swarm-controller: KV-store + serve per-agent status (#3341 item 2)

This commit is contained in:
damocles 2026-09-02 04:53:22 +02:00 committed by mara
commit 162b646e5b
3 changed files with 406 additions and 1 deletions

View file

@ -0,0 +1,304 @@
//! Swarm-wide view of what each agent last said about itself.
//!
//! Sibling of [`crate::status`], not a mode of it — see
//! `swarm_queue_client::agent_status`'s module doc for why the two buckets
//! stay separate. Everything about *how* a snapshot is read (queue is the
//! store, no cache, freshness derived at read time, rows come from the
//! roster so an empty bucket cannot render as "every agent is fine") is
//! identical to [`crate::status`]; this module differs only in whose
//! roster it reads and how it recovers a hive name for a reporting agent.
//!
//! **The roster here is agent *names* only** ([`crate::auth::AuthBridge::list_agent_identities`]) —
//! it does not say which hive an agent lives on. That is not a gap this
//! module needs to close: a *reporting* agent's hive comes straight out of
//! its bucket key (`swarm_queue_client::agent_status::split_key`), and a
//! *never-reported* agent's hive is unknowable regardless of what any
//! roster might claim, so [`AgentStatusRow::hive`] is `None` in exactly
//! that one case rather than a second lookup this module would have to
//! keep in sync with the bucket.
use std::collections::BTreeMap;
use std::time::{Duration, SystemTime, UNIX_EPOCH};
use anyhow::{Context, Result};
use futures_util::TryStreamExt as _;
use serde::{Deserialize, Serialize};
use utoipa::ToSchema;
use crate::status::Freshness;
/// One row of the aggregate.
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, ToSchema)]
pub struct AgentStatusRow {
pub name: String,
/// The hive this agent reported from, taken from its bucket key.
/// `None` when the agent has never reported — see the module doc for
/// why that is not answered from anywhere else.
pub hive: Option<String>,
pub freshness: Freshness,
/// When the snapshot was stored, unix seconds — the bucket's own
/// stamp, same rule as [`crate::status::HiveStatus::last_seen_unix`].
pub last_seen_unix: Option<i64>,
pub age_seconds: Option<u64>,
/// The agent's status text + running flag, unopened. `None` exactly
/// when `freshness` is `NeverReported`, or when the stored bytes
/// failed to decode as [`swarm_queue_client::agent_status::AgentStatus`]
/// (logged as a warning naming the agent).
pub snapshot: Option<serde_json::Value>,
}
/// A snapshot as retained by the bucket, with the hive it was published
/// under already split out of the key.
#[derive(Clone, Debug)]
struct Offered {
hive: String,
received_at: SystemTime,
payload: Option<serde_json::Value>,
}
/// Reads the per-agent status aggregate out of the KV bucket. Same shape
/// as [`crate::status::StatusReader`] — see that type for why the bucket
/// is resolved lazily and cached, and why a resolution failure is not.
pub struct AgentStatusReader {
client: async_nats::Client,
store: tokio::sync::OnceCell<async_nats::jetstream::kv::Store>,
stale_after: Duration,
}
impl AgentStatusReader {
#[must_use]
pub fn new(client: async_nats::Client, stale_after: Duration) -> Self {
Self {
client,
store: tokio::sync::OnceCell::new(),
stale_after,
}
}
async fn store(
&self,
) -> std::result::Result<&async_nats::jetstream::kv::Store, swarm_queue_client::Error> {
self.store
.get_or_try_init(|| swarm_queue_client::agent_status::open_or_create(&self.client))
.await
}
/// The aggregate, rendered against `now`.
///
/// Every roster agent produces a row whether or not it has ever
/// reported; a reporting agent outside the roster produces one too —
/// same two-sided shape as [`crate::status::StatusReader::view`].
pub async fn view(&self, roster: &[String], now: SystemTime) -> Result<Vec<AgentStatusRow>> {
swarm_queue_client::ensure_connected(&self.client)?;
let store = self.store().await?;
let mut keys = store
.keys()
.await
.context("listing agent-status bucket keys")?;
let mut entries: BTreeMap<String, Offered> = BTreeMap::new();
while let Some(key) = keys
.try_next()
.await
.context("reading the agent-status bucket's key list")?
{
let Some((hive, agent)) = swarm_queue_client::agent_status::split_key(&key) else {
tracing::warn!(%key, "agent-status bucket key doesn't split into hive/agent, skipping");
continue;
};
let Some(entry) = store
.entry(&key)
.await
.with_context(|| format!("reading agent-status entry {key}"))?
else {
continue;
};
let payload = match serde_json::from_slice::<
