bifrost-io/pallet-bcmp

Pallet-Bcmp

Base layer pallet which implement base features such as emitting MessageSent event and verifying committee's signature.

Pallet-Bcmp must No Re-Creation or it will cause to LOST ASSET.

Pallet-Bcmp-Consumer

Consumer pallet depends on pallet-bcmp and supports custom features.

Steps to use Bcmp:

1. Write custom consumer pallet. ie: consumer-template.

Note:

a. Consumer pallet must depend on pallet-bcmp to emit MessageSent event and other receive message logic.

b. Consumer pallet must implement ConsumerLayer trait define at pallet-bcmp.

c. AnchorAddress at config should set by constant to ensure same as address which was registered at pallet-bcmp.

2. Add pallet-bcmp and pallet-bcmp-consumer to Runtime:

parameter_types! {
    pub const PureMessage: H256 = pallet_bcmp::PURE_MESSAGE;
    pub const DefaultAdmin: Option<AccountId> = consts::DefaultAdmin;
}

impl pallet_bcmp::Config for Runtime {
    type RuntimeEvent = ******;
    type Currency = ******;
    type PureMessage = PureMessage;
    type DefaultAdmin = DefaultAdmin;
    // Consumers can instance for (Consumer1, Consumer2, ..)
    type Consumers = BcmpConsumer;
    type WeightInfo = pallet_bcmp::weight::BcmpWeight<Runtime>;
}

parameter_types! {
    pub const AnchorAddress: H256 = ******;
}

impl pallet_bcmp_consumer::Config for Runtime {
    type RuntimeEvent = ******;
    type Currency = ******;
    type AnchorAddress = AnchorAddress;
}

Note:

Bcmp's PureMessage must use pallet_bcmp::PURE_MESSAGE constant.

Bcmp's DefaultAdmin is supplied for No-Sudo chain, it will init WhiteList storage if the value is Some.

Bcmp's Consumers support instance by (Consumer1, Consumer2, ..), anyone in tuple should implement ConsumerLayer trait.

Consumer's AnchorAddress can generate by keccak256(&b"PALLET_CONSUMER")).

3. Init pallet-bcmp:

• Step1: Set whitelist by call set_whitelist. We support two ways to set whitelist: Root or Role::Admin. if you want to call by the latter, DefaultAdmin of pallet-bcmp should set with Some Value.
• • You can use Role::Admin account to set other authority account.
• Step2: Call set_this_chain_id with the Id represent this chain, ie sha2_256("Bool-Local".as_bytes())[..4] to u32(big-endian).
• Step3: Call set_chain_id to support other chain.
• • It will be failed if you don't set support chain id when enable path for anchor later.
• • Step4(Optional): Call set_fee_config to manage targe chain's fee config, default config to calculate fee is return 0.
• • Step5(Optional): Call emergency_control to control send_message and receive_message to pause handle processing logic, require Root or Role::Admin.

4. Init pallet-bcmp-consumer:

• Step1: Create target committee and waiting for committee's pubkey has been generated.
• Step2: Call register_anchor at pallet-bcmp.
• • anchor is a constant at consumer's config.
• • cmt_pk was generated at Step1.
• Step3: Call enable_path at pallet-bcmp to bind other chain's anchor and committee.

5. Send cross-tx from you chain to another chain:

• Call send_message at pallet-bcmp-consumer, it should call pallet-bcmp's send_message finally to emit MessageSent event.
• fee parameter can calculate at bcmp-fee-config.

6. Receive message from another chain:

• After deliverer call the receive_message at pallet-bcmp, it will call consumer pallet's receive_op at trait ConsumerLayer if dispatch Message's element dst_anchor successfully.