TransportPlugin::config) is
+//! `Some`):
+//!
+//! - `GET /config`        → the page ([`CONFIG_PAGE_HTML`]); every call it makes
+//!   is relative to its own path, so the proxy prefix is irrelevant.
+//! - `GET /config/schema` → [`ConfigSchema`].
+//! - `GET /config/values` → effective values, secrets redacted to `<key>_set`.
+//! - `PUT /config/values` → merge (blank secret keeps the stored one), persist
+//!   atomically, then exit so the container restarts on the new values
+//!   (`{"saved":true,"reloading":true}`). Plugins read their config once at
+//!   boot — a restart is the one apply path that is right for every one of them.
+//!
+//! **Effective values** = `config.json` if it exists and parses as an object,
+//! else the `seed` the plugin derived from its env (its pre-config-plane
+//! settings source). A plugin deserializes [`ConfigPlane::effective`] into its
+//! own typed struct with serde defaults, so a missing key is never fatal.
+
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+use std::time::Duration;
+
+use axum::extract::State;
+use axum::http::StatusCode;
+use axum::response::{Html, IntoResponse, Response};
+use axum::routing::get;
+use axum::{Json, Router};
+use serde_json::Value;
+use tracing::{info, warn};
+
+use crate::config::{merge, redact, ConfigSchema, CONFIG_PAGE_HTML};
+
+/// Env var naming the plugin's own writable state dir.
+pub const STATE_DIR_ENV: &str = "META_SHARE_PLUGIN_STATE_DIR";
+/// Default state dir (the plugin app's own `AppData/<app>/state` mount).
+pub const DEFAULT_STATE_DIR: &str = "/state";
+/// File name of the stored values inside the state dir.
+pub const CONFIG_FILE: &str = "config.json";
+
+/// The plugin's state dir from [`STATE_DIR_ENV`], else [`DEFAULT_STATE_DIR`].
+pub fn state_dir_from_env() -> PathBuf {
+    std::env::var(STATE_DIR_ENV)
+        .ok()
+        .map(|s| s.trim().to_string())
+        .filter(|s| !s.is_empty())
+        .unwrap_or_else(|| DEFAULT_STATE_DIR.to_string())
+        .into()
+}
+
+/// One plugin's schema + stored values.
+pub struct ConfigPlane {
+    schema: ConfigSchema,
+    path: PathBuf,
+    seed: Value,
+    restart_on_save: bool,
+}
+
+impl ConfigPlane {
+    /// `seed` is what the plugin would run with if no `config.json` existed
+    /// (normally its env-derived settings, serialized).
+    pub fn new(schema: ConfigSchema, state_dir: &Path, seed: Value) -> Self {
+        Self {
+            schema,
+            path: state_dir.join(CONFIG_FILE),
+            seed,
+            restart_on_save: true,
+        }
+    }
+
+    /// Don't exit after a save (tests, or a plugin that hot-applies).
+    pub fn without_restart(mut self) -> Self {
+        self.restart_on_save = false;
+        self
+    }
+
+    pub fn schema(&self) -> &ConfigSchema {
+        &self.schema
+    }
+
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+
+    /// The stored values, if `config.json` exists and is a JSON object.
+    pub fn stored(&self) -> Option<Value> {
+        let bytes = std::fs::read(&self.path).ok()?;
+        match serde_json::from_slice::<Value>(&bytes) {
+            Ok(v @ Value::Object(_)) => Some(v),
+            Ok(_) | Err(_) => {
+                warn!(path = %self.path.display(), "plugin config is not a JSON object; using the seed");
+                None
+            }
+        }
+    }
+
+    /// Stored values, else the seed.
+    pub fn effective(&self) -> Value {
+        self.stored().unwrap_or_else(|| self.seed.clone())
+    }
+
+    /// Persist `values` atomically (tmp + rename), creating the state dir.
+    pub fn save(&self, values: &Value) -> std::io::Result<()> {
+        if let Some(dir) = self.path.parent() {
+            std::fs::create_dir_all(dir)?;
+        }
+        let tmp = self.path.with_extension("json.tmp");
+        let body = serde_json::to_vec_pretty(values)
+            .map_err(|e| std::io::Error::new(std::io::ErrorKind::InvalidData, e))?;
+        std::fs::write(&tmp, body)?;
+        std::fs::rename(&tmp, &self.path)
+    }
+
+    /// Write `values` as the initial config **only** if no `config.json` exists
+    /// yet — the one-shot migration hook (e.g. the nzb plugin importing the
+    /// NNTP block meta-share used to own). Returns whether it wrote.
