Robert Habermeier
8130d8210e
* note that the initializer is responsible for buffering session changes * amend initializer definition to include session change buffering * support buffered changes before `on_initialize` * implement and test session buffering * Update roadmap/implementors-guide/src/runtime/README.md Co-authored-by: Bernhard Schuster <bernhard@ahoi.io> * expand on how this affects misbehavior reports * fix typo Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
2.0 KiB
Initializer Module
This module is responsible for initializing the other modules in a deterministic order. It also has one other purpose as described in the overview of the runtime: accepting and forwarding session change notifications.
Storage
HasInitialized: bool;
// buffered session changes along with the block number at which they should be applied.
//
// typically this will be empty or one element long. ordered ascending by BlockNumber and insertion
// order.
BufferedSessionChanges: Vec<(BlockNumber, ValidatorSet, ValidatorSet)>;
Initialization
Before initializing modules, remove all changes from the BufferedSessionChanges with number less than or equal to the current block number, and apply the last one. The session change is applied to all modules in the same order as initialization.
The other parachains modules are initialized in this order:
- Configuration
- Paras
- Scheduler
- Inclusion
- Validity.
- Router.
The Configuration Module is first, since all other modules need to operate under the same configuration as each other. It would lead to inconsistency if, for example, the scheduler ran first and then the configuration was updated before the Inclusion module.
Set HasInitialized to true.
Session Change
Store the session change information in BufferedSessionChange along with the block number at which it was submitted, plus one. Although the expected operational parameters of the block authorship system should prevent more than one change from being buffered at any time, it may occur. Regardless, we always need to track the block number at which the session change can be applied so as to remain flexible over session change notifications being issued before or after initialization of the current block.
Finalization
Finalization order is less important in this case than initialization order, so we finalize the modules in the reverse order from initialization.
Set HasInitialized to false.