OpenTelemetry epic

[lucacasonato]

• Land initial support for user created traces + exporting with OTLP
• Land initial support for exporting console.log with OTLP (with associated traces)
• Land initial support for user created metrics + exporting with OTLP
• Configure trace sampling through OTEL_TRACES_SAMPLER
• Respect OTEL_SDK_DISABLED
• Respect OTEL_PROPAGATORS
• Ensure telemetry is flushed in all cases:
  • console.log("foo"); // Program naturally exits here
  • console.log("foo"); Deno.exit(0);
  • console.log("foo"); throw new Error("uncaught");
    • Ensure that "uncaught" is also collected by logging
  • Web worker logs something and immediate calls self.close()
  • Web worker logs something and calls Deno.exit() (self.close() alias in workers?)
  • Web worker logs something and the main worker immediately calls worker.terminate()
  • Web worker logs something and throws an exception.

Then there is a bunch of work to auto instrument built in APIs. A very basic initial list that will be expanded:

• Deno.serve / node:http (server)
  • Create traces for incoming requests
    • Ensure that users can set http.route attribute on the automatic span
  • Propagation of trace ID from incoming headers
  • Metrics for latency
• fetch / node:http (client)
  • Create traces for outbound requests
  • Propagation of trace ID into outgoing headers
  • Metrics for latency
  • Metrics for connection pool