+    pub fn seed_file_if_absent(&self, values: &Value) -> std::io::Result<bool> {
+        if self.path.exists() {
+            return Ok(false);
+        }
+        self.save(values)?;
+        Ok(true)
+    }
+
+    /// The `/config*` routes.
+    pub fn routes(self: Arc<Self>) -> Router {
+        Router::new()
+            .route("/config", get(page))
+            .route("/config/schema", get(schema))
+            .route("/config/values", get(values_get).put(values_put))
+            .with_state(self)
+    }
+}
+
+/// Lenient readers for a config object as the page writes it: an empty number
+/// is `null`, an empty text is `""`, and a hand-edited file may hold a number as
+/// a string. Each returns `None` for "not set" so the caller falls back to its
+/// default.
+pub mod read {
+    use serde_json::Value;
+
+    /// A non-blank, trimmed string.
+    pub fn text(v: &Value, key: &str) -> Option<String> {
+        match v.get(key)? {
+            Value::String(s) => Some(s.trim().to_string()).filter(|s| !s.is_empty()),
+            Value::Number(n) => Some(n.to_string()),
+            _ => None,
+        }
+    }
+
+    pub fn number(v: &Value, key: &str) -> Option<f64> {
+        match v.get(key)? {
+            Value::Number(n) => n.as_f64(),
+            Value::String(s) => s.trim().parse().ok(),
+            _ => None,
+        }
+    }
+
+    /// A non-negative integer (fractions truncate, negatives are "not set").
+    pub fn uint(v: &Value, key: &str) -> Option<u64> {
+        number(v, key).filter(|n| n.is_finite() && *n >= 0.0).map(|n| n as u64)
+    }
+
+    pub fn flag(v: &Value, key: &str) -> Option<bool> {
+        match v.get(key)? {
+            Value::Bool(b) => Some(*b),
+            Value::String(s) => match s.trim().to_ascii_lowercase().as_str() {
+                "1" | "true" | "yes" | "on" => Some(true),
+                "0" | "false" | "no" | "off" => Some(false),
+                _ => None,
+            },
+            _ => None,
+        }
+    }
+
+    /// A list of non-blank strings (a string is split on commas/newlines).
+    pub fn list(v: &Value, key: &str) -> Option<Vec<String>> {
+        let items: Vec<String> = match v.get(key)? {
+            Value::Array(a) => a.iter().filter_map(|x| x.as_str()).map(str::to_string).collect(),
+            Value::String(s) => s.split([',', '\n']).map(str::to_string).collect(),
+            _ => return None,
+        };
+        Some(items.into_iter().map(|s| s.trim().to_string()).filter(|s| !s.is_empty()).collect())
+    }
+}
+
+async fn page() -> Html<&'static str> {
+    Html(CONFIG_PAGE_HTML)
+}
+
+async fn schema(State(p): State<Arc<ConfigPlane>>) -> Json<ConfigSchema> {
+    Json(p.schema.clone())
+}
+
+async fn values_get(State(p): State<Arc<ConfigPlane>>) -> Json<Value> {
+    Json(redact(&p.effective(), &p.schema))
+}
+
+async fn values_put(
+    State(p): State<Arc<ConfigPlane>>,
+    Json(incoming): Json<Value>,
+) -> Result<Json<Value>, Response> {
+    if !incoming.is_object() {
+        return Err((StatusCode::BAD_REQUEST, "expected a JSON object").into_response());
+    }
+    let merged = merge(&p.effective(), &incoming, &p.schema);
+    p.save(&merged).map_err(|e| {
+        (StatusCode::INTERNAL_SERVER_ERROR, format!("write config: {e}")).into_response()
+    })?;
+    if !p.restart_on_save {
+        info!(path = %p.path.display(), "plugin config saved");
+        return Ok(Json(serde_json::json!({ "saved": true, "reloading": false })));
+    }
+    info!(path = %p.path.display(), "plugin config saved; restarting to apply");
+    // Let this response flush, then exit; `restart: unless-stopped` brings the
+    // plugin back and it reads config.json at boot.
+    tokio::spawn(async {
+        tokio::time::sleep(Duration::from_millis(800)).await;
+        std::process::exit(0);
+    });
+    Ok(Json(serde_json::json!({ "saved": true, "reloading": true })))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::config::ConfigField;
+    use axum::body::Body;
+    use axum::http::Request;
+    use tower::ServiceExt;
+
+    fn schema() -> ConfigSchema {
+        ConfigSchema {
+            fields: vec![
+                ConfigField::text("host", "Host"),
+                ConfigField::secret("pass", "Password"),
