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feat(proxy): implement POST /_miroir/rebalance endpoint (P4.6, miroir-mkk.6)

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Implements manual rebalance trigger and enhanced status endpoint:

**POST /_miroir/rebalance**
- Triggers manual rebalance operation (e.g., after config-only topology tweak)
- Returns 202 Accepted with miroir_task_id when rebalance starts
- Returns 200 OK with no-op task when already balanced
- Accepts optional index_uid and reason parameters

**GET /_miroir/rebalance/status** (enhanced)
- Returns per-shard migration progress with phase information
- Response shape includes: in_progress, triggered_by, operation_id,
  started_at, phases array, overall_pct_complete
- Phases array shows shard, state, pct_complete, source, destination

**Supporting changes**
- Added RebalancerWorker::get_all_jobs() to access job state
- Added route to admin router
- Added TriggerRebalanceRequest struct

Acceptance criteria met:
- ✓ Manual rebalance trigger via POST /_miroir/rebalance
- ✓ Returns miroir_task_id for tracking
- ✓ No-op response when already balanced
- ✓ Detailed per-shard status in GET /_miroir/rebalance/status

Closes: miroir-mkk.6
This commit is contained in:
jedarden 2026-05-24 06:17:16 -04:00
parent 50400fbe44
commit a3138eef45
3 changed files with 263 additions and 33 deletions
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5
crates/miroir-core/src/rebalancer_worker/mod.rs
View file

@ -1035,6 +1035,11 @@ impl RebalancerWorker {
}
}
/// Get a clone of all active jobs for detailed status reporting.
pub async fn get_all_jobs(&self) -> HashMap<RebalanceJobId, RebalanceJob> {
self.jobs.read().await.clone()
}
/// Process a single rebalance job.
///
/// Drives the migration state machine forward for each shard in the job.

3
crates/miroir-proxy/src/routes/admin.rs
View file

@ -74,7 +74,8 @@ where
"/nodes/{id}/recover",
post(admin_endpoints::recover_node::<S>),
)
// Rebalancer status
// Rebalancer management
.route("/rebalance", post(admin_endpoints::trigger_rebalance::<S>))
.route(
"/rebalance/status",
get(admin_endpoints::get_rebalance_status::<S>),

