Avoid snappy dependency

[janianttonen]

Avoid snappy dependency

[avaly]

An alternative would be to make snappy an optional dependency of this package, and if it is not available at runtime switch the transport protocol from protobuf to JSON.

[cnoelle]

I think this kind of fallback is problematic, since in Loki the default port used for protobuf is different from the JSON port (9095 vs 3100).

winston-loki/src/batcher.js

Lines 50 to 60 in a554797

	// If snappy binaries have not been built, fallback to JSON transport
	if (!this.options.json) {
	try {
	snappy = this.loadSnappy()
	} catch (error) {
	this.options.json = true
	}
	if (!snappy) {
	this.options.json = true
	}
	}

If protobuf transport is configured and snappy not found you will enter the catch-block here and end up trying to send JSON to the grpc endpoint, which will silently fail. Better fail fast and throw an exception (or don't catch in the first place).

Having snappy as an optional dependency still makes perfectly sense for the case that JSON transport is configured explicitly.

[JaniAnttonen]

True, good suggestion with the optionality.

Since it is a must-have when using protobuf transport, there's no real option when doing that. The protobuf implementation was meant to be a bit of a proof of concept at first, but then it became the default since it got so much love from me.

The JSON part of things needs to be better for sure.