ChainBridge

---

Calls

---

acknowledge_proposal

Commits a vote in favour of the provided proposal.

If a proposal with the given nonce and source chain ID does not already exist, it will be created with an initial vote in favour from the caller.

# <weight> - weight of proposed call, regardless of whether execution is performed # </weight>

Attributes

Name	Type
nonce	DepositNonce
src_id	ChainId
r_id	ResourceId
call	Box<<T as Config>::Proposal>

Python

call = substrate.compose_call(
    'ChainBridge', 'acknowledge_proposal', {
    'call': 'Call',
    'nonce': 'u64',
    'r_id': '[u8; 32]',
    'src_id': 'u8',
}
)

---

add_relayer

Adds a new relayer to the relayer set.

# <weight> - O(1) lookup and insert # </weight>

Attributes

Name	Type
v	T::AccountId

Python

call = substrate.compose_call(
    'ChainBridge', 'add_relayer', {'v': 'AccountId'}
)

---

eval_vote_state

Evaluate the state of a proposal given the current vote threshold.

A proposal with enough votes will be either executed or cancelled, and the status will be updated accordingly.

# <weight> - weight of proposed call, regardless of whether execution is performed # </weight>

Attributes

Name	Type
nonce	DepositNonce
src_id	ChainId
prop	Box<<T as Config>::Proposal>

Python

call = substrate.compose_call(
    'ChainBridge', 'eval_vote_state', {
    'nonce': 'u64',
    'prop': 'Call',
    'src_id': 'u8',
}
)

---

redistribute_fees

Redistributes accumulated fees between relayers.

Attributes

No attributes

Python

call = substrate.compose_call(
    'ChainBridge', 'redistribute_fees', {}
)

---

reject_proposal

Commits a vote against a provided proposal.

# <weight> - Fixed, since execution of proposal should not be included # </weight>

Attributes

Name	Type
nonce	DepositNonce
src_id	ChainId
r_id	ResourceId
call	Box<<T as Config>::Proposal>

Python

call = substrate.compose_call(
    'ChainBridge', 'reject_proposal', {
    'call': 'Call',
    'nonce': 'u64',
    'r_id': '[u8; 32]',
    'src_id': 'u8',
}
)

---

remove_relayer

Removes an existing relayer from the set.

# <weight> - O(1) lookup and removal # </weight>

Attributes

Name	Type
v	T::AccountId

Python

call = substrate.compose_call(
    'ChainBridge', 'remove_relayer', {'v': 'AccountId'}
)

---

remove_resource

Removes a resource ID from the resource mapping.

After this call, bridge transfers with the associated resource ID will be rejected.

# <weight> - O(1) removal # </weight>

Attributes

Name	Type
id	ResourceId

Python

call = substrate.compose_call(
    'ChainBridge', 'remove_resource', {'id': '[u8; 32]'}
)

---

set_fee

Sets fee for chain id.

After that the transfers will get the fee from runtime storage. # <weight> - O(1) write # </weight>

Attributes

Name	Type
chain_id	ChainId
fee	T::Balance

Python

call = substrate.compose_call(
    'ChainBridge', 'set_fee', {'chain_id': 'u8', 'fee': 'u128'}
)

---

set_min_nonce

Sets minimal deposit nonce for chain id

# <weight> - O(1) lookup and insert # </weight>

Attributes

Name	Type
chain_id	ChainId
min_nonce	DepositNonce

Python

call = substrate.compose_call(
    'ChainBridge', 'set_min_nonce', {'chain_id': 'u8', 'min_nonce': 'u64'}
)

---

set_proposal_lifetime

Sets proposal lifetime.

This lifetime is used for determine how many blocks have relays to votes for deposit. # <weight> - O(1) write # </weight>

Attributes

Name	Type
lifetime	T::BlockNumber

Python

call = substrate.compose_call(
    'ChainBridge', 'set_proposal_lifetime', {'lifetime': 'u32'}
)

---

set_resource

Stores a method name on chain under an associated resource ID.

