feat: First draft of flexible http outcalls

docs/references/_attachments/ic.did

@@ -102,11 +102,28 @@ type http_request_resource_report = record {
 
 type flexible_http_request_err = record {
   cause: opt variant {
-    timeout : vec record { principal; http_request_resource_report; };
-    invalid_parameters: reserved;
-    limits_exceeded: vec record { principal; http_request_resource_report; };
-    out_of_cycles : vec record { principal; http_request_resource_report; };
-    responses_too_large : vec record { principal; nat64; };
+    global_err: opt variant {
+      invalid_parameters : reserved;
+      timeout : reserved;
+      out_of_cycles : reserved;
+      responses_too_large : reserved;
+    };
+    local_errs : vec record {
+      node: principal;
+      cause : opt variant {
+        limit_exceeded : opt variant {
+          request_time : reserved;
+          response_bytes : reserved;
+          transform_instructions : reserved;
+          transformed_response_bytes : reserved;
+        };
+        out_of_cycles : reserved;
+      };
+    };
+  };
+  resource_reports: vec record {
+    node: principal;
+    report: http_request_resource_report;
   };
   message: text;
 };

docs/references/ic-interface-spec.md

@@ -3049,17 +3049,24 @@ The response from the remote server must not exceed `2MB`. Moreover, the total s
 
 Cycles to pay for the call must be explicitly transferred with the call, i.e., they are not automatically deducted from the caller's balance implicitly (e.g., as for inter-canister calls). The upfront cycles cost covers a call that maxes out the resource usage during processing, for example, hitting the `2MB` limit on the size of the response. The unused cycles are then refunded to the caller.
 
-The method may return an error of the `flexible_http_request_err` type. The error includes an error message, and may also include a variant describing the error cause:
+The method may return an error of the `flexible_http_request_err` type. The error includes an error message, and may also include a variant describing the error cause. The causes may include:
+- an optional "global" error preventing the successful response from being created:
 
-- `timeout`, meaning that less than `min_responses` from the nodes have been collected before some system-defined timeout. The value is accompanied by a vector of available resource reports at the point when the timeout went off.
+    - `timeout`, meaning that less than `min_responses` from the nodes have been collected before some system-defined timeout. The value is accompanied by a vector of available resource reports at the point when the timeout went off.
 
-- `invalid_parameters`, indicating that the parameters to the call violated one of the conditions.
+    - `invalid_parameters`, indicating that the parameters to the call violated one of the conditions.
 
-- `limits_exceeded`, indicating that less than `min_responses` from the nodes were available, and that the other nodes exceeded some of the system-defined resource limits while the processing of the outcall. The resource reports of the individual nodes are provided (as a pair of node ID and the report).
+    - `out_of_cycles` indicating that the attached cycles were not enough to cover the processing of at least `min_responses`.
 
-- `out_of_cycles` indicating that less than `min_responses` from the nodes were available, and that the provided cycles were not sufficient for some of the other nodes to cover their resources. The resource reports of the individual nodes are provided (as a pair of node ID and the report).
+    - `responses_too_large` : indicating that no combination of at least `min_responses` available responses could fit into the 2MB total limit.
 
-- `responses_too_large` : indicating that no combination of at least `min_responses` available responses could fit into the 2MB total limit. The sizes of available responses at each replica are reported.
+- local errors, where the processing was unsuccessful at some nodes. For each such node, the possible error is reported:
+
+    - `limits_exceeded`, indicating the node exceeded one of the system-defined resource limits while the processing the outcall.
+
+    - `out_of_cycles`, indicating that the this node's portion of the attached cycles was not enough to cover the resources used for processing the outcall.
+
+Additionally, the available reports on resources used by nodes for processing the outcall are provided. A simple textual representation of the error is also returned.
 
 ### IC method `node_metrics_history` {#ic-node_metrics_history}