Add more tests around JSON/YAML decoding from the CLI

Switch the ignore stream errors behavior to print a Warningf on
failure to parse, not v(2)

hack/test-cmd.sh

@@ -138,6 +138,19 @@ for version in "${kube_api_versions[@]}"; do
   output_service=$(kubectl get service frontend -o json --output-version=v1beta3 "${kube_flags[@]}")
   kubectl delete service frontend "${kube_flags[@]}"
   echo "${output_service}" | kubectl create -f - "${kube_flags[@]}"
+  kubectl create -f - "${kube_flags[@]}" << __EOF__
+      {
+          "kind": "Service",
+          "apiVersion": "v1beta1",
+          "id": "service-${version}-test",
+          "port": 80,
+          "protocol": "TCP",
+          "labels": {
+              "name": "${version}"
+          }
+      }
+__EOF__
+  kubectl get services "something-${version}" "${kube_flags[@]}"
   kubectl get services "${kube_flags[@]}"
   kubectl delete service frontend "${kube_flags[@]}"
 

pkg/kubectl/resource/visitor.go

@@ -337,7 +337,10 @@ type StreamVisitor struct {
 }
 
 // NewStreamVisitor creates a visitor that will return resources that were encoded into the provided
-// stream. If ignoreErrors is set, unrecognized or invalid objects will be skipped and logged.
+// stream. If ignoreErrors is set, unrecognized or invalid objects will be skipped and logged. An
+// empty stream is treated as an error for now.
+// TODO: convert ignoreErrors into a func(data, error, count) bool that consumers can use to decide
+// what to do with ignored errors.
 func NewStreamVisitor(r io.Reader, mapper *Mapper, source string, ignoreErrors bool) Visitor {
 	return &StreamVisitor{r, mapper, source, ignoreErrors}
 }
@@ -356,7 +359,7 @@ func (v *StreamVisitor) Visit(fn VisitorFunc) error {
 		info, err := v.InfoForData(ext.RawJSON, v.Source)
 		if err != nil {
 			if v.IgnoreErrors {
-				glog.V(2).Infof("Unable to read item from stream %q: %v", err)
+				glog.Warningf("Could not read an encoded object from %s: %v", v.Source, err)
 				glog.V(4).Infof("Unreadable: %s", string(ext.RawJSON))
 				continue
 			}

pkg/util/yaml/decoder.go

@@ -149,6 +149,6 @@ func guessJSONStream(r io.Reader, size int) (io.Reader, bool) {
 // Return true if the first non-whitespace bytes in buf is
 // prefix
 func hasPrefix(buf []byte, prefix []byte) bool {
-	buf = bytes.TrimLeftFunc(buf, unicode.IsSpace)
+	trim := bytes.TrimLeftFunc(buf, unicode.IsSpace)
-	return bytes.HasPrefix(buf, prefix)
+	return bytes.HasPrefix(trim, prefix)
 }

pkg/util/yaml/decoder_test.go

@@ -61,6 +61,21 @@ func TestSplitYAMLDocument(t *testing.T) {
 	}
 }
 
+func TestGuessJSON(t *testing.T) {
+	if r, isJSON := guessJSONStream(bytes.NewReader([]byte(" \n{}")), 100); !isJSON {
+		t.Fatalf("expected stream to be JSON")
+	} else {
+		b := make([]byte, 30)
+		n, err := r.Read(b)
+		if err != nil || n != 4 {
+			t.Fatalf("unexpected body: %d / %v", n, err)
+		}
+		if string(b[:n]) != " \n{}" {
+			t.Fatalf("unexpected body: %q", string(b[:n]))
+		}
+	}
+}
+
 func TestScanYAML(t *testing.T) {
 	s := bufio.NewScanner(bytes.NewReader([]byte(`---
 stuff: 1
@@ -130,7 +145,10 @@ func TestYAMLOrJSONDecoder(t *testing.T) {
 		{" \na: b", 2, false, false, []generic{
 			{"a": "b"},
 		}},
-		{` \n{"a": "b"}`, 2, false, true, []generic{
+		{" \n{\"a\": \"b\"}", 2, false, true, []generic{
+			{"a": "b"},
+		}},
+		{" \n{\"a\": \"b\"}", 3, true, false, []generic{
 			{"a": "b"},
 		}},
 		{`   {"a":"b"}`, 100, true, false, []generic{