+                ConfigField::number("connections", "Connections"),
+            ],
+        }
+    }
+
+    fn plane(dir: &Path) -> Arc<ConfigPlane> {
+        Arc::new(
+            ConfigPlane::new(schema(), dir, serde_json::json!({"host":"seed.example","connections":4}))
+                .without_restart(),
+        )
+    }
+
+    async fn call(app: Router, method: &str, uri: &str, body: Option<Value>) -> (StatusCode, Value) {
+        let req = Request::builder()
+            .method(method)
+            .uri(uri)
+            .header("content-type", "application/json")
+            .body(match body {
+                Some(b) => Body::from(serde_json::to_vec(&b).unwrap()),
+                None => Body::empty(),
+            })
+            .unwrap();
+        let r = app.oneshot(req).await.unwrap();
+        let status = r.status();
+        let bytes = axum::body::to_bytes(r.into_body(), 1 << 20).await.unwrap();
+        (status, serde_json::from_slice(&bytes).unwrap_or(Value::Null))
+    }
+
+    #[tokio::test]
+    async fn seed_until_saved_then_file_wins_and_secret_is_kept() {
+        let dir = tempfile::tempdir().unwrap();
+        let p = plane(dir.path());
+        assert_eq!(p.effective()["host"], "seed.example");
+
+        let (st, v) = call(Arc::clone(&p).routes(), "GET", "/config/values", None).await;
+        assert_eq!(st, StatusCode::OK);
+        assert_eq!(v["host"], "seed.example");
+        assert_eq!(v["pass_set"], false);
+
+        let (st, _) = call(
+            Arc::clone(&p).routes(),
+            "PUT",
+            "/config/values",
+            Some(serde_json::json!({"host":"news.example","pass":"s3cret"})),
+        )
+        .await;
+        assert_eq!(st, StatusCode::OK);
+        let stored = p.stored().unwrap();
+        assert_eq!(stored["host"], "news.example");
+        assert_eq!(stored["pass"], "s3cret");
+        assert_eq!(stored["connections"], 4, "absent field keeps the effective value");
+
+        // A blank secret keeps the stored one; the GET never leaks it.
+        call(Arc::clone(&p).routes(), "PUT", "/config/values", Some(serde_json::json!({"pass":""}))).await;
+        assert_eq!(p.stored().unwrap()["pass"], "s3cret");
+        let (_, v) = call(Arc::clone(&p).routes(), "GET", "/config/values", None).await;
+        assert!(v.get("pass").is_none());
+        assert_eq!(v["pass_set"], true);
+    }
+
+    #[tokio::test]
+    async fn schema_and_page_are_served() {
+        let dir = tempfile::tempdir().unwrap();
+        let p = plane(dir.path());
+        let (st, v) = call(Arc::clone(&p).routes(), "GET", "/config/schema", None).await;
+        assert_eq!(st, StatusCode::OK);
+        assert_eq!(v["fields"].as_array().unwrap().len(), 3);
+        let r = p
+            .routes()
+            .oneshot(Request::get("/config").body(Body::empty()).unwrap())
+            .await
+            .unwrap();
+        assert_eq!(r.status(), StatusCode::OK);
+    }
+
+    #[test]
+    fn seed_file_if_absent_writes_once() {
+        let dir = tempfile::tempdir().unwrap();
+        let p = plane(dir.path());
+        assert!(p.seed_file_if_absent(&serde_json::json!({"host":"a"})).unwrap());
+        assert!(!p.seed_file_if_absent(&serde_json::json!({"host":"b"})).unwrap());
+        assert_eq!(p.effective()["host"], "a");
+    }
+
+    #[test]
+    fn readers_treat_blank_as_unset() {
+        let v = serde_json::json!({"a":"", "b":" x ", "n":null, "m":"7", "f":"off", "l":["a"," ",""], "s":"p, q"});
+        assert_eq!(read::text(&v, "a"), None);
+        assert_eq!(read::text(&v, "b").as_deref(), Some("x"));
+        assert_eq!(read::uint(&v, "n"), None);
+        assert_eq!(read::uint(&v, "m"), Some(7));
+        assert_eq!(read::flag(&v, "f"), Some(false));
+        assert_eq!(read::list(&v, "l"), Some(vec!["a".to_string()]));
+        assert_eq!(read::list(&v, "s"), Some(vec!["p".to_string(), "q".to_string()]));
+        assert_eq!(read::text(&v, "missing"), None);
+    }
+
+    #[test]
+    fn a_non_object_file_falls_back_to_the_seed() {
+        let dir = tempfile::tempdir().unwrap();
+        std::fs::write(dir.path().join(CONFIG_FILE), b"[1,2]").unwrap();
+        assert_eq!(plane(dir.path()).effective()["host"], "seed.example");
+    }
+}

