notify router: deliveries log, dry-run hit counts, api and page

swarm-controller/src/notify_router_api.rs

@@ -0,0 +1,335 @@
+//! `GET /api/notify/deliveries` and `GET /api/notify/dry-run`: what the
+//! notification router has delivered, and what the saved flows would do with
+//! the newest forge events.
+//!
+//! The router keeps the log and the events, so each is a NATS request to it
+//! (`swarm_wire::router_api`). A router that predates them, or none at all,
+//! has no subscriber: the queue answers "no responders" at once and these
+//! answer 503 saying so, as they do when it hears the request and stays
+//! silent. The saved document is what `GET /api/notify/flows` shows; a draft
+//! is run by sending the same request with another document.
+
+use axum::Json;
+use axum::extract::{Query, State};
+use axum::http::StatusCode;
+use problem_details::ProblemDetails;
+use serde::Deserialize;
+use serde::de::DeserializeOwned;
+use swarm_wire::notify_flows::Document;
+use swarm_wire::router_api::{
+    DELIVERIES_SUBJECT, DRY_RUN_SUBJECT, Deliveries, DeliveriesRequest, DryRun, DryRunRequest,
+    REPLY_DEADLINE, Refused,
+};
+use utoipa::IntoParams;
+
+use crate::notify_flows::{Stored, open, queue_problem, stored, unreadable};
+use crate::routes::{AppState, error_problem};
+use crate::schedules::{queue, refused};
+
+/// Ask the router on `subject` and decode its answer as `T`.
+///
+/// 503: nothing hears the request, or what hears it does not answer in time;
+/// both mean the running router does not have this feature. 502: it answered
+/// with a refusal or with something this build cannot read.
+async fn ask<T: DeserializeOwned>(
+    client: &async_nats::Client,
+    subject: &str,
+    body: Vec<u8>,
+) -> Result<T, ProblemDetails> {
+    use async_nats::RequestErrorKind;
+
+    let sent = async_nats::Request::new()
+        .payload(body.into())
+        .timeout(Some(REPLY_DEADLINE));
+    let reply = client
+        .send_request(subject.to_owned(), sent)
+        .await
+        .map_err(|e| {
+            let detail = match e.kind() {
+                RequestErrorKind::NoResponders => "the notification router does not answer this: \
+                 it is not running, or it is an older build than this controller"
+                    .to_owned(),
+                RequestErrorKind::TimedOut => format!(
+                    "the notification router sent no answer within {}s",
+                    REPLY_DEADLINE.as_secs()
+                ),
+                _ => format!("asking the notification router failed: {e}"),
+            };
+            error_problem(StatusCode::SERVICE_UNAVAILABLE, &detail)
+        })?;
+    if let Ok(answer) = serde_json::from_slice::<T>(&reply.payload) {
+        return Ok(answer);
+    }
+    let detail = match serde_json::from_slice::<Refused>(&reply.payload) {
+        Ok(Refused { error }) => format!("the notification router refused: {error}"),
+        Err(e) => format!("the notification router's answer did not decode: {e}"),
+    };
+    Err(error_problem(StatusCode::BAD_GATEWAY, &detail))
+}
+
+/// `get_deliveries`'s query.
+#[derive(Deserialize, IntoParams)]
+pub struct DeliveriesQuery {
+    /// At most this many rows; 100 when absent, and the log keeps 500.
+    limit: Option<usize>,
+}
+
+/// The newest deliveries the router made, newest first.
+#[utoipa::path(
+    get,
+    path = "/api/notify/deliveries",
+    params(DeliveriesQuery),
+    responses(
+        (status = 200, description = "the router's deliveries log, newest first: when, which \
+            flow and node, the event and issue, who got it, and whether it went through",
+            body = Deliveries),
+        (status = 502, description = "the router refused, or its answer did not decode \
+            (problem+json)", body = String),
+        (status = 503, description = "no swarm queue is configured or connected here, or the \
+            router does not answer: it is not running, or it predates the log (problem+json)",
+            body = String),
+    ),
+    tag = "notify"
+)]
+pub(crate) async fn get_deliveries(
+    State(state): State<AppState>,
+    Query(query): Query<DeliveriesQuery>,
+) -> Result<Json<Deliveries>, ProblemDetails> {
+    let client = queue(&state).map_err(refused)?;
+    let body =
+        serde_json::to_vec(&DeliveriesRequest { limit: query.limit }).expect("a request encodes");
+    ask(&client, DELIVERIES_SUBJECT, body).await.map(Json)
+}
+
+/// The saved flows run over the newest 50 forge events, delivering nothing:
+/// how many events reached each node.
