Improve EngineBuilder error message

[goblinfactory]

Improve the StorageProvider error message so that when a user only references Memstate and follows the getting started guide that the error message will help the user fall into the pit of success i.e. tells the user what to do to resolve the error.

Currently if you only reference memstate and don't include a serializer package, you will get this error after calling Engine.Build ..

It would be much more helpful if the error message, in addition to the current message could include a message saying something like

It looks like you may be missing one of the default serializers. You may need to add a reference to Memstate.Wire, Memstate.JsonNet, Memstate.Postgres or Memstate.Eventstor, or implement your own serializer and include that. For more help see [link to docs]

The full list can be automatically generated by the StorageProviders class.

[rofr]

Good call. I think BinarySerializer is back in some netstandard version, also the new System.Json
If we choose one of these as defaults, then we eliminate this problem altogether. Of course, we need to implement them in the core Memstate nuget. What do you think?

[goblinfactory]

sounds great, worth a spike branch to test?

[rofr]

As long as we are on netstandard <=2.1 an external library is necessary for System.Text.Json
https://docs.microsoft.com/en-us/dotnet/standard/serialization/system-text-json-overview

I'm reluctant to adding it, any other opinions?

[goblinfactory]

I've not dived deep into system.text.json vs newtonsoft.json.
At a quick glance Newtonsoft on .netstandard 2.0 appears to have no dependancies? Compared to a lot more with System.Text.Json.
I'd be leaning towards Newtonsoft.Json, for now, just because memstate user base (well, everyone) is more familiar with Newtonsoft, and later we can upgrade to System.Text.Json if there's a need to?

both require an external package, though most folk see Newtonsoft.Json as really simply saying you have a dependency on doing Json things :D like floats or decimals.

[goblinfactory]

we should err on what will be easier for us to support moving forward and should be able to swap it out later if needed. If we start working aggresively on improving memstate then we should not be afraid to bring up new major versions as and when it makes sense. i.e. this decision is just a temporary one.

[goblinfactory]

Also, I think it's easily a reversible decision?

[rofr]

BinaryFormatter is netstandard 2.0 so we could use that as default without introducing dependencies.

The downside is it needs the Serializable attribute on all types.

Should we make it default or move the Newtonsoft.Json implementation into the core lib and make that the default?

[rofr]

Definitely Newtonsoft over System.Text.Json given all those dependencies. Yikes!

[goblinfactory]

Ah, just had a thought, ...snap, you just ruined my idea, saying it needs the Serializable atttribute on all types... shudder, and .. yuk.

I was going to say, if we include BinaryFormatter out of the box by default, we can always have a 3 lines "how to" guide that we can take a new user through the process of configuring memstate to use a Json Serializer, as part of the getting started.

[goblinfactory]

busy reading : https://stackoverflow.com/questions/39264293/binary-serialization-without-serializable-attribute

[goblinfactory]

Why don't we make wire default? Nice and performant, and allows users to follow the getting started to optionally bring in either JsonNet or System.Text.Json depending on their preferences, and both are ridiculously easy. boom... no [Serializable]'s? Not too familiar with wire. And Include BinaryFormatter in the "next steps", then have a link to "advanced" which takes you to postgres and AzureTable Storage. I need AzureTable storage for myself, then plan has been to write one for a long time. ...life!

[rofr]

Hadn't considered that option actually, but why not.. Wire is by @rogeralsing (akka.net and protoactor wizard) so pretty solid but guessing it's not actively maintained. Only a single dependency and uncommon so not likely to cause conflict with users other deps. A human-readable format would be nice though...

[goblinfactory]

protobuf rulez!

[goblinfactory]

The "human readable" is the "reward" you get for sticking with the getting started guide and writing another 3 lines of code :D
it's all totally up to you (the dev) what you use.

[goblinfactory]

also, cof cof... won't hurt that the default out of the box is just a little quick, and compact. In case folk evaluate tools by looking at the default setup.