config.md

Configuration

Relayer Home Folder Layout

The following is the folder structure for the relayer --home directory when there are two chains (ibc0 an ibc1) properly configured with keys and lite clients

~/.relayer
├── config
│   └── config.yaml
├── keys
│   ├── keyring-test-ibc0
│   └── keyring-test-ibc1
└── lite
    ├── ibc0.db
    └── ibc1.db

Configuring the Relayer

There are three major parts of relayer configuration:

type Config struct {
	Global GlobalConfig    `yaml:"global"`
	Chains []ChainConfig   `yaml:"chains"`
	Paths  []relayer.Paths `yaml:"paths"`
}

Global Configuration

• Amount of time to sleep between relayer loops
• Number of block headers to cache for the lite client

NOTE: Additional global configuration will be added/removed in this section as relayer development progresses

// NOTE: are there any other items that could be useful here?
type Global struct {
	Timeout       string `yaml:"timeout"`
	LiteCacheSize int    `yaml:"lite-cache-size"`
}

Chains config

The ConfigChain abstraction contains all the necessary data to connect to a given chain, query it's state, and send transactions to it. The config will contain an array of these chains ([]ChainConfig). These ChainConfig instances will then be converted into the relayer.Chain abstration to perform all the necessary tasks. The following data will be needed by each relayer.Chain and is passed in via ChainConfigs:

NOTE: We need to add the chain unbonding time to this struct and relayer.Chain as well: cosmos/relayer#56

// ChainConfig describes the config necessary for an individual chain
type ChainConfig struct {
	Key            string  `yaml:"key" json:"key"`
	ChainID        string  `yaml:"chain-id" json:"chain-id"`
	RPCAddr        string  `yaml:"rpc-addr" json:"rpc-addr"`
	AccountPrefix  string  `yaml:"account-prefix" json:"account-prefix"`
	Gas            uint64  `yaml:"gas,omitempty" json:"gas,omitempty"`
	GasAdjustment  float64 `yaml:"gas-adjustment,omitempty" json:"gas-adjustment,omitempty"`
	GasPrices      string  `yaml:"gas-prices,omitempty" json:"gas-prices,omitempty"`
	DefaultDenom   string  `yaml:"default-denom,omitempty" json:"default-denom,omitempty"`
	Memo           string  `yaml:"memo,omitempty" json:"memo,omitempty"`
	TrustingPeriod string  `yaml:"trusting-period" json:"trusting-period"`
}

NOTE: This may be a redundent struct. A refactor that could be undertaken would be to replace this with the relayer.Chain in the config parsing see: cosmos/relayer#31

Paths

The Paths in the configuration define which Paths the relayer will move packets between. It also defines the Strategy that will be used by the relayer. It contains all the identifers necessary to connect two chains:

// Path represents a pair of chains and the identifiers needed to
// relay over them
type Path struct {
	Src      *PathEnd     `yaml:"src" json:"src"`
	Dst      *PathEnd     `yaml:"dst" json:"dst"`
	Strategy *StrategyCfg `yaml:"strategy" json:"strategy"`
}

// StrategyCfg defines which relaying strategy to take for a given path
type StrategyCfg struct {
	Type        string            `json:"type" yaml:"type"`
	Constraints map[string]string `json:"constraints,omitempty" yaml:"constraints,omitempty"`
}

// PathEnd represents the local connection identifers for a relay path
// The path is set on the chain before performing operations
type PathEnd struct {
	ChainID      string `yaml:"chain-id,omitempty" json:"chain-id,omitempty"`
	ClientID     string `yaml:"client-id,omitempty" json:"client-id,omitempty"`
	ConnectionID string `yaml:"connection-id,omitempty" json:"connection-id,omitempty"`
	ChannelID    string `yaml:"channel-id,omitempty" json:"channel-id,omitempty"`
	PortID       string `yaml:"port-id,omitempty" json:"port-id,omitempty"`
}

NOTE: An Order field needs to be added to this struct along with support for UNORDERED channels: cosmos/relayer#52