kaniko.go

package kaniko

import (
	"fmt"
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"strings"

	"github.com/drone/drone-kaniko/pkg/artifact"
	"github.com/drone/drone-kaniko/pkg/output"
	"github.com/drone/drone-kaniko/pkg/tagger"
	"golang.org/x/mod/semver"
)

type (
	// Build defines Docker build parameters.
	Build struct {
		DroneCommitRef      string   // Drone git commit reference
		DroneRepoBranch     string   // Drone repo branch
		Dockerfile          string   // Docker build Dockerfile
		Context             string   // Docker build context
		Tags                []string // Docker build tags
		AutoTag             bool     // Set this to auto detect tags from git commits and semver-tagged labels
		AutoTagSuffix       string   // Suffix to append to the auto detect tags
		ExpandTag           bool     // Set this to expand the `Tags` into semver-tagged labels
		Args                []string // Docker build args
		ArgsNew             []string // docker build args with comma seperated values
		IsMultipleBuildArgs bool     // env variable for fallback for docker build args
		Target              string   // Docker build target
		Repo                string   // Docker build repository
		Mirrors             []string // Docker repository mirrors
		Labels              []string // Label map
		SkipTlsVerify       bool     // Docker skip tls certificate verify for registry
		SnapshotMode        string   // Kaniko snapshot mode
		EnableCache         bool     // Whether to enable kaniko cache
		CacheRepo           string   // Remote repository that will be used to store cached layers
		CacheTTL            int      // Cache timeout in hours
		DigestFile          string   // Digest file location
		NoPush              bool     // Set this flag if you only want to build the image, without pushing to a registry
		Verbosity           string   // Log level
		Platform            string   // Allows to build with another default platform than the host, similarly to docker build --platform
		SkipUnusedStages    bool     // Build only used stages
		TarPath             string   // Set this flag to save the image as a tarball at path

		Cache                       bool   // Enable or disable caching during the build process.
		CacheDir                    string // Directory to store cached layers.
		CacheCopyLayers             bool   // Enable or disable copying layers from the cache.
		CacheRunLayers              bool   // Enable or disable running layers from the cache.
		Cleanup                     bool   // Enable or disable cleanup of temporary files.
		CompressedCaching           *bool  // Enable or disable compressed caching.
		ContextSubPath              string // Sub-path within the context to build.
		CustomPlatform              string // Platform to use for building.
		Force                       bool   // Force building the image even if it already exists.
		Git                         bool   // Branch to clone if build context is a git repository .
		ImageNameWithDigestFile     string // Write image name with digest to a file.
		ImageNameTagWithDigestFile  string // Write image name with tag and digest to a file.
		Insecure                    bool   // Allow connecting to registries without TLS.
		InsecurePull                bool   // Allow insecure pulls from the registry.
		InsecureRegistry            string // Use plain HTTP for registry communication.
		Label                       string // Add metadata to an image.
		LogFormat                   string // Set the log format for build output.
		LogTimestamp                bool   // Show timestamps in build output.
		OCILayoutPath               string // Directory to store OCI layout.
		PushRetry                   int    // Number of times to retry pushing an image.
		RegistryCertificate         string // Path to a file containing a registry certificate.
		RegistryClientCert          string // Path to a file containing a registry client certificate.
		RegistryMirror              string // Mirror for registry pulls.
		SkipDefaultRegistryFallback bool   // Skip Docker Hub and default registry fallback.
		Reproducible                bool   // Create a reproducible image.
		SingleSnapshot              bool   // Only create a single snapshot of the image.
		SkipTLSVerify               bool   // Skip TLS verification when connecting to the registry.
		SkipPushPermissionCheck     bool   // Skip permission check when pushing.
		SkipTLSVerifyPull           bool   // Skip TLS verification when pulling.
		SkipTLSVerifyRegistry       bool   // Skip TLS verification when connecting to a registry.
		UseNewRun                   bool   // Use the new container runtime (`runc`) for builds.
		IgnoreVarRun                *bool  // Ignore `/var/run` when copying from the context.
		IgnorePath                  string // Ignore files matching the specified path pattern.
		ImageFSExtractRetry         int    // Number of times to retry extracting the image filesystem.
		ImageDownloadRetry          int    // Number of times to retry downloading layers.
	}

