add support for using custom upstream llm (#365)

crates/common/src/configuration.rs

@@ -162,15 +162,34 @@ pub struct EmbeddingProviver {
     pub model: String,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub enum LlmProviderType {
+    #[serde(rename = "openai")]
+    OpenAI,
+    #[serde(rename = "mistral")]
+    Mistral,
+}
+
+impl Display for LlmProviderType {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            LlmProviderType::OpenAI => write!(f, "openai"),
+            LlmProviderType::Mistral => write!(f, "mistral"),
+        }
+    }
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 //TODO: use enum for model, but if there is a new model, we need to update the code
 pub struct LlmProvider {
     pub name: String,
-    pub provider: String,
+    pub provider_interface: LlmProviderType,
     pub access_key: Option<String>,
     pub model: String,
     pub default: Option<bool>,
     pub stream: Option<bool>,
+    pub endpoint: Option<String>,
+    pub port: Option<u16>,
     pub rate_limits: Option<LlmRatelimit>,
 }