From b1122a3e0b0f64a9e9748ae3794f4e99db6a6e1e Mon Sep 17 00:00:00 2001
From: Sean Sullivan <seans@google.com>
Date: Tue, 14 Jan 2020 15:34:47 -0800
Subject: [PATCH] Adds PrependGroupingObject() as apply pre-processor

---
 cmd/kubectl/kubectlcobra/commands.go      | 26 ++++++++++
 cmd/kubectl/kubectlcobra/commands_test.go | 58 +++++++++++++++++++++++
 2 files changed, 84 insertions(+)
 create mode 100644 cmd/kubectl/kubectlcobra/commands_test.go

diff --git a/cmd/kubectl/kubectlcobra/commands.go b/cmd/kubectl/kubectlcobra/commands.go
index fd365e2b0..ade1205cc 100644
--- a/cmd/kubectl/kubectlcobra/commands.go
+++ b/cmd/kubectl/kubectlcobra/commands.go
@@ -6,6 +6,7 @@ package kubectlcobra
 
 import (
 	"flag"
+	"fmt"
 	"os"
 	"strings"
 
@@ -80,6 +81,7 @@ func updateHelp(names []string, c *cobra.Command) {
 func NewCmdApply(baseName string, f util.Factory, ioStreams genericclioptions.IOStreams) *cobra.Command {
 	o := apply.NewApplyOptions(ioStreams)
 	so := newStatusOptions(f, ioStreams)
+	o.PreProcessorFn = PrependGroupingObject(o)
 
 	cmd := &cobra.Command{
 		Use:                   "apply (-f FILENAME | -k DIRECTORY)",
@@ -118,3 +120,27 @@ func NewCmdApply(baseName string, f util.Factory, ioStreams genericclioptions.IO
 
 	return cmd
 }
+
+// PrependGroupingObject orders the objects to apply so the "grouping"
+// object stores the inventory, and it is first to be applied.
+func PrependGroupingObject(o *apply.ApplyOptions) func() error {
+	return func() error {
+		if o == nil {
+			return fmt.Errorf("ApplyOptions are nil")
+		}
+		infos, err := o.GetObjects()
+		if err != nil {
+			return err
+		}
+		_, exists := findGroupingObject(infos)
+		if exists {
+			if err := addInventoryToGroupingObj(infos); err != nil {
+				return err
+			}
+			if !sortGroupingObject(infos) {
+				return err
+			}
+		}
+		return nil
+	}
+}
diff --git a/cmd/kubectl/kubectlcobra/commands_test.go b/cmd/kubectl/kubectlcobra/commands_test.go
new file mode 100644
index 000000000..4d6b5ee5d
--- /dev/null
+++ b/cmd/kubectl/kubectlcobra/commands_test.go
@@ -0,0 +1,58 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+// package kubectlcobra contains cobra commands from kubectl
+package kubectlcobra
+
+import (
+	"testing"
+
+	"k8s.io/cli-runtime/pkg/resource"
+	"k8s.io/kubectl/pkg/cmd/apply"
+)
+
+func TestPrependGroupingObject(t *testing.T) {
+	tests := []struct {
+		infos []*resource.Info
+	}{
+		{
+			infos: []*resource.Info{copyGroupingInfo()},
+		},
+		{
+			infos: []*resource.Info{pod1Info, pod3Info, copyGroupingInfo()},
+		},
+		{
+			infos: []*resource.Info{pod1Info, pod2Info, copyGroupingInfo(), pod3Info},
+		},
+	}
+
+	for _, test := range tests {
+		applyOptions := createApplyOptions(test.infos)
+		f := PrependGroupingObject(applyOptions)
+		err := f()
+		if err != nil {
+			t.Errorf("Error running pre-processor callback: %s", err)
+		}
+		infos, _ := applyOptions.GetObjects()
+		if len(test.infos) != len(infos) {
+			t.Fatalf("Wrong number of objects after prepending grouping object")
+		}
+		groupingInfo := infos[0]
+		if !isGroupingObject(groupingInfo.Object) {
+			t.Fatalf("First object is not the grouping object")
+		}
+		inventory, _ := retrieveInventoryFromGroupingObj(infos)
+		if len(inventory) != (len(infos) - 1) {
+			t.Errorf("Wrong number of inventory items stored in grouping object")
+		}
+	}
+
+}
+
+// createApplyOptions is a helper function to assemble the ApplyOptions
+// with the passed objects (infos).
+func createApplyOptions(infos []*resource.Info) *apply.ApplyOptions {
+	applyOptions := &apply.ApplyOptions{}
+	applyOptions.SetObjects(infos)
+	return applyOptions
+}