Refactor remote pull to provide progress

podman and podman-remote do not exactly match as the lower layer code
checks if the output is destined for a  TTY before creating the progress
bars.  A future PR for containers/images could change this behavior.

Fixes #7543

Tested with:

$ (echo '# start'; podman-remote pull nginx ) 2>&1 | ts '[%Y-%m-%d %H:%M:%.S]'
$ (echo '# start'; podman pull nginx ) 2>&1 | ts '[%Y-%m-%d %H:%M:%.S]'

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

1 files changed, 98 insertions, 0 deletions

diff --git a/pkg/bindings/images/pull.go b/pkg/bindings/images/pull.go
new file mode 100644
index 000000000..261a481a2
--- /dev/null
+++ b/pkg/bindings/images/pull.go
@@ -0,0 +1,98 @@
+package images
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"os"
+	"strconv"
+
+	"github.com/containers/image/v5/types"
+	"github.com/containers/podman/v2/pkg/auth"
+	"github.com/containers/podman/v2/pkg/bindings"
+	"github.com/containers/podman/v2/pkg/domain/entities"
+	"github.com/hashicorp/go-multierror"
+)
+
+// Pull is the binding for libpod's v2 endpoints for pulling images.  Note that
+// `rawImage` must be a reference to a registry (i.e., of docker transport or be
+// normalized to one).  Other transports are rejected as they do not make sense
+// in a remote context. Progress reported on stderr
+func Pull(ctx context.Context, rawImage string, options entities.ImagePullOptions) ([]string, error) {
+	conn, err := bindings.GetClient(ctx)
+	if err != nil {
+		return nil, err
+	}
+	params := url.Values{}
+	params.Set("reference", rawImage)
+	params.Set("overrideArch", options.OverrideArch)
+	params.Set("overrideOS", options.OverrideOS)
+	params.Set("overrideVariant", options.OverrideVariant)
+
+	if options.SkipTLSVerify != types.OptionalBoolUndefined {
+		// Note: we have to verify if skipped is false.
+		verifyTLS := bool(options.SkipTLSVerify == types.OptionalBoolFalse)
+		params.Set("tlsVerify", strconv.FormatBool(verifyTLS))
+	}
+	params.Set("allTags", strconv.FormatBool(options.AllTags))
+
+	// TODO: have a global system context we can pass around (1st argument)
+	header, err := auth.Header(nil, options.Authfile, options.Username, options.Password)
+	if err != nil {
+		return nil, err
+	}
+
+	response, err := conn.DoRequest(nil, http.MethodPost, "/images/pull", params, header)
+	if err != nil {
+		return nil, err
+	}
+	defer response.Body.Close()
+
+	if !response.IsSuccess() {
+		return nil, response.Process(err)
+	}
+
+	// Historically pull writes status to stderr
+	stderr := io.Writer(os.Stderr)
+	if options.Quiet {
+		stderr = ioutil.Discard
+	}
+
+	dec := json.NewDecoder(response.Body)
+	var images []string
+	var mErr error
+	for {
+		var report entities.ImagePullReport
+		if err := dec.Decode(&report); err != nil {
+			if errors.Is(err, io.EOF) {
+				break
+			}
+			report.Error = err.Error() + "\n"
+		}
+
+		select {
+		case <-response.Request.Context().Done():
+			return images, mErr
+		default:
+			// non-blocking select
+		}
+
+		switch {
+		case report.Stream != "":
+			fmt.Fprint(stderr, report.Stream)
+		case report.Error != "":
+			mErr = multierror.Append(mErr, errors.New(report.Error))
+		case len(report.Images) > 0:
+			images = report.Images
+		default:
+			return images, errors.New("failed to parse pull results stream, unexpected input")
+		}
+
+	}
+	return images, mErr
+}