lucicfg/cli/cmds/generate/generate.go

// Copyright 2018 The LUCI Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// Package generate implements 'generate' subcommand.
package generate

import (
	"context"
	"fmt"
	"os"
	"path/filepath"
	"sort"

	"github.com/maruel/subcommands"

	"go.chromium.org/luci/common/cli"
	"go.chromium.org/luci/starlark/interpreter"

	"go.chromium.org/luci/lucicfg"
	"go.chromium.org/luci/lucicfg/cli/base"
)

// Cmd is 'generate' subcommand.
func Cmd(params base.Parameters) *subcommands.Command {
	return &subcommands.Command{
		UsageLine: "generate <input.star>",
		ShortDesc: "interprets a high-level config, generating *.cfg files",
		CommandRun: func() subcommands.CommandRun {
			c := &generateRun{}
			c.Init(params, false)
			return c
		},
	}
}

type generateRun struct {
	base.Subcommand
}

type generateResult struct {
	// TODO
}

func (c *generateRun) Run(a subcommands.Application, args []string, env subcommands.Env) int {
	if !c.CheckArgs(args, 1, 1) {
		return 1
	}
	ctx := cli.GetContext(a, c, env)
	return c.Done(c.run(ctx, args[0]))
}

func (c *generateRun) run(ctx context.Context, inputFile string) (*generateResult, error) {
	abs, err := filepath.Abs(inputFile)
	if err != nil {
		return nil, err
	}

	// Make sure the input file exists, to make the error message in this case be
	// more humane. lucicfg.Generate will formulate this error as "no such module"
	// which looks confusing.
	switch _, err := os.Stat(abs); {
	case os.IsNotExist(err):
		return nil, fmt.Errorf("no such file: %s", inputFile)
	case err != nil:
		return nil, err
	}

	// The directory with the input file becomes the root of the main package.
	root, main := filepath.Split(abs)

	state, err := lucicfg.Generate(ctx, lucicfg.Inputs{
		Code:         interpreter.FileSystemLoader(root),
		Entry:        main,
		TextPBHeader: "# Auto-generated by lucicfg.\n# Do not modify manually.\n\n",
	})
	if err != nil {
		return nil, err
	}

	// TODO: write generated files somewhere.

	files := make([]string, 0, len(state.Configs))
	for f := range state.Configs {
		files = append(files, f)
	}
	sort.Strings(files)

	for _, f := range files {
		fmt.Println("--------------------------------------------------")
		fmt.Println(f)
		fmt.Println("--------------------------------------------------")
		fmt.Print(state.Configs[f])
		fmt.Println("--------------------------------------------------")
	}
	return nil, nil
}