+#[utoipa::path(
+    get,
+    path = "/api/notify/dry-run",
+    responses(
+        (status = 200, description = "per flow that would run, the number of the newest 50 \
+            events that reached each node", body = DryRun),
+        (status = 409, description = "the stored document is not one this build reads \
+            (problem+json)", body = String),
+        (status = 502, description = "the router refused, or its answer did not decode \
+            (problem+json)", body = String),
+        (status = 503, description = "no swarm queue is configured or connected here, or the \
+            router does not answer: it is not running, or it predates the dry run \
+            (problem+json)", body = String),
+        (status = 500, description = "the saved flows could not be read (problem+json)",
+            body = String),
+    ),
+    tag = "notify"
+)]
+pub(crate) async fn get_dry_run(
+    State(state): State<AppState>,
+) -> Result<Json<DryRun>, ProblemDetails> {
+    let client = queue(&state).map_err(refused)?;
+    let store = open(&client).await.map_err(|e| queue_problem(&e))?;
+    let (saved, _) = stored(&store).await.map_err(|e| queue_problem(&e))?;
+    let document = match saved {
+        Stored::Nothing => Document::default(),
+        Stored::Document(doc) => doc,
+        Stored::Unreadable(e) => return Err(unreadable(&e)),
+    };
+    let body = serde_json::to_vec(&DryRunRequest { document }).expect("a request encodes");
+    ask(&client, DRY_RUN_SUBJECT, body).await.map(Json)
+}
+
+#[cfg(test)]
+mod tests {
+    use futures_util::StreamExt as _;
+    use swarm_wire::notify_flows::{self, Document};
+    use swarm_wire::router_api::{FlowHits, NodeHits};
+
+    use super::*;
+    use crate::test_nats::TestNats;
+
+    fn query(limit: Option<usize>) -> Query<DeliveriesQuery> {
+        Query(DeliveriesQuery { limit })
+    }
+
+    /// Answer the next request on `subject` with `reply`, handing the request
+    /// body back.
+    async fn answer(
+        client: &async_nats::Client,
+        subject: &'static str,
+        reply: Vec<u8>,
+    ) -> tokio::task::JoinHandle<Vec<u8>> {
+        let mut requests = client.subscribe(subject).await.expect("subscribed");
+        client.flush().await.expect("flushed");
+        let client = client.clone();
+        tokio::spawn(async move {
+            let m = requests.next().await.expect("a request");
+            client
+                .publish(m.reply.expect("a reply subject"), reply.into())
+                .await
+                .expect("answered");
+            m.payload.to_vec()
+        })
+    }
+
+    /// A router that predates the log and the dry run has no subscriber: both
+    /// answer 503 with the reason, not 500 and not a hang. The control is the
+    /// same two calls with a router answering.
+    #[tokio::test]
+    async fn without_a_router_that_answers_both_are_unavailable() {
+        let nats = TestNats::start();
+        let client = nats.client().await;
+        let state = crate::agent_limits::tests::state(&client);
+
+        let deliveries = get_deliveries(State(state.clone()), query(None))
+            .await
+            .expect_err("nobody answers");
+        assert_eq!(deliveries.status, Some(StatusCode::SERVICE_UNAVAILABLE));
+        assert!(
+            deliveries
+                .detail
+                .as_deref()
+                .unwrap_or_default()
+                .contains("older build"),
+            "{deliveries:?}"
+        );
+        let dry = get_dry_run(State(state.clone()))
+            .await
+            .expect_err("nobody answers");
+        assert_eq!(dry.status, Some(StatusCode::SERVICE_UNAVAILABLE));
+        assert!(
+            dry.detail
+                .as_deref()
+                .unwrap_or_default()
+                .contains("older build"),
+            "{dry:?}"
+        );
+
+        // Control: with a router answering, the same calls are 200.
+        let rows = answer(&client, DELIVERIES_SUBJECT, br#"{"rows":[]}"#.to_vec()).await;
+        let Json(got) = get_deliveries(State(state.clone()), query(None))
+            .await
+            .expect("answered");
+        assert!(got.rows.is_empty());
+        rows.await.expect("the router task");
+        let hits = DryRun {
+            events: 0,
+            flows: Vec::new(),
+        };
+        let dry_run = answer(&client, DRY_RUN_SUBJECT, serde_json::to_vec(&hits).unwrap()).await;
+        let Json(got) = get_dry_run(State(state)).await.expect("answered");
+        assert_eq!(got, hits);
+        dry_run.await.expect("the router task");
+    }
+
+    /// No queue on this host is 503 too.