# <weight> - O(1) write # </weight>

Attributes

Name	Type
id	ResourceId
method	Vec<u8>

Python

call = substrate.compose_call(
    'ChainBridge', 'set_resource', {'id': '[u8; 32]', 'method': 'Bytes'}
)

---

set_threshold

Sets the vote threshold for proposals.

This threshold is used to determine how many votes are required before a proposal is executed.

# <weight> - O(1) lookup and insert # </weight>

Attributes

Name	Type
threshold	u32

Python

call = substrate.compose_call(
    'ChainBridge', 'set_threshold', {'threshold': 'u32'}
)

---

toggle_chain

Sets transfers allowability.

This param is used for determine transfers possibility for chain. # <weight> - O(1) write # </weight>

Attributes

Name	Type
chain_id	ChainId
enabled	bool

Python

call = substrate.compose_call(
    'ChainBridge', 'toggle_chain', {'chain_id': 'u8', 'enabled': 'bool'}
)

---

whitelist_chain

Enables a chain ID as a source or destination for a bridge transfer.

# <weight> - O(1) lookup and insert # </weight>

Attributes

Name	Type
id	ChainId
fee	T::Balance

Python

call = substrate.compose_call(
    'ChainBridge', 'whitelist_chain', {'fee': 'u128', 'id': 'u8'}
)

---

Events

---

ChainToggled

Allowability transfers for the chain has changed. [chain_id, enabled]

Attributes

Name	Type	Composition
None	ChainId	u8
None	bool	bool

---

ChainWhitelisted

Chain now available for transfers. [chain_id]

Attributes

Name	Type	Composition
None	ChainId	u8

---

FeeChanged

Fee for chain has changed. [chain_id, fee]

Attributes

Name	Type	Composition
None	ChainId	u8
None	T::Balance	u128

---

FungibleTransfer

FunglibleTransfer is for relaying fungibles. [dest_id, nonce, resource_id, amount, recipient]

Attributes

Name	Type	Composition
None	ChainId	u8
None	DepositNonce	u64
None	ResourceId	[u8; 32]
None	U256	scale_info::72
None	Vec<u8>	Bytes

---

GenericTransfer

GenericTransfer is for a generic data payload. [dest_id, nonce, resource_id, metadata]

Attributes

Name	Type	Composition
None	ChainId	u8
None	DepositNonce	u64
None	ResourceId	[u8; 32]
None	Vec<u8>	Bytes

---

NonFungibleTransfer

NonFungibleTransfer is for relaying NFTS. [dest_id, nonce, resource_id, token_id, recipient, metadata]

Attributes

Name	Type	Composition
None	ChainId	u8
None	DepositNonce	u64
None	ResourceId	[u8; 32]
None	Vec<u8>	Bytes
None	Vec<u8>	Bytes
None	Vec<u8>	Bytes

---

ProposalApproved

Voting successful for a proposal. [dest_id, nonce]

Attributes

Name	Type	Composition
None	ChainId	u8
None	DepositNonce	u64

---

ProposalFailed

Execution of call failed. [dest_id, nonce]

Attributes

Name	Type	Composition
None	ChainId	u8
None	DepositNonce	u64

---

ProposalLifetimeChanged

Proposal lifetime has changed. [lifetime]

Attributes

Name	Type	Composition
None	T::BlockNumber	u32

---

ProposalRejected

Voting rejected a proposal. [dest_id, nonce]

Attributes

Name	Type	Composition
None	ChainId	u8
None	DepositNonce	u64

---

ProposalSucceeded

Execution of call succeeded. [dest_id, nonce]

Attributes

Name	Type	Composition
None	ChainId	u8
None	DepositNonce	u64

---

RelayerAdded

Relayer added to set. [who]

Attributes

Name	Type	Composition
None	T::AccountId	AccountId

---

RelayerRemoved

Relayer removed from set. [who]

Attributes

Name	Type	Composition
None	T::AccountId	AccountId

---

RelayerThresholdChanged

Vote threshold has changed. [new_threshold]

Attributes

Name	Type	Composition
None	u32	u32

---

VoteAgainst

Vot submitted against proposal. [dest_id, nonce, who]

Attributes

Name	Type	Composition
None	ChainId	u8
None	DepositNonce	u64
None	T::AccountId	AccountId

---

VoteFor

Vote submitted in favour of proposal. [dest_id, nonce, who]

Attributes

Name	Type	Composition
None	ChainId	u8
None	DepositNonce	u64
None	T::AccountId	AccountId

---

Storage functions

---

ChainNonces

All whitelisted chains and their respective transaction counts.

