Introduce the first version of the /chat route that mimics the OpenAI API

Cargo.lock

@@ -6067,9 +6067,9 @@ dependencies = [
 
 [[package]]
 name = "tokio"
-version = "1.45.0"
+version = "1.45.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2513ca694ef9ede0fb23fe71a4ee4107cb102b9dc1930f6d0fd77aae068ae165"
+checksum = "75ef51a33ef1da925cea3e4eb122833cb377c61439ca401b770f54902b806779"
 dependencies = [
  "backtrace",
  "bytes",

crates/meilisearch-types/src/keys.rs

@@ -389,6 +389,7 @@ impl Action {
             EXPERIMENTAL_FEATURES_UPDATE => Some(Self::ExperimentalFeaturesUpdate),
             NETWORK_GET => Some(Self::NetworkGet),
             NETWORK_UPDATE => Some(Self::NetworkUpdate),
+            CHAT_GET => Some(Self::ChatGet),
             _otherwise => None,
         }
     }

crates/meilisearch/src/routes/chat.rs

@@ -0,0 +1,32 @@
+use actix_web::web::{self, Data};
+use actix_web::HttpResponse;
+use async_openai::config::OpenAIConfig;
+use async_openai::types::CreateChatCompletionRequest;
+use async_openai::Client;
+use index_scheduler::IndexScheduler;
+use meilisearch_types::error::ResponseError;
+use meilisearch_types::keys::actions;
+
+use crate::extractors::authentication::policies::ActionPolicy;
+use crate::extractors::authentication::GuardedData;
+
+pub fn configure(cfg: &mut web::ServiceConfig) {
+    cfg.service(web::resource("").route(web::post().to(chat)));
+}
+
+/// Get a chat completion
+async fn chat(
+    _index_scheduler: GuardedData<ActionPolicy<{ actions::CHAT_GET }>, Data<IndexScheduler>>,
+    web::Json(chat_completion): web::Json<CreateChatCompletionRequest>,
+) -> Result<HttpResponse, ResponseError> {
+    // To enable later on, when the feature will be experimental
+    // index_scheduler.features().check_chat("Using the /chat route")?;
+
+    let api_key = std::env::var("MEILI_OPENAI_API_KEY")
+        .expect("cannot find OpenAI API Key (MEILI_OPENAI_API_KEY)");
+    let config = OpenAIConfig::default().with_api_key(&api_key); // we can also change the API base
+    let client = Client::with_config(config);
+    let response = client.chat().create(chat_completion).await.unwrap();
+
+    Ok(HttpResponse::Ok().json(response))
+}