Support export size detail message

With this update, the support export command now reports the
resulting archive file's size along with usage instructions. In
cases where the file is larger than 25MiB, an additional note is
displayed with further instructions due to common email attachment
size limits.

Issue: [sc-18005]

Author: tjmoore4

internal/cmd/export.go

@@ -50,6 +50,21 @@ import (
 	"github.com/crunchydata/postgres-operator-client/internal/util"
 )
 
+const (
+	// define one mebibyte in float64
+	// - https://mathworld.wolfram.com/Mebibyte.html
+	mebibyte float64 = (1 << 20)
+
+	// Default support export message
+	msg1 = "\n" + `Archive file size: %.2f MiB
+Email the support export archive to [email protected]
+or attach as a email reply to your existing Support Ticket` + "\n"
+
+	// Additional support export message. Shown when size is greater than 25 MiB.
+	msg2 = `Archive file (%.2f MiB) may be too big to email.
+Please request file share link by emailing [email protected]` + "\n"
+)
+
 var namespacedResources = []schema.GroupVersionResource{{
 	Group:    appsv1.SchemeGroupVersion.Group,
 	Version:  appsv1.SchemeGroupVersion.Version,
@@ -313,12 +328,35 @@ kubectl pgo support export daisy --monitoring-namespace another-namespace --outp
 			return logErr
 		}
 
+		// Print final message
+		if err == nil {
+			info, err := os.Stat(outputDir + "/" + outputFile)
+
+			if err == nil {
+				fmt.Print(exportSizeReport(float64(info.Size())))
+			}
+		}
+
 		return err
 	}
 
 	return cmd
 }
 
+// exportSizeReport defines the message displayed when a support export archive
+// is created. If the size of the archive file is greater than 25MiB, an additional
+// message is displayed.
+func exportSizeReport(size float64) string {
+	finalMsg := fmt.Sprintf(msg1, size/mebibyte)
+
+	// if file size is > 25 MiB, print additional message
+	if size > mebibyte*25 {
+		finalMsg = finalMsg + fmt.Sprintf(msg2, size/mebibyte)
+	}
+
+	return finalMsg
+}
+
 // gatherKubeServerVersion collects the server version from the Kubernetes cluster
 func gatherKubeServerVersion(_ context.Context,
 	client *discovery.DiscoveryClient,

internal/cmd/export_test.go

@@ -0,0 +1,45 @@
+// Copyright 2021 - 2023 Crunchy Data Solutions, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cmd
+
+import (
+	"fmt"
+	"testing"
+
+	"gotest.tools/v3/assert"
+)
+
+func TestFileSizeReport(t *testing.T) {
+	testsCases := []struct {
+		desc   string
+		bytes  float64
+		output string
+	}{
+		{"Zero value", 0, fmt.Sprintf(msg1, 0/mebibyte)},
+		{"Less than 25 MiB", 10000, fmt.Sprintf(msg1, 10000/mebibyte)},
+		{"25 MiB", 26214400, fmt.Sprintf(msg1, 26214400/mebibyte)},
+		{"25 MiB + 1 byte", 26214401,
+			fmt.Sprintf(msg1, 26214401/mebibyte) + fmt.Sprintf(msg2, 26214400/mebibyte)},
+		{"3 GiB", 3221225472,
+			fmt.Sprintf(msg1, 3221225472/mebibyte) + fmt.Sprintf(msg2, 3221225472/mebibyte)},
+		{"Something went wrong...", -1, fmt.Sprintf(msg1, -1/mebibyte)},
+	}
+
+	for _, tc := range testsCases {
+		t.Run(tc.desc, func(t *testing.T) {
+			assert.Equal(t, exportSizeReport(tc.bytes), tc.output)
+		})
+	}
+}