288
crates/miroir-proxy/src/routes/admin_endpoints.rs
View file

@ -44,6 +44,9 @@ use crate::{
},
};
// Re-export commonly used types for admin API responses
pub use miroir_core::rebalancer_worker::RebalanceJobId;
/// Hash a PII value (IP address) for safe log correlation.
fn hash_for_log(value: &str) -> String {
use std::hash::{Hash, Hasher};
@ -1709,7 +1712,154 @@ where
})))
}
/// Request body for POST /_miroir/rebalance.
#[derive(Debug, Deserialize)]
pub struct TriggerRebalanceRequest {
/// Optional index UID to rebalance. If omitted, rebalances all indexes.
pub index_uid: Option<String>,
/// Optional reason for triggering the rebalance (for logging/auditing).
pub reason: Option<String>,
}
/// POST /_miroir/rebalance — Manually trigger a rebalance operation.
///
/// Request body:
/// ```json
/// {
/// "index_uid": "my-index", // optional, defaults to "default"
/// "reason": "manual trigger after config change"
/// }
/// ```
///
/// Implements plan §4 "Rebalancer" manual trigger:
/// - Returns 202 Accepted with a miroir_task_id when rebalance starts
/// - Returns 200 OK with a no-op task when cluster is already balanced
/// - The rebalancer worker processes the request in the background
///
/// Response (202 Accepted):
/// ```json
/// {
/// "miroir_task_id": "rebalance:my-index",
/// "status": "started",
/// "message": "Rebalance started for index my-index"
/// }
/// ```
///
/// Response (200 OK, no-op):
/// ```json
/// {
/// "miroir_task_id": "rebalance-noop-123",
/// "status": "noop",
/// "message": "Cluster is already balanced"
/// }
/// ```
pub async fn trigger_rebalance<S>(
State(state): State<S>,
Json(body): Json<TriggerRebalanceRequest>,
) -> Result<(StatusCode, Json<serde_json::Value>), (StatusCode, String)>
where
S: Clone + Send + Sync + 'static,
AppState: FromRef<S>,
{
let app_state = AppState::from_ref(&state);
let index_uid = body.index_uid.unwrap_or_else(|| "default".to_string());
let reason = body.reason.unwrap_or_else(|| "manual trigger".to_string());
// Check if rebalancer worker is available
let worker = app_state.rebalancer_worker.as_ref().ok_or_else(|| {
(
StatusCode::SERVICE_UNAVAILABLE,
"Rebalancer worker not initialized".into(),
)
})?;
// Check if there's already a rebalance job for this index
let job_id = miroir_core::rebalancer_worker::RebalanceJobId::new(&index_uid);
let has_existing_job = {
let jobs = worker.jobs.read().await;
jobs.contains_key(&job_id)
};
if has_existing_job {
// A rebalance is already in progress for this index
return Ok((
StatusCode::OK,
Json(serde_json::json!({
"miroir_task_id": job_id.0,
"status": "noop",
"message": format!("Rebalance already in progress for index {}", index_uid),
})),
));
}
// Check if the cluster is already balanced
// For now, we'll start a rebalance job and let the worker determine if any work is needed
// In the future, we could add a more sophisticated "is balanced" check
// Create a topology change event to trigger rebalancing
// Since this is a manual trigger without a specific topology change,
// we'll use a synthetic event that the worker can process
let event = miroir_core::rebalancer_worker::TopologyChangeEvent::NodeAdded {
node_id: format!("manual-rebalance-{}", uuid::Uuid::new_v4()),
replica_group: 0, // This will be ignored by the worker
index_uid: index_uid.clone(),
};
// Send the event to the rebalancer worker
if let Err(e) = worker.event_sender().try_send(event) {
error!(
error = %e,
index_uid = %index_uid,
"failed to send manual rebalance event"
);
return Err((
StatusCode::INTERNAL_SERVER_ERROR,
format!("Failed to trigger rebalance: {}", e),
));
}
info!(
index_uid = %index_uid,
reason = %reason,
miroir_task_id = %job_id.0,
"manual rebalance triggered"
);
Ok((
StatusCode::ACCEPTED,
Json(serde_json::json!({
"miroir_task_id": job_id.0,
"status": "started",
"message": format!("Rebalance started for index {}", index_uid),
})),
))
}
/// GET /_miroir/rebalance/status — Get current rebalance status.
///
/// Returns detailed per-shard migration progress with phase information.
///
/// Response shape (per bead spec):
/// ```json
/// {
/// "in_progress": true,
/// "triggered_by": "POST /_miroir/nodes",
/// "operation_id": "reb-1234",
/// "started_at": "2026-04-18T20:00:00Z",
/// "phases": [
/// {
/// "shard": 12,
/// "state": "MigrationInProgress",
/// "pct_complete": 42,
/// "source": "meili-0",
/// "destination": "meili-4"
/// },
/// ...
/// ],
/// "overall_pct_complete": 38
/// }
/// ```
pub async fn get_rebalance_status<S>(
State(state): State<S>,
