From 70add17e0865a2ef8516697e5abd90aaa5d1b310 Mon Sep 17 00:00:00 2001
From: Sandeep Rajan <srajan@infoblox.com>
Date: Thu, 18 Apr 2019 13:29:35 -0400
Subject: [PATCH 1/5] Initial commit for the corefile-tool cli for the
 migration tool

---
 kubernetes/corefile-tool/.gitignore           |  3 +
 kubernetes/corefile-tool/README.md            | 62 ++++++++++++++++++
 kubernetes/corefile-tool/cmd/default.go       | 54 ++++++++++++++++
 kubernetes/corefile-tool/cmd/deprecated.go    | 59 +++++++++++++++++
 kubernetes/corefile-tool/cmd/migrate.go       | 63 +++++++++++++++++++
 kubernetes/corefile-tool/cmd/removed.go       | 58 +++++++++++++++++
 kubernetes/corefile-tool/cmd/root.go          | 34 ++++++++++
 kubernetes/corefile-tool/cmd/unsupported.go   | 57 +++++++++++++++++
 kubernetes/corefile-tool/cmd/validversions.go | 24 +++++++
 kubernetes/corefile-tool/main.go              |  7 +++
 kubernetes/migration/migrate.go               |  9 ++-
 11 files changed, 427 insertions(+), 3 deletions(-)
 create mode 100644 kubernetes/corefile-tool/.gitignore
 create mode 100644 kubernetes/corefile-tool/README.md
 create mode 100644 kubernetes/corefile-tool/cmd/default.go
 create mode 100644 kubernetes/corefile-tool/cmd/deprecated.go
 create mode 100644 kubernetes/corefile-tool/cmd/migrate.go
 create mode 100644 kubernetes/corefile-tool/cmd/removed.go
 create mode 100644 kubernetes/corefile-tool/cmd/root.go
 create mode 100644 kubernetes/corefile-tool/cmd/unsupported.go
 create mode 100644 kubernetes/corefile-tool/cmd/validversions.go
 create mode 100644 kubernetes/corefile-tool/main.go

