Run prometheus-exporter as a module #671

sandbox/run.sh

@@ -7,8 +7,4 @@ if [[ "$GRIST_SANDBOX_FLAVOR" = "gvisor" ]]; then
   source ./sandbox/gvisor/get_checkpoint_path.sh
 fi
 
-if [[ -n "$GRIST_PROMCLIENT_PORT" ]]; then
-  require_promclient="--require ./_build/stubs/app/server/prometheus-exporter.js"
-fi
-
 NODE_PATH=_build:_build/stubs:_build/ext node ${require_promclient} _build/stubs/app/server/server.js

sandbox/watch.sh

@@ -15,12 +15,6 @@ if [ ! -e _build ]; then
   buildtools/build.sh
 fi
 
-if [ -n "$GRIST_PROMCLIENT_PORT" ]; then
-  require_promclient="--require ./_build/stubs/app/server/prometheus-exporter.js"
-fi
-
-ls _build/stubs/app/server
-
 tsc --build -w --preserveWatchOutput $PROJECT &
 catw app/client/*.css app/client/*/*.css -o static/bundle.css -v & webpack --config $WEBPACK_CONFIG --mode development --watch &
 NODE_PATH=_build:_build/stubs:_build/ext nodemon ${NODE_INSPECT:+--inspect} --delay 1 -w _build/app/server -w _build/app/common ${require_promclient} _build/stubs/app/server/server.js &

stubs/app/server/prometheus-exporter.ts

@@ -1,24 +1,25 @@
 import { collectDefaultMetrics, register } from 'prom-client';
 import http from 'http';
 
-collectDefaultMetrics();
-
-const server = http.createServer((req: http.IncomingMessage, res: http.ServerResponse) => {
+const reqListener = (req: http.IncomingMessage, res: http.ServerResponse) => {
   register.metrics().then((metrics) => {
     res.writeHead(200, { 'Content-Type': register.contentType });
     res.end(metrics);
   }).catch((e) => {
     res.writeHead(500);
     res.end(e.message);
   });
-});
+};
 
-const port = parseInt(process.env.GRIST_PROMCLIENT_PORT!, 10);
-if (isNaN(port)) {
-  throw new Error(`Invalid port: ${process.env.GRIST_PROMCLIENT_PORT}`);
-}
-server.listen(port, '0.0.0.0');
+export function runPrometheusExporter(port: number) {
+  collectDefaultMetrics();
 
-console.log("---------------------------------------------");
-console.log(`Prometheus exporter listening on port ${port}`);
-console.log("---------------------------------------------");
+  if (isNaN(port)) {
+    throw new Error(`Invalid port: ${process.env.GRIST_PROMCLIENT_PORT}`);
+  }
+  const server = http.createServer(reqListener);
+  server.listen(port, '0.0.0.0');
+
+  console.log(`Prometheus exporter listening on port ${port}.`);
+  return server;
+}

stubs/app/server/server.ts

@@ -36,6 +36,7 @@ setDefaultEnv('GRIST_WIDGET_LIST_URL', commonUrls.gristLabsWidgetRepository);
 import {updateDb} from 'app/server/lib/dbUtils';
 import {main as mergedServerMain, parseServerTypes} from 'app/server/mergedServerMain';
 import * as fse from 'fs-extra';
+import {runPrometheusExporter} from './prometheus-exporter';
 
 const G = {
   port: parseInt(process.env.PORT!, 10) || 8484,
@@ -102,6 +103,10 @@ export async function main() {
     console.log('For full logs, re-run with DEBUG=1');
   }
 
+  if (process.env.GRIST_PROMCLIENT_PORT) {
+    runPrometheusExporter(parseInt(process.env.GRIST_PROMCLIENT_PORT, 10));
+  }
+
   // If SAML is not configured, there's no login system, so provide a default email address.
   setDefaultEnv('GRIST_DEFAULT_EMAIL', '[email protected]');
   // Set directory for uploaded documents.