dynamo/lib/runtime/src/service.rs

297 lines
9.9 KiB
Rust

// SPDX-FileCopyrightText: Copyright (c) 2024-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
// SPDX-License-Identifier: Apache-2.0
// TODO - refactor this entire module
//
// we want to carry forward the concept of live vs ready for the components
// we will want to associate the components cancellation token with the
// component's "service state"
use crate::{
DistributedRuntime,
component::Component,
metrics::{MetricsHierarchy, prometheus_names},
traits::*,
transports::nats,
utils::stream,
};
use anyhow::Result;
use anyhow::anyhow as error;
use async_nats::Message;
use async_stream::try_stream;
use bytes::Bytes;
use derive_getters::Dissolve;
use futures::stream::{StreamExt, TryStreamExt};
use prometheus;
use serde::{Deserialize, Serialize, de::DeserializeOwned};
use std::time::Duration;
pub struct ServiceClient {
nats_client: nats::Client,
}
impl ServiceClient {
pub fn new(nats_client: nats::Client) -> Self {
ServiceClient { nats_client }
}
}
/// ServiceSet contains a collection of services with their endpoints and metrics
///
/// Tree structure:
/// Structure:
/// - ServiceSet
/// - services: Vec<ServiceInfo>
/// - name: String
/// - id: String
/// - version: String
/// - started: String
/// - endpoints: Vec<EndpointInfo>
/// - name: String
/// - subject: String
/// - data: Option<NatsStatsMetrics>
/// - average_processing_time: f64
/// - last_error: String
/// - num_errors: u64
/// - num_requests: u64
/// - processing_time: u64
/// - queue_group: String
/// - data: serde_json::Value (custom stats)
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ServiceSet {
services: Vec<ServiceInfo>,
}
/// This is a example JSON from `nats req '$SRV.STATS.dynamo_backend'`:
/// {
/// "type": "io.nats.micro.v1.stats_response",
/// "name": "dynamo_backend",
/// "id": "bdu7nA8tbhy9mEkxIWlkBA",
/// "version": "0.0.1",
/// "started": "2025-08-08T05:07:17.720783523Z",
/// "endpoints": [
/// {
/// "name": "dynamo_backend-generate-694d988806b92e39",
/// "subject": "dynamo_backend.generate-694d988806b92e39",
/// "num_requests": 0,
/// "num_errors": 0,
/// "processing_time": 0,
/// "average_processing_time": 0,
/// "last_error": "",
/// "data": {
/// "val": 10
/// },
/// "queue_group": "q"
/// }
/// ]
/// }
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ServiceInfo {
pub name: String,
pub id: String,
pub version: String,
pub started: String,
pub endpoints: Vec<EndpointInfo>,
}
/// Each endpoint has name, subject, num_requests, num_errors, processing_time, average_processing_time, last_error, queue_group, and data
#[derive(Debug, Clone, Serialize, Deserialize, Dissolve)]
pub struct EndpointInfo {
pub name: String,
pub subject: String,
/// Extra fields that don't fit in EndpointInfo will be flattened into the Metrics struct.
#[serde(flatten)]
pub data: Option<NatsStatsMetrics>,
}
impl EndpointInfo {
pub fn id(&self) -> Result<i64> {
let id = self
.subject
.split('-')
.next_back()
.ok_or_else(|| error!("No id found in subject"))?;
i64::from_str_radix(id, 16).map_err(|e| error!("Invalid id format: {}", e))
}
}
// TODO: This is _really_ close to the async_nats::service::Stats object,
// but it's missing a few fields like "name", so use a temporary struct
// for easy deserialization. Ideally, this type already exists or can
// be exposed in the library somewhere.
