Refactor server picker and limit ping requests

src/server/serverHealth.js

@@ -0,0 +1,27 @@
+export const SERVER_HEALTH_MAX_COUNT = 30;
+export const SERVER_HEALTH_CONCURRENCY = 4;
+
+export async function checkServerHealth(servers, ping, {
+  maxCount = SERVER_HEALTH_MAX_COUNT,
+  concurrency = SERVER_HEALTH_CONCURRENCY,
+} = {}) {
+  const queue = servers.slice(0, maxCount);
+  const results = new Array(queue.length);
+  let nextIndex = 0;
+
+  async function worker() {
+    while (nextIndex < queue.length) {
+      const index = nextIndex++;
+      const server = queue[index];
+      results[index] = {
+        id: server.id,
+        tag: server.label,
+        ...await ping(server.host, server.port),
+        checkedAt: new Date().toISOString(),
+      };
+    }
+  }
+
+  await Promise.all(Array.from({ length: Math.min(concurrency, queue.length) }, worker));
+  return results;
+}