adds cache_control

crates/g3-providers/src/lib.rs

@@ -21,6 +21,11 @@ pub trait LLMProvider: Send + Sync {
     fn has_native_tool_calling(&self) -> bool {
         false
     }
+    
+    /// Check if the provider supports cache control
+    fn supports_cache_control(&self) -> bool {
+        false
+    }
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -32,10 +37,22 @@ pub struct CompletionRequest {
     pub tools: Option<Vec<Tool>>,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum CacheControl {
+    Ephemeral,
+    #[serde(rename = "5minute")]
+    FiveMinute,
+    #[serde(rename = "1hour")]
+    OneHour,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct Message {
     pub role: MessageRole,
     pub content: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub cache_control: Option<CacheControl>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -95,6 +112,45 @@ pub use databricks::DatabricksProvider;
 pub use embedded::EmbeddedProvider;
 pub use openai::OpenAIProvider;
 
+impl Message {
+    /// Create a new message with optional cache control
+    pub fn new(role: MessageRole, content: String) -> Self {
+        Self {
+            role,
+            content,
+            cache_control: None,
+        }
+    }
+
+    /// Create a new message with cache control
+    pub fn with_cache_control(role: MessageRole, content: String, cache_control: CacheControl) -> Self {
+        Self {
+            role,
+            content,
+            cache_control: Some(cache_control),
+        }
+    }
+    
+    /// Create a message with cache control, with provider validation
+    pub fn with_cache_control_validated(
+        role: MessageRole, 
+        content: String, 
+        cache_control: CacheControl,
+        provider: &dyn LLMProvider
+    ) -> Self {
+        if !provider.supports_cache_control() {
+            tracing::warn!(
+                "Cache control requested for provider '{}' which does not support it. \
+                Cache control is only supported by Anthropic and Anthropic via Databricks.",
+                provider.name()
+            );
+            return Self::new(role, content);
+        }
+        
+        Self::with_cache_control(role, content, cache_control)
+    }
+}
+
 /// Provider registry for managing multiple LLM providers
 pub struct ProviderRegistry {
     providers: HashMap<String, Box<dyn LLMProvider>>,
@@ -144,3 +200,36 @@ impl Default for ProviderRegistry {
         Self::new()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_message_serialization_without_cache_control() {
+        let msg = Message::new(MessageRole::User, "Hello".to_string());
+        let json = serde_json::to_string(&msg).unwrap();
+        
+        println!("Message JSON without cache_control: {}", json);
+        assert!(!json.contains("cache_control"), 
+                "JSON should not contain 'cache_control' field when not configured");
+    }
+
+    #[test]
+    fn test_message_serialization_with_cache_control() {
+        let msg = Message::with_cache_control(
+            MessageRole::User,
+            "Hello".to_string(),
+            CacheControl::Ephemeral,
+        );
+        let json = serde_json::to_string(&msg).unwrap();
+        
+        println!("Message JSON with cache_control: {}", json);
+        assert!(json.contains("cache_control"), 
+                "JSON should contain 'cache_control' field when configured");
+        assert!(json.contains("ephemeral"), 
+                "JSON should contain 'ephemeral' value");
+        assert!(!json.contains("null"), 
+                "JSON should not contain null values");
+    }
+}