host: expose harness state and actions over the world API

host/js/input.ts

@@ -1,20 +1,31 @@
 // Channel submissions target any conversation. EOF and Stop close the harness cleanly.
-export async function serve(harness: any, context: any, afterSubmit?: () => Promise<void>) {
+export async function serve(harness: any, context: any, afterSubmit?: () => Promise<void>, api?: any) {
+  const pending = new Set<Promise<void>>();
+  const track = (work: Promise<void>) => {
+    const task = work.catch(error => Deno.core.ops.op_output(`${String(error)}\n`)).finally(() => pending.delete(task));
+    pending.add(task);
+  };
   while (true) {
     const input = await Deno.core.ops.op_input();
     if (input === null || input.type === 'stop') {
       await harness.waitForIdle(context);
+      await Promise.all(pending);
       return;
     }
+    if (input.type === 'api') {
+      track(api.handle(input));
+      continue;
+    }
     const conversation = await harness.conversation(input.conversation, context);
     if (!conversation) throw new Error(`Unknown conversation: ${input.conversation}`);
     const submission = await conversation.submit({
       type: 'input', content: input.content, requestId: input.requestId,
     }, context);
     if (afterSubmit) {
-      const result = await submission.wait(context);
-      await afterSubmit();
-      if (result.status !== 'done') throw new Error(`Run ended: ${JSON.stringify(result)}`);
+      track(submission.wait(context).then(async (result: any) => {
+        await afterSubmit();
+        if (result.status !== 'done') throw new Error(`Run ended: ${JSON.stringify(result)}`);
+      }));
     }
   }
 }