GenesisConfig presets for runtime

[michalkucharczyk]

The runtime now can provide a number of predefined presets of RuntimeGenesisConfig struct. This presets are intended to be used in different deployments, e.g.: local, staging, etc, and should be included into the corresponding chain-specs.

Having GenesisConfig presets in runtime allows to fully decouple node from runtime types (the problem is described in #1984).

Summary of changes:

• The GenesisBuilder API was adjusted to enable this functionality (and provide better naming - Adjust GenesisBuilder naming #150):

   fn preset_names() -> Vec<PresetId>;
   fn get_preset(id: Option<PresetId>) -> Option<serde_json::Value>; //`None` means default
   fn build_state(value: serde_json::Value);
   pub struct PresetId(Vec<u8>);

• Breaking change: Old create_default_config method was removed, build_config was renamed to build_state. As a consequence a node won't be able to interact with genesis config for older runtimes. The cleanup was made for sake of API simplicity. Also IMO maintaining compatibility with old API is not so crucial.

• Reference implementation was provided for substrate-test-runtime and rococo runtimes. For rococo new genesis_configs_presets module was added and is used in GenesisBuilder presets-related methods.

• The chain-spec-builder util was also improved and allows to (doc):

  • list presets provided by given runtime (list-presets),
  • display preset or default config provided by the runtime (display-preset),
  • build chain-spec using named preset (create ... named-preset),

• The ChainSpecBuilder is extended with with_genesis_config_preset_name method which allows to build chain-spec using named preset provided by the runtime. Sample usage on the node side here.

Implementation of #1984.
fixes: #150
part of: #25

[michalkucharczyk]

This requires #2044.

Allows some nice functionality:

• list GenesisConfig presets provided by runtime:

  ./chain-spec-builder list-presets -r substrate_test_runtime.wasm
  Known presets are:
  [
      "foobar",
      "staging",
  ]
  

• display the GenesisConfig preset with given name:

  ./chain-spec-builder display-preset -r substrate_test_runtime.wasm -p "staging"
  {"balances":{"balances":[["5FHneW46xGXgs5mUiveU4sbTyGBzmstUspZC92UhjJM694ty",1000000000000000],["5FLSigC9HGRKVhB9FiEo4Y3koPsNmBmLJbpXg2mp1hXcS59Y",1000000000000000]]},"substrateTest":{"authorities":["5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY","5CiPPseXPECbkjWCa6MnjNokrgYjMqmKndv2rSnekmSK2DjL"]}}
  

  please note: it may contain only the keys that should be overwritten in default runtime GenesisConfig.
• and finally, build the chain-spec using the named GenesisConfig preset:

  ./chain-spec-builder create -r substrate_test_runtime.wasm named-preset staging
  

[michalkucharczyk]

@bkchr I'd appreciate feedback on naming. config is not advised (see #150), so maybe preset will do the job?

I am also not sure if we need to keep create_default_config method. Maybe we can remove it?

[ggwpez]

I am also not sure if we need to keep create_default_config method. Maybe we can remove it?

I am currently using that in the new chain-agnostic runtime benchmarker (#3512), how would i know what preset is the default?
RuntimeGenesisConfig does implement Default after all.

[michalkucharczyk]

get_preset(None) would return default (equivalent of create_default_config)

[michalkucharczyk]

Did some cleanup here.

I dropped old API and introduced new functions as I assume the node will not support old runtimes when it comes to spec generating.

[Polkadot-Forum]

This pull request has been mentioned on Polkadot Forum. There might be relevant details there:

https://forum.polkadot.network/t/stabilizing-polkadot/7175/24