Add logging and metrics

Signed-off-by: Romain Barissat <[email protected]>

package.json

@@ -7,21 +7,29 @@
     "url": "https://github.com/olivr/app-nodejs.git"
   },
   "dependencies": {
+    "@opentelemetry/api": "^1.0.3",
+    "@opentelemetry/instrumentation-dns": "^0.26.0",
+    "@opentelemetry/instrumentation-express": "^0.26.0",
+    "@opentelemetry/instrumentation-http": "^0.26.0",
+    "@opentelemetry/instrumentation-net": "^0.26.0",
+    "@opentelemetry/instrumentation-pino": "^0.26.0",
+    "@opentelemetry/sdk-node": "^0.26.0",
     "express": "^4.17.1",
-    "js-yaml": "^4.1.0"
+    "js-yaml": "^4.1.0",
+    "pino-http": "^5.8.0",
+    "prom-client": "^14.0.0"
   },
   "author": "Romain Barissat",
   "license": "Apache-2.0",
   "devDependencies": {
-    "nodemon": "^2.0.14"
+    "nodemon": "^2.0.14",
+    "pino-pretty": "^7.1.0"
   },
   "scripts": {
     "dev": "yarn dev:local",
-
     "dev:local": "yarn nodemon --inspect src/index.js",
     "dev:docker": "yarn docker:cleanup & yarn docker:build:dev && yarn docker:start:dev",
     "dev:k8s": "yarn k8s:start:dev",
-
     "docker:build:dev": "docker build --target dev --build-arg node_env=development -t my-app .",
     "docker:build:debug": "docker build --target debug -t my-app .",
     "docker:build:prod": "docker build -t my-app .",
@@ -30,7 +38,6 @@
     "docker:start:prod": "docker run -d -p 3001:3000 my-app",
     "docker:cleanup": "docker rm $(docker stop $(docker ps -a -q --filter ancestor=my-app))",
     "docker:logs": "docker logs $(docker ps -q --filter ancestor=my-app) -f",
-
     "k8s:init": "ctlptl create cluster kind --registry=ctlptl-registry",
     "k8s:destroy": "ctlptl delete cluster kind-kind",
     "k8s:start:dev": "tilt up",

src/index.js

@@ -1,20 +1,26 @@
+const { settings } = require("./settings");
 const express = require("express");
-const yaml = require("js-yaml");
-const fs = require("fs");
-const path = require("path");
+const expressMeter = require("./observability/meter");
+const { expressLogger, logger } = require("./observability/logger");
 
 try {
-  const settings = yaml.load(
-    fs.readFileSync(path.join(__dirname, "config/settings.yaml"), "utf8")
-  );
-
   const port = process.env.PORT || settings.general.defaultPort || 3000;
-
   const app = express();
-  app.get("/", (req, res) =>
-    res.send(`Hello ${settings.general.welcomeName}!`)
-  );
-  app.listen(port, () => console.log(`App listening on port ${port}!`));
+
+  app.use(expressLogger);
+  app.use(expressMeter);
+
+  app.get("/", (req, res) => {
+    req.log.info("Visited homepage");
+    req.log.error("Example error");
+    req.log.debug("Example debug");
+    req.log.trace("Example trace");
+    res.send(`Hello ${settings.general.welcomeName}!`);
+  });
+
+  app.listen(port, () => {
+    logger.info(`App listening on port ${port}!`);
+  });
 } catch (e) {
-  console.error(e);
+  logger.error(e);
 }

src/observability/logger.js

@@ -0,0 +1,6 @@
+const expressLogger = require("pino-http")();
+
+const logger = expressLogger.logger;
+logger.level = process.env.LOG_LEVEL || "info";
+
+module.exports = { expressLogger, logger };

src/observability/meter.js

@@ -0,0 +1,18 @@
+const express = require("express");
+const prometheus = require("prom-client");
+
+const register = new prometheus.Registry();
+prometheus.collectDefaultMetrics({ register });
+
+const router = express.Router();
+router.get("/metrics", async (req, res) => {
+  try {
+    res.set("Content-Type", register.contentType);
+    res.end(await register.metrics());
+  } catch (e) {
+    req.log.error(e);
+    res.status(500).end(e);
+  }
+});
+
+module.exports = router;

src/settings.js

@@ -0,0 +1,13 @@
+const fs = require("fs");
+const path = require("path");
+const yaml = require("js-yaml");
+const { logger } = require("./observability/logger");
+
+try {
+  const settings = yaml.load(
+    fs.readFileSync(path.join(__dirname, "config/settings.yaml"), "utf8")
+  );
+  exports.settings = settings;
+} catch (e) {
+  logger.error(e);
+}