43 api handle semantic failures in requests

edgeless_api/proto/messages.proto

@@ -53,6 +53,16 @@ message SpawnFunctionRequest {
     StateSpecification state_specification = 6;
 }
 
+// Message to request the creation a new function instance.
+message SpawnFunctionResponse {
+    // If present it means that the request has been rejected.
+    // In this case, other fields may not be present or contain meaningful data.
+    optional ResponseError response_error = 1;
+
+    // The identifier of the newly-spawned function instance, if accepted.
+    optional InstanceId instance_id = 2;
+}
+
 // Message to request the update of a function instance.
 message UpdateFunctionLinksRequest {
     // The function instance identifier.
@@ -97,6 +107,16 @@ message SpawnWorkflowRequest {
     map<string, string> workflow_annotations = 4;
 }
 
+// Response to a request to create a new workflow.
+message SpawnWorkflowResponse {
+    // If present it means that the request has been rejected.
+    // In this case, other fields may not be present or contain meaningful data.
+    optional ResponseError response_error = 1;
+
+    // The status of the newly-created workflow, if request accepted.
+    optional WorkflowInstanceStatus workflow_status = 2;
+}
+
 // Function instance mapping.
 message WorkflowFunctionMapping {
     // Name of the function within the workflow.
@@ -176,3 +196,32 @@ message ResourceInstanceSpecification {
     // Map between the callbacks and instances that will be called.
     map<string, InstanceId> output_callback_definitions = 3;
 }
+
+// Response to a request to create a new resource.
+message SpawnResourceResponse {
+    // If present it means that the request has been rejected.
+    // In this case, other fields may not be present or contain meaningful data.
+    optional ResponseError response_error = 1;
+
+    // The status of the newly-created resource, if request accepted.
+    optional InstanceId instance_id = 2;
+}
+
+// Message containing information provided as response to failed request.
+// The fields are inspired from the "problem detail" responses:
+//
+// https://www.rfc-editor.org/rfc/rfc7807.txt
+//
+// Currently all the fields are human-readable, i.e., they are intended to
+// be shown and processed by human operators. Further optional fields might be
+// added in the future that contain binary representations of information
+// intended for machine processing, instead.
+message ResponseError {
+    // A short, human-readable summary of the problem type.
+    // It should not change from occurrence to occurrence of the error.
+    string summary = 1;
+
+    // A human-readable explanation specific to this occurrence of the problem.
+    optional string detail = 2;
+}
+

edgeless_api/proto/services.proto

@@ -9,8 +9,8 @@ package edgeless_api;
 service FunctionInstance {
     // Start a new function instance.
     // Input: request containing the description of the function to create.
-    // Output: the function instance identifier assigned
-    rpc Start (SpawnFunctionRequest) returns (InstanceId);
+    // Output: the function instance identifier assigned, if accepted.
+    rpc Start (SpawnFunctionRequest) returns (SpawnFunctionResponse);
 
     // Stop a running function instance.
     // Input: the identifier of the function instance to tear down.
@@ -28,14 +28,14 @@ service FunctionInstance {
 service WorkflowInstance {
     // Start a new workflow.
     // Input: request containing the description of the workflow to create.
-    // Output: the status of workflow instance newly created.
-    rpc Start (SpawnWorkflowRequest) returns (WorkflowInstanceStatus);
+    // Output: the status of workflow instance newly created, if accepted.
+    rpc Start (SpawnWorkflowRequest) returns (SpawnWorkflowResponse);
 
     // Stop an active workflow.
     // Input: the identifier of the workflow to tear down.
     // Output: none.
-
     rpc Stop (WorkflowId) returns (google.protobuf.Empty);
+
     // List the active workflows or shows the status of a given active workflow.
     // Input: the identifier of the active workflow or a special value indicating all workflows.
     // Output: the list of status of the active workflow instances.
@@ -54,8 +54,8 @@ service FunctionInvocation {
 service ResourceConfiguration {
     // Create a new resource.
     // Input: specification of the resource to be created.
-    // Output: the identifier of the newly created resource.
-    rpc Start (ResourceInstanceSpecification) returns (InstanceId);
+    // Output: the identifier of the newly created resource, if accepted.
+    rpc Start (ResourceInstanceSpecification) returns (SpawnResourceResponse);
 
