cmd/specs/generators/fuchsia_py.go

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package generators

import (
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"strings"

	recipes "fuchsia.googlesource.com/infra/infra/fxicfg/starlark/protos/recipes"
	"fuchsia.googlesource.com/infra/infra/starlark/starlarkgen"
	"github.com/golang/protobuf/proto"
)

// FuchsiaPySpecGenerator produces Starlark code that generates a spec for the fuchsia.py
// recipe.
type FuchsiaPySpecGenerator struct {
	w io.Writer
}

func NewFuchsiaPySpecGenerator(output io.Writer) *FuchsiaPySpecGenerator {
	return &FuchsiaPySpecGenerator{output}
}

func (g *FuchsiaPySpecGenerator) Generate(in io.Reader) error {
	spec, err := g.parseTextproto(in)
	if err != nil {
		return fmt.Errorf("failed to parse input: %v", err)
	}
	output := starlarkgen.Generate(spec)
	fmt.Fprintf(g.w, output)
	return nil
}

// parse parses a spec for the Fuchsia recipe from the given io.Reader.
func (g *FuchsiaPySpecGenerator) parseTextproto(r io.Reader) (*recipes.Fuchsia, error) {
	bytes, err := ioutil.ReadAll(r)
	if err != nil {
		return nil, err
	}
	textproto := strings.TrimSpace(string(bytes))
	if textproto == "" {
		return nil, errors.New("input is empty")
	}
	spec := new(recipes.Fuchsia)
	if err := proto.UnmarshalText(string(textproto), spec); err != nil {
		return nil, err
	}
	return spec, nil
}