	// Artifact defines content of artifact file
	Artifact struct {
		Tags         []string                  // Docker artifact tags
		Repo         string                    // Docker artifact repository
		Registry     string                    // Docker artifact registry
		RegistryType artifact.RegistryTypeEnum // Rocker artifact registry type
		ArtifactFile string                    // Artifact file location
	}

	// Output defines content of output file
	Output struct {
		OutputFile string // File where plugin output are saved
	}

	// Plugin defines the Docker plugin parameters.
	Plugin struct {
		Build    Build    // Docker build configuration
		Artifact Artifact // Artifact file content
		Output   Output   // Output file content
	}
)

// labelsForTag returns the labels to use for the given tag, subject to the value of ExpandTag.
//
// Build information (e.g. +linux_amd64) is carried through to all labels.
// Pre-release information (e.g. -rc1) suppresses major and major+minor auto-labels.
func (b Build) labelsForTag(tag string) (labels []string) {
	// We strip "v" off of the beginning of semantic versions, as they are not used in docker tags
	const VersionPrefix = "v"

	// Semantic Versions don't allow underscores, so replace them with dashes.
	//   https://semver.org/
	semverTag := strings.ReplaceAll(tag, "_", "-")

	// Allow tags of the form "1.2.3" as well as "v1.2.3" to avoid confusion.
	if withV := VersionPrefix + semverTag; !semver.IsValid(semverTag) && semver.IsValid(withV) {
		semverTag = withV
	}

	// Pass through tags if expand-tag is not set, or if the tag is not a semantic version
	if !b.ExpandTag || !semver.IsValid(semverTag) {
		return []string{tag}
	}
	tag = semverTag

	// If the version is pre-release, only the full release should be tagged, not the major/minor versions.
	if semver.Prerelease(tag) != "" {
		return []string{
			strings.TrimPrefix(tag, VersionPrefix),
		}
	}

	// tagFor carries any build information from the semantic version through to major and minor tags.
	labelFor := func(base string) string {
		return strings.TrimPrefix(base, VersionPrefix) + semver.Build(tag)
	}
	return []string{
		labelFor(semver.Major(tag)),
		labelFor(semver.MajorMinor(tag)),
		labelFor(semver.Canonical(tag)),
	}
}

// Returns the auto detected tags. See the AutoTag section of
// https://plugins.drone.io/drone-plugins/drone-docker/ for more info.
func (b Build) AutoTags() (tags []string, err error) {
	if len(b.Tags) > 1 || len(b.Tags) == 1 && b.Tags[0] != "latest" {
		err = fmt.Errorf("The auto-tag flag does not work with user provided tags %s", b.Tags)
		return
	}
	// We have tried the best to prevent enabling auto-tag and passing in
	// user specified at the same time. Starts to auto detect tags.
	// Note: passing in a "latest" tag with auto-tag enabled won't trigger the
	// early returns above, because we cannot tell if the tag is provided by
	// the default value or by the users.
	commitRef := b.DroneCommitRef
	if !tagger.UseAutoTag(commitRef, b.DroneRepoBranch) {
		err = fmt.Errorf("Could not auto detect the tag. Skipping automated docker build for commit %s", commitRef)
		return
	}
	tags, err = tagger.AutoTagsSuffix(commitRef, b.AutoTagSuffix)
	if err != nil {
		err = fmt.Errorf("Invalid semantic version when auto detecting the tag. Skipping automated docker build for %s.", commitRef)
	}
	return
}

// Exec executes the plugin step
func (p Plugin) Exec() error {
	if !p.Build.NoPush && p.Build.Repo == "" {
		return fmt.Errorf("repository name to publish image must be specified")
	}

	if _, err := os.Stat(p.Build.Dockerfile); os.IsNotExist(err) {
		return fmt.Errorf("dockerfile does not exist at path: %s", p.Build.Dockerfile)
	}

	var tags = p.Build.Tags
	if p.Build.AutoTag && p.Build.ExpandTag {
		return fmt.Errorf("The auto-tag flag conflicts with the expand-tag flag")
	}
	if p.Build.AutoTag {
		var err error
		tags, err = p.Build.AutoTags()
		if err != nil {
			return err
		}
	}

	cmdArgs := []string{
		fmt.Sprintf("--dockerfile=%s", p.Build.Dockerfile),
		fmt.Sprintf("--context=dir://%s", p.Build.Context),
	}

