util/yaml: Added package which helps working with yamls

It allows to get/set some basic info like kind or name to k8s objects
stored as yamls

pkg/util/yaml/yaml.go

@@ -0,0 +1,53 @@
+// Copyright (C) 2017 ScyllaDB
+
+package yaml
+
+import (
+	"bufio"
+	"io"
+
+	"github.com/pkg/errors"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	apiyaml "k8s.io/apimachinery/pkg/util/yaml"
+	"sigs.k8s.io/yaml"
+)
+
+// ToUnstructured takes a YAML and converts it to a list of Unstructured objects
+func ToUnstructured(rawyaml io.Reader) ([]unstructured.Unstructured, error) {
+	var objs []unstructured.Unstructured
+
+	reader := apiyaml.NewYAMLReader(bufio.NewReader(rawyaml))
+	count := 1
+	for {
+		// Read one YAML document at a time, until io.EOF is returned
+		b, err := reader.Read()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return nil, errors.Wrapf(err, "failed to read yaml")
+		}
+		if len(b) == 0 {
+			break
+		}
+
+		var m map[string]interface{}
+		if err := yaml.Unmarshal(b, &m); err != nil {
+			return nil, errors.Wrapf(err, "failed to unmarshal the %d yaml document: %q", count, string(b))
+		}
+
+		var u unstructured.Unstructured
+		u.SetUnstructuredContent(m)
+
+		// Ignore empty objects.
+		// Empty objects are generated if there are weird things in manifest files like e.g. two --- in a row without a yaml doc in the middle
+		if u.Object == nil {
+			continue
+		}
+
+		objs = append(objs, u)
+		count++
+	}
+
+	return objs, nil
+}

pkg/util/yaml/yaml_test.go

@@ -0,0 +1,139 @@
+// Copyright (C) 2017 ScyllaDB
+
+package yaml
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func TestToUnstructured(t *testing.T) {
+	type args struct {
+		rawyaml []byte
+	}
+	tests := []struct {
+		name          string
+		args          args
+		wantObjsCount int
+		err           string
+	}{
+		{
+			name: "single object",
+			args: args{
+				rawyaml: []byte("apiVersion: v1\n" +
+					"kind: ConfigMap\n"),
+			},
+			wantObjsCount: 1,
+		},
+		{
+			name: "multiple objects are detected",
+			args: args{
+				rawyaml: []byte("apiVersion: v1\n" +
+					"kind: ConfigMap\n" +
+					"---\n" +
+					"apiVersion: v1\n" +
+					"kind: Secret\n"),
+			},
+			wantObjsCount: 2,
+		},
+		{
+			name: "empty object are dropped",
+			args: args{
+				rawyaml: []byte("---\n" + //empty objects before
+					"---\n" +
+					"---\n" +
+					"apiVersion: v1\n" +
+					"kind: ConfigMap\n" +
+					"---\n" + // empty objects in the middle
+					"---\n" +
+					"---\n" +
+					"apiVersion: v1\n" +
+					"kind: Secret\n" +
+					"---\n" + //empty objects after
+					"---\n" +
+					"---\n"),
+			},
+			wantObjsCount: 2,
+		},
+		{
+			name: "--- in the middle of objects are ignored",
+			args: args{
+				[]byte("apiVersion: v1\n" +
+					"kind: ConfigMap\n" +
+					"data: \n" +
+					" key: |\n" +
+					"  ··Several lines of text,\n" +
+					"  ··with some --- \n" +
+					"  ---\n" +
+					"  ··in the middle\n" +
+					"---\n" +
+					"apiVersion: v1\n" +
+					"kind: Secret\n"),
+			},
+			wantObjsCount: 2,
+		},
+		{
+			name: "returns error for invalid yaml",
+			args: args{
+				rawyaml: []byte("apiVersion: v1\n" +
+					"kind: ConfigMap\n" +
+					"---\n" +
+					"apiVersion: v1\n" +
+					"foobar\n" +
+					"kind: Secret\n"),
+			},
+			err: "failed to unmarshal the 2 yaml document",
+		},
+		{
+			name: "returns error for invalid yaml",
+			args: args{
+				rawyaml: []byte("apiVersion: v1\n" +
+					"kind: ConfigMap\n" +
+					"---\n" +
+					"apiVersion: v1\n" +
+					"kind: Pod\n" +
+					"---\n" +
+					"apiVersion: v1\n" +
+					"kind: Deployment\n" +
+					"---\n" +
+					"apiVersion: v1\n" +
+					"foobar\n" +
+					"kind: ConfigMap\n"),
+			},
+			err: "failed to unmarshal the 4 yaml document",
+		},
+		{
+			name: "returns error for invalid yaml",
+			args: args{
+				rawyaml: []byte("apiVersion: v1\n" +
+					"foobar\n" +
+					"kind: ConfigMap\n" +
+					"---\n" +
+					"apiVersion: v1\n" +
+					"kind: Secret\n"),
+			},
+			err: "failed to unmarshal the 1 yaml document",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ToUnstructured(bytes.NewReader(tt.args.rawyaml))
+			if tt.err != "" {
+				if err == nil {
+					t.Fatal("expected error, got nil")
+				}
+				if !strings.Contains(err.Error(), tt.err) {
+					t.Errorf("expected err %q got %q", tt.err, err)
+				}
+			} else {
+				if err != nil {
+					t.Errorf("expected nil error, got %s", err)
+				}
+				if len(got) != tt.wantObjsCount {
+					t.Errorf("expected %d object, got %d", tt.wantObjsCount, len(got))
+				}
+			}
+		})
+	}
+}