     // Terminate an existing resource.
     // Input: the identifier of the resource to be terminated.

edgeless_api/src/common/mod.rs

@@ -0,0 +1,5 @@
+#[derive(Clone, Debug)]
+pub struct ResponseError {
+    pub summary: String,
+    pub detail: Option<String>,
+}

edgeless_api/src/function_instance/mod.rs

@@ -1,3 +1,5 @@
+use crate::common::ResponseError;
+
 // TODO(raphaelhetzel) These should be actual types in the future to allow for type-safety.
 pub type NodeId = uuid::Uuid;
 pub type NodeLocalComponentId = uuid::Uuid;
@@ -57,6 +59,21 @@ pub struct SpawnFunctionRequest {
     pub state_specification: StateSpecification,
 }
 
+#[derive(Debug, Clone)]
+pub struct SpawnFunctionResponse {
+    pub response_error: Option<ResponseError>,
+    pub instance_id: Option<InstanceId>,
+}
+
+impl SpawnFunctionResponse {
+    pub fn good(instance_id: crate::function_instance::InstanceId) -> Self {
+        Self {
+            response_error: None,
+            instance_id: Some(instance_id),
+        }
+    }
+}
+
 #[derive(Debug)]
 pub struct UpdateFunctionLinksRequest {
     pub instance_id: Option<InstanceId>,
@@ -65,7 +82,7 @@ pub struct UpdateFunctionLinksRequest {
 
 #[async_trait::async_trait]
 pub trait FunctionInstanceAPI: FunctionInstanceAPIClone + Sync + Send {
-    async fn start(&mut self, spawn_request: SpawnFunctionRequest) -> anyhow::Result<InstanceId>;
+    async fn start(&mut self, spawn_request: SpawnFunctionRequest) -> anyhow::Result<SpawnFunctionResponse>;
     async fn stop(&mut self, id: InstanceId) -> anyhow::Result<()>;
     async fn update_links(&mut self, update: UpdateFunctionLinksRequest) -> anyhow::Result<()>;
 }

edgeless_api/src/grpc_impl/common.rs

@@ -0,0 +1,31 @@
+pub struct CommonConverters {}
+
+impl CommonConverters {
+    pub fn parse_response_error(api_request: &crate::grpc_impl::api::ResponseError) -> anyhow::Result<crate::common::ResponseError> {
+        Ok(crate::common::ResponseError {
+            summary: api_request.summary.to_string(),
+            detail: api_request.detail.clone(),
+        })
+    }
+
+    pub fn parse_instance_id(api_id: &crate::grpc_impl::api::InstanceId) -> anyhow::Result<crate::function_instance::InstanceId> {
+        Ok(crate::function_instance::InstanceId {
+            node_id: uuid::Uuid::parse_str(&api_id.node_id)?,
+            function_id: uuid::Uuid::parse_str(&api_id.function_id)?,
+        })
+    }
+
+    pub fn serialize_response_error(crate_function: &crate::common::ResponseError) -> crate::grpc_impl::api::ResponseError {
+        crate::grpc_impl::api::ResponseError {
+            summary: crate_function.summary.clone(),
+            detail: crate_function.detail.clone(),
+        }
+    }
+
+    pub fn serialize_instance_id(instance_id: &crate::function_instance::InstanceId) -> crate::grpc_impl::api::InstanceId {
+        crate::grpc_impl::api::InstanceId {
+            node_id: instance_id.node_id.to_string(),
+            function_id: instance_id.function_id.to_string(),
+        }
+    }
+}