feat: add adaptors for various backends (#40)

* ollama
* tgi
* api-inference
* OpenAI based APIs

crates/llm-ls/src/adaptors.rs

@@ -0,0 +1,250 @@
+use super::{
+    internal_error, APIError, APIResponse, CompletionParams, Generation, Ide, RequestParams, NAME,
+    VERSION,
+};
+use reqwest::header::{HeaderMap, HeaderValue, AUTHORIZATION, USER_AGENT};
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+use std::fmt::Display;
+use tower_lsp::jsonrpc;
+
+fn build_tgi_body(prompt: String, params: &RequestParams) -> Value {
+    serde_json::json!({
+        "inputs": prompt,
+        "parameters": params,
+    })
+}
+
+fn build_tgi_headers(api_token: Option<&String>, ide: Ide) -> Result<HeaderMap, jsonrpc::Error> {
+    let mut headers = HeaderMap::new();
+    let user_agent = format!("{NAME}/{VERSION}; rust/unknown; ide/{ide:?}");
+    headers.insert(
+        USER_AGENT,
+        HeaderValue::from_str(&user_agent).map_err(internal_error)?,
+    );
+
+    if let Some(api_token) = api_token {
+        headers.insert(
+            AUTHORIZATION,
+            HeaderValue::from_str(&format!("Bearer {api_token}")).map_err(internal_error)?,
+        );
+    }
+
+    Ok(headers)
+}
+
+fn parse_tgi_text(text: &str) -> Result<Vec<Generation>, jsonrpc::Error> {
+    let generations =
+        match serde_json::from_str(text).map_err(internal_error)? {
+            APIResponse::Generation(gen) => vec![gen],
+            APIResponse::Generations(_) => {
+                return Err(internal_error(
+                    "You are attempting to parse a result in the API inference format when using the `tgi` adaptor",
+                ))
+            }
+            APIResponse::Error(err) => return Err(internal_error(err)),
+        };
+    Ok(generations)
+}
+
+fn build_api_body(prompt: String, params: &RequestParams) -> Value {
+    build_tgi_body(prompt, params)
+}
+
+fn build_api_headers(api_token: Option<&String>, ide: Ide) -> Result<HeaderMap, jsonrpc::Error> {
+    build_tgi_headers(api_token, ide)
+}
+
+fn parse_api_text(text: &str) -> Result<Vec<Generation>, jsonrpc::Error> {
+    let generations = match serde_json::from_str(text).map_err(internal_error)? {
+        APIResponse::Generation(gen) => vec![gen],
+        APIResponse::Generations(gens) => gens,
+        APIResponse::Error(err) => return Err(internal_error(err)),
+    };
+    Ok(generations)
+}
+
+fn build_ollama_body(prompt: String, params: &CompletionParams) -> Value {
+    serde_json::json!({
+        "prompt": prompt,
+        "model": params.request_body.as_ref().ok_or_else(|| internal_error("missing request_body")).expect("Unable to make request for ollama").get("model"),
+        "stream": false,
+        // As per [modelfile](https://github.com/jmorganca/ollama/blob/main/docs/modelfile.md#valid-parameters-and-values)
+        "options": {
+            "num_predict": params.request_params.max_new_tokens,
+            "temperature": params.request_params.temperature,
+            "top_p": params.request_params.top_p,
+            "stop": params.request_params.stop_tokens.clone(),
+        }
+    })
+}
+fn build_ollama_headers() -> Result<HeaderMap, jsonrpc::Error> {
+    Ok(HeaderMap::new())
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct OllamaGeneration {
+    response: String,
+}
+
+impl From<OllamaGeneration> for Generation {
+    fn from(value: OllamaGeneration) -> Self {
+        Generation {
+            generated_text: value.response,
+        }
+    }
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(untagged)]
+enum OllamaAPIResponse {
+    Generation(OllamaGeneration),
+    Error(APIError),
+}
+
+fn parse_ollama_text(text: &str) -> Result<Vec<Generation>, jsonrpc::Error> {
+    let generations = match serde_json::from_str(text).map_err(internal_error)? {
+        OllamaAPIResponse::Generation(gen) => vec![gen.into()],
+        OllamaAPIResponse::Error(err) => return Err(internal_error(err)),
+    };
+    Ok(generations)
+}
+
+fn build_openai_body(prompt: String, params: &CompletionParams) -> Value {
+    serde_json::json!({
+        "prompt": prompt,
