Allow Customers to set Initial Store State on Project Genesis

[jiqiang90]

Why

Customers want to be able to insert 'genesis data' into their SubQuery project. This could include seed data or constants that they want to reference.

Description

Create some kind of Genesis handler that is always run when a project starts for the first time on a fresh database.

• Create genesis data in Subquery projects.
• Get called before all other handlers
• Only called once , in metadata we could record if it been called once, it should never call again.
• Should have access to all standard store queries

[jamesbayly]

Via #1987

[stwiname]

This can be achieved by having a startBlock equal to the endBlock with this feature

[dlebee]

Are there any exmaples how to deal with genesis state, using this endblock feature.

I assume it means block 1 to block 1? but just wondering.

Thank you

[jamesbayly]

Correct, if you have the following it will index just one block (block 1) for that set of mapping functions (remember you can have multiple of these)

startBlock: 1,
endBlock: 1,

Take a read of this https://academy.subquery.network/indexer/miscellaneous/faq.html#inserting-seed-data-at-project-initiation