swarm_queue_client::agent_status::AgentStatus,
>(&entry.value)
{
Ok(status) => serde_json::to_value(status).ok(),
Err(e) => {
tracing::warn!(
%agent, %hive, error = %e,
"agent-status snapshot didn't decode; reporting the timestamp without it"
);
None
}
};
entries.insert(
agent.to_owned(),
Offered {
hive: hive.to_owned(),
received_at: to_system_time(entry.created.unix_timestamp()),
payload,
},
);
}
Ok(render(roster, &entries, now, self.stale_after))
}
}
fn to_system_time(unix_seconds: i64) -> SystemTime {
u64::try_from(unix_seconds).map_or(UNIX_EPOCH, |secs| UNIX_EPOCH + Duration::from_secs(secs))
}
/// Turn a roster plus whatever the bucket held into the rendered rows. Pure
/// for the same testing reason as [`crate::status::render`].
fn render(
roster: &[String],
entries: &BTreeMap<String, Offered>,
now: SystemTime,
stale_after: Duration,
) -> Vec<AgentStatusRow> {
let mut rows: Vec<AgentStatusRow> = roster
.iter()
.map(|name| match entries.get(name) {
Some(offered) => row(name.clone(), Freshness::Fresh, offered, now, stale_after),
None => AgentStatusRow {
name: name.clone(),
hive: None,
freshness: Freshness::NeverReported,
last_seen_unix: None,
age_seconds: None,
snapshot: None,
},
})
.collect();
rows.extend(
entries
.iter()
.filter(|(name, _)| !roster.iter().any(|r| r == *name))
.map(|(name, offered)| {
row(name.clone(), Freshness::Unknown, offered, now, stale_after)
}),
);
rows
}
/// `default_freshness` is `Unknown` for an agent outside the roster and
/// `Fresh` for one inside it — `row` then downgrades to `Stale` on age,
/// same two-step [`crate::status::row`] uses.
fn row(
name: String,
default_freshness: Freshness,
offered: &Offered,
now: SystemTime,
stale_after: Duration,
) -> AgentStatusRow {
let age = now.duration_since(offered.received_at).ok();
let freshness = match (default_freshness, age) {
(Freshness::Unknown, _) => Freshness::Unknown,
(_, Some(age)) if age > stale_after => Freshness::Stale,
_ => Freshness::Fresh,
};
AgentStatusRow {
name,
hive: Some(offered.hive.clone()),
freshness,
last_seen_unix: offered
.received_at
.duration_since(UNIX_EPOCH)
.ok()
.and_then(|d| i64::try_from(d.as_secs()).ok()),
age_seconds: age.map(|age| age.as_secs()),
snapshot: offered.payload.clone(),
}
}
#[cfg(test)]
mod tests {
use super::{Freshness, Offered, render};
use std::collections::BTreeMap;
use std::time::{Duration, SystemTime};
fn roster() -> Vec<String> {
vec!["iris".to_owned(), "atlas".to_owned()]
}
fn entries(rows: &[(&str, &str, SystemTime)]) -> BTreeMap<String, Offered> {
rows.iter()
.map(|(agent, hive, at)| {
(
(*agent).to_owned(),
Offered {
hive: (*hive).to_owned(),
received_at: *at,
payload: Some(serde_json::json!({ "running": true })),
},
)
})
.collect()
}
fn t0() -> SystemTime {
SystemTime::UNIX_EPOCH + Duration::from_secs(1_700_000_000)
}
#[test]
fn an_empty_bucket_renders_every_roster_agent_as_never_reported() {
let rows = render(&roster(), &BTreeMap::new(), t0(), Duration::from_mins(2));
assert_eq!(rows.len(), 2);
assert!(rows.iter().all(|r| r.freshness == Freshness::NeverReported));
assert!(rows.iter().all(|r| r.hive.is_none()));
}
#[test]
fn a_reporting_agent_gets_its_hive_from_the_bucket_key() {
let rows = render(
&roster(),
&entries(&[("iris", "pr1ma", t0())]),
t0(),
Duration::from_mins(2),
);
let iris = rows.iter().find(|r| r.name == "iris").expect("present");
assert_eq!(iris.hive.as_deref(), Some("pr1ma"));
assert_eq!(iris.freshness, Freshness::Fresh);
}
#[test]
fn a_stale_report_still_carries_its_hive() {
let rows = render(
&roster(),
&entries(&[("iris", "pr1ma", t0())]),
t0() + Duration::from_mins(10),
Duration::from_mins(2),
);
let iris = rows.iter().find(|r| r.name == "iris").expect("present");
assert_eq!(iris.freshness, Freshness::Stale);
assert_eq!(iris.hive.as_deref(), Some("pr1ma"), "stale is not absent");
}
#[test]
fn an_agent_outside_the_roster_is_surfaced_as_unknown() {
let rows = render(
&roster(),
&entries(&[("ghost", "pr1ma", t0())]),
t0(),
Duration::from_mins(2),
);
assert_eq!(rows.len(), 3, "two roster agents plus the stranger");
let ghost = rows.iter().find(|r| r.name == "ghost").expect("present");
assert_eq!(ghost.freshness, Freshness::Unknown);
assert_eq!(
ghost.hive.as_deref(),
Some("pr1ma"),
"still known from its key"
);
}
#[test]
fn one_agent_reporting_does_not_vouch_for_a_silent_one() {
let rows = render(
&roster(),
&entries(&[("iris", "pr1ma", t0())]),
t0(),
Duration::from_mins(2),
);
let atlas = rows.iter().find(|r| r.name == "atlas").expect("present");
assert_eq!(atlas.freshness, Freshness::NeverReported);
}
}