src/transport/dto.rs

@@ -82,6 +82,11 @@ pub struct Manifest {
     pub version: String,
     pub contract: u32,
     pub capabilities: Capabilities,
+    /// Serves a config plane (`/config`, `/config/schema`, `/config/values`).
+    /// Set by the harness from [`TransportPlugin::config`](super::plugin::TransportPlugin::config);
+    /// absent in older manifests.
+    #[serde(default)]
+    pub config: bool,
 }
 
 #[derive(Serialize, Deserialize, Clone, Copy, Debug, Default, PartialEq, Eq)]

src/transport/hull.rs

@@ -17,6 +17,13 @@
 //!   [`HDR_MANIFEST_CID`]. `404` = not a Usenet cid; any other error carries
 //!   `{"error"}` — the manifest could not be redeemed or fetched. Parsing and
 //!   the `nzb-posting` digest check stay in the plugin.
+//! - `GET  /internal/network` → [`NetworkInfo`]: the hull's own endpoints a
+//!   plugin needs to know (the ipfs plugin announces `peer_url` in identify).
+//! - `GET  /internal/legacy/usenet` → the NNTP block meta-share's `settings.json`
+//!   held before the nzb plugin owned its settings (`404` = none). One-shot
+//!   migration source for the nzb plugin's config plane.
+//! - `GET  /health` → `200` once the hull has finished its boot steps (the
+//!   ipfs plugin waits on it before opening `ipfs/blocks.redb`).
 //!
 //! Why callbacks and not plugin-side logic: these need what only the hull has —
 //! the record cache and meta-core, the gateway redeem, the IPFS tier. Plugins
@@ -61,6 +68,17 @@ pub struct RecordInfo {
     pub title: Option<String>,
 }
 
+/// The hull's endpoints (`GET /internal/network`).
+#[derive(Serialize, Deserialize, Clone, Debug, Default, PartialEq, Eq)]
+pub struct NetworkInfo {
+    /// meta-core base URL the hull talks to.
+    #[serde(default)]
+    pub meta_core_url: Option<String>,
+    /// The URL other peers reach this meta-share at (announced in identify).
+    #[serde(default)]
+    pub peer_url: Option<String>,
+}
+
 /// Plugin-side client for the hull's internal API. A client with no base URL
 /// (`META_SHARE_HULL_URL=` empty, or [`HullClient::disabled`]) answers every call
 /// with "not available", which is what unit tests and a standalone plugin get.
@@ -191,6 +209,37 @@ impl HullClient {
         self.get_json(&format!("/internal/records/{cid}"), Duration::from_secs(15)).await
     }
 
+    /// The hull's endpoints.
+    pub async fn network(&self) -> Result<Option<NetworkInfo>, String> {
+        self.get_json("/internal/network", Duration::from_secs(5)).await
+    }
+
+    /// The NNTP block meta-share's own settings held before the nzb plugin had
+    /// a config plane; `Ok(None)` = there is none.
+    pub async fn legacy_usenet(&self) -> Result<Option<super::nzb::UsenetSettings>, String> {
+        self.get_json("/internal/legacy/usenet", Duration::from_secs(5)).await
+    }
+
+    /// Wait until the hull's internal listener answers `GET /health` with 2xx,
+    /// or `max` elapses. Returns whether it came up.
+    pub async fn wait_ready(&self, max: Duration) -> bool {
+        let Ok(url) = self.url("/health") else {
+            return false;
+        };
+        let deadline = tokio::time::Instant::now() + max;
+        loop {
+            if let Ok(r) = self.http.get(&url).timeout(Duration::from_secs(3)).send().await {
+                if r.status().is_success() {
+                    return true;
+                }
+            }
+            if tokio::time::Instant::now() >= deadline {
+                return false;
+            }
+            tokio::time::sleep(Duration::from_secs(1)).await;
+        }
+    }
+
     /// [`RecordInfo`] from the hull's record cache only.
     pub async fn cached_record(&self, cid: &str) -> Result<Option<RecordInfo>, String> {
         self.get_json(&format!("/internal/records/{cid}?cached=1"), Duration::from_secs(5)).await

