build.go

/*
Copyright 2019 Google LLC All Rights Reserved.

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 options

import (
	"errors"
	"fmt"
	"os"
	"path/filepath"

	"github.com/google/go-containerregistry/pkg/name"
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
	"golang.org/x/tools/go/packages"

	"github.com/google/ko/pkg/build"
)

const (
	// configDefaultBaseImage is the default base image if not specified in .ko.yaml.
	configDefaultBaseImage = "gcr.io/distroless/static:nonroot"
)

// BuildOptions represents options for the ko builder.
type BuildOptions struct {
	// BaseImage enables setting the default base image programmatically.
	// If non-empty, this takes precedence over the value in `.ko.yaml`.
	BaseImage string

	// BaseImageOverrides stores base image overrides for import paths.
	BaseImageOverrides map[string]string

	// WorkingDirectory allows for setting the working directory for invocations of the `go` tool.
	// Empty string means the current working directory.
	WorkingDirectory string

	ConcurrentBuilds     int
	DisableOptimizations bool
	Platform             string
	Labels               []string
	// UserAgent enables overriding the default value of the `User-Agent` HTTP
	// request header used when retrieving the base image.
	UserAgent string

	InsecureRegistry bool

	// BuildConfigs stores the per-image build config from `.ko.yaml`.
	BuildConfigs map[string]build.Config
}

func AddBuildOptions(cmd *cobra.Command, bo *BuildOptions) {
	cmd.Flags().IntVarP(&bo.ConcurrentBuilds, "jobs", "j", 0,
		"The maximum number of concurrent builds (default GOMAXPROCS)")
	cmd.Flags().BoolVar(&bo.DisableOptimizations, "disable-optimizations", bo.DisableOptimizations,
		"Disable optimizations when building Go code. Useful when you want to interactively debug the created container.")
	cmd.Flags().StringVar(&bo.Platform, "platform", "",
		"Which platform to use when pulling a multi-platform base. Format: all | <os>[/<arch>[/<variant>]][,platform]*")
	cmd.Flags().StringSliceVar(&bo.Labels, "image-label", []string{},
		"Which labels (key=value) to add to the image.")
}

// LoadConfig reads build configuration from defaults, environment variables, and the `.ko.yaml` config file.
func (bo *BuildOptions) LoadConfig() error {
	v := viper.New()
	if bo.WorkingDirectory == "" {
		bo.WorkingDirectory = "."
	}
	// If omitted, use this base image.
	v.SetDefault("defaultBaseImage", configDefaultBaseImage)
	v.SetConfigName(".ko") // .yaml is implicit
	v.SetEnvPrefix("KO")
	v.AutomaticEnv()

	if override := os.Getenv("KO_CONFIG_PATH"); override != "" {
		v.AddConfigPath(override)
	}

	v.AddConfigPath(bo.WorkingDirectory)

	if err := v.ReadInConfig(); err != nil {
		if !errors.As(err, &viper.ConfigFileNotFoundError{}) {
			return fmt.Errorf("error reading config file: %w", err)
		}
	}

	if bo.BaseImage == "" {
		ref := v.GetString("defaultBaseImage")
		if _, err := name.ParseReference(ref); err != nil {
			return fmt.Errorf("'defaultBaseImage': error parsing %q as image reference: %w", ref, err)
		}
		bo.BaseImage = ref
	}

	if len(bo.BaseImageOverrides) == 0 {
		baseImageOverrides := map[string]string{}
		overrides := v.GetStringMapString("baseImageOverrides")
		for key, value := range overrides {
			if _, err := name.ParseReference(value); err != nil {
				return fmt.Errorf("'baseImageOverrides': error parsing %q as image reference: %w", value, err)
			}
			baseImageOverrides[key] = value
		}
		bo.BaseImageOverrides = baseImageOverrides
	}

	if len(bo.BuildConfigs) == 0 {
		var builds []build.Config
		if err := v.UnmarshalKey("builds", &builds); err != nil {
			return fmt.Errorf("configuration section 'builds' cannot be parsed")
		}
		buildConfigs, err := createBuildConfigMap(bo.WorkingDirectory, builds)
		if err != nil {
			return fmt.Errorf("could not create build config map: %w", err)
		}
		bo.BuildConfigs = buildConfigs
	}

	return nil
}

func createBuildConfigMap(workingDirectory string, configs []build.Config) (map[string]build.Config, error) {
	buildConfigsByImportPath := make(map[string]build.Config)
	for i, config := range configs {
		// In case no ID is specified, use the index of the build config in
		// the ko YAML file as a reference (debug help).
		if config.ID == "" {
			config.ID = fmt.Sprintf("#%d", i)
		}

		// Make sure to behave like GoReleaser by defaulting to the current
		// directory in case the build or main field is not set, check
		// https://goreleaser.com/customization/build/ for details
		if config.Dir == "" {
			config.Dir = "."
		}
		if config.Main == "" {
			config.Main = "."
		}

		// baseDir is the directory where `go list` will be run to look for package information
		baseDir := filepath.Join(workingDirectory, config.Dir)

		// To behave like GoReleaser, check whether the configured `main` config value points to a
		// source file, and if so, just use the directory it is in
		path := config.Main
		if fi, err := os.Stat(filepath.Join(baseDir, config.Main)); err == nil && fi.Mode().IsRegular() {
			path = filepath.Dir(config.Main)
		}

		// Verify that the path actually leads to a local file (/~https://github.com/google/ko/issues/483)
		if _, err := os.Stat(filepath.Join(baseDir, path)); err != nil {
			return nil, err
		}

		// By default, paths configured in the builds section are considered
		// local import paths, therefore add a "./" equivalent as a prefix to
		// the constructured import path
		localImportPath := fmt.Sprint(".", string(filepath.Separator), path)

		pkgs, err := packages.Load(&packages.Config{Mode: packages.NeedName, Dir: baseDir}, localImportPath)
		if err != nil {
			return nil, fmt.Errorf("'builds': entry #%d does not contain a valid local import path (%s) for directory (%s): %w", i, localImportPath, baseDir, err)
		}

		if len(pkgs) != 1 {
			return nil, fmt.Errorf("'builds': entry #%d results in %d local packages, only 1 is expected", i, len(pkgs))
		}
		importPath := pkgs[0].PkgPath
		buildConfigsByImportPath[importPath] = config
	}

	return buildConfigsByImportPath, nil
}