Refactor API build endpoint to be more compliant

* Refactor/Rename channel.WriteCloser() to encapsulate the channel
* Refactor build endpoint to "live" stream buildah output channels
  over API rather then buffering output
* Refactor bindings/tunnel build because endpoint changes
  * building tar file now in bindings rather then depending on
    caller
* Cleanup initiating extra image engine
* Remove setting fields to zero values (less noise in code)
* Update tests to support remote builds

Fixes #7136
Fixes #7137

Signed-off-by: Jhon Honce <jhonce@redhat.com>

2 files changed, 227 insertions, 110 deletions

diff --git a/pkg/bindings/images/build.go b/pkg/bindings/images/build.go
new file mode 100644
index 000000000..9082670a7
--- /dev/null
+++ b/pkg/bindings/images/build.go
@@ -0,0 +1,227 @@
+package images
+
+import (
+	"archive/tar"
+	"context"
+	"encoding/json"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/containers/buildah"
+	"github.com/containers/podman/v2/pkg/bindings"
+	"github.com/containers/podman/v2/pkg/domain/entities"
+	"github.com/docker/go-units"
+	"github.com/hashicorp/go-multierror"
+	jsoniter "github.com/json-iterator/go"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+// Build creates an image using a containerfile reference
+func Build(ctx context.Context, containerFiles []string, options entities.BuildOptions) (*entities.BuildReport, error) {
+	params := url.Values{}
+
+	if t := options.Output; len(t) > 0 {
+		params.Set("t", t)
+	}
+	for _, tag := range options.AdditionalTags {
+		params.Add("t", tag)
+	}
+	if options.Quiet {
+		params.Set("q", "1")
+	}
+	if options.NoCache {
+		params.Set("nocache", "1")
+	}
+	//	 TODO cachefrom
+	if options.PullPolicy == buildah.PullAlways {
+		params.Set("pull", "1")
+	}
+	if options.RemoveIntermediateCtrs {
+		params.Set("rm", "1")
+	}
+	if options.ForceRmIntermediateCtrs {
+		params.Set("forcerm", "1")
+	}
+	if mem := options.CommonBuildOpts.Memory; mem > 0 {
+		params.Set("memory", strconv.Itoa(int(mem)))
+	}
+	if memSwap := options.CommonBuildOpts.MemorySwap; memSwap > 0 {
+		params.Set("memswap", strconv.Itoa(int(memSwap)))
+	}
+	if cpuShares := options.CommonBuildOpts.CPUShares; cpuShares > 0 {
+		params.Set("cpushares", strconv.Itoa(int(cpuShares)))
+	}
+	if cpuSetCpus := options.CommonBuildOpts.CPUSetCPUs; len(cpuSetCpus) > 0 {
+		params.Set("cpusetcpues", cpuSetCpus)
+	}
+	if cpuPeriod := options.CommonBuildOpts.CPUPeriod; cpuPeriod > 0 {
+		params.Set("cpuperiod", strconv.Itoa(int(cpuPeriod)))
+	}
+	if cpuQuota := options.CommonBuildOpts.CPUQuota; cpuQuota > 0 {
+		params.Set("cpuquota", strconv.Itoa(int(cpuQuota)))
+	}
+	if buildArgs := options.Args; len(buildArgs) > 0 {
+		bArgs, err := jsoniter.MarshalToString(buildArgs)
+		if err != nil {
+			return nil, err
+		}
+		params.Set("buildargs", bArgs)
+	}
+	if shmSize := options.CommonBuildOpts.ShmSize; len(shmSize) > 0 {
+		shmBytes, err := units.RAMInBytes(shmSize)
+		if err != nil {
+			return nil, err
+		}
+		params.Set("shmsize", strconv.Itoa(int(shmBytes)))
+	}
+	if options.Squash {
+		params.Set("squash", "1")
+	}
+	if labels := options.Labels; len(labels) > 0 {
+		l, err := jsoniter.MarshalToString(labels)
+		if err != nil {
+			return nil, err
+		}