diff --git a/kubernetes/corefile-tool/.gitignore b/kubernetes/corefile-tool/.gitignore
new file mode 100644
index 0000000..adefe92
--- /dev/null
+++ b/kubernetes/corefile-tool/.gitignore
@@ -0,0 +1,3 @@
+Corefile
+corefile-tool
+*.yaml
\ No newline at end of file
diff --git a/kubernetes/corefile-tool/README.md b/kubernetes/corefile-tool/README.md
new file mode 100644
index 0000000..9d488ac
--- /dev/null
+++ b/kubernetes/corefile-tool/README.md
@@ -0,0 +1,62 @@
+## Corefile-tool
+
+Corefile-tool is a simple command line tool which helps you to evaluate and migrate your CoreDNS Corefile Configuration.
+It is based on the [CoreDNS migration tool library](https://github.com/coredns/deployment/tree/master/kubernetes/migration).
+
+## Usage
+
+Use the following syntax to run the `corefile-tool` command:
+
+`corefile-tool [command] [flags]`
+
+where `command`, `flags` are:
+
+- `command`: The operation you want to perform. 
+- `flags`  : Specifies flags required to carry out the operations.
+
+
+### Operations
+
+The following operations are supported:
+- `default`: Default returns true if the Corefile is the default for a that version of Kubernetes. 
+If the Kubernetes version is omitted, returns true if the Corefile is the default for any version.
+
+- `deprecated`    : Deprecated returns a list of deprecated plugins or directives present in the Corefile.
+- `migrate`       : Migrate your CoreDNS corefile.
+- `removed`       : Removed returns a list of removed plugins or directives present in the Corefile.
+- `unsupported`   : Unsupported returns a list of plugins that are not recognized/supported by the migration tool (but may still be valid in CoreDNS).
+- `validversions` : Shows valid versions of CoreDNS.
+
+
+### Examples
+
+The following examples will help you understand the basic usage of the migration tool.
+
+```bash
+# See if the Corefile is the default in CoreDNS v1.4.0. 
+corefile-tool default --k8sversion 1.4.0 --corefile /path/to/Corefile
+```
+
+```bash
+# See deprecated plugins CoreDNS from v1.4.0 to v1.5.0. 
+corefile-tool deprecated --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile
+```
+
+```bash
+# See unsupported plugins CoreDNS from v1.4.0 to v1.5.0. 
+corefile-tool unsupported --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile
+```
+
+```bash
+# See removed plugins CoreDNS from v1.4.0 to v1.5.0. 
+corefile-tool removed --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile
+```
+
+```bash
+# Migrate CoreDNS from v1.4.0 to v1.5.0 and handle deprecations . 
+corefile-tool migrate --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile  --deprecations true
+
+# Migrate CoreDNS from v1.2.2 to v1.3.1 and do not handle deprecations .
+corefile-tool migrate --from 1.2.2 --to 1.3.1 --corefile /path/to/Corefile  --deprecations false
+```
+
diff --git a/kubernetes/corefile-tool/cmd/default.go b/kubernetes/corefile-tool/cmd/default.go
new file mode 100644
index 0000000..ea97321
--- /dev/null
+++ b/kubernetes/corefile-tool/cmd/default.go
@@ -0,0 +1,54 @@
+package cmd
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/coredns/deployment/kubernetes/migration"
+
+	"github.com/spf13/cobra"
+)
+
+// defaultCmd represents the default command
+var defaultCmd = &cobra.Command{
+	Use:   "default",
+	Short: "default returns true if the Corefile is the default for a that version of Kubernetes. If the Kubernetes version is omitted, returns true if the Corefile is the default for any version.",
+	Example: `# See if the Corefile is the default in CoreDNS v1.4.0. 
+corefile-tool default --k8sversion 1.4.0 --corefile /path/to/Corefile`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		k8sversion, _ := cmd.Flags().GetString("k8sversion")
+		corefile, _ := cmd.Flags().GetString("corefile")
+
+		isDefault, err := defaultCorefileFromPath(k8sversion, corefile)
+		if err != nil {
+			return fmt.Errorf("error while checking if the Corefile is the default: %v \n", err)
+		}
+		fmt.Println(isDefault)
+
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(defaultCmd)
+
+	defaultCmd.Flags().String("k8sversion", "", "The Kuberenetes version for which you are checking the default.")
+	defaultCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
+	defaultCmd.MarkFlagRequired("corefile")
+}
+
+// defaultCorefileFromPath takes the path where the Corefile is located and checks
+// if the Corefile is the default for a that version of Kubernetes.
+func defaultCorefileFromPath(k8sVersion, corefilePath string) (bool, error) {
+	if _, err := os.Stat(corefilePath); os.IsNotExist(err) {
+		return false, err
+	}
+
+	fileBytes, err := ioutil.ReadFile(corefilePath)
+	if err != nil {
+		return false, err
+	}
+	corefileStr := string(fileBytes)
+	return migration.Default(k8sVersion, corefileStr), nil
+}
diff --git a/kubernetes/corefile-tool/cmd/deprecated.go b/kubernetes/corefile-tool/cmd/deprecated.go
new file mode 100644
index 0000000..535bc0c
--- /dev/null
+++ b/kubernetes/corefile-tool/cmd/deprecated.go
@@ -0,0 +1,59 @@
+package cmd
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/coredns/deployment/kubernetes/migration"
+
+	"github.com/spf13/cobra"
+)
+
+// deprecatedCmd represents the deprecated command
+var deprecatedCmd = &cobra.Command{
+	Use:   "deprecated",
+	Short: "Deprecated returns a list of deprecated plugins or directives present in the Corefile.",
