BridgePolkadotParachain¶

Calls¶

set_operating_mode¶

Halt or resume all pallet operations.

May only be called either by root, or by PalletOwner.

Attributes¶

Name	Type
operating_mode	`BasicOperatingMode`

Python¶

call = substrate.compose_call(
    'BridgePolkadotParachain', 'set_operating_mode', {
    'operating_mode': (
        'Normal',
        'Halted',
    ),
}
)

set_owner¶

Change PalletOwner.

May only be called either by root, or by PalletOwner.

Attributes¶

Name	Type
new_owner	`Option<T::AccountId>`

Python¶

call = substrate.compose_call(
    'BridgePolkadotParachain', 'set_owner', {'new_owner': (None, '[u8; 20]')}
)

submit_parachain_heads¶

Submit proof of one or several parachain heads.

The proof is supposed to be proof of some Heads entries from the polkadot-runtime-parachains::paras pallet instance, deployed at the bridged chain. The proof is supposed to be crafted at the relay_header_hash that must already be imported by corresponding GRANDPA pallet at this chain.

Attributes¶

Name	Type
at_relay_block	`(RelayBlockNumber, RelayBlockHash)`
parachains	`Vec<(ParaId, ParaHash)>`
parachain_heads_proof	`ParaHeadsProof`

Python¶

call = substrate.compose_call(
    'BridgePolkadotParachain', 'submit_parachain_heads', {
    'at_relay_block': (
        'u32',
        '[u8; 32]',
    ),
    'parachain_heads_proof': ['Bytes'],
    'parachains': [('u32', '[u8; 32]')],
}
)

Events¶

IncorrectParachainHeadHash¶

The caller has provided parachain head hash that is not matching the hash read from the storage proof.

Attributes¶

Name	Type	Composition
parachain	`ParaId`	`u32`
parachain_head_hash	`ParaHash`	`[u8; 32]`
actual_parachain_head_hash	`ParaHash`	`[u8; 32]`

MissingParachainHead¶

The caller has declared that he has provided given parachain head, but it is missing from the storage proof.

Attributes¶

Name	Type	Composition
parachain	`ParaId`	`u32`

RejectedLargeParachainHead¶

The caller has provided parachain head that exceeds the maximal configured head size.

Attributes¶

Name	Type	Composition
parachain	`ParaId`	`u32`
parachain_head_hash	`ParaHash`	`[u8; 32]`
parachain_head_size	`u32`	`u32`

RejectedObsoleteParachainHead¶

The caller has provided obsolete parachain head, which is already known to the pallet.

Attributes¶

Name	Type	Composition
parachain	`ParaId`	`u32`
parachain_head_hash	`ParaHash`	`[u8; 32]`

UntrackedParachainRejected¶

The caller has provided head of parachain that the pallet is not configured to track.

Attributes¶

Name	Type	Composition
parachain	`ParaId`	`u32`

UpdatedParachainHead¶

Parachain head has been updated.

Attributes¶

Name	Type	Composition
parachain	`ParaId`	`u32`
parachain_head_hash	`ParaHash`	`[u8; 32]`

Storage functions¶

ImportedParaHashes¶

A ring buffer of imported parachain head hashes. Ordered by the insertion time.

Python¶

result = substrate.query(
    'BridgePolkadotParachain', 'ImportedParaHashes', ['u32', 'u32']
)

Return value¶

'[u8; 32]'

ImportedParaHeads¶

Parachain heads which have been imported into the pallet.

Python¶

result = substrate.query(
    'BridgePolkadotParachain', 'ImportedParaHeads', ['u32', '[u8; 32]']
)

Return value¶

'Bytes'

PalletOperatingMode¶

The current operating mode of the pallet.

Depending on the mode either all, or no transactions will be allowed.

Python¶

result = substrate.query(
    'BridgePolkadotParachain', 'PalletOperatingMode', []
)

Return value¶

('Normal', 'Halted')

PalletOwner¶

Optional pallet owner.

Pallet owner has a right to halt all pallet operations and then resume them. If it is None, then there are no direct ways to halt/resume pallet operations, but other runtime methods may still be used to do that (i.e. democracy::referendum to update halt flag directly or call the halt_operations).

Python¶

result = substrate.query(
    'BridgePolkadotParachain', 'PalletOwner', []
)

Return value¶

'[u8; 20]'

ParasInfo¶

Parachains info.

Contains the following info: - best parachain head hash - the head of the ImportedParaHashes ring buffer

Python¶

result = substrate.query(
    'BridgePolkadotParachain', 'ParasInfo', ['u32']
)

Return value¶

{'best_head_hash': {'at_relay_block_number': 'u32', 'head_hash': '[u8; 32]'}, 'next_imported_hash_position': 'u32'}

Constants¶

HeadsToKeep¶

Maximal number of single parachain heads to keep in the storage.

The setting is there to prevent growing the on-chain state indefinitely. Note the setting does not relate to parachain block numbers - we will simply keep as much items in the storage, so it doesn't guarantee any fixed timeframe for heads.

Incautious change of this constant may lead to orphan entries in the runtime storage.

Value¶

Python¶

constant = substrate.get_constant('BridgePolkadotParachain', 'HeadsToKeep')

MaxParaHeadSize¶

Maximal size (in bytes) of the SCALE-encoded parachain head.

Keep in mind that the size of any tracked parachain header must not exceed this value. So if you're going to track multiple parachains, one of which is storing large digests in its headers, you shall choose this maximal value.

There's no mandatory headers in this pallet, so it can't stall if there's some header that exceeds this bound.

Value¶

Python¶

constant = substrate.get_constant('BridgePolkadotParachain', 'MaxParaHeadSize')

ParasPalletName¶

Name of the original paras pallet in the construct_runtime!() call at the bridged chain.

Please keep in mind that this should be the name of the runtime_parachains::paras pallet from polkadot repository, not the pallet-bridge-parachains.

Value¶

'Paras'

Python¶

constant = substrate.get_constant('BridgePolkadotParachain', 'ParasPalletName')

Errors¶

BridgeModule¶

Error generated by the OwnedBridgeModule trait.

FailedToExtractStateRoot¶

Failed to extract state root from given parachain head.

InvalidRelayChainBlockNumber¶

The number of stored relay block is different from what the relayer has provided.

InvalidStorageProof¶

Invalid storage proof has been passed.

StorageRootMismatch¶

The storage proof doesn't contains storage root. So it is invalid for given header.

UnknownParaHead¶

Given parachain head is unknown.

UnknownRelayChainBlock¶

Relay chain block hash is unknown to us.