+        "model": params.request_body.as_ref().ok_or_else(|| internal_error("missing request_body")).expect("Unable to make request for openai").get("model"),
+        "max_tokens": params.request_params.max_new_tokens,
+        "temperature": params.request_params.temperature,
+        "top_p": params.request_params.top_p,
+        "stop": params.request_params.stop_tokens.clone(),
+    })
+}
+
+fn build_openai_headers(api_token: Option<&String>, ide: Ide) -> Result<HeaderMap, jsonrpc::Error> {
+    build_api_headers(api_token, ide)
+}
+
+#[derive(Debug, Deserialize)]
+struct OpenAIGenerationChoice {
+    text: String,
+}
+
+impl From<OpenAIGenerationChoice> for Generation {
+    fn from(value: OpenAIGenerationChoice) -> Self {
+        Generation {
+            generated_text: value.text,
+        }
+    }
+}
+
+#[derive(Debug, Deserialize)]
+struct OpenAIGeneration {
+    choices: Vec<OpenAIGenerationChoice>,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(untagged)]
+enum OpenAIErrorLoc {
+    String(String),
+    Int(u32),
+}
+
+impl Display for OpenAIErrorLoc {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            OpenAIErrorLoc::String(s) => s.fmt(f),
+            OpenAIErrorLoc::Int(i) => i.fmt(f),
+        }
+    }
+}
+
+#[derive(Debug, Deserialize)]
+struct OpenAIErrorDetail {
+    loc: OpenAIErrorLoc,
+    msg: String,
+    r#type: String,
+}
+
+#[derive(Debug, Deserialize)]
+struct OpenAIError {
+    detail: Vec<OpenAIErrorDetail>,
+}
+
+impl Display for OpenAIError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        for (i, item) in self.detail.iter().enumerate() {
+            if i != 0 {
+                writeln!(f)?;
+            }
+            write!(f, "{}: {} ({})", item.loc, item.msg, item.r#type)?;
+        }
+        Ok(())
+    }
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(untagged)]
+enum OpenAIAPIResponse {
+    Generation(OpenAIGeneration),
+    Error(OpenAIError),
+}
+
+fn parse_openai_text(text: &str) -> Result<Vec<Generation>, jsonrpc::Error> {
+    match serde_json::from_str(text).map_err(internal_error) {
+        Ok(OpenAIAPIResponse::Generation(completion)) => {
+            Ok(completion.choices.into_iter().map(|x| x.into()).collect())
+        }
+        Ok(OpenAIAPIResponse::Error(err)) => Err(internal_error(err)),
+        Err(err) => Err(internal_error(err)),
+    }
+}
+
+const TGI: &str = "tgi";
+const HUGGING_FACE: &str = "huggingface";
+const OLLAMA: &str = "ollama";
+const OPENAI: &str = "openai";
+const DEFAULT_ADAPTOR: &str = HUGGING_FACE;
+
+fn unknown_adaptor_error(adaptor: Option<&String>) -> jsonrpc::Error {
+    internal_error(format!("Unknown adaptor {:?}", adaptor))
+}
+
+pub fn adapt_body(prompt: String, params: &CompletionParams) -> Result<Value, jsonrpc::Error> {
+    match params
+        .adaptor
+        .as_ref()
+        .unwrap_or(&DEFAULT_ADAPTOR.to_string())
+        .as_str()
+    {
+        TGI => Ok(build_tgi_body(prompt, &params.request_params)),
+        HUGGING_FACE => Ok(build_api_body(prompt, &params.request_params)),
+        OLLAMA => Ok(build_ollama_body(prompt, params)),
+        OPENAI => Ok(build_openai_body(prompt, params)),
+        _ => Err(unknown_adaptor_error(params.adaptor.as_ref())),
+    }
+}
+
+pub fn adapt_headers(
+    adaptor: Option<&String>,
+    api_token: Option<&String>,
+    ide: Ide,
+) -> Result<HeaderMap, jsonrpc::Error> {
+    match adaptor.unwrap_or(&DEFAULT_ADAPTOR.to_string()).as_str() {
+        TGI => build_tgi_headers(api_token, ide),
+        HUGGING_FACE => build_api_headers(api_token, ide),
+        OLLAMA => build_ollama_headers(),
+        OPENAI => build_openai_headers(api_token, ide),
+        _ => Err(unknown_adaptor_error(adaptor)),
+    }
+}
+
+pub fn parse_generations(adaptor: Option<&String>, text: &str) -> jsonrpc::Result<Vec<Generation>> {
+    match adaptor.unwrap_or(&DEFAULT_ADAPTOR.to_string()).as_str() {
+        TGI => parse_tgi_text(text),
+        HUGGING_FACE => parse_api_text(text),
+        OLLAMA => parse_ollama_text(text),
+        OPENAI => parse_openai_text(text),
+        _ => Err(unknown_adaptor_error(adaptor)),
+    }
+}