+    #[tokio::test]
+    async fn without_a_queue_both_are_unavailable() {
+        let (state, _) = crate::routes::tests::state_with_roster();
+        let a = get_deliveries(State(state.clone()), query(None))
+            .await
+            .expect_err("no queue");
+        let b = get_dry_run(State(state)).await.expect_err("no queue");
+        assert_eq!(a.status, Some(StatusCode::SERVICE_UNAVAILABLE));
+        assert_eq!(b.status, Some(StatusCode::SERVICE_UNAVAILABLE));
+    }
+
+    /// The limit reaches the router, and the dry run sends the saved document.
+    #[tokio::test]
+    async fn the_limit_and_the_saved_document_reach_the_router() {
+        let nats = TestNats::start();
+        let client = nats.client().await;
+        let state = crate::agent_limits::tests::state(&client);
+
+        let asked = answer(&client, DELIVERIES_SUBJECT, br#"{"rows":[]}"#.to_vec()).await;
+        let _ = get_deliveries(State(state.clone()), query(Some(7)))
+            .await
+            .expect("answered");
+        let request: DeliveriesRequest =
+            serde_json::from_slice(&asked.await.expect("task")).expect("a request");
+        assert_eq!(request.limit, Some(7));
+
+        // Nothing saved: the default document.
+        let reply = DryRun {
+            events: 3,
+            flows: vec![FlowHits {
+                flow: "assigned".to_owned(),
+                nodes: vec![NodeHits {
+                    node: "source".to_owned(),
+                    hits: 3,
+                }],
+            }],
+        };
+        let asked = answer(
+            &client,
+            DRY_RUN_SUBJECT,
+            serde_json::to_vec(&reply).unwrap(),
+        )
+        .await;
+        let Json(got) = get_dry_run(State(state.clone())).await.expect("answered");
+        assert_eq!(got, reply);
+        let sent: DryRunRequest =
+            serde_json::from_slice(&asked.await.expect("task")).expect("a request");
+        assert_eq!(sent.document, Document::default());
+
+        // A saved document: the router gets that one.
+        let store = open(&client).await.expect("bucket");
+        let saved = Document {
+            disabled_builtins: vec!["closed".to_owned()],
+            ..Document::default()
+        };
+        store
+            .put(
+                notify_flows::KEY,
+                serde_json::to_vec(&saved).unwrap().into(),
+            )
+            .await
+            .expect("seed");
+        let asked = answer(
+            &client,
+            DRY_RUN_SUBJECT,
+            serde_json::to_vec(&reply).unwrap(),
+        )
+        .await;
+        let _ = get_dry_run(State(state)).await.expect("answered");
+        let sent: DryRunRequest =
+            serde_json::from_slice(&asked.await.expect("task")).expect("a request");
+        assert_eq!(sent.document, saved);
+    }
+
+    /// A refusal from the router is 502 with its reason; an unreadable saved
+    /// document is 409 and never reaches the router.
+    #[tokio::test]
+    async fn a_refusal_is_502_and_an_unreadable_document_is_409() {
+        let nats = TestNats::start();
+        let client = nats.client().await;
+        let state = crate::agent_limits::tests::state(&client);
+
+        let router = answer(
+            &client,
+            DRY_RUN_SUBJECT,
+            br#"{"error":"no events"}"#.to_vec(),
+        )
+        .await;
+        let refused = get_dry_run(State(state.clone()))
+            .await
+            .expect_err("refused");
+        assert_eq!(refused.status, Some(StatusCode::BAD_GATEWAY));
+        assert!(
+            refused
+                .detail
+                .as_deref()
+                .unwrap_or_default()
+                .contains("no events")
+        );
+        router.await.expect("the router task");
+
+        let store = open(&client).await.expect("bucket");
+        store
+            .put(
+                notify_flows::KEY,
+                br#"{"version":2,"flows":[]}"#.to_vec().into(),
+            )
+            .await
+            .expect("seed");
+        let unreadable = get_dry_run(State(state)).await.expect_err("version 2");
+        assert_eq!(unreadable.status, Some(StatusCode::CONFLICT));
+    }
+}