Allow customization of the model used for tool calling (#15479)

We also eliminate the `completion` crate and moved its logic into
`LanguageModelRegistry`.

Release Notes:

- N/A

---------

Co-authored-by: Nathan <nathan@zed.dev>

crates/language_model/src/provider/ollama.rs

@@ -12,7 +12,7 @@ use ui::{prelude::*, ButtonLike, ElevationIndex};
 use crate::{
     settings::AllLanguageModelSettings, LanguageModel, LanguageModelId, LanguageModelName,
     LanguageModelProvider, LanguageModelProviderId, LanguageModelProviderName,
-    LanguageModelProviderState, LanguageModelRequest, Role,
+    LanguageModelProviderState, LanguageModelRequest, RateLimiter, Role,
 };
 
 const OLLAMA_DOWNLOAD_URL: &str = "https://ollama.com/download";
@@ -39,7 +39,7 @@ struct State {
 }
 
 impl State {
-    fn fetch_models(&self, cx: &ModelContext<Self>) -> Task<Result<()>> {
+    fn fetch_models(&mut self, cx: &mut ModelContext<Self>) -> Task<Result<()>> {
         let settings = &AllLanguageModelSettings::get_global(cx).ollama;
         let http_client = self.http_client.clone();
         let api_url = settings.api_url.clone();
@@ -80,37 +80,10 @@ impl OllamaLanguageModelProvider {
                 }),
             }),
         };
-        this.fetch_models(cx).detach();
+        this.state
+            .update(cx, |state, cx| state.fetch_models(cx).detach());
         this
     }
-
-    fn fetch_models(&self, cx: &AppContext) -> Task<Result<()>> {
-        let settings = &AllLanguageModelSettings::get_global(cx).ollama;
-        let http_client = self.http_client.clone();
-        let api_url = settings.api_url.clone();
-
-        let state = self.state.clone();
-        // As a proxy for the server being "authenticated", we'll check if its up by fetching the models
-        cx.spawn(|mut cx| async move {
-            let models = get_models(http_client.as_ref(), &api_url, None).await?;
-
-            let mut models: Vec<ollama::Model> = models
-                .into_iter()
-                // Since there is no metadata from the Ollama API
-                // indicating which models are embedding models,
-                // simply filter out models with "-embed" in their name
-                .filter(|model| !model.name.contains("-embed"))
-                .map(|model| ollama::Model::new(&model.name))
-                .collect();
-
-            models.sort_by(|a, b| a.name.cmp(&b.name));
-
-            state.update(&mut cx, |this, cx| {
-                this.available_models = models;
-                cx.notify();
-            })
-        })
-    }
 }
 
 impl LanguageModelProviderState for OllamaLanguageModelProvider {
@@ -140,6 +113,7 @@ impl LanguageModelProvider for OllamaLanguageModelProvider {
                     id: LanguageModelId::from(model.name.clone()),
                     model: model.clone(),
                     http_client: self.http_client.clone(),
+                    request_limiter: RateLimiter::new(4),
                 }) as Arc<dyn LanguageModel>
             })
             .collect()
@@ -158,11 +132,11 @@ impl LanguageModelProvider for OllamaLanguageModelProvider {
         !self.state.read(cx).available_models.is_empty()
     }
 
-    fn authenticate(&self, cx: &AppContext) -> Task<Result<()>> {
+    fn authenticate(&self, cx: &mut AppContext) -> Task<Result<()>> {
         if self.is_authenticated(cx) {
             Task::ready(Ok(()))
         } else {
-            self.fetch_models(cx)
+            self.state.update(cx, |state, cx| state.fetch_models(cx))
         }
     }
 
@@ -176,8 +150,8 @@ impl LanguageModelProvider for OllamaLanguageModelProvider {
             .into()
     }
 
-    fn reset_credentials(&self, cx: &AppContext) -> Task<Result<()>> {
-        self.fetch_models(cx)
+    fn reset_credentials(&self, cx: &mut AppContext) -> Task<Result<()>> {
+        self.state.update(cx, |state, cx| state.fetch_models(cx))
     }
 }
 
@@ -185,6 +159,7 @@ pub struct OllamaLanguageModel {
     id: LanguageModelId,
     model: ollama::Model,
     http_client: Arc<dyn HttpClient>,
+    request_limiter: RateLimiter,
 }
 
 impl OllamaLanguageModel {
@@ -235,14 +210,14 @@ impl LanguageModel for OllamaLanguageModel {
         LanguageModelProviderName(PROVIDER_NAME.into())
     }
 
-    fn max_token_count(&self) -> usize {
-        self.model.max_token_count()
-    }
-
     fn telemetry_id(&self) -> String {
         format!("ollama/{}", self.model.id())
     }
 
+    fn max_token_count(&self) -> usize {
+        self.model.max_token_count()
+    }
+
     fn count_tokens(
         &self,
         request: LanguageModelRequest,
@@ -275,10 +250,10 @@ impl LanguageModel for OllamaLanguageModel {
             return futures::future::ready(Err(anyhow!("App state dropped"))).boxed();
         };
 
-        async move {
-            let request =
-                stream_chat_completion(http_client.as_ref(), &api_url, request, low_speed_timeout);
-            let response = request.await?;
+        let future = self.request_limiter.stream(async move {
+            let response =
+                stream_chat_completion(http_client.as_ref(), &api_url, request, low_speed_timeout)
+                    .await?;
             let stream = response
                 .filter_map(|response| async move {
                     match response {
@@ -295,11 +270,12 @@ impl LanguageModel for OllamaLanguageModel {
                 })
                 .boxed();
             Ok(stream)
-        }
-        .boxed()
+        });
+
+        async move { Ok(future.await?.boxed()) }.boxed()
     }
 
-    fn use_tool(
+    fn use_any_tool(
         &self,
         _request: LanguageModelRequest,
         _name: String,