+	Example: `# See deprecated plugins CoreDNS from v1.4.0 to v1.5.0. 
+corefile-tool deprecated --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		from, _ := cmd.Flags().GetString("from")
+		to, _ := cmd.Flags().GetString("to")
+		corefile, _ := cmd.Flags().GetString("corefile")
+		deprecated, err := deprecatedCorefileFromPath(from, to, corefile)
+		if err != nil {
+			return fmt.Errorf("error while listing deprecated plugins: %v \n", err)
+		}
+		for _, dep := range deprecated {
+			fmt.Println(dep.ToString())
+		}
+		return nil
+	},
+}
+
+func init() {
+
+	rootCmd.AddCommand(deprecatedCmd)
+
+	deprecatedCmd.Flags().String("from", "", "Required: The version you are migrating from. ")
+	deprecatedCmd.MarkFlagRequired("from")
+	deprecatedCmd.Flags().String("to", "", "Required: The version you are migrating to.")
+	deprecatedCmd.MarkFlagRequired("to")
+	deprecatedCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
+	deprecatedCmd.MarkFlagRequired("corefile")
+}
+
+// deprecatedCorefileFromPath takes the path where the Corefile is located and returns the deprecated plugins or directives
+// present in the Corefile.
+func deprecatedCorefileFromPath(fromCoreDNSVersion, toCoreDNSVersion, corefilePath string) ([]migration.Notice, error) {
+	if _, err := os.Stat(corefilePath); os.IsNotExist(err) {
+		return nil, err
+	}
+
+	fileBytes, err := ioutil.ReadFile(corefilePath)
+	if err != nil {
+		return nil, err
+	}
+	corefileStr := string(fileBytes)
+	return migration.Deprecated(fromCoreDNSVersion, toCoreDNSVersion, corefileStr)
+}
diff --git a/kubernetes/corefile-tool/cmd/migrate.go b/kubernetes/corefile-tool/cmd/migrate.go
new file mode 100644
index 0000000..2213d23
--- /dev/null
+++ b/kubernetes/corefile-tool/cmd/migrate.go
@@ -0,0 +1,63 @@
+package cmd
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/coredns/deployment/kubernetes/migration"
+
+	"github.com/spf13/cobra"
+)
+
+// migrateCmd represents the migrate command
+var migrateCmd = &cobra.Command{
+	Use:   "migrate",
+	Short: "Migrate your CoreDNS corefile",
+	Example: `# Migrate CoreDNS from v1.4.0 to v1.5.0 and handle deprecations . 
+corefile-tool migrate --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile  --deprecations true
+
+# Migrate CoreDNS from v1.2.2 to v1.3.1 and do not handle deprecations .
+corefile-tool migrate --from 1.2.2 --to 1.3.1 --corefile /path/to/Corefile  --deprecations false`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		from, _ := cmd.Flags().GetString("from")
+		to, _ := cmd.Flags().GetString("to")
+		corefile, _ := cmd.Flags().GetString("corefile")
+		deprecations, _ := cmd.Flags().GetBool("deprecations")
+
+		migrated, err := migrateCorefileFromPath(from, to, corefile, deprecations)
+		if err != nil {
+			return fmt.Errorf("error while migration: %v \n", err)
+		}
+		fmt.Println(migrated)
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(migrateCmd)
+
+	migrateCmd.Flags().String("from", "", "Required: The version you are migrating from. ")
+	migrateCmd.MarkFlagRequired("from")
+	migrateCmd.Flags().String("to", "", "Required: The version you are migrating to.")
+	migrateCmd.MarkFlagRequired("to")
+	migrateCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
+	migrateCmd.MarkFlagRequired("corefile")
+	migrateCmd.Flags().Bool("deprecations", false, "Required: Specify whether you want to handle plugin deprecations. [True | False] ")
+	migrateCmd.MarkFlagRequired("deprecations")
+}
+
+// migrateCorefileFromPath takes the path where the Corefile is located and returns the deprecated plugins or directives
+// present in the Corefile.
+func migrateCorefileFromPath(fromCoreDNSVersion, toCoreDNSVersion, corefilePath string, deprecations bool) (string, error) {
+	if _, err := os.Stat(corefilePath); os.IsNotExist(err) {
+		return "", err
+	}
+
+	fileBytes, err := ioutil.ReadFile(corefilePath)
+	if err != nil {
+		return "", err
+	}
+	corefileStr := string(fileBytes)
+	return migration.Migrate(fromCoreDNSVersion, toCoreDNSVersion, corefileStr, deprecations)
+}
diff --git a/kubernetes/corefile-tool/cmd/removed.go b/kubernetes/corefile-tool/cmd/removed.go
new file mode 100644
index 0000000..b1178f1
--- /dev/null
+++ b/kubernetes/corefile-tool/cmd/removed.go
@@ -0,0 +1,58 @@
+package cmd
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/coredns/deployment/kubernetes/migration"
+
+	"github.com/spf13/cobra"
+)
+
+// removedCmd represents the removed command
+var removedCmd = &cobra.Command{
+	Use:   "removed",
+	Short: "Removed returns a list of removed plugins or directives present in the Corefile.",
+	Example: `# See removed plugins CoreDNS from v1.4.0 to v1.5.0. 
+corefile-tool removed --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		from, _ := cmd.Flags().GetString("from")
+		to, _ := cmd.Flags().GetString("to")
+		corefile, _ := cmd.Flags().GetString("corefile")
+		removed, err := removedCorefileFromPath(from, to, corefile)
+		if err != nil {
+			return fmt.Errorf("error while listing deprecated plugins: %v \n", err)
+		}
+		for _, rem := range removed {
+			fmt.Println(rem.ToString())
+		}
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(removedCmd)
+
+	removedCmd.Flags().String("from", "", "Required: The version you are migrating from. ")
+	removedCmd.MarkFlagRequired("from")
+	removedCmd.Flags().String("to", "", "Required: The version you are migrating to.")
+	removedCmd.MarkFlagRequired("to")
