feat: Workflow logger improvements

[bergundy]

• Lazily initialize the default sinks logger
• Export log from workflow - a logger that funnels messages to the default worker logger sink.

Example:

import * as workflow from '@temporalio/workflow';

export async function myWorkflow(): Promise<void> {
  workflow.log.info('hello from my workflow', { key: 'value' });
}

[mjameswh]

I'm thinking that maybe we should clone arguments (ie. JSON.parse(JSON.stringify(args))) on Workflow side (before they get captured by the sink plumbing). I got bitten once because an object that was being passed to a sink was being modified afterward (but in the same WFT), so the sink would receive the object in its modified state rather than the object in the state it was at the moment the sink was called in code...

[mjameswh]

For similar reason, wondering if we should maybe capture the real time at the moment log was called...

[mjameswh]

For now, I suggest we simply mark this as experimental. Let's get this in as is, and we'll see later if either of my previous concern turns out to be justified.

[bergundy]

I wouldn't want to impose JSON serializability here, postMessage accepts a wider variety of types.

[Sushisource]

Why not just use this which is mentioned in the linked docs? https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm

I think the point James makes seems pretty important

[bergundy]

I agree that the point is important, I’ll look into it

[bergundy]

All good points @mjameswh , thanks

[lorensr]

Suggested change

	* The messages emitted by this logger are funnelled to the worker's `defaultSinks`, which are installed by default.
	* The messages emitted by this logger are funnelled to the worker's {@link defaultSinks}, which are installed by default.

[bergundy]

I'll try that and see if it gets linked properly, defaultSinks is in a different package.

[lorensr]

Suggested change

	* `defaultSinks` accepts a user logger and defaults to the `Runtime`'s logger.
	* `defaultSinks` accepts a user logger and defaults to the {@link RuntimeOptions.logger | `Runtime`'s logger}.

[lorensr]

Suggested change

	*
	* See the documentation for `WorkerOptions`, `defaultSinks`, and `Runtime` for more information.

prefer linking above, when the terms are used. didn't see a place for {@link WorkerOptions.sinks}

[mjameswh]

I know this is not new, but any reason why getting nano time through core was preferred over process.hrtime?

[bergundy]

We need to compare timestamps of logs emitted by Core and Lang when buffering Core logs so they can be emitted in order.

[bergundy]

From the hrtime docs:

These times are relative to an arbitrary time in the past, and not related to the time of day and therefore not subject to clock drift. The primary use is for measuring performance between intervals:

We need time of day in nanosecond resolution.

[bergundy]

I'm merging this and opening a new PR to call structuredClone on every sink call.