Send Telemetry to Lightstep from WebAssembly in Deno

Overview

Enables the extraction of traces/spans from Wasm modules executing in a Deno environment and emits them to Lightstep.

Installation

Deno will install the package if it detects that you've imported it in your source code. See the example below.

Example

A basic Typescript program that loads a Wasm module and executes it using the native WebAssembly runtime.

import lightstep from "npm:@dylibso/observe-sdk-lightstep";
const {
  LightstepAdapter,
  LightstepConfig,
} = lightstep;

import Context from "https://deno.land/std@0.192.0/wasi/snapshot_preview1.ts";
import { load } from "https://deno.land/std/dotenv/mod.ts";

// setup some confgiruation and create a new instance of the Lightstep adapter
const env = await load();
const apiKey = env["LIGHTSTEP_API_KEY"];

const config: LightstepConfig = {
  apiKey: apiKey,
  serviceName: "deno",
  emitTracesInterval: 1000,
  traceBatchMax: 100,
  host: "https://ingest.lightstep.com",
};

const adapter = new LightstepAdapter(config);

// load up a Wasm module
const bytes = await Deno.readFile("your_module.wasm");

// create an optional filter that instructs the adapter to throw away any
// spans below a configured threshold
const opts = {
  spanFilter: {
    minDurationMicroseconds: 100,
  },
};

// start the adapter with the Wasm module bytes and options
const traceContext = await adapter.start(bytes, opts);

// load, instantiate and run the Wasm module
const module = new WebAssembly.Module(bytes);
const runtime = new Context({
  stdin: Deno.stdin.rid,
  stdout: Deno.stdout.rid,
});
const instance = new WebAssembly.Instance(
  module,
  {
    "wasi_snapshot_preview1": runtime.exports,
    ...traceContext.getImportObject(),
  },
);
runtime.start(instance);

// instruct the adapter to stop the trace
traceContext.stop();

Adapter Configuration

You may modify the behavior of your adapter by passing in a configuration when initializing the adapter. A configuration has the following fields:

const config = {
  // the URL of your OpenTelemetry collector
  host: "https://ingest.lightstep.com",
  // your Lightstep API key
  apiKey: "YOUR_API_KEY_HERE",
  // the dataset to group your observability data under
  dataset: "deno",
  // how often to send new traces
  emitTracesInterval: 1000,
  // the maximum number of traces to send per request
  traceBatchMax: 100,
};
const adapter = new LightstepAdapter(config);