feature: add prometheus metrics evaluation example

Signed-off-by: Shardul Srivastava <[email protected]>

functions-runtime/samples/ts/prometheus.ts

@@ -0,0 +1,42 @@
+let text = Deno.env.get("DATA");
+let data;
+if (text != "") {
+  data = JSON.parse(text);
+}
+
+function getPrometheusURL(url: string, metrics: string): string {
+  let dateTime = new Date().toISOString();
+  let hasPort = url.includes(":9090");
+  let hasProtocol = url.includes("http://");
+  let queryURL: string = url;
+  if (!hasPort) {
+    queryURL = queryURL + ":9090";
+  }
+  if (!hasProtocol) {
+    queryURL = "http://" + queryURL;
+  }
+
+  return queryURL + "/api/v1/query?query=" + metrics + "&time=" + dateTime;
+}
+
+let promtheusURL = getPrometheusURL(data.url, data.metrics);
+console.log("Prometheus URL => " + promtheusURL);
+let value;
+try {
+  let jsonResponse = await fetch(promtheusURL);
+  let jsonData = await jsonResponse.json();
+  value = jsonData.data.result[0].value[1];
+  //status = jsonData.status
+} catch (error) {
+  console.error("Could not fetch ");
+  Deno.exit(1);
+}
+
+console.log("Expected Value => " + data.expected_value + ", Value => " + value);
+if (value == data.expected_value) {
+  console.log("Evaluation Successful");
+  Deno.exit(0);
+} else {
+  console.log("Evaluation Failed");
+  Deno.exit(1);
+}