Python

result = substrate.query(
    'ChainBridge', 'ChainNonces', ['u8']
)

Return value

'u64'

---

DisabledChains

Permission to voting and making transfers.

Python

result = substrate.query(
    'ChainBridge', 'DisabledChains', ['u8']
)

Return value

()

---

Fees

Fee to charge for a bridge transfer S->E.

Python

result = substrate.query(
    'ChainBridge', 'Fees', ['u8']
)

Return value

'u128'

---

MinDepositNonce

Minimal allowed value for deposit nonce per chain id

Python

result = substrate.query(
    'ChainBridge', 'MinDepositNonce', ['u8']
)

Return value

'u64'

---

ProposalLifetime

Time in blocks for relays voting

Python

result = substrate.query(
    'ChainBridge', 'ProposalLifetime', []
)

Return value

'u32'

---

RelayerCount

Number of relayers in set.

Python

result = substrate.query(
    'ChainBridge', 'RelayerCount', []
)

Return value

'u32'

---

RelayerThreshold

Number of votes required for a proposal to execute.

Python

result = substrate.query(
    'ChainBridge', 'RelayerThreshold', []
)

Return value

'u32'

---

Relayers

Tracks current relayer set.

Python

result = substrate.query(
    'ChainBridge', 'Relayers', ['AccountId']
)

Return value

'bool'

---

Resources

Utilized by the bridge software to map resource IDs to actual methods.

Python

result = substrate.query(
    'ChainBridge', 'Resources', ['[u8; 32]']
)

Return value

'Bytes'

---

Votes

All known proposals. The key is the hash of the call and the deposit ID, to ensure it's unique.

Python

result = substrate.query(
    'ChainBridge', 'Votes', ['u8', ('u64', 'Call')]
)

Return value

{
    'expiry': 'u32',
    'status': ('Initiated', 'Approved', 'Rejected'),
    'votes_against': ['AccountId'],
    'votes_for': ['AccountId'],
}

---

Constants

---

ChainIdentity

The identifier for this chain. This must be unique and must not collide with existing IDs within a set of bridged chains.

Value

7

Python

constant = substrate.get_constant('ChainBridge', 'ChainIdentity')

---

Errors

---

AllowabilityEqual

Bridge transfers to this chain have equal allowability

---

ChainAlreadyWhitelisted

Chain has already been enabled

---

ChainNotWhitelisted

Interactions with this chain is not permitted

---

DisabledChain

Bridge transfers to this chain are disabled

---

InvalidChainId

Provided chain Id is not valid

---

InvalidFee

Fee cannot be less than 0

---

InvalidProposalLifetime

Proposal lifetime cannot be equal 0

---

InvalidThreshold

Relayer threshold cannot be 0

---

MinimalNonce

Minimal nonce check not passed

---

MustBeRelayer

Protected operation, must be performed by relayer

---

ProposalAlreadyComplete

Proposal has either failed or succeeded

---

ProposalAlreadyExists

A proposal with these parameters has already been submitted

---

ProposalDoesNotExist

No proposal with the ID was found

---

ProposalExpired

Lifetime of proposal has been exceeded

---

ProposalNotComplete

Cannot complete proposal, needs more votes

---

RelayerAlreadyExists

Relayer already in set

---

RelayerAlreadyVoted

Relayer has already submitted some vote for this proposal

---

RelayerInvalid

Provided accountId is not a relayer

---

ResourceDoesNotExist

Resource ID provided isn&#x27;t mapped to anything

---

ThresholdNotSet

Relayer threshold not set

---