Extend delete invocation REST endpoint to support different terminati…

…on modes

This commit extends the existing delete invocation REST endpoint to accept an
additional query parameter mode which allows to select between cancel and kill.
The default is cancel.

This fixes #996.

crates/meta/src/rest_api/invocations.rs

@@ -11,28 +11,65 @@
 use super::error::*;
 use super::state::*;
 
-use axum::extract::{Path, State};
+use axum::extract::{Path, Query, State};
+use axum::http::StatusCode;
 use okapi_operation::*;
 use restate_types::identifiers::InvocationId;
 use restate_types::invocation::InvocationTermination;
+use serde::Deserialize;
 use std::sync::Arc;
 
-/// Cancel/kill an invocation
+#[derive(Debug, Default, Deserialize, JsonSchema)]
+pub enum TerminationMode {
+    #[default]
+    #[serde(alias = "cancel")]
+    Cancel,
+    #[serde(alias = "kill")]
+    Kill,
+}
+#[derive(Debug, Default, Deserialize, JsonSchema)]
+pub struct DeleteInvocationParams {
+    pub mode: Option<TerminationMode>,
+}
+
+/// Terminate an invocation
 #[openapi(
-    summary = "Kill an invocation",
-    description = "Kill the given invocation. When killing, consistency is not guaranteed for service instance state, in-flight invocation to other services, etc. Future releases will support graceful invocation cancellation.",
-    operation_id = "cancel_invocation",
+    summary = "Terminate an invocation",
+    description = "Terminate the given invocation. By default, an invocation is terminated by gracefully \
+    cancelling it. This ensures service state consistency. Alternatively, an invocation can be killed which \
+    does not guarantee consistency for service instance state, in-flight invocation to other services, etc.",
+    operation_id = "terminate_invocation",
     tags = "invocation",
-    parameters(path(
-        name = "invocation_id",
-        description = "Invocation identifier.",
-        schema = "std::string::String"
-    ))
+    parameters(
+        path(
+            name = "invocation_id",
+            description = "Invocation identifier.",
+            schema = "std::string::String"
+        ),
+        query(
+            name = "mode",
+            description = "If cancel, it will gracefully terminate the invocation. If kill, it will terminate the invocation with a hard stop.",
+            required = false,
+            style = "simple",
+            allow_empty_value = false,
+            schema = "TerminationMode",
+        )
+    ),
+    responses(
+        ignore_return_type = true,
+        response(
+            status = "202",
+            description = "Accepted",
+            content = "okapi_operation::Empty",
+        ),
+        from_type = "MetaApiError",
+    )
 )]
-pub async fn cancel_invocation<S, W>(
+pub async fn delete_invocation<S, W>(
     State(state): State<Arc<RestEndpointState<S, W>>>,
     Path(invocation_id): Path<String>,
-) -> Result<(), MetaApiError>
+    Query(DeleteInvocationParams { mode }): Query<DeleteInvocationParams>,
+) -> Result<StatusCode, MetaApiError>
 where
     W: restate_worker_api::Handle + Send,
     W::Future: Send,
@@ -41,9 +78,15 @@ where
         .parse::<InvocationId>()
         .map_err(|e| MetaApiError::InvalidField("invocation_id", e.to_string()))?;
 
+    let invocation_termination = match mode.unwrap_or_default() {
+        TerminationMode::Cancel => InvocationTermination::cancel(invocation_id),
+        TerminationMode::Kill => InvocationTermination::kill(invocation_id),
+    };
+
     state
         .worker_handle()
-        .terminate_invocation(InvocationTermination::kill(invocation_id))
+        .terminate_invocation(invocation_termination)
         .await?;
-    Ok(())
+
+    Ok(StatusCode::ACCEPTED)
 }

crates/meta/src/rest_api/mod.rs

@@ -129,7 +129,7 @@ impl MetaRestEndpoint {
             )
             .route(
                 "/invocations/:invocation_id",
-                delete(openapi_handler!(invocations::cancel_invocation)),
+                delete(openapi_handler!(invocations::delete_invocation)),
             )
             .route(
                 "/subscriptions",