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, 70 insertions, 0 deletions

diff --git a/pkg/channel/doc.go b/pkg/channel/doc.go
new file mode 100644
index 000000000..656fbddaa
--- /dev/null
+++ b/pkg/channel/doc.go
@@ -0,0 +1,17 @@
+/*
+Package channel provides helper structs/methods/funcs for working with channels
+
+Proxy from an io.Writer to a channel:
+
+	w := channel.NewWriter(make(chan []byte, 10))
+	go func() {
+		w.Write([]byte("Hello, World"))
+	}()
+
+	fmt.Println(string(<-w.Chan()))
+    w.Close()
+
+Use of the constructor is required to initialize the channel.
+Provide a channel of sufficient size to handle messages from writer(s).
+*/
+package channel
diff --git a/pkg/channel/writer.go b/pkg/channel/writer.go
new file mode 100644
index 000000000..dbb38e416
--- /dev/null
+++ b/pkg/channel/writer.go
@@ -0,0 +1,53 @@
+package channel
+
+import (
+	"io"
+	"sync"
+
+	"github.com/pkg/errors"
+)
+
+// WriteCloser is an io.WriteCloser that that proxies Write() calls to a channel
+// The []byte buffer of the Write() is queued on the channel as one message.
+type WriteCloser interface {
+	io.WriteCloser
+	Chan() <-chan []byte
+}
+
+type writeCloser struct {
+	ch  chan []byte
+	mux sync.Mutex
+}
+
+// NewWriter initializes a new channel writer
+func NewWriter(c chan []byte) WriteCloser {
+	return &writeCloser{
+		ch: c,
+	}
+}
+
+// Chan returns the R/O channel behind WriteCloser
+func (w *writeCloser) Chan() <-chan []byte {
+	return w.ch
+}
+
+// Write method for WriteCloser
+func (w *writeCloser) Write(b []byte) (int, error) {
+	if w == nil || w.ch == nil {
+		return 0, errors.New("use channel.NewWriter() to initialize a WriteCloser")
+	}
+
+	w.mux.Lock()
+	buf := make([]byte, len(b))
+	copy(buf, b)
+	w.ch <- buf
+	w.mux.Unlock()
+
+	return len(b), nil
+}
+
+// Close method for WriteCloser
+func (w *writeCloser) Close() error {
+	close(w.ch)
+	return nil
+}