+	removedCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
+	removedCmd.MarkFlagRequired("corefile")
+}
+
+// removedCorefileFromPath takes the path where the Corefile is located and returns the plugins or directives
+// that have been removed.
+func removedCorefileFromPath(fromCoreDNSVersion, toCoreDNSVersion, corefilePath string) ([]migration.Notice, error) {
+	if _, err := os.Stat(corefilePath); os.IsNotExist(err) {
+		return nil, err
+	}
+
+	fileBytes, err := ioutil.ReadFile(corefilePath)
+	if err != nil {
+		return nil, err
+	}
+	corefileStr := string(fileBytes)
+	return migration.Removed(fromCoreDNSVersion, toCoreDNSVersion, corefileStr)
+}
diff --git a/kubernetes/corefile-tool/cmd/root.go b/kubernetes/corefile-tool/cmd/root.go
new file mode 100644
index 0000000..7ebf69f
--- /dev/null
+++ b/kubernetes/corefile-tool/cmd/root.go
@@ -0,0 +1,34 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/lithammer/dedent"
+	"github.com/spf13/cobra"
+)
+
+// rootCmd represents the base command for the corefile-tool.
+var rootCmd = &cobra.Command{
+	Use:   "corefile-tool",
+	Short: "A brief description of your application",
+	Long: dedent.Dedent(`
+
+			    ┌──────────────────────────────────────────────────────────┐
+			    │ CoreDNS Migration Tool                                   │
+			    │ Easily Migrate your Corefile                             │
+			    │                                                          │
+			    │ Please give us feedback at:                              │
+			    │ https://github.com/coredns/deployment/issues             │
+			    └──────────────────────────────────────────────────────────┘
+
+		`),
+}
+
+// Execute adds all child commands to the root command and sets flags appropriately.
+func Execute() {
+	if err := rootCmd.Execute(); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+}
diff --git a/kubernetes/corefile-tool/cmd/unsupported.go b/kubernetes/corefile-tool/cmd/unsupported.go
new file mode 100644
index 0000000..eb94e41
--- /dev/null
+++ b/kubernetes/corefile-tool/cmd/unsupported.go
@@ -0,0 +1,57 @@
+package cmd
+
+import (
+	"fmt"
+	"github.com/coredns/deployment/kubernetes/migration"
+	"io/ioutil"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+// unsupportedCmd represents the unsupported command
+var unsupportedCmd = &cobra.Command{
+	Use:   "unsupported",
+	Short: "Unsupported returns a list of plugins that are not recognized/supported by the migration tool (but may still be valid in CoreDNS).",
+	Example: `# See unsupported plugins CoreDNS from v1.4.0 to v1.5.0. 
+corefile-tool unsupported --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		from, _ := cmd.Flags().GetString("from")
+		to, _ := cmd.Flags().GetString("to")
+		corefile, _ := cmd.Flags().GetString("corefile")
+		unsupported, err := unsupportedCorefileFromPath(from, to, corefile)
+		if err != nil {
+			return fmt.Errorf("error while listing deprecated plugins: %v \n", err)
+		}
+		for _, unsup := range unsupported {
+			fmt.Println(unsup.ToString())
+		}
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(unsupportedCmd)
+
+	unsupportedCmd.Flags().String("from", "", "Required: The version you are migrating from. ")
+	unsupportedCmd.MarkFlagRequired("from")
+	unsupportedCmd.Flags().String("to", "", "Required: The version you are migrating to.")
+	unsupportedCmd.MarkFlagRequired("to")
+	unsupportedCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
+	unsupportedCmd.MarkFlagRequired("corefile")
+}
+
+// unsupportedCorefileFromPath takes the path where the Corefile is located and returns a list of  plugins
+// that have been removed.
+func unsupportedCorefileFromPath(fromCoreDNSVersion, toCoreDNSVersion, corefilePath string) ([]migration.Notice, error) {
+	if _, err := os.Stat(corefilePath); os.IsNotExist(err) {
+		return nil, err
+	}
+
+	fileBytes, err := ioutil.ReadFile(corefilePath)
+	if err != nil {
+		return nil, err
+	}
+	corefileStr := string(fileBytes)
+	return migration.Unsupported(fromCoreDNSVersion, toCoreDNSVersion, corefileStr)
+}
diff --git a/kubernetes/corefile-tool/cmd/validversions.go b/kubernetes/corefile-tool/cmd/validversions.go
new file mode 100644
index 0000000..61b3720
--- /dev/null
+++ b/kubernetes/corefile-tool/cmd/validversions.go
@@ -0,0 +1,24 @@
+package cmd
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/coredns/deployment/kubernetes/migration"
+
+	"github.com/spf13/cobra"
+)
+
+// validversionsCmd represents the validversions command
+var validversionsCmd = &cobra.Command{
+	Use:   "validversions",
+	Short: "Shows valid versions of CoreDNS",
+	Run: func(cmd *cobra.Command, args []string) {
+		fmt.Println("The following are valid CoreDNS versions:")
+		fmt.Println(strings.Join(migration.ValidVersions(), ", "))
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(validversionsCmd)
+}
diff --git a/kubernetes/corefile-tool/main.go b/kubernetes/corefile-tool/main.go
new file mode 100644
index 0000000..af58c90
--- /dev/null
+++ b/kubernetes/corefile-tool/main.go
@@ -0,0 +1,7 @@
+package main
+
+import "github.com/coredns/deployment/kubernetes/corefile-tool/cmd"
+
+func main() {
+	cmd.Execute()
+}
diff --git a/kubernetes/migration/migrate.go b/kubernetes/migration/migrate.go
index 7459b72..6c59ce5 100644
--- a/kubernetes/migration/migrate.go
+++ b/kubernetes/migration/migrate.go
@@ -7,6 +7,8 @@ package migration
 