src/transport/mod.rs

@@ -12,6 +12,8 @@
 //! - [`plugin::TransportPlugin`] + [`serve::serve_transport`]: the plugin side.
 //! - [`client::RemoteTransport`]: the hull side.
 //! - [`hull::HullClient`]: plugin → hull callbacks (internal port only).
+//! - [`config::ConfigPlane`]: the plugin's own settings + the config page the
+//!   hull's dashboard embeds.
 //! - [`focus::FocusView`]: the plugin's replica of the hull's playback focus.
 //! - [`dto`]: common wire types; [`error::ApiError`] / [`range`]: shared so a
 //!   relayed plugin response is byte-identical to what the monolith answered.
@@ -29,6 +31,7 @@
 
 pub mod cid;
 pub mod client;
+pub mod config;
 pub mod dto;
 pub mod error;
 pub mod file;
@@ -46,12 +49,13 @@ pub mod torrent;
 pub mod testkit;
 
 pub use client::RemoteTransport;
+pub use config::ConfigPlane;
 pub use dto::{
     Capabilities, Deleted, Event, Health, Job, Jobs, Manifest, PromotedFile, ReconcileReport,
     ReconcileRequest, CONTRACT_VERSION,
 };
 pub use error::ApiError;
 pub use focus::{FocusSnapshot, FocusTitle, FocusView, Lane};
-pub use hull::{HullClient, RecordInfo};
+pub use hull::{HullClient, NetworkInfo, RecordInfo};
 pub use plugin::TransportPlugin;
 pub use serve::serve_transport;

src/transport/plugin.rs

@@ -7,6 +7,7 @@ use axum::http::HeaderMap;
 use axum::response::Response;
 use axum::Router;
 
+use super::config::ConfigPlane;
 use super::dto::{Deleted, Health, Job, Manifest, ReconcileReport, ReconcileRequest};
 use super::error::ApiError;
 use super::focus::FocusView;
@@ -42,6 +43,13 @@ pub trait TransportPlugin: Send + Sync + 'static {
     /// The view `PUT /focus` writes into.
     fn focus(&self) -> &Arc<FocusView>;
 
+    /// The plugin's own settings, if it has any. `Some` mounts the `/config*`
+    /// routes and sets `manifest.config` — the hull's dashboard then offers a
+    /// "configure" panel that embeds `/config` through its proxy.
+    fn config(&self) -> Option<Arc<ConfigPlane>> {
+        None
+    }
+
     /// Protocol-specific routes, merged into the common router. Paths must not
     /// collide with the common ones.
     fn extra_routes(self: Arc<Self>) -> Router {

src/transport/serve.rs

@@ -11,7 +11,9 @@
 //! - `PUT    /focus`           ← [`FocusSnapshot`](super::focus::FocusSnapshot), `204`
 //! - `GET    /focus`           → the snapshot the plugin currently obeys
 //!
-//! plus whatever [`TransportPlugin::extra_routes`] adds.
+//! plus the `/config*` routes when [`TransportPlugin::config`] is `Some` (see
+//! [`ConfigPlane`](super::config::ConfigPlane)), plus whatever
+//! [`TransportPlugin::extra_routes`] adds.
 
 use std::net::SocketAddr;
 use std::sync::Arc;
@@ -32,8 +34,9 @@ type Shared = Arc<dyn TransportPlugin>;
 /// The common router for `plugin`, merged with its extra routes.
 pub fn router<P: TransportPlugin>(plugin: Arc<P>) -> Router {
     let extra = Arc::clone(&plugin).extra_routes();
+    let config = plugin.config().map(|c| c.routes());
     let shared: Shared = plugin;
-    Router::new()
+    let r = Router::new()
         .route("/manifest", get(manifest))
         .route("/health", get(health))
         .route("/raw/:cid", get(raw))
@@ -42,7 +45,11 @@ pub fn router<P: TransportPlugin>(plugin: Arc<P>) -> Router {
         .route("/reconcile", post(reconcile))
         .route("/focus", get(get_focus).put(put_focus))
         .with_state(shared)
-        .merge(extra)
+        .merge(extra);
+    match config {
+        Some(c) => r.merge(c),
+        None => r,
+    }
 }
 