+		params.Set("labels", l)
+	}
+
+	stdout := io.Writer(os.Stdout)
+	if options.Out != nil {
+		stdout = options.Out
+	}
+
+	// TODO network?
+
+	var platform string
+	if OS := options.OS; len(OS) > 0 {
+		platform += OS
+	}
+	if arch := options.Architecture; len(arch) > 0 {
+		platform += "/" + arch
+	}
+	if len(platform) > 0 {
+		params.Set("platform", platform)
+	}
+
+	entries := make([]string, len(containerFiles))
+	copy(entries, containerFiles)
+	entries = append(entries, options.ContextDirectory)
+	tarfile, err := nTar(entries...)
+	if err != nil {
+		return nil, err
+	}
+	defer tarfile.Close()
+	params.Set("dockerfile", filepath.Base(containerFiles[0]))
+
+	conn, err := bindings.GetClient(ctx)
+	if err != nil {
+		return nil, err
+	}
+	response, err := conn.DoRequest(tarfile, http.MethodPost, "/build", params, nil)
+	if err != nil {
+		return nil, err
+	}
+	defer response.Body.Close()
+
+	if !response.IsSuccess() {
+		return nil, response.Process(err)
+	}
+
+	body := response.Body.(io.Reader)
+	if logrus.IsLevelEnabled(logrus.DebugLevel) {
+		if v, found := os.LookupEnv("PODMAN_RETAIN_BUILD_ARTIFACT"); found {
+			if keep, _ := strconv.ParseBool(v); keep {
+				t, _ := ioutil.TempFile("", "build_*_client")
+				defer t.Close()
+				body = io.TeeReader(response.Body, t)
+			}
+		}
+	}
+
+	dec := json.NewDecoder(body)
+	re := regexp.MustCompile(`[0-9a-f]{12}`)
+
+	var id string
+	for {
+		var s struct {
+			Stream string `json:"stream,omitempty"`
+			Error  string `json:"error,omitempty"`
+		}
+		if err := dec.Decode(&s); err != nil {
+			if errors.Is(err, io.EOF) {
+				return &entities.BuildReport{ID: id}, nil
+			}
+			s.Error = err.Error() + "\n"
+		}
+
+		switch {
+		case s.Stream != "":
+			stdout.Write([]byte(s.Stream))
+			if re.Match([]byte(s.Stream)) {
+				id = s.Stream
+			}
+		case s.Error != "":
+			return nil, errors.New(s.Error)
+		default:
+			return &entities.BuildReport{ID: id}, errors.New("failed to parse build results stream, unexpected input")
+		}
+	}
+}
+
+func nTar(sources ...string) (io.ReadCloser, error) {
+	if len(sources) == 0 {
+		return nil, errors.New("No source(s) provided for build")
+	}
+
+	pr, pw := io.Pipe()
+	tw := tar.NewWriter(pw)
+
+	var merr error
+	go func() {
+		defer pw.Close()
+		defer tw.Close()
+
+		for _, src := range sources {
+			s := src
+			err := filepath.Walk(s, func(path string, info os.FileInfo, err error) error {
+				if err != nil {
+					return err
+				}
+				if !info.Mode().IsRegular() || path == s {
+					return nil
+				}
+
+				f, lerr := os.Open(path)
+				if lerr != nil {
+					return lerr
+				}
+
+				name := strings.TrimPrefix(path, s+string(filepath.Separator))
+				hdr, lerr := tar.FileInfoHeader(info, name)
+				if lerr != nil {
+					f.Close()
+					return lerr
+				}
+				hdr.Name = name
+				if lerr := tw.WriteHeader(hdr); lerr != nil {
+					f.Close()
+					return lerr
+				}
+
+				_, cerr := io.Copy(tw, f)
+				f.Close()
+				return cerr
+			})
+			merr = multierror.Append(merr, err)
+		}
+	}()
+	return pr, merr
+}
diff --git a/pkg/bindings/images/images.go b/pkg/bindings/images/images.go
index a80c94025..05ab25d5b 100644
--- a/pkg/bindings/images/images.go
+++ b/pkg/bindings/images/images.go
@@ -1,7 +1,6 @@
 package images
 