	// Set the destination repository only when we push or save to tarball
	if !p.Build.NoPush || p.Build.TarPath != "" {
		for _, tag := range tags {
			for _, label := range p.Build.labelsForTag(tag) {
				cmdArgs = append(cmdArgs, fmt.Sprintf("--destination=%s:%s", p.Build.Repo, label))
			}
		}
	}

	// Set the build arguments
	if p.Build.IsMultipleBuildArgs {
		for _, arg := range p.Build.ArgsNew {
			cmdArgs = append(cmdArgs, "--build-arg", arg)
		}
	} else {
		for _, arg := range p.Build.Args {
			cmdArgs = append(cmdArgs, "--build-arg", arg)
		}
	}
	// Set the labels
	for _, label := range p.Build.Labels {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--label=%s", label))
	}
	// Set repository mirrors
	for _, mirror := range p.Build.Mirrors {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--registry-mirror=%s", mirror))
	}
	if p.Build.Target != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--target=%s", p.Build.Target))
	}

	if p.Build.SkipTlsVerify {
		cmdArgs = append(cmdArgs, "--skip-tls-verify=true")
	}

	if p.Build.SnapshotMode != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--snapshot-mode=%s", p.Build.SnapshotMode))
	}

	if p.Build.EnableCache {
		cmdArgs = append(cmdArgs, "--cache=true")

		if p.Build.CacheRepo != "" {
			cmdArgs = append(cmdArgs, fmt.Sprintf("--cache-repo=%s", p.Build.CacheRepo))
		}
	}

	if p.Build.CacheTTL != 0 {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--cache-ttl=%dh", p.Build.CacheTTL))
	}

	if p.Build.DigestFile != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--digest-file=%s", p.Build.DigestFile))
	}

	if p.Build.NoPush {
		cmdArgs = append(cmdArgs, "--no-push")
	}

	if p.Build.Verbosity != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--verbosity=%s", p.Build.Verbosity))
	}

	if p.Build.Platform != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--customPlatform=%s", p.Build.Platform))
	}

	if p.Build.SkipUnusedStages {
		cmdArgs = append(cmdArgs, "--skip-unused-stages")
	}

	if p.Build.TarPath != "" {
		tarDir := filepath.Dir(p.Build.TarPath)
		if _, err := os.Stat(tarDir); os.IsNotExist(err) {
			if mkdirErr := os.MkdirAll(tarDir, 0755); mkdirErr != nil {
				return fmt.Errorf("failed to create directory for tar path %s: %v", tarDir, mkdirErr)
			}
		}
		cmdArgs = append(cmdArgs, fmt.Sprintf("--tar-path=%s", p.Build.TarPath))
	}

	if p.Build.CacheCopyLayers {
		cmdArgs = append(cmdArgs, "--cache-copy-layers")
	}

	if p.Build.CacheRunLayers {
		cmdArgs = append(cmdArgs, "--cache-run-layers=true")
	}

	if p.Build.Cleanup {
		cmdArgs = append(cmdArgs, "--cleanup=true")
	}

	if p.Build.CompressedCaching != nil {
		if *p.Build.CompressedCaching {
			cmdArgs = append(cmdArgs, "--compressed-caching=true")
		} else {
			cmdArgs = append(cmdArgs, "--compressed-caching=false")
		}
	}

	if p.Build.ContextSubPath != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--context-sub-path=%s", p.Build.ContextSubPath))
	}

	if p.Build.CustomPlatform != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--custom-platform=%s", p.Build.CustomPlatform))
	}

	if p.Build.Force {
		cmdArgs = append(cmdArgs, "--force")
	}

	if p.Build.Git {
		cmdArgs = append(cmdArgs, "--git")
	}

	if p.Build.ImageNameWithDigestFile != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--image-name-with-digest-file=%s", p.Build.ImageNameWithDigestFile))
	}

	if p.Build.ImageNameTagWithDigestFile != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--image-name-tag-with-digest-file=%s", p.Build.ImageNameTagWithDigestFile))
	}

	if p.Build.Insecure {
		cmdArgs = append(cmdArgs, "--insecure")
	}

	if p.Build.InsecurePull {
		cmdArgs = append(cmdArgs, "--insecure-pull")
	}

	if p.Build.InsecureRegistry != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--insecure-registry=%s", p.Build.InsecureRegistry))
	}