View file

@ -40,6 +40,7 @@ use swarm_authelia_bridge_sock::BridgeResponse;
use utoipa::{OpenApi, ToSchema};
use utoipa_axum::{router::OpenApiRouter, routes};
mod agent_status;
mod auth;
mod config_pr;
mod forge;
@ -436,6 +437,10 @@ struct AppState {
/// up, so there is nowhere to publish a declaration to. Shares that
/// reader's connection rather than opening a second one.
wanted: Option<Arc<wanted::WantedWriter>>,
/// Per-agent status, sharing `status`'s connection — same "one queue
/// connection, several consumers" rationale as `wanted` above. `None`
/// in exactly the state `status` is.
agent_status: Option<Arc<agent_status::AgentStatusReader>>,
/// The swarm-level job graph, wrapped in its
/// [`hive_jobq::scheduler::Scheduler`] now that something drives it
/// (`spawn_jobq_worker`) — the graph alone was enough for the
@ -726,6 +731,22 @@ fn wanted_writer(status: Option<&Arc<status::StatusReader>>) -> Option<Arc<wante
status.map(|s| Arc::new(wanted::WantedWriter::new(s.queue_client())))
}
/// The per-agent status reader, sharing the status reader's connection and
/// staleness threshold — same rationale as [`wanted_writer`], and the same
/// threshold on purpose: both buckets are fed by the same publisher cadence
/// (`hive-c0re`'s `PUBLISH_INTERVAL`), so two separately-configured
/// thresholds would just be two ways to get out of sync with one cadence.
fn agent_status_reader(
status: Option<&Arc<status::StatusReader>>,
) -> Option<Arc<agent_status::AgentStatusReader>> {
status.map(|s| {
Arc::new(agent_status::AgentStatusReader::new(
s.queue_client(),
status::StatusReader::stale_after_from_env(),
))
})
}
/// Both handlers below take the same hive name and reject it the same way.
///
/// Reports the status and the detail rather than a rendered
@ -868,6 +889,49 @@ async fn get_hives_status(
}
}
/// What each agent last said about itself, read from the swarm queue at
/// request time.
///
/// Every agent in the roster gets a row whether or not it has ever
/// reported — see the `agent_status` module for why, and for why its hive
/// comes from its own bucket key rather than a second lookup.
#[utoipa::path(
get,
path = "/api/agents/status",
responses(
(status = 200, description = "a row per agent, freshness derived now", body = Vec<agent_status::AgentStatusRow>),
(status = 503, description = "no swarm queue is configured here, no identity bridge is configured, or either store could not be read", body = String),
),
tag = "agents"
)]
async fn get_agents_status(
State(state): State<AppState>,
) -> Result<Json<Vec<agent_status::AgentStatusRow>>, StatusUnavailable> {
let Some(reader) = state.agent_status.as_ref() else {
return Err(StatusUnavailable(
"no swarm queue is configured on this host".to_owned(),
));
};
let Some(bridge) = state.auth.as_ref() else {
return Err(StatusUnavailable(
"no identity bridge is configured on this host".to_owned(),
));
};
let roster = bridge.list_agent_identities().await.map_err(|e| {
