[ENH] Use figment configuration for chroma-load

This mirrors the compactor and query services (and can even merge with
their configs if we so choose).

rust/load/Cargo.toml

@@ -8,6 +8,7 @@ async-trait = "0.1.83"
 axum = "0.7"
 chromadb = { git = "https://github.com/rescrv/chromadb-rs", rev = "e364e35c34c660d4e8e862436ea600ddc2f46a1e" }
 chrono = "0.4.38"
+figment = { version = "0.10.12", features = ["env", "yaml", "test"] }
 guacamole = { version = "0.9", default-features = false }
 serde.workspace = true
 

rust/load/chroma_load.yaml

@@ -0,0 +1,4 @@
+load_service:
+  service_name: chroma-load
+  otel_endpoint: "http://otel-collector:4317"
+  port: 3000

rust/load/src/config.rs

@@ -0,0 +1,47 @@
+use figment::providers::{Env, Format, Yaml};
+use serde::Deserialize;
+
+const DEFAULT_CONFIG_PATH: &str = "./chroma_config.yaml";
+
+#[derive(Deserialize)]
+/// Root config for chroma-load service.  Can be part of a larger config file.
+pub struct RootConfig {
+    pub load_service: LoadServiceConfig,
+}
+
+impl RootConfig {
+    pub fn load() -> Self {
+        Self::load_from_path(DEFAULT_CONFIG_PATH)
+    }
+
+    // NOTE:  Copied from ../worker/src/config.rs.
+    pub fn load_from_path(path: &str) -> Self {
+        // Unfortunately, figment doesn't support environment variables with underscores. So we have to map and replace them.
+        // Excluding our own environment variables, which are prefixed with CHROMA_.
+        let mut f = figment::Figment::from(Env::prefixed("CHROMA_").map(|k| match k {
+            k if k == "my_member_id" => k.into(),
+            k => k.as_str().replace("__", ".").into(),
+        }));
+        if std::path::Path::new(path).exists() {
+            f = figment::Figment::from(Yaml::file(path)).merge(f);
+        }
+        // Apply defaults - this seems to be the best way to do it.
+        // https://github.com/SergioBenitez/Figment/issues/77#issuecomment-1642490298
+        // f = f.join(Serialized::default(
+        //     "worker.num_indexing_threads",
+        //     num_cpus::get(),
+        // ));
+        let res = f.extract();
+        match res {
+            Ok(config) => config,
+            Err(e) => panic!("Error loading config: {}", e),
+        }
+    }
+}
+
+#[derive(Deserialize)]
+pub struct LoadServiceConfig {
+    pub service_name: String,
+    pub otel_endpoint: String,
+    pub port: u16,
+}

rust/load/src/lib.rs

@@ -18,11 +18,14 @@ use tower_http::trace::TraceLayer;
 use tracing::Instrument;
 use uuid::Uuid;
 
+pub mod config;
 pub mod data_sets;
 pub mod opentelemetry_config;
 pub mod rest;
 pub mod workloads;
 
+const CONFIG_PATH_ENV_VAR: &str = "CONFIG_PATH";
+
 /////////////////////////////////////////////// Error //////////////////////////////////////////////
 
 #[derive(Debug)]
@@ -659,10 +662,14 @@ async fn uninhibit(State(state): State<AppState>) -> Result<String, Error> {
 }
 
 pub async fn entrypoint() {
-    opentelemetry_config::init_otel_tracing(
-        &"chroma-load".to_string(),
-        &"localhost:4317".to_string(),
-    );
+    let config = match std::env::var(CONFIG_PATH_ENV_VAR) {
+        Ok(config_path) => config::RootConfig::load_from_path(&config_path),
+        Err(_) => config::RootConfig::load(),
+    };
+
+    let config = config.load_service;
+
+    opentelemetry_config::init_otel_tracing(&config.service_name, &config.otel_endpoint);
     let load = Arc::new(LoadService::default());
     let state = AppState {
         load: Arc::clone(&load),
@@ -690,7 +697,9 @@ pub async fn entrypoint() {
             }),
         )
         .with_state(state);
-    let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await.unwrap();
+    let listener = tokio::net::TcpListener::bind(format!("0.0.0.0:{}", config.port))
+        .await
+        .unwrap();
     let runner = tokio::task::spawn(async move { load.run().await });
     axum::serve(listener, app).await.unwrap();
     runner.abort();

rust/worker/src/config.rs

@@ -53,6 +53,7 @@ impl RootConfig {
     /// # Notes
     /// The environment variables are prefixed with CHROMA_ and are uppercase.
     /// Values in the envionment variables take precedence over values in the YAML file.
+    // NOTE:  Copied to ../load/src/config.rs.
     pub(crate) fn load_from_path(path: &str) -> Self {
         // Unfortunately, figment doesn't support environment variables with underscores. So we have to map and replace them.
         // Excluding our own environment variables, which are prefixed with CHROMA_.