	if p.Build.LogFormat != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--log-format=%s", p.Build.LogFormat))
	}

	if p.Build.LogTimestamp {
		cmdArgs = append(cmdArgs, "--log-timestamp")
	}

	if p.Build.OCILayoutPath != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--oci-layout-path=%s", p.Build.OCILayoutPath))
	}

	if p.Build.PushRetry != 0 {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--push-retry=%d", p.Build.PushRetry))
	}

	if p.Build.RegistryCertificate != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--registry-certificate=%s", p.Build.RegistryCertificate))
	}

	if p.Build.RegistryClientCert != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--registry-client-cert=%s", p.Build.RegistryClientCert))
	}

	if p.Build.SkipDefaultRegistryFallback {
		cmdArgs = append(cmdArgs, "--skip-default-registry-fallback")
	}

	if p.Build.Reproducible {
		cmdArgs = append(cmdArgs, "--reproducible")
	}

	if p.Build.SingleSnapshot {
		cmdArgs = append(cmdArgs, "--single-snapshot")
	}

	if p.Build.SkipPushPermissionCheck {
		cmdArgs = append(cmdArgs, "--skip-push-permission-check")
	}

	if p.Build.SkipTLSVerifyPull {
		cmdArgs = append(cmdArgs, "--skip-tls-verify-pull")
	}

	if p.Build.SkipTLSVerifyRegistry {
		cmdArgs = append(cmdArgs, "--skip-tls-verify-registry")
	}

	if p.Build.UseNewRun {
		cmdArgs = append(cmdArgs, "--use-new-run")
	}

	if p.Build.IgnoreVarRun != nil {
		if *p.Build.IgnoreVarRun {
			cmdArgs = append(cmdArgs, "--ignore-var-run=true")
		} else {
			cmdArgs = append(cmdArgs, "--ignore-var-run=false")
		}
	}

	if p.Build.IgnorePath != "" {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--ignore-path=%s", p.Build.IgnorePath))
	}

	if p.Build.ImageFSExtractRetry != 0 {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--image-fs-extract-retry=%d", p.Build.ImageFSExtractRetry))
	}

	if p.Build.ImageDownloadRetry != 0 {
		cmdArgs = append(cmdArgs, fmt.Sprintf("--image-download-retry=%d", p.Build.ImageDownloadRetry))
	}

	cmd := exec.Command("/kaniko/executor", cmdArgs...)
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	trace(cmd)

	err := cmd.Run()
	if err != nil {
		return err
	}

	if p.Build.DigestFile != "" && p.Artifact.ArtifactFile != "" {
		err = artifact.WritePluginArtifactFile(p.Artifact.RegistryType, p.Artifact.ArtifactFile, p.Artifact.Registry, p.Artifact.Repo, getDigest(p.Build.DigestFile), p.Artifact.Tags)
		if err != nil {
			fmt.Fprintf(os.Stderr, "failed to write plugin artifact file at path: %s with error: %s\n", p.Artifact.ArtifactFile, err)
		}
	}

	if p.Output.OutputFile != "" {
		var tarPath string
		if p.Build.TarPath != "" {
			tarPath = getTarPath(p.Build.TarPath)
		}
		if err = output.WritePluginOutputFile(p.Output.OutputFile, getDigest(p.Build.DigestFile), tarPath); err != nil {
			fmt.Fprintf(os.Stderr, "failed to write plugin output file at path: %s with error: %s\n", p.Output.OutputFile, err)
		}
	}

	return nil
}

func getTarPath(tarPath string) string {
	tarDir := filepath.Dir(tarPath)
	if _, err := os.Stat(tarDir); err != nil && os.IsNotExist(err) {
		fmt.Fprintf(os.Stderr, "Warning: tar path does not exist: %s\n", tarPath)
		return ""
	}
	return tarPath
}

func getDigest(digestFile string) string {
	content, err := ioutil.ReadFile(digestFile)
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to read digest file contents at path: %s with error: %s\n", digestFile, err)
	}
	return string(content)
}

// trace writes each command to stdout with the command wrapped in an xml
// tag so that it can be extracted and displayed in the logs.
func trace(cmd *exec.Cmd) {
	fmt.Fprintf(os.Stdout, "+ %s\n", strings.Join(cmd.Args, " "))
}