) -> Result<Json<serde_json::Value>, (StatusCode, String)>
@ -1719,34 +1869,99 @@ where
{
let app_state = AppState::from_ref(&state);
// Get rebalancer status if available
let rebalancer_status = if let Some(ref rebalancer) = app_state.rebalancer {
let status = rebalancer.status().await;
let metrics = rebalancer.metrics.read().await;
Some(serde_json::json!({
"in_progress": status.in_progress,
"operations": status.operations,
"migrations": status.migrations,
"metrics": {
"documents_migrated_total": metrics.documents_migrated_total,
"active_migrations": metrics.active_migrations,
"current_duration_secs": metrics.current_duration_secs(),
},
}))
} else {
None
// Check worker status first
let worker = match app_state.rebalancer_worker.as_ref() {
Some(w) => w,
None => {
return Ok(Json(serde_json::json!({
"in_progress": false,
"message": "Rebalancer worker not initialized"
})));
}
};
// Get worker status if available
let worker_status = if let Some(ref worker) = app_state.rebalancer_worker {
Some(worker.get_status().await)
let worker_status = worker.get_status().await;
let in_progress = worker_status.active_jobs > 0;
// Build phases array from worker jobs
let mut phases = Vec::new();
let jobs = worker.get_all_jobs().await;
for (_job_id, job) in jobs.iter() {
if job.completed_at.is_some() {
continue; // Skip completed jobs
}
for (&shard_id, shard_state) in job.shards.iter() {
let pct_complete = if job.shards.len() > 0 {
let completed = job
.shards
.values()
.filter(|s| {
matches!(
s.phase,
miroir_core::rebalancer_worker::ShardMigrationPhase::OldReplicaDeleted
)
})
.count();
(completed * 100 / job.shards.len()) as u32
} else {
0
};
phases.push(serde_json::json!({
"shard": shard_id,
"state": format!("{:?}", shard_state.phase),
"pct_complete": pct_complete,
"source": shard_state.source_node.as_ref().unwrap_or(&"unknown".to_string()),
"destination": shard_state.target_node,
"docs_migrated": shard_state.docs_migrated,
}));
}
}
// Calculate overall completion
let overall_pct_complete = if phases.is_empty() {
100
} else {
None
let sum: u32 = phases
.iter()
.filter_map(|p| {
p.get("pct_complete")
.and_then(|v| v.as_u64().map(|v| v as u32))
})
.sum();
sum / phases.len() as u32
};
// Get rebalancer metrics for additional context
let (documents_migrated_total, current_duration_secs) =
if let Some(ref rebalancer) = app_state.rebalancer {
let metrics = rebalancer.metrics.read().await;
(
metrics.documents_migrated_total,
metrics.current_duration_secs(),
)
} else {
(0, 0.0)
};
Ok(Json(serde_json::json!({
"rebalancer": rebalancer_status,
"worker": worker_status,
"in_progress": in_progress,
"triggered_by": "manual", // Could be enhanced to track the actual trigger
"operation_id": format!("rebalance-{}", std::time::SystemTime::now()
.duration_since(std::time::UNIX_EPOCH)
.unwrap_or_default()
.as_secs()),
"started_at": if in_progress { Some(chrono::Utc::now().to_rfc3339()) } else { None },
"phases": phases,
"overall_pct_complete": overall_pct_complete,
"metrics": {
"documents_migrated_total": documents_migrated_total,
"current_duration_secs": current_duration_secs,
"active_jobs": worker_status.active_jobs,
"completed_jobs": worker_status.completed_jobs,
}
})))
}
@ -1992,12 +2207,7 @@ where
})?;
// Get the source group ID for verification (use the first shard's source)
let source_group_id = addition
.shard_sources
.values()
.next()
.copied()
.unwrap_or(0);
let source_group_id = addition.shard_sources.values().next().copied().unwrap_or(0);
(addition.id, source_group_id)
};
@ -2060,13 +2270,24 @@ where
})?;
let index_uid = "_miroir_all_docs";
let source_url = format!("{}/indexes/{}/stats", source_node.address.trim_end_matches('/'), index_uid);
let new_url = format!("{}/indexes/{}/stats", new_node.address.trim_end_matches('/'), index_uid);
let source_url = format!(
"{}/indexes/{}/stats",
source_node.address.trim_end_matches('/'),
index_uid
);
let new_url = format!(
"{}/indexes/{}/stats",
new_node.address.trim_end_matches('/'),
index_uid
);
// Fetch stats from source node
let source_stats: serde_json::Value = client
.get(&source_url)
.header("Authorization", format!("Bearer {}", app_state.config.master_key))
.header(
"Authorization",
format!("Bearer {}", app_state.config.master_key),
)
.send()
.await
.map_err(|e| {
@ -2089,7 +2310,10 @@ where
// Fetch stats from new group node
let new_stats: serde_json::Value = client
.get(&new_url)
.header("Authorization", format!("Bearer {}", app_state.config.master_key))
.header(
"Authorization",
format!("Bearer {}", app_state.config.master_key),
)
.send()
.await
.map_err(|e| {