let detail = format!("{e:#}");
tracing::warn!(error = %detail, "reading the agent roster failed");
StatusUnavailable(detail)
})?;
match reader.view(&roster, std::time::SystemTime::now()).await {
Ok(rows) => Ok(Json(rows)),
Err(e) => {
let detail = format!("{e:#}");
tracing::warn!(error = %detail, "reading the agent-status bucket failed");
Err(StatusUnavailable(detail))
}
}
}
/// Body of `POST /api/agents` — the agent name to create, and the hive the
/// creation is aimed at. The repo name inside `forge::CONFIG_ORG` is the
/// same string as `name`: one repo per agent, named after it, same
@ -1480,6 +1544,7 @@ async fn main() -> Result<()> {
hives: Arc::new(load_hives()),
links: Arc::new(load_links()),
wanted: wanted_writer(status.as_ref()),
agent_status: agent_status_reader(status.as_ref()),
status,
jobq,
webhook_secret,
@ -1514,6 +1579,7 @@ fn build_app(state: AppState) -> axum::Router {
.routes(routes!(get_config_prs))
.routes(routes!(create_agent))
.routes(routes!(get_agents))
.routes(routes!(get_agents_status))
.routes(routes!(set_agent_state))
.routes(routes!(get_hive_wanted))
.routes(routes!(issue_report::get_repos))
@ -1622,6 +1688,7 @@ mod tests {
// No queue, for the same reason as `status`: these tests drive
// agent creation, which publishes no declaration.
wanted: None,
agent_status: None,
jobq: std::sync::Arc::clone(&sched),
webhook_secret: None,
config_prs: None,

View file

@ -49,6 +49,25 @@ pub fn key(hive: &str, agent: &str) -> String {
format!("{hive}/{agent}")
}
/// The inverse of [`key`]: split a bucket key back into `(hive, agent)`.
///
/// `None` for a key with zero or more than one `/` — a hive publishing
/// under [`key`] never produces one, so a malformed key means something
/// else wrote this bucket. Splitting on the *first* `/` would be equally
/// valid today (neither name can contain one), but this rejects rather
/// than guesses, so a future name-charset change can't silently start
/// misreading old keys.
#[must_use]
pub fn split_key(key: &str) -> Option<(&str, &str)> {
let mut parts = key.splitn(3, '/');
let hive = parts.next()?;
let agent = parts.next()?;
if parts.next().is_some() {
return None;
}
Some((hive, agent))
}
/// One agent's status snapshot, as published under [`key`].
///
/// Mirrors the tuple `container_view::read_agent_status_live` returns on
@ -106,13 +125,28 @@ pub async fn open_or_create(
#[cfg(test)]
mod tests {
use super::{AgentStatus, key};
use super::{AgentStatus, key, split_key};
#[test]
fn key_joins_hive_and_agent_with_a_slash() {
assert_eq!(key("prod", "iris"), "prod/iris");
}
#[test]
fn split_key_is_the_inverse_of_key() {
assert_eq!(split_key(&key("prod", "iris")), Some(("prod", "iris")));
}
#[test]
fn split_key_rejects_a_key_with_no_slash() {
assert_eq!(split_key("iris"), None);
}
#[test]
fn split_key_rejects_a_key_with_two_slashes() {
assert_eq!(split_key("prod/iris/extra"), None);
}
#[test]
fn agent_status_round_trips() {
let status = AgentStatus {