add ability to specify custom http headers in api endpoint

arch/arch_config_schema.yaml

@@ -131,6 +131,10 @@ properties:
               enum:
                 - GET
                 - POST
+            http_headers:
+              type: object
+              additionalProperties:
+                type: string
           additionalProperties: false
           required:
             - name

crates/common/src/configuration.rs

@@ -242,6 +242,7 @@ pub struct EndpointDetails {
     pub path: Option<String>,
     #[serde(rename = "http_method")]
     pub method: Option<HttpMethod>,
+    pub http_headers: Option<HashMap<String, String>>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]

crates/prompt_gateway/src/stream_context.rs

@@ -317,27 +317,35 @@ impl StreamContext {
         };
 
         let http_method = endpoint.method.unwrap_or_default().to_string();
-        let mut headers = vec![
+        let mut headers: HashMap<_, _> = [
             (ARCH_UPSTREAM_HOST_HEADER, endpoint.name.as_str()),
             (":method", &http_method),
             (":path", &path),
             (":authority", endpoint.name.as_str()),
             ("content-type", "application/json"),
             ("x-envoy-max-retries", "3"),
-        ];
+        ]
+        .into_iter()
+        .collect();
 
         if self.request_id.is_some() {
-            headers.push((REQUEST_ID_HEADER, self.request_id.as_ref().unwrap()));
+            headers.insert(REQUEST_ID_HEADER, self.request_id.as_ref().unwrap());
         }
 
         if self.traceparent.is_some() {
-            headers.push((TRACE_PARENT_HEADER, self.traceparent.as_ref().unwrap()));
+            headers.insert(TRACE_PARENT_HEADER, self.traceparent.as_ref().unwrap());
+        }
+
+        // override http headers that are set in the prompt target
+        let http_headers = endpoint.http_headers.unwrap_or_default();
+        for (key, value) in http_headers.iter() {
+            headers.insert(key.as_str(), value.as_str());
         }
 
         let call_args = CallArgs::new(
             ARCH_INTERNAL_CLUSTER_NAME,
             &path,
-            headers,
+            headers.into_iter().collect(),
             Some(tool_params_json_str.as_bytes()),
             vec![],
             Duration::from_secs(5),

demos/currency_exchange/arch_config.yaml

@@ -8,7 +8,7 @@ listener:
 
 llm_providers:
   - name: gpt-4o
-    access_key: $OPENAI_API_KEY
+    access_key: $OPENAI_API_KEY1
     provider_interface: openai
     model: gpt-4o
 
@@ -33,6 +33,8 @@ prompt_targets:
     endpoint:
       name: frankfurther_api
       path: /v1/latest?base=USD&symbols={currency_symbol}
+      http_headers:
+        Authorization: "Bearer $FRANKFURT_API_KEY"
     system_prompt: |
       You are a helpful assistant. Show me the currency symbol you want to convert from USD.
 
@@ -41,11 +43,12 @@ prompt_targets:
     endpoint:
       name: frankfurther_api
       path: /v1/currencies
+      http_headers:
+        Authorization: "Bearer $FRANKFURT_API_KEY"
 
 endpoints:
   frankfurther_api:
-    endpoint: api.frankfurter.dev:443
-    protocol: https
+    endpoint: host.docker.internal:1122
 
 tracing:
   random_sampling: 100