Feature: true ping, rename old ping to siteMonitor (#2215)

src/pages/api/siteMonitor.js

@@ -0,0 +1,52 @@
+import { performance } from "perf_hooks";
+
+import { getServiceItem } from "utils/config/service-helpers";
+import createLogger from "utils/logger";
+import { httpProxy } from "utils/proxy/http";
+
+const logger = createLogger("siteMonitor");
+
+export default async function handler(req, res) {
+  const { group, service } = req.query;
+  const serviceItem = await getServiceItem(group, service);
+  if (!serviceItem) {
+    logger.debug(`No service item found for group ${group} named ${service}`);
+    return res.status(400).send({
+      error: "Unable to find service, see log for details.",
+    });
+  }
+
+  const { siteMonitor: monitorURL } = serviceItem;
+
+  if (!monitorURL) {
+    logger.debug("No http monitor URL specified");
+    return res.status(400).send({
+      error: "No http monitor URL given",
+    });
+  }
+
+  try {
+    let startTime = performance.now();
+    let [status] = await httpProxy(monitorURL, {
+      method: "HEAD",
+    });
+    let endTime = performance.now();
+
+    if (status > 403) {
+      // try one more time as a GET in case HEAD is rejected for whatever reason
+      startTime = performance.now();
+      [status] = await httpProxy(monitorURL);
+      endTime = performance.now();
+    }
+
+    return res.status(200).json({
+      status,
+      latency: endTime - startTime,
+    });
+  } catch (e) {
+    logger.debug("Error attempting http monitor: %s", e);
+    return res.status(400).send({
+      error: "Error attempting http monitor, see logs.",
+    });
+  }
+}