Config

Config is a central place where all sub-system specific configurations come together. Sub-system specific config are defined on each corresponding packages. The CLI defines all its parameters as structs. Out of this structs we generate a configuration file (in toml format) and CLI flags (via go-flags).

Ideally all parameters defined in the toml config should be exposed via flags, we might have a case where a parameter exists as a flag but not in the config, like -c | --config which defines the path of the config. Thereby, cli flags are a super set of the config parameters.

How to use it

Structs define fields which maps to parameters:

// Config is the configuration of the execution package
type Config struct {
  ...
  Level encoding.LogLevel             `long:"log-level"`
  InsurancePoolInitialBalance uint64  `long:"insurance-pool-initial-balance" description:"Some description"`
  Matching   matching.Config          `group:"Matching" namespace:"matching"`
  ...
}

A Config struct can hold native to types like uint64, custom types like encoding.LogLevel and other structures like matching.Config. The long:log-level tag will be mapped to a --log-level= flag, also the description: tag will be displayed as documentation for that particular flag. These are the two main tag that we use, see Available field tags for reference. When there are nested structs, we use the group and namespace tag. While the group tag will be displayed in the help to group the documentation, the namespace tag will affect the final flag name. In this case the Matching options are going to be prefixed with the --matching. See matching.Config for reference

$ vega node --help
Usage:
  vega [OPTIONS] node [node-OPTIONS]

Runs a vega node

    Execution:
          --execution.log-level=
          --execution.insurance-pool-initial-balance=         Some description (default: 

    Execution::Matching:
          --execution.matching.log-level=
          --execution.matching.log-price-levels-debug
          --execution.matching.log-removed-orders-debug

Default values

Default values are displayed in the help if a) description annotation is set and b) if the value of the parameter is anything different from its zero value