/// Stats structure returned from NATS service API
/// https://github.com/nats-io/nats.rs/blob/main/async-nats/src/service/endpoint.rs
#[derive(Debug, Clone, Serialize, Deserialize, Dissolve)]
pub struct NatsStatsMetrics {
// Standard NATS Stats Service API fields from $SRV.STATS.<service_name> requests
pub average_processing_time: u64, // in nanoseconds according to nats-io
pub last_error: String,
pub num_errors: u64,
pub num_requests: u64,
pub processing_time: u64, // in nanoseconds according to nats-io
pub queue_group: String,
// Field containing custom stats handler data
pub data: serde_json::Value,
}
impl NatsStatsMetrics {
pub fn decode<T: for<'de> Deserialize<'de>>(self) -> Result<T> {
serde_json::from_value(self.data).map_err(Into::into)
}
}
impl ServiceClient {
pub async fn unary(
&self,
subject: impl Into<String>,
payload: impl Into<Bytes>,
) -> Result<Message> {
let response = self
.nats_client
.client()
.request(subject.into(), payload.into())
.await?;
Ok(response)
}
pub async fn collect_services(
&self,
service_name: &str,
timeout: Duration,
) -> Result<ServiceSet> {
let sub = self.nats_client.scrape_service(service_name).await?;
if timeout.is_zero() {
tracing::warn!("collect_services: timeout is zero");
}
if timeout > Duration::from_secs(10) {
tracing::warn!("collect_services: timeout is greater than 10 seconds");
}
let deadline = tokio::time::Instant::now() + timeout;
let mut services = vec![];
let mut s = stream::until_deadline(sub, deadline);
while let Some(message) = s.next().await {
if message.payload.is_empty() {
// Expected while we wait for KV metrics in worker to start
tracing::trace!(service_name, "collect_services: empty payload from nats");
continue;
}
let info = serde_json::from_slice::<ServiceInfo>(&message.payload);
match info {
Ok(info) => services.push(info),
Err(err) => {
let payload = String::from_utf8_lossy(&message.payload);
tracing::debug!(%err, service_name, %payload, "error decoding service info");
}
}
}
Ok(ServiceSet { services })
}
}
impl ServiceSet {
pub fn into_endpoints(self) -> impl Iterator<Item = EndpointInfo> {
self.services
.into_iter()
.flat_map(|s| s.endpoints.into_iter())
}
/// Get a reference to the services in this ServiceSet
pub fn services(&self) -> &[ServiceInfo] {
&self.services
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_service_set() {
let services = vec![
ServiceInfo {
name: "service1".to_string(),
id: "1".to_string(),
version: "1.0".to_string(),
started: "2021-01-01".to_string(),
endpoints: vec![
EndpointInfo {
name: "endpoint1".to_string(),
subject: "subject1".to_string(),
data: Some(NatsStatsMetrics {
average_processing_time: 100_000, // 0.1ms = 100,000 nanoseconds
last_error: "none".to_string(),
num_errors: 0,
num_requests: 10,
processing_time: 100,
queue_group: "group1".to_string(),
data: serde_json::json!({"key": "value1"}),
}),
},
EndpointInfo {
name: "endpoint2-foo".to_string(),
subject: "subject2".to_string(),
data: Some(NatsStatsMetrics {
average_processing_time: 100_000, // 0.1ms = 100,000 nanoseconds
last_error: "none".to_string(),
num_errors: 0,
num_requests: 10,
processing_time: 100,
queue_group: "group1".to_string(),
data: serde_json::json!({"key": "value1"}),
}),
},
],
},
ServiceInfo {
name: "service1".to_string(),
id: "2".to_string(),
version: "1.0".to_string(),
started: "2021-01-01".to_string(),
endpoints: vec![
EndpointInfo {
name: "endpoint1".to_string(),
subject: "subject1".to_string(),
data: Some(NatsStatsMetrics {
average_processing_time: 100_000, // 0.1ms = 100,000 nanoseconds
last_error: "none".to_string(),
num_errors: 0,
num_requests: 10,
processing_time: 100,
queue_group: "group1".to_string(),
data: serde_json::json!({"key": "value1"}),
}),
},
EndpointInfo {
name: "endpoint2-bar".to_string(),
subject: "subject2".to_string(),
data: Some(NatsStatsMetrics {
average_processing_time: 100_000, // 0.1ms = 100,000 nanoseconds
last_error: "none".to_string(),
num_errors: 0,
num_requests: 10,
processing_time: 100,
queue_group: "group1".to_string(),
data: serde_json::json!({"key": "value2"}),
}),
},
],
},
];
let service_set = ServiceSet { services };
let endpoints: Vec<_> = service_set
.into_endpoints()
.filter(|e| e.name.starts_with("endpoint2"))
.collect();
assert_eq!(endpoints.len(), 2);
}
}