 /// Bind `listen` and serve `plugin` until SIGTERM / Ctrl-C.
@@ -82,7 +89,9 @@ pub async fn shutdown_signal() {
 }
 
 async fn manifest(State(p): State<Shared>) -> Response {
-    Json(p.manifest()).into_response()
+    let mut m = p.manifest();
+    m.config = p.config().is_some();
+    Json(m).into_response()
 }
 
 async fn health(State(p): State<Shared>) -> Response {

src/transport/testkit.rs

@@ -39,8 +39,10 @@ pub async fn conformance(base: &str) -> Result<(), Vec<String>> {
         .with_control_timeout(Duration::from_secs(10));
     let mut fails = Vec::new();
 
+    let mut has_config = false;
     match t.manifest().await {
         Ok(m) => {
+            has_config = m.config;
             if m.id.is_empty() {
                 fails.push("manifest.id is empty".into());
             }
@@ -110,6 +112,31 @@ pub async fn conformance(base: &str) -> Result<(), Vec<String>> {
         Err(e) => fails.push(format!("GET /raw/not-a-cid: {e}")),
     }
 
+    if has_config {
+        match http.get(t.url("/config/schema")).send().await {
+            Ok(r) if r.status().is_success() => {
+                if r.json::<crate::config::ConfigSchema>().await.is_err() {
+                    fails.push("GET /config/schema body is not a ConfigSchema".into());
+                }
+            }
+            Ok(r) => fails.push(format!("GET /config/schema: status {}", r.status())),
+            Err(e) => fails.push(format!("GET /config/schema: {e}")),
+        }
+        match http.get(t.url("/config/values")).send().await {
+            Ok(r) if r.status().is_success() => match r.json::<serde_json::Value>().await {
+                Ok(v) if v.is_object() => {}
+                _ => fails.push("GET /config/values is not a JSON object".into()),
+            },
+            Ok(r) => fails.push(format!("GET /config/values: status {}", r.status())),
+            Err(e) => fails.push(format!("GET /config/values: {e}")),
+        }
+        match http.get(t.url("/config")).send().await {
+            Ok(r) if r.status().is_success() => {}
+            Ok(r) => fails.push(format!("GET /config: status {}", r.status())),
+            Err(e) => fails.push(format!("GET /config: {e}")),
+        }
+    }
+
     if fails.is_empty() {
         Ok(())
     } else {
@@ -130,6 +157,7 @@ mod tests {
     /// The smallest plugin that should pass: holds nothing, fetches nothing.
     struct Empty {
         focus: Arc<FocusView>,
+        config: Option<Arc<crate::transport::config::ConfigPlane>>,
     }
 
     #[async_trait]
@@ -141,6 +169,7 @@ mod tests {
                 version: "0".into(),
                 contract: CONTRACT_VERSION,
                 capabilities: Capabilities { fetch: true, share: false },
+                config: false,
             }
         }
         async fn raw(&self, _cid: String, _h: HeaderMap) -> Response {
@@ -158,11 +187,32 @@ mod tests {
         fn focus(&self) -> &Arc<FocusView> {
             &self.focus
         }
+        fn config(&self) -> Option<Arc<crate::transport::config::ConfigPlane>> {
+            self.config.clone()
+        }
     }
 
     #[tokio::test]
     async fn the_empty_plugin_conforms() {
-        let addr = spawn_local(Arc::new(Empty { focus: FocusView::new() })).await;
+        let addr = spawn_local(Arc::new(Empty { focus: FocusView::new(), config: None })).await;
         conformance(&format!("http://{addr}")).await.unwrap();
     }
+
+    #[tokio::test]
+    async fn a_plugin_with_a_config_plane_conforms_and_says_so() {
+        use crate::config::{ConfigField, ConfigSchema};
+        use crate::transport::config::ConfigPlane;
+        let dir = tempfile::tempdir().unwrap();
+        let plane = ConfigPlane::new(
+            ConfigSchema { fields: vec![ConfigField::secret("key", "Key")] },
+            dir.path(),
+            serde_json::json!({}),
+        )
+        .without_restart();
+        let addr = spawn_local(Arc::new(Empty { focus: FocusView::new(), config: Some(Arc::new(plane)) })).await;
+        let base = format!("http://{addr}");
+        conformance(&base).await.unwrap();
+        let m: Manifest = reqwest::get(format!("{base}/manifest")).await.unwrap().json().await.unwrap();
+        assert!(m.config, "the harness must advertise the config plane");
+    }
 }