feat: observe retained worker sessions without restore

crates/server-api/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "server-api"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+api-macros = { workspace = true, features = ["reqwest", "axum"] }
+runtime-api.workspace = true
+serde = { workspace = true, features = ["derive"] }
+workspace-api.workspace = true
+
+[dev-dependencies]
+serde_json.workspace = true
+tokio = { workspace = true }

crates/server-api/src/lib.rs

@@ -0,0 +1,59 @@
+//! Generated Workspace Server REST contract for public clients.
+
+use api_macros::api;
+pub use api_macros::axum as server_support;
+pub use api_macros::reqwest as client_support;
+pub use api_macros::{ApiContract, HttpMethod};
+use serde::{Deserialize, Serialize};
+use workspace_api::WorkspaceWorkerSubject;
+
+pub type ServerApiError = runtime_api::RuntimeApiError;
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct WorkspaceWorkerSessionResponse {
+    pub subject: WorkspaceWorkerSubject,
+    #[serde(flatten)]
+    pub observation: runtime_api::WorkerSessionAvailability,
+}
+
+#[api(reqwest, axum)]
+pub trait ServerApi {
+    #[get(
+        "/api/w/{workspace_id}/runtimes/{runtime_id}/workers/{worker_id}/session",
+        status = 200,
+        error_status = 400
+    )]
+    async fn worker_session(
+        &self,
+        #[path] workspace_id: String,
+        #[path] runtime_id: String,
+        #[path] worker_id: String,
+    ) -> Result<WorkspaceWorkerSessionResponse, ServerApiError>;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn worker_session_contract_and_flattened_availability_are_stable() {
+        let operations = ServerApiMetadata::OPERATIONS;
+        assert_eq!(operations.len(), 1);
+        assert_eq!(operations[0].method, HttpMethod::Get);
+        assert_eq!(
+            operations[0].path,
+            "/api/w/{workspace_id}/runtimes/{runtime_id}/workers/{worker_id}/session"
+        );
+
+        let response = WorkspaceWorkerSessionResponse {
+            subject: WorkspaceWorkerSubject::RuntimeWorker {
+                runtime_id: "runtime-a".to_string(),
+                worker_id: "worker-a".to_string(),
+            },
+            observation: runtime_api::WorkerSessionAvailability::LiveProtocol,
+        };
+        let value = serde_json::to_value(response).unwrap();
+        assert_eq!(value["availability"], "live_protocol");
+        assert_eq!(value["subject"]["kind"], "runtime_worker");
+    }
+}