pflags

Pflags generator

Generate strongly typed CLI flags for the fields of a Go struct, including nested structs. With the config package, these flags can override configuration values.

Build and install

From the repository root, build the binary:

make -C flytestdlib compile

The binary is written to flytestdlib/bin/pflags. Add that directory to PATH before running go generate.

Alternatively, install it into GOBIN (or GOPATH/bin):

go install ./flytestdlib/cli/pflags

Usage

Run the generator in the destination package directory:

pflags MyStruct --package myproject/mypackage

The package defaults to the current directory. You can also add a directive to the file declaring the struct:

//go:generate pflags MyStruct

The target must be a struct. Supported field types include basic types, JSON-unmarshalable types, nested structs, and supported slices and maps.

The generator writes mystruct_flags.go and mystruct_flags_test.go. By default, it looks for a variable named defaultConfig to provide defaults. Use --default-var to select another variable, or --bind-default-var to bind flags to that variable's fields.

Field tags

Use the pflag tag to specify a default value and help text as a comma-separated pair. A matching default variable takes precedence over the tag's default value.

type MyStruct struct {
    StringValue string `json:"str" pflag:"\"hello world\",\"life is short\""`
    BoolValue   bool   `json:"bl" pflag:",This is a bool value that will default to false."`
}

Use pflag:"-" to exclude a field.