Image Render: Support Tracing

default.json

@@ -20,6 +20,10 @@
       }
     },
 
+    "tracing": {
+      "enabled": false
+    },
+
     "security": {
       "authToken": "-"
     }

dev.json

@@ -15,6 +15,10 @@
         "json": false,
         "colorize": true
       }
+    },
+
+    "tracing": {
+      "enabled": true
     }
   },
   "rendering": {

devenv/docker/custom-config/config.json

@@ -15,6 +15,10 @@
         "json": true,
         "colorize": false
       }
+    },
+
+    "tracing": {
+      "enabled": false
     }
   },
   "rendering": {

package.json

@@ -28,6 +28,12 @@
     "@grpc/grpc-js": "^1.8.22",
     "@grpc/proto-loader": "^0.7.2",
     "@hapi/boom": "^10.0.0",
+    "@opentelemetry/api": "^1.9.0",
+    "@opentelemetry/auto-instrumentations-node": "^0.49.0",
+    "@opentelemetry/exporter-trace-otlp-http": "^0.52.1",
+    "@opentelemetry/resources": "^1.25.1",
+    "@opentelemetry/sdk-node": "^0.52.1",
+    "@opentelemetry/semantic-conventions": "^1.25.1",
     "@puppeteer/browsers": "^2.3.1",
     "chokidar": "^3.5.2",
     "dompurify": "^2.5.4",
@@ -54,7 +60,7 @@
     "@types/jest": "^29.5.12",
     "@types/jsdom": "20.0.0",
     "@types/multer": "1.4.7",
-    "@types/node": "^18.7.18",
+    "@types/node": "^22.1.0",
     "@types/pixelmatch": "^5.2.6",
     "@types/supertest": "^2.0.15",
     "@typescript-eslint/eslint-plugin": "5.37.0",

src/app.ts

@@ -1,3 +1,4 @@
+import { startTracing } from './tracing';
 import * as path from 'path';
 import * as _ from 'lodash';
 import * as fs from 'fs';
@@ -65,6 +66,10 @@ async function main() {
 
     const logger = new ConsoleLogger(config.service.logging);
 
+    if (config.service.tracing.enabled) {
+      startTracing(logger);
+    }
+
     const sanitizer = createSanitizer();
     const server = new HttpServer(config, logger, sanitizer);
     await server.start();

src/logger.ts

@@ -1,5 +1,6 @@
 import * as winston from 'winston';
 import { LoggingConfig } from './service/config';
+import {context, trace} from "@opentelemetry/api";
 
 export interface LogWriter {
   write(message, encoding);
@@ -45,6 +46,8 @@ export class ConsoleLogger implements Logger {
       transports.push(new winston.transports.Console(options));
     }
 
+//@opentelemetry/instrumentation-winston auto inject trace-context into Winston log records 
+
     this.logger = winston.createLogger({
       level: config.level,
       exitOnError: false,

src/service/config.ts

@@ -7,6 +7,10 @@ export interface MetricsConfig {
   requestDurationBuckets: number[];
 }
 
+export interface TracesConfig {
+  enabled: boolean;
+}
+
 export interface ConsoleLoggerConfig {
   level?: string;
   json: boolean;
@@ -29,6 +33,7 @@ export interface ServiceConfig {
     metrics: MetricsConfig;
     logging: LoggingConfig;
     security: SecurityConfig;
+    tracing: TracesConfig;
   };
   rendering: RenderingConfig;
 }
@@ -50,6 +55,9 @@ export const defaultServiceConfig: ServiceConfig = {
         colorize: false,
       },
     },
+    tracing: {
+      enabled: false,
+    },
     security: {
       authToken: '-',
     },

src/service/http-server.integration.test.ts

@@ -47,6 +47,9 @@ const serviceConfig: ServiceConfig = {
         colorize: false,
       },
     },
+    tracing: {
+      enabled: true,
+    },
     security: {
       authToken: '-',
     },

src/tracing.ts

@@ -0,0 +1,41 @@
+import {NodeSDK} from '@opentelemetry/sdk-node';
+import {getNodeAutoInstrumentations} from '@opentelemetry/auto-instrumentations-node';
+import {OTLPTraceExporter} from '@opentelemetry/exporter-trace-otlp-http';
+import {SEMRESATTRS_SERVICE_NAME} from '@opentelemetry/semantic-conventions';
+import {Resource} from '@opentelemetry/resources';
+import {Logger} from "./logger";
+
+// For troubleshooting, set the log level to DiagLogLevel.DEBUG
+// const { diag, DiagConsoleLogger, DiagLogLevel } = require('@opentelemetry/api');
+// diag.setLogger(new DiagConsoleLogger(), DiagLogLevel.DEBUG);
+
+const traceExporter = new OTLPTraceExporter({
+    url: process.env['OTEL_EXPORTER_OTLP_TRACES_ENDPOINT'],
+});
+
+const sdk = new NodeSDK({
+    resource: new Resource({
+        [SEMRESATTRS_SERVICE_NAME]: 'image-renderer-service',
+    }),
+    traceExporter,
+    instrumentations: [
+        getNodeAutoInstrumentations({
+        // only instrument fs if it is part of another trace
+        '@opentelemetry/instrumentation-fs': {
+          requireParentSpan: true,
+        },
+      })
+    ],
+});
+
+export  function startTracing(log: Logger) {
+    sdk.start();
+    log.info('Starting tracing');
+
+    process.on('SIGTERM', () => {
+        sdk.shutdown()
+            .then(() => log.debug('Tracing terminated'))
+            .catch((error) => log.error('Error terminating tracing', error))
+            .finally(() => process.exit(0));
+    });
+}