podmanV2: implement build

Implement `podman build` for the local client.  The remote client will
require some rather large work in the backend and a new build endpoint
for the libpod rest API.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

2 files changed, 492 insertions, 0 deletions

diff --git a/cmd/podman/build.go b/cmd/podman/build.go
new file mode 100644
index 000000000..43a2f7ab5
--- /dev/null
+++ b/cmd/podman/build.go
@@ -0,0 +1,470 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/containers/buildah"
+	"github.com/containers/buildah/imagebuildah"
+	buildahCLI "github.com/containers/buildah/pkg/cli"
+	"github.com/containers/buildah/pkg/parse"
+	"github.com/containers/libpod/cmd/podman/registry"
+	"github.com/containers/libpod/cmd/podman/utils"
+	"github.com/containers/libpod/pkg/domain/entities"
+	"github.com/docker/go-units"
+	"github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+)
+
+// buildFlagsWrapper are local to cmd/ as the build code is using Buildah-internal
+// types.  Hence, after parsing, we are converting buildFlagsWrapper to the entities'
+// options which essentially embed the Buildah types.
+type buildFlagsWrapper struct {
+	// Buildah stuff first
+	buildahCLI.BudResults
+	buildahCLI.LayerResults
+	buildahCLI.FromAndBudResults
+	buildahCLI.NameSpaceResults
+	buildahCLI.UserNSResults
+
+	// SquashAll squashes all layers into a single layer.
+	SquashAll bool
+}
+
+var (
+	// Command: podman _diff_ Object_ID
+	buildDescription = "Builds an OCI or Docker image using instructions from one or more Containerfiles and a specified build context directory."
+	buildCmd         = &cobra.Command{
+		Use:              "build [flags] [CONTEXT]",
+		Short:            "Build an image using instructions from Containerfiles",
+		Long:             buildDescription,
+		TraverseChildren: true,
+		RunE:             build,
+		Example: `podman build .
+  podman build --creds=username:password -t imageName -f Containerfile.simple .
+  podman build --layers --force-rm --tag imageName .`,
+	}
+
+	buildOpts = buildFlagsWrapper{}
+)
+
+// useLayers returns false if BUILDAH_LAYERS is set to "0" or "false"
+// otherwise it returns true
+func useLayers() string {
+	layers := os.Getenv("BUILDAH_LAYERS")
+	if strings.ToLower(layers) == "false" || layers == "0" {
+		return "false"
+	}
+	return "true"
+}
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
+		Command: buildCmd,
+	})
+	flags := buildCmd.Flags()
+
+	// Podman flags
+	flags.BoolVarP(&buildOpts.SquashAll, "squash-all", "", false, "Squash all layers into a single layer")
+
+	// Bud flags
+	budFlags := buildahCLI.GetBudFlags(&buildOpts.BudResults)
+	// --pull flag
+	flag := budFlags.Lookup("pull")
+	if err := flag.Value.Set("true"); err != nil {
+		logrus.Errorf("unable to set --pull to true: %v", err)
+	}
+	flag.DefValue = "true"
+	flags.AddFlagSet(&budFlags)
+
+	// Layer flags
+	layerFlags := buildahCLI.GetLayerFlags(&buildOpts.LayerResults)
+	// --layers flag
+	flag = layerFlags.Lookup("layers")
+	useLayersVal := useLayers()
+	if err := flag.Value.Set(useLayersVal); err != nil {
+		logrus.Errorf("unable to set --layers to %v: %v", useLayersVal, err)
+	}
+	flag.DefValue = useLayersVal
+	// --force-rm flag
+	flag = layerFlags.Lookup("force-rm")
+	if err := flag.Value.Set("true"); err != nil {
+		logrus.Errorf("unable to set --force-rm to true: %v", err)
+	}
+	flag.DefValue = "true"
+	flags.AddFlagSet(&layerFlags)
+
+	// FromAndBud flags
+	fromAndBudFlags, err := buildahCLI.GetFromAndBudFlags(&buildOpts.FromAndBudResults, &buildOpts.UserNSResults, &buildOpts.NameSpaceResults)
+	if err != nil {
+		logrus.Errorf("error setting up build flags: %v", err)
+		os.Exit(1)
+	}
+	flags.AddFlagSet(&fromAndBudFlags)
+}
+
+// build executes the build command.