 import (
 	"fmt"
+	"sort"
+
 	"github.com/coredns/deployment/kubernetes/migration/corefile"
 )
 
@@ -243,9 +245,10 @@ func Released(dockerImageID string) bool {
 // ValidVersions returns a list of all versions defined
 func ValidVersions() []string {
 	var vStrs []string
-	for vStr, _ := range Versions {
+	for vStr := range Versions {
 		vStrs = append(vStrs, vStr)
 	}
+	sort.Strings(vStrs)
 	return vStrs
 }
 
@@ -261,11 +264,11 @@ func validateVersions(fromCoreDNSVersion, toCoreDNSVersion string) error {
 	if err != nil {
 		return err
 	}
-	for next := Versions[fromCoreDNSVersion].nextVersion; next != ""; next = Versions[next].nextVersion  {
+	for next := Versions[fromCoreDNSVersion].nextVersion; next != ""; next = Versions[next].nextVersion {
 		if next != toCoreDNSVersion {
 			continue
 		}
 		return nil
 	}
 	return fmt.Errorf("cannot migrate to '%v' from '%v'", toCoreDNSVersion, fromCoreDNSVersion)
-}
\ No newline at end of file
+}

From f961ffff751c88a7d5ffab16e9f3645467bec61b Mon Sep 17 00:00:00 2001
From: Sandeep Rajan <srajan@infoblox.com>
Date: Thu, 18 Apr 2019 16:01:09 -0400
Subject: [PATCH 2/5] cleanup implementation

---
 kubernetes/corefile-tool/cmd/default.go       | 43 +++++++++--------
 kubernetes/corefile-tool/cmd/deprecated.go    | 46 +++++++++----------
 kubernetes/corefile-tool/cmd/migrate.go       | 43 +++++++++--------
 kubernetes/corefile-tool/cmd/removed.go       | 44 +++++++++---------
 kubernetes/corefile-tool/cmd/root.go          | 20 ++++++--
 kubernetes/corefile-tool/cmd/unsupported.go   | 42 ++++++++---------
 kubernetes/corefile-tool/cmd/validversions.go | 23 +++++-----
 7 files changed, 133 insertions(+), 128 deletions(-)

diff --git a/kubernetes/corefile-tool/cmd/default.go b/kubernetes/corefile-tool/cmd/default.go
index ea97321..a9d2173 100644
--- a/kubernetes/corefile-tool/cmd/default.go
+++ b/kubernetes/corefile-tool/cmd/default.go
@@ -10,32 +10,31 @@ import (
 	"github.com/spf13/cobra"
 )
 
-// defaultCmd represents the default command
-var defaultCmd = &cobra.Command{
-	Use:   "default",
-	Short: "default returns true if the Corefile is the default for a that version of Kubernetes. If the Kubernetes version is omitted, returns true if the Corefile is the default for any version.",
-	Example: `# See if the Corefile is the default in CoreDNS v1.4.0. 
+// NewDefaultCmd represents the default command
+func NewDefaultCmd() *cobra.Command {
+	defaultCmd := &cobra.Command{
+		Use:   "default",
+		Short: "default returns true if the Corefile is the default for a that version of Kubernetes. If the Kubernetes version is omitted, returns true if the Corefile is the default for any version.",
+		Example: `# See if the Corefile is the default in CoreDNS v1.4.0. 
 corefile-tool default --k8sversion 1.4.0 --corefile /path/to/Corefile`,
-	RunE: func(cmd *cobra.Command, args []string) error {
-		k8sversion, _ := cmd.Flags().GetString("k8sversion")
-		corefile, _ := cmd.Flags().GetString("corefile")
-
-		isDefault, err := defaultCorefileFromPath(k8sversion, corefile)
-		if err != nil {
-			return fmt.Errorf("error while checking if the Corefile is the default: %v \n", err)
-		}
-		fmt.Println(isDefault)
-
-		return nil
-	},
-}
-
-func init() {
-	rootCmd.AddCommand(defaultCmd)
-
+		RunE: func(cmd *cobra.Command, args []string) error {
+			k8sversion, _ := cmd.Flags().GetString("k8sversion")
+			corefile, _ := cmd.Flags().GetString("corefile")
+
+			isDefault, err := defaultCorefileFromPath(k8sversion, corefile)
+			if err != nil {
+				return fmt.Errorf("error while checking if the Corefile is the default: %v \n", err)
+			}
+			fmt.Println(isDefault)
+
+			return nil
+		},
+	}
 	defaultCmd.Flags().String("k8sversion", "", "The Kuberenetes version for which you are checking the default.")
 	defaultCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
 	defaultCmd.MarkFlagRequired("corefile")
+
+	return defaultCmd
 }
 
