Crate cumulus_pallet_xcmp_queue

A pallet which uses the XCMP transport layer to handle both incoming and outgoing XCM message sending and dispatch, queuing, signalling and backpressure. To do so, it implements:

• XcmpMessageHandler
• XcmpMessageSource

Also provides an implementation of SendXcm which can be placed in a router tuple for relaying XCM over XCMP if the destination is Parent/Parachain. It requires an implementation of XcmExecutor for dispatching incoming XCM messages.

To prevent out of memory errors on the OutboundXcmpMessages queue, an exponential fee factor (DeliveryFeeFactor) is set, much like the one used in DMP. The fee factor increases whenever the total size of messages in a particular channel passes a threshold. This threshold is defined as a percentage of the maximum total size the channel can have. More concretely, the threshold is max_total_size / THRESHOLD_FACTOR, where:

• max_total_size is the maximum size, in bytes, of the channel, not number of messages. It is defined in the channel configuration.
• THRESHOLD_FACTOR just declares which percentage of the max size is the actual threshold. If it’s 2, then the threshold is half of the max size, if it’s 4, it’s a quarter, and so on.

Re-exports

• pub use weights::WeightInfo;
• pub use pallet::*;

Modules

• bridging
• delivery_fee_constants
  Constants related to delivery fee calculation
• migration
  A module that is responsible for migration of storage.
• pallet
  The pallet module in each FRAME pallet hosts the most important items needed to construct this pallet.
• weights
  Autogenerated weights for cumulus_pallet_xcmp_queue

Structs

• OutboundChannelDetails
  Struct containing detailed information about the outbound channel.
• QueueConfigData

Enums

• ChannelSignal
• OutboundState

Type Aliases

• MaxXcmpMessageLenOf
  The max length of an XCMP message.
• OverweightIndex
  Index used to identify overweight XCMs.