+func build(cmd *cobra.Command, args []string) error {
+	if (cmd.Flags().Changed("squash") && cmd.Flags().Changed("layers")) ||
+		(cmd.Flags().Changed("squash-all") && cmd.Flags().Changed("layers")) ||
+		(cmd.Flags().Changed("squash-all") && cmd.Flags().Changed("squash")) {
+		return errors.New("cannot specify --squash, --squash-all and --layers options together")
+	}
+
+	contextDir, containerFiles, err := extractContextAndFiles(args, buildOpts.File)
+	if err != nil {
+		return err
+	}
+
+	ie, err := registry.NewImageEngine(cmd, args)
+	if err != nil {
+		return err
+	}
+
+	apiBuildOpts, err := buildFlagsWrapperToOptions(cmd, contextDir, &buildOpts)
+	if err != nil {
+		return err
+	}
+
+	_, err = ie.Build(registry.GetContext(), containerFiles, *apiBuildOpts)
+	return err
+}
+
+// extractContextAndFiles parses args and files to extract a context directory
+// and {Container,Docker}files.
+//
+// TODO: this was copied and altered from the v1 client which in turn was
+// copied and altered from the Buildah code. Ideally, all of this code should
+// be cleanly consolidated into a package that is shared between Buildah and
+// Podman.
+func extractContextAndFiles(args, files []string) (string, []string, error) {
+	// Extract container files from the CLI (i.e., --file/-f) first.
+	var containerFiles []string
+	for _, f := range files {
+		if f == "-" {
+			containerFiles = append(containerFiles, "/dev/stdin")
+		} else {
+			containerFiles = append(containerFiles, f)
+		}
+	}
+
+	// Determine context directory.
+	var contextDir string
+	if len(args) > 0 {
+		// The context directory could be a URL.  Try to handle that.
+		tempDir, subDir, err := imagebuildah.TempDirForURL("", "buildah", args[0])
+		if err != nil {
+			return "", nil, errors.Wrapf(err, "error prepping temporary context directory")
+		}
+		if tempDir != "" {
+			// We had to download it to a temporary directory.
+			// Delete it later.
+			defer func() {
+				if err = os.RemoveAll(tempDir); err != nil {
+					logrus.Errorf("error removing temporary directory %q: %v", contextDir, err)
+				}
+			}()
+			contextDir = filepath.Join(tempDir, subDir)
+		} else {
+			// Nope, it was local.  Use it as is.
+			absDir, err := filepath.Abs(args[0])
+			if err != nil {
+				return "", nil, errors.Wrapf(err, "error determining path to directory %q", args[0])
+			}
+			contextDir = absDir
+		}
+	} else {
+		// No context directory or URL was specified.  Try to use the home of
+		// the first locally-available Containerfile.
+		for i := range containerFiles {
+			if strings.HasPrefix(containerFiles[i], "http://") ||
+				strings.HasPrefix(containerFiles[i], "https://") ||
+				strings.HasPrefix(containerFiles[i], "git://") ||
+				strings.HasPrefix(containerFiles[i], "github.com/") {
+				continue
+			}
+			absFile, err := filepath.Abs(containerFiles[i])
+			if err != nil {
+				return "", nil, errors.Wrapf(err, "error determining path to file %q", containerFiles[i])
+			}
+			contextDir = filepath.Dir(absFile)
+			break
+		}
+	}
+
+	if contextDir == "" {
+		return "", nil, errors.Errorf("no context directory and no Containerfile specified")
+	}
+	if !utils.IsDir(contextDir) {
+		return "", nil, errors.Errorf("context must be a directory: %q", contextDir)
+	}
+	if len(containerFiles) == 0 {
+		if utils.FileExists(filepath.Join(contextDir, "Containerfile")) {
+			containerFiles = append(containerFiles, filepath.Join(contextDir, "Containerfile"))
+		} else {
+			containerFiles = append(containerFiles, filepath.Join(contextDir, "Dockerfile"))
+		}
+	}
+
+	return contextDir, containerFiles, nil
+}
+
+// buildFlagsWrapperToOptions converts the local build flags to the build options used
+// in the API which embed Buildah types used across the build code.  Doing the
+// conversion here prevents the API from doing that (redundantly).
+//
+// TODO: this code should really be in Buildah.
+func buildFlagsWrapperToOptions(c *cobra.Command, contextDir string, flags *buildFlagsWrapper) (*entities.BuildOptions, error) {
+	output := ""
+	tags := []string{}
+	if c.Flag("tag").Changed {
+		tags = flags.Tag
+		if len(tags) > 0 {
+			output = tags[0]
+			tags = tags[1:]
+		}
+	}
+
+	pullPolicy := imagebuildah.PullNever
+	if flags.Pull {
+		pullPolicy = imagebuildah.PullIfMissing
+	}
+	if flags.PullAlways {
+		pullPolicy = imagebuildah.PullAlways
+	}
+
+	args := make(map[string]string)
+	if c.Flag("build-arg").Changed {
+		for _, arg := range flags.BuildArg {
+			av := strings.SplitN(arg, "=", 2)
+			if len(av) > 1 {
+				args[av[0]] = av[1]
+			} else {
+				delete(args, av[0])
+			}
+		}
+	}
+	// Check to see if the BUILDAH_LAYERS environment variable is set and
+	// override command-line.
