Send Telemetry to Datadog from WebAssembly in Deno

Overview

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

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 datadog from "npm:@dylibso/observe-sdk-datadog";
const { DatadogAdapter } = datadog;

import Context from "https://deno.land/std@0.192.0/wasi/snapshot_preview1.ts";

// create a new instance of the Datadog adapter
// this assumes you have a datadog agent running on localhost, you may also pass a config
const adapter = new DatadogAdapter();

// 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 the Datadog agent
  agentHost: new URL("https://locationofyourdatadogagent.com:8126"),
  // the service name to group your observability data under
  serviceName: "my-wasm-service",
  // default metadata that apply to every trace
  defaultTags: new Map<string, string>(),
  // the type of trace being captured
  traceType: DatadogTraceType.Web,
  // how often to send new traces to the agent
  emitTracesInterval: 1000, 
  // the maximum number of traces to send to the agent per request
  traceBatchMax: 100,
};
const adapter = new DatadogAdapter(config);