Updates lambda functions with more robust err handling

server/lambda/server-status.js

@@ -7,13 +7,13 @@ exports.handler = async function(event, context) {
   if (!url) {
     return {
       statusCode: 400,
-      body: JSON.stringify({ message: 'You must provide a URL query parameter!' }),
+      body: JSON.stringify({ error: 'You must provide a URL query parameter!' }),
     };
   }
 
   let dnsLookupTime;
   let responseCode;
-  let startTime = performance.now();
+  let startTime;
 
   const obs = new PerformanceObserver((items) => {
     dnsLookupTime = items.getEntries()[0].duration;
@@ -24,28 +24,46 @@ exports.handler = async function(event, context) {
 
   performance.mark('A');
 
-  return new Promise((resolve) => {
-    https.get(url, (res) => {
-      let data = '';
-      responseCode = res.statusCode;
-      res.on('data', (chunk) => {
-        data += chunk;
-      });
-      res.on('end', () => {
-        performance.mark('B');
-        performance.measure('A to B', 'A', 'B');
-        let responseTime = performance.now() - startTime;
-        obs.disconnect();
-        resolve({
-          statusCode: 200,
-          body: JSON.stringify({ isUp: true, dnsLookupTime, responseTime, responseCode }),
+  try {
+    startTime = performance.now();
+    const response = await new Promise((resolve, reject) => {
+      const req = https.get(url, res => {
+        let data = '';
+        responseCode = res.statusCode;
+        res.on('data', chunk => {
+          data += chunk;
+        });
+        res.on('end', () => {
+          resolve(res);
         });
       });
-    }).on('error', (e) => {
-      resolve({
-        statusCode: 500,
-        body: JSON.stringify({ isUp: false, error: e.message }),
-      });
+
+      req.on('error', reject);
+      req.end();
     });
-  });
+
+    if (responseCode < 200 || responseCode >= 400) {
+      return {
+        statusCode: 200,
+        body: JSON.stringify({ error: `Received non-success response code: ${responseCode}` }),
+      };
+    }
+
+    performance.mark('B');
+    performance.measure('A to B', 'A', 'B');
+    let responseTime = performance.now() - startTime;
+    obs.disconnect();
+
+    return {
+      statusCode: 200,
+      body: JSON.stringify({ isUp: true, dnsLookupTime, responseTime, responseCode }),
+    };
+
+  } catch (error) {
+    obs.disconnect();
+    return {
+      statusCode: 200,
+      body: JSON.stringify({ error: `Error during operation: ${error.message}` }),
+    };
+  }
 };