 // defaultCorefileFromPath takes the path where the Corefile is located and checks
diff --git a/kubernetes/corefile-tool/cmd/deprecated.go b/kubernetes/corefile-tool/cmd/deprecated.go
index 535bc0c..3f03fd5 100644
--- a/kubernetes/corefile-tool/cmd/deprecated.go
+++ b/kubernetes/corefile-tool/cmd/deprecated.go
@@ -10,37 +10,35 @@ import (
 	"github.com/spf13/cobra"
 )
 
-// deprecatedCmd represents the deprecated command
-var deprecatedCmd = &cobra.Command{
-	Use:   "deprecated",
-	Short: "Deprecated returns a list of deprecated plugins or directives present in the Corefile.",
-	Example: `# See deprecated plugins CoreDNS from v1.4.0 to v1.5.0. 
+// NewDeprecatedCmd represents the deprecated command
+func NewDeprecatedCmd() *cobra.Command {
+	deprecatedCmd := &cobra.Command{
+		Use:   "deprecated",
+		Short: "Deprecated returns a list of deprecated plugins or directives present in the Corefile.",
+		Example: `# See deprecated plugins CoreDNS from v1.4.0 to v1.5.0. 
 corefile-tool deprecated --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile`,
-	RunE: func(cmd *cobra.Command, args []string) error {
-		from, _ := cmd.Flags().GetString("from")
-		to, _ := cmd.Flags().GetString("to")
-		corefile, _ := cmd.Flags().GetString("corefile")
-		deprecated, err := deprecatedCorefileFromPath(from, to, corefile)
-		if err != nil {
-			return fmt.Errorf("error while listing deprecated plugins: %v \n", err)
-		}
-		for _, dep := range deprecated {
-			fmt.Println(dep.ToString())
-		}
-		return nil
-	},
-}
-
-func init() {
-
-	rootCmd.AddCommand(deprecatedCmd)
-
+		RunE: func(cmd *cobra.Command, args []string) error {
+			from, _ := cmd.Flags().GetString("from")
+			to, _ := cmd.Flags().GetString("to")
+			corefile, _ := cmd.Flags().GetString("corefile")
+			deprecated, err := deprecatedCorefileFromPath(from, to, corefile)
+			if err != nil {
+				return fmt.Errorf("error while listing deprecated plugins: %v \n", err)
+			}
+			for _, dep := range deprecated {
+				fmt.Println(dep.ToString())
+			}
+			return nil
+		},
+	}
 	deprecatedCmd.Flags().String("from", "", "Required: The version you are migrating from. ")
 	deprecatedCmd.MarkFlagRequired("from")
 	deprecatedCmd.Flags().String("to", "", "Required: The version you are migrating to.")
 	deprecatedCmd.MarkFlagRequired("to")
 	deprecatedCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
 	deprecatedCmd.MarkFlagRequired("corefile")
+
+	return deprecatedCmd
 }
 
 // deprecatedCorefileFromPath takes the path where the Corefile is located and returns the deprecated plugins or directives
diff --git a/kubernetes/corefile-tool/cmd/migrate.go b/kubernetes/corefile-tool/cmd/migrate.go
index 2213d23..83e0b40 100644
--- a/kubernetes/corefile-tool/cmd/migrate.go
+++ b/kubernetes/corefile-tool/cmd/migrate.go
@@ -11,32 +11,29 @@ import (
 )
 
 // migrateCmd represents the migrate command
-var migrateCmd = &cobra.Command{
-	Use:   "migrate",
-	Short: "Migrate your CoreDNS corefile",
-	Example: `# Migrate CoreDNS from v1.4.0 to v1.5.0 and handle deprecations . 
+func NewMigrateCmd() *cobra.Command {
+	var migrateCmd = &cobra.Command{
+		Use:   "migrate",
+		Short: "Migrate your CoreDNS corefile",
+		Example: `# Migrate CoreDNS from v1.4.0 to v1.5.0 and handle deprecations . 
 corefile-tool migrate --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile  --deprecations true
 