+	if _, ok := os.LookupEnv("BUILDAH_LAYERS"); ok {
+		flags.Layers = true
+	}
+
+	// `buildah bud --layers=false` acts like `docker build --squash` does.
+	// That is all of the new layers created during the build process are
+	// condensed into one, any layers present prior to this build are
+	// retained without condensing.  `buildah bud --squash` squashes both
+	// new and old layers down into one.  Translate Podman commands into
+	// Buildah.  Squash invoked, retain old layers, squash new layers into
+	// one.
+	if c.Flags().Changed("squash") && buildOpts.Squash {
+		flags.Squash = false
+		flags.Layers = false
+	}
+	// Squash-all invoked, squash both new and old layers into one.
+	if c.Flags().Changed("squash-all") {
+		flags.Squash = true
+		flags.Layers = false
+	}
+
+	var stdin, stdout, stderr, reporter *os.File
+	stdin = os.Stdin
+	stdout = os.Stdout
+	stderr = os.Stderr
+	reporter = os.Stderr
+
+	if c.Flag("logfile").Changed {
+		f, err := os.OpenFile(flags.Logfile, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0600)
+		if err != nil {
+			return nil, errors.Errorf("error opening logfile %q: %v", flags.Logfile, err)
+		}
+		defer f.Close()
+		logrus.SetOutput(f)
+		stdout = f
+		stderr = f
+		reporter = f
+	}
+
+	var memoryLimit, memorySwap int64
+	var err error
+	if c.Flags().Changed("memory") {
+		memoryLimit, err = units.RAMInBytes(flags.Memory)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if c.Flags().Changed("memory-swap") {
+		memorySwap, err = units.RAMInBytes(flags.MemorySwap)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	nsValues, err := getNsValues(flags)
+	if err != nil {
+		return nil, err
+	}
+
+	networkPolicy := buildah.NetworkDefault
+	for _, ns := range nsValues {
+		if ns.Name == "none" {
+			networkPolicy = buildah.NetworkDisabled
+			break
+		} else if !filepath.IsAbs(ns.Path) {
+			networkPolicy = buildah.NetworkEnabled
+			break
+		}
+	}
+
+	// `buildah bud --layers=false` acts like `docker build --squash` does.
+	// That is all of the new layers created during the build process are
+	// condensed into one, any layers present prior to this build are retained
+	// without condensing.  `buildah bud --squash` squashes both new and old
+	// layers down into one.  Translate Podman commands into Buildah.
+	// Squash invoked, retain old layers, squash new layers into one.
+	if c.Flags().Changed("squash") && flags.Squash {
+		flags.Squash = false
+		flags.Layers = false
+	}
+	// Squash-all invoked, squash both new and old layers into one.
+	if c.Flags().Changed("squash-all") {
+		flags.Squash = true
+		flags.Layers = false
+	}
+
+	compression := imagebuildah.Gzip
+	if flags.DisableCompression {
+		compression = imagebuildah.Uncompressed
+	}
+
+	isolation, err := parse.IsolationOption(flags.Isolation)
+	if err != nil {
+		return nil, errors.Wrapf(err, "error parsing ID mapping options")
+	}
+
+	usernsOption, idmappingOptions, err := parse.IDMappingOptions(c, isolation)
+	if err != nil {
+		return nil, errors.Wrapf(err, "error parsing ID mapping options")
+	}
+	nsValues = append(nsValues, usernsOption...)
+
+	systemContext, err := parse.SystemContextFromOptions(c)
+	if err != nil {
+		return nil, errors.Wrapf(err, "error building system context")
+	}
+
+	format := ""
+	flags.Format = strings.ToLower(flags.Format)
+	switch {
+	case strings.HasPrefix(flags.Format, buildah.OCI):
+		format = buildah.OCIv1ImageManifest
+	case strings.HasPrefix(flags.Format, buildah.DOCKER):
+		format = buildah.Dockerv2ImageManifest
+	default:
+		return nil, errors.Errorf("unrecognized image type %q", flags.Format)
+	}
+
+	runtimeFlags := []string{}
+	for _, arg := range flags.RuntimeFlags {
+		runtimeFlags = append(runtimeFlags, "--"+arg)
+	}
+
+	// FIXME: the code below needs to be enabled (and adjusted) once the
+	// global/root flags are supported.
