Warning

**Deprecation Notice**: The Coralogix Bunyan logger package (`coralogix-logger-bunyan`) will be deprecated in favor of the [OpenTelemetry SDK](https://opentelemetry.io/docs/languages/js/) and will no longer be supported after **June 30, 2026**. See the [end-of-life notice](https://coralogix.com/docs/user-guides/latest-updates/deprecations/nodejs-bunyan-sdk/index.md) for migration details.

# Node.js Bunyan

This guide shows how to send [Bunyan](https://github.com/trentm/node-bunyan) logs from a Node.js application to Coralogix using the [OpenTelemetry Node.js SDK](https://opentelemetry.io/docs/languages/js/) with the [Bunyan instrumentation](https://www.npmjs.com/package/@opentelemetry/instrumentation-bunyan), exporting logs over OTLP/gRPC.

## Package dependencies setup

Add the following packages to your project (versions are examples; prefer the latest compatible releases from the JavaScript package registry):

- `@opentelemetry/api`
- `@opentelemetry/sdk-node`
- `@opentelemetry/sdk-logs`
- `@opentelemetry/exporter-logs-otlp-grpc`
- `@opentelemetry/instrumentation-bunyan`
- `@opentelemetry/resources`
- `@opentelemetry/semantic-conventions`
- `bunyan`

Install them with the Node package manager:

```bash
npm install @opentelemetry/api @opentelemetry/sdk-node @opentelemetry/sdk-logs \
  @opentelemetry/exporter-logs-otlp-grpc @opentelemetry/instrumentation-bunyan \
  @opentelemetry/resources @opentelemetry/semantic-conventions bunyan
```

Here is a minimal `package.json` you can use as a starting point:

```json
{
  "name": "nodejs-bunyan-otel-app",
  "version": "1.0.0",
  "main": "index.js",
  "type": "commonjs",
  "scripts": {
    "start": "node index.js"
  },
  "dependencies": {
    "@opentelemetry/api": "^1.9.1",
    "@opentelemetry/exporter-logs-otlp-grpc": "^0.214.0",
    "@opentelemetry/instrumentation-bunyan": "^0.59.0",
    "@opentelemetry/resources": "^2.6.1",
    "@opentelemetry/sdk-logs": "^0.214.0",
    "@opentelemetry/sdk-node": "^0.214.0",
    "@opentelemetry/semantic-conventions": "^1.40.0",
    "bunyan": "^1.8.15"
  }
}
```

Select the https://ingress.\[[DOMAIN_VALUE]\] endpoint that corresponds to your Coralogix [domain](https://coralogix.com/docs/user-guides/account-management/account-settings/coralogix-domain/index.md) using the domain selector at the top of the page.

Pin or update packages to the latest versions when you use this example for testing.

## Application implementation

Start the OpenTelemetry `NodeSDK` with a log record processor and `BunyanInstrumentation` **before** you `require("bunyan")`, so the instrumentation can patch Bunyan. Map Coralogix application and subsystem names on the resource using `cx.application.name` and `cx.subsystem.name`.

The following example sends logs to a local OpenTelemetry Collector on OTLP gRPC port `4317` by default. Override the endpoint with `OTEL_EXPORTER_OTLP_LOGS_ENDPOINT` or `OTEL_EXPORTER_OTLP_ENDPOINT`.

```javascript
"use strict";

const { trace } = require("@opentelemetry/api");
const { NodeSDK } = require("@opentelemetry/sdk-node");
const { BatchLogRecordProcessor } = require("@opentelemetry/sdk-logs");
const { OTLPLogExporter } = require("@opentelemetry/exporter-logs-otlp-grpc");
const { BunyanInstrumentation } = require("@opentelemetry/instrumentation-bunyan");
const { resourceFromAttributes } = require("@opentelemetry/resources");
const { ATTR_SERVICE_NAME } = require("@opentelemetry/semantic-conventions");

const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

const endpoint =
  process.env.OTEL_EXPORTER_OTLP_LOGS_ENDPOINT ||
  process.env.OTEL_EXPORTER_OTLP_ENDPOINT ||
  "http://localhost:4317";

async function main() {
  const sdk = new NodeSDK({
    resource: resourceFromAttributes({
      [ATTR_SERVICE_NAME]: process.env.OTEL_SERVICE_NAME || "bunyan-otel-sample",
      "cx.application.name": process.env.CORALOGIX_APPLICATION || "bunyan-otel-app",
      "cx.subsystem.name": process.env.CORALOGIX_SUBSYSTEM || "worker",
    }),
    logRecordProcessors: [new BatchLogRecordProcessor(new OTLPLogExporter({ url: endpoint }))],
    instrumentations: [new BunyanInstrumentation()],
  });

  await sdk.start();

  // Keep bunyan require after SDK start, so instrumentation patches it.
  const bunyan = require("bunyan");
  const logger = bunyan.createLogger({ name: "bunyan-otel-example" });

  logger.info({ category: "root" }, "hello bunyan with OpenTelemetry");

  const tracer = trace.getTracer("bunyan-otel-example");
  tracer.startActiveSpan("manual-span", (span) => {
    logger.info({ category: "in-span" }, "bunyan log with trace correlation");
    span.end();
  });

  // Give batch processor a moment before shutdown flush.
  await sleep(1500);
  try {
    await sdk.shutdown();
  } catch (err) {
    console.error("Shutdown completed with exporter error:", err.message || err);
  }
  console.log("Done: flush + shutdown completed");
}

main().catch(async (err) => {
  console.error("Application failed:", err);
  process.exit(1);
});
```

**Notes**

- Bunyan and the log exporter batch asynchronously. On process exit, call `sdk.shutdown()` (or equivalent flush) so pending log records are exported.
- If you enable tracing, logs emitted inside an active span are correlated with the current trace context.

### Logging output

With the OpenTelemetry SDK, you can send logs either to a local [OpenTelemetry Collector](https://coralogix.com/docs/opentelemetry/kubernetes-observability/kubernetes-observability-using-opentelemetry/index.md) or directly to Coralogix using an OTLP endpoint.

#### OpenTelemetry Collector

Point `OTEL_EXPORTER_OTLP_ENDPOINT` (or `OTEL_EXPORTER_OTLP_LOGS_ENDPOINT`) at your collector’s OTLP/gRPC address (often port `4317`). You should see application logs arrive at the collector and can forward them to Coralogix from there.

#### Coralogix OpenTelemetry endpoint

Configure the exporter to send to your Coralogix OTLP endpoint and authenticate with your [Send-Your-Data API key](https://coralogix.com/docs/user-guides/account-management/api-keys/send-your-data-api-key/index.md). Set resource attributes for application and subsystem names.

```bash
OTEL_EXPORTER_OTLP_ENDPOINT=https://ingress.[[DOMAIN_VALUE]]:443
OTEL_EXPORTER_OTLP_HEADERS="Authorization=Bearer send_your_data_key"
OTEL_RESOURCE_ATTRIBUTES="service.name=bunyan-otel-sample,cx.application.name=AppName,cx.subsystem.name=SubName"
```

### Additional resources

|                          |                                                                                             |
| ------------------------ | ------------------------------------------------------------------------------------------- |
| OpenTelemetry JavaScript | [OpenTelemetry JS docs](https://opentelemetry.io/docs/languages/js/)                        |
| Coralogix Endpoints      | [Coralogix Endpoints](https://coralogix.com/docs/integrations/coralogix-endpoints/index.md) |

### Support

For help, use in-app chat or email [support@coralogix.com](mailto:support@coralogix.com).