 # Migrate CoreDNS from v1.2.2 to v1.3.1 and do not handle deprecations .
 corefile-tool migrate --from 1.2.2 --to 1.3.1 --corefile /path/to/Corefile  --deprecations false`,
-	RunE: func(cmd *cobra.Command, args []string) error {
-		from, _ := cmd.Flags().GetString("from")
-		to, _ := cmd.Flags().GetString("to")
-		corefile, _ := cmd.Flags().GetString("corefile")
-		deprecations, _ := cmd.Flags().GetBool("deprecations")
-
-		migrated, err := migrateCorefileFromPath(from, to, corefile, deprecations)
-		if err != nil {
-			return fmt.Errorf("error while migration: %v \n", err)
-		}
-		fmt.Println(migrated)
-		return nil
-	},
-}
-
-func init() {
-	rootCmd.AddCommand(migrateCmd)
-
+		RunE: func(cmd *cobra.Command, args []string) error {
+			from, _ := cmd.Flags().GetString("from")
+			to, _ := cmd.Flags().GetString("to")
+			corefile, _ := cmd.Flags().GetString("corefile")
+			deprecations, _ := cmd.Flags().GetBool("deprecations")
+
+			migrated, err := migrateCorefileFromPath(from, to, corefile, deprecations)
+			if err != nil {
+				return fmt.Errorf("error while migration: %v \n", err)
+			}
+			fmt.Println(migrated)
+			return nil
+		},
+	}
 	migrateCmd.Flags().String("from", "", "Required: The version you are migrating from. ")
 	migrateCmd.MarkFlagRequired("from")
 	migrateCmd.Flags().String("to", "", "Required: The version you are migrating to.")
@@ -45,6 +42,8 @@ func init() {
 	migrateCmd.MarkFlagRequired("corefile")
 	migrateCmd.Flags().Bool("deprecations", false, "Required: Specify whether you want to handle plugin deprecations. [True | False] ")
 	migrateCmd.MarkFlagRequired("deprecations")
+
+	return migrateCmd
 }
 
 // migrateCorefileFromPath takes the path where the Corefile is located and returns the deprecated plugins or directives
diff --git a/kubernetes/corefile-tool/cmd/removed.go b/kubernetes/corefile-tool/cmd/removed.go
index b1178f1..d77efc8 100644
--- a/kubernetes/corefile-tool/cmd/removed.go
+++ b/kubernetes/corefile-tool/cmd/removed.go
@@ -10,36 +10,36 @@ import (
 	"github.com/spf13/cobra"
 )
 
-// removedCmd represents the removed command
-var removedCmd = &cobra.Command{
-	Use:   "removed",
-	Short: "Removed returns a list of removed plugins or directives present in the Corefile.",
-	Example: `# See removed plugins CoreDNS from v1.4.0 to v1.5.0. 
+// NewRemovedCmd represents the removed command
+func NewRemovedCmd() *cobra.Command {
+	removedCmd := &cobra.Command{
+		Use:   "removed",
+		Short: "Removed returns a list of removed plugins or directives present in the Corefile.",
+		Example: `# See removed plugins CoreDNS from v1.4.0 to v1.5.0. 
 corefile-tool removed --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile`,
-	RunE: func(cmd *cobra.Command, args []string) error {
-		from, _ := cmd.Flags().GetString("from")
-		to, _ := cmd.Flags().GetString("to")
-		corefile, _ := cmd.Flags().GetString("corefile")
-		removed, err := removedCorefileFromPath(from, to, corefile)
-		if err != nil {
-			return fmt.Errorf("error while listing deprecated plugins: %v \n", err)
-		}
-		for _, rem := range removed {
-			fmt.Println(rem.ToString())
-		}
-		return nil
-	},
-}
-
-func init() {
-	rootCmd.AddCommand(removedCmd)
+		RunE: func(cmd *cobra.Command, args []string) error {
+			from, _ := cmd.Flags().GetString("from")
+			to, _ := cmd.Flags().GetString("to")
+			corefile, _ := cmd.Flags().GetString("corefile")
+			removed, err := removedCorefileFromPath(from, to, corefile)
+			if err != nil {
+				return fmt.Errorf("error while listing deprecated plugins: %v \n", err)
+			}
+			for _, rem := range removed {
+				fmt.Println(rem.ToString())
+			}
+			return nil
+		},
 
+	}
 	removedCmd.Flags().String("from", "", "Required: The version you are migrating from. ")
 	removedCmd.MarkFlagRequired("from")
 	removedCmd.Flags().String("to", "", "Required: The version you are migrating to.")
 	removedCmd.MarkFlagRequired("to")
 	removedCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
 	removedCmd.MarkFlagRequired("corefile")
+
+	return removedCmd
 }
 
 // removedCorefileFromPath takes the path where the Corefile is located and returns the plugins or directives
diff --git a/kubernetes/corefile-tool/cmd/root.go b/kubernetes/corefile-tool/cmd/root.go
index 7ebf69f..2c85b28 100644
--- a/kubernetes/corefile-tool/cmd/root.go
+++ b/kubernetes/corefile-tool/cmd/root.go
@@ -9,10 +9,11 @@ import (
 )
 
 // rootCmd represents the base command for the corefile-tool.
-var rootCmd = &cobra.Command{
-	Use:   "corefile-tool",
-	Short: "A brief description of your application",
-	Long: dedent.Dedent(`
+func CorefileTool() *cobra.Command {
+	rootCmd := &cobra.Command{
+		Use:   "corefile-tool",
+		Short: "A brief description of your application",
+		Long: dedent.Dedent(`
 
 			    ┌──────────────────────────────────────────────────────────┐
 			    │ CoreDNS Migration Tool                                   │
@@ -23,11 +24,20 @@ var rootCmd = &cobra.Command{
 			    └──────────────────────────────────────────────────────────┘
 