+
+	//	conf, err := runtime.GetConfig()
+	//	if err != nil {
+	//		return err
+	//	}
+	//	if conf != nil && conf.Engine.CgroupManager == config.SystemdCgroupsManager {
+	//		runtimeFlags = append(runtimeFlags, "--systemd-cgroup")
+	//	}
+
+	opts := imagebuildah.BuildOptions{
+		AddCapabilities: flags.CapAdd,
+		AdditionalTags:  tags,
+		Annotations:     flags.Annotation,
+		Architecture:    flags.Arch,
+		Args:            args,
+		BlobDirectory:   flags.BlobCache,
+		CNIConfigDir:    flags.CNIConfigDir,
+		CNIPluginPath:   flags.CNIPlugInPath,
+		CommonBuildOpts: &buildah.CommonBuildOptions{
+			AddHost:      flags.AddHost,
+			CgroupParent: flags.CgroupParent,
+			CPUPeriod:    flags.CPUPeriod,
+			CPUQuota:     flags.CPUQuota,
+			CPUShares:    flags.CPUShares,
+			CPUSetCPUs:   flags.CPUSetCPUs,
+			CPUSetMems:   flags.CPUSetMems,
+			Memory:       memoryLimit,
+			MemorySwap:   memorySwap,
+			ShmSize:      flags.ShmSize,
+			Ulimit:       flags.Ulimit,
+			Volumes:      flags.Volumes,
+		},
+		Compression:      compression,
+		ConfigureNetwork: networkPolicy,
+		ContextDirectory: contextDir,
+		//		DefaultMountsFilePath:   FIXME: this requires global flags to be working!
+		Devices:                 flags.Devices,
+		DropCapabilities:        flags.CapDrop,
+		Err:                     stderr,
+		ForceRmIntermediateCtrs: flags.ForceRm,
+		IDMappingOptions:        idmappingOptions,
+		IIDFile:                 flags.Iidfile,
+		In:                      stdin,
+		Isolation:               isolation,
+		Labels:                  flags.Label,
+		Layers:                  flags.Layers,
+		NamespaceOptions:        nsValues,
+		NoCache:                 flags.NoCache,
+		OS:                      flags.OS,
+		Out:                     stdout,
+		Output:                  output,
+		OutputFormat:            format,
+		PullPolicy:              pullPolicy,
+		Quiet:                   flags.Quiet,
+		RemoveIntermediateCtrs:  flags.Rm,
+		ReportWriter:            reporter,
+		RuntimeArgs:             runtimeFlags,
+		SignBy:                  flags.SignBy,
+		SignaturePolicyPath:     flags.SignaturePolicy,
+		Squash:                  flags.Squash,
+		SystemContext:           systemContext,
+		Target:                  flags.Target,
+		TransientMounts:         flags.Volumes,
+	}
+
+	return &entities.BuildOptions{BuildOptions: opts}, nil
+}
+
+func getNsValues(flags *buildFlagsWrapper) ([]buildah.NamespaceOption, error) {
+	var ret []buildah.NamespaceOption
+	if flags.Network != "" {
+		switch {
+		case flags.Network == "host":
+			ret = append(ret, buildah.NamespaceOption{
+				Name: string(specs.NetworkNamespace),
+				Host: true,
+			})
+		case flags.Network == "container":
+			ret = append(ret, buildah.NamespaceOption{
+				Name: string(specs.NetworkNamespace),
+			})
+		case flags.Network[0] == '/':
+			ret = append(ret, buildah.NamespaceOption{
+				Name: string(specs.NetworkNamespace),
+				Path: flags.Network,
+			})
+		default:
+			return nil, errors.Errorf("unsupported configuration network=%s", flags.Network)
+		}
+	}
+	return ret, nil
+}
diff --git a/cmd/podman/utils/utils.go b/cmd/podman/utils/utils.go
new file mode 100644
index 000000000..c7d105ba4
--- /dev/null
+++ b/cmd/podman/utils/utils.go
@@ -0,0 +1,22 @@
+package utils
+
+import "os"
+
+// IsDir returns true if the specified path refers to a directory.
+func IsDir(path string) bool {
+	file, err := os.Stat(path)
+	if err != nil {
+		return false
+	}
+	return file.IsDir()
+}
+
+// FileExists returns true if path refers to an existing file.
+func FileExists(path string) bool {
+	file, err := os.Stat(path)
+	// All errors return file == nil
+	if err != nil {
+		return false
+	}
+	return !file.IsDir()
+}