 import (
-	"bytes"
 	"context"
 	"fmt"
 	"io"
@@ -9,14 +8,11 @@ import (
 	"net/url"
 	"strconv"
 
-	"github.com/containers/buildah"
 	"github.com/containers/image/v5/types"
 	"github.com/containers/podman/v2/pkg/api/handlers"
 	"github.com/containers/podman/v2/pkg/auth"
 	"github.com/containers/podman/v2/pkg/bindings"
 	"github.com/containers/podman/v2/pkg/domain/entities"
-	"github.com/docker/go-units"
-	jsoniter "github.com/json-iterator/go"
 	"github.com/pkg/errors"
 )
 
@@ -242,112 +238,6 @@ func Untag(ctx context.Context, nameOrID, tag, repo string) error {
 	return response.Process(nil)
 }
 
-// Build creates an image using a containerfile reference
-func Build(ctx context.Context, containerFiles []string, options entities.BuildOptions, tarfile io.Reader) (*entities.BuildReport, error) {
-	var (
-		platform string
-		report   entities.BuildReport
-	)
-	conn, err := bindings.GetClient(ctx)
-	if err != nil {
-		return nil, err
-	}
-	params := url.Values{}
-	params.Set("dockerfile", containerFiles[0])
-	if t := options.Output; len(t) > 0 {
-		params.Set("t", t)
-	}
-	for _, tag := range options.AdditionalTags {
-		params.Add("t", tag)
-	}
-	//	TODO Remote, Quiet
-	if options.NoCache {
-		params.Set("nocache", "1")
-	}
-	//	 TODO cachefrom
-	if options.PullPolicy == buildah.PullAlways {
-		params.Set("pull", "1")
-	}
-	if options.RemoveIntermediateCtrs {
-		params.Set("rm", "1")
-	}
-	if options.ForceRmIntermediateCtrs {
-		params.Set("forcerm", "1")
-	}
-	if mem := options.CommonBuildOpts.Memory; mem > 0 {
-		params.Set("memory", strconv.Itoa(int(mem)))
-	}
-	if memSwap := options.CommonBuildOpts.MemorySwap; memSwap > 0 {
-		params.Set("memswap", strconv.Itoa(int(memSwap)))
-	}
-	if cpuShares := options.CommonBuildOpts.CPUShares; cpuShares > 0 {
-		params.Set("cpushares", strconv.Itoa(int(cpuShares)))
-	}
-	if cpuSetCpus := options.CommonBuildOpts.CPUSetCPUs; len(cpuSetCpus) > 0 {
-		params.Set("cpusetcpues", cpuSetCpus)
-	}
-	if cpuPeriod := options.CommonBuildOpts.CPUPeriod; cpuPeriod > 0 {
-		params.Set("cpuperiod", strconv.Itoa(int(cpuPeriod)))
-	}
-	if cpuQuota := options.CommonBuildOpts.CPUQuota; cpuQuota > 0 {
-		params.Set("cpuquota", strconv.Itoa(int(cpuQuota)))
-	}
-	if buildArgs := options.Args; len(buildArgs) > 0 {
-		bArgs, err := jsoniter.MarshalToString(buildArgs)
-		if err != nil {
-			return nil, err
-		}
-		params.Set("buildargs", bArgs)
-	}
-	if shmSize := options.CommonBuildOpts.ShmSize; len(shmSize) > 0 {
-		shmBytes, err := units.RAMInBytes(shmSize)
-		if err != nil {
-			return nil, err
-		}
-		params.Set("shmsize", strconv.Itoa(int(shmBytes)))
-	}
-	if options.Squash {
-		params.Set("squash", "1")
-	}
-	if labels := options.Labels; len(labels) > 0 {
-		l, err := jsoniter.MarshalToString(labels)
-		if err != nil {
-			return nil, err
-		}
-		params.Set("labels", l)
-	}
-
-	// TODO network?
-	if OS := options.OS; len(OS) > 0 {
-		platform += OS
-	}
-	if arch := options.Architecture; len(arch) > 0 {
-		platform += "/" + arch
-	}
-	if len(platform) > 0 {
-		params.Set("platform", platform)
-	}
-	//	TODO outputs?
-
-	response, err := conn.DoRequest(tarfile, http.MethodPost, "/build", params, nil)
-	if err != nil {
-		return nil, err
-	}
-	var streamReponse []byte
-	bb := bytes.NewBuffer(streamReponse)
-	if _, err = io.Copy(bb, response.Body); err != nil {
-		return nil, err
-	}
-	var s struct {
-		Stream string `json:"stream"`
-	}
-	if err := jsoniter.UnmarshalFromString(bb.String(), &s); err != nil {
-		return nil, err
-	}
-	fmt.Print(s.Stream)
-	return &report, nil
-}
-
 // Imports adds the given image to the local image store.  This can be done by file and the given reader
 // or via the url parameter.  Additional metadata can be associated with the image by using the changes and
 // message parameters.  The image can also be tagged given a reference. One of url OR r must be provided.