 		`),
+	}
+	rootCmd.AddCommand(NewRemovedCmd())
+	rootCmd.AddCommand(NewMigrateCmd())
+	rootCmd.AddCommand(NewDefaultCmd())
+	rootCmd.AddCommand(NewDeprecatedCmd())
+	rootCmd.AddCommand(NewUnsupportedCmd())
+	rootCmd.AddCommand(NewValidVersionsCmd())
+
+	return rootCmd
 }
 
 // Execute adds all child commands to the root command and sets flags appropriately.
 func Execute() {
-	if err := rootCmd.Execute(); err != nil {
+	if err := CorefileTool().Execute(); err != nil {
 		fmt.Println(err)
 		os.Exit(1)
 	}
diff --git a/kubernetes/corefile-tool/cmd/unsupported.go b/kubernetes/corefile-tool/cmd/unsupported.go
index eb94e41..39d8204 100644
--- a/kubernetes/corefile-tool/cmd/unsupported.go
+++ b/kubernetes/corefile-tool/cmd/unsupported.go
@@ -10,28 +10,26 @@ import (
 )
 
 // unsupportedCmd represents the unsupported command
-var unsupportedCmd = &cobra.Command{
-	Use:   "unsupported",
-	Short: "Unsupported returns a list of plugins that are not recognized/supported by the migration tool (but may still be valid in CoreDNS).",
-	Example: `# See unsupported plugins CoreDNS from v1.4.0 to v1.5.0. 
+func NewUnsupportedCmd() *cobra.Command {
+	unsupportedCmd := &cobra.Command{
+		Use:   "unsupported",
+		Short: "Unsupported returns a list of plugins that are not recognized/supported by the migration tool (but may still be valid in CoreDNS).",
+		Example: `# See unsupported plugins CoreDNS from v1.4.0 to v1.5.0. 
 corefile-tool unsupported --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile`,
-	RunE: func(cmd *cobra.Command, args []string) error {
-		from, _ := cmd.Flags().GetString("from")
-		to, _ := cmd.Flags().GetString("to")
-		corefile, _ := cmd.Flags().GetString("corefile")
-		unsupported, err := unsupportedCorefileFromPath(from, to, corefile)
-		if err != nil {
-			return fmt.Errorf("error while listing deprecated plugins: %v \n", err)
-		}
-		for _, unsup := range unsupported {
-			fmt.Println(unsup.ToString())
-		}
-		return nil
-	},
-}
-
-func init() {
-	rootCmd.AddCommand(unsupportedCmd)
+		RunE: func(cmd *cobra.Command, args []string) error {
+			from, _ := cmd.Flags().GetString("from")
+			to, _ := cmd.Flags().GetString("to")
+			corefile, _ := cmd.Flags().GetString("corefile")
+			unsupported, err := unsupportedCorefileFromPath(from, to, corefile)
+			if err != nil {
+				return fmt.Errorf("error while listing deprecated plugins: %v \n", err)
+			}
+			for _, unsup := range unsupported {
+				fmt.Println(unsup.ToString())
+			}
+			return nil
+		},
+	}
 
 	unsupportedCmd.Flags().String("from", "", "Required: The version you are migrating from. ")
 	unsupportedCmd.MarkFlagRequired("from")
@@ -39,6 +37,8 @@ func init() {
 	unsupportedCmd.MarkFlagRequired("to")
 	unsupportedCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
 	unsupportedCmd.MarkFlagRequired("corefile")
+
+	return unsupportedCmd
 }
 
 // unsupportedCorefileFromPath takes the path where the Corefile is located and returns a list of  plugins
diff --git a/kubernetes/corefile-tool/cmd/validversions.go b/kubernetes/corefile-tool/cmd/validversions.go
index 61b3720..e411d8c 100644
--- a/kubernetes/corefile-tool/cmd/validversions.go
+++ b/kubernetes/corefile-tool/cmd/validversions.go
@@ -9,16 +9,15 @@ import (
 	"github.com/spf13/cobra"
 )
 
-// validversionsCmd represents the validversions command
-var validversionsCmd = &cobra.Command{
-	Use:   "validversions",
-	Short: "Shows valid versions of CoreDNS",
-	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("The following are valid CoreDNS versions:")
-		fmt.Println(strings.Join(migration.ValidVersions(), ", "))
-	},
-}
-
-func init() {
-	rootCmd.AddCommand(validversionsCmd)
+// NewValidVersionsCmd represents the validversions command
+func NewValidVersionsCmd() *cobra.Command {
+	validversionsCmd := &cobra.Command{
+		Use:   "validversions",
+		Short: "Shows valid versions of CoreDNS",
+		Run: func(cmd *cobra.Command, args []string) {
+			fmt.Println("The following are valid CoreDNS versions:")
+			fmt.Println(strings.Join(migration.ValidVersions(), ", "))
+		},
+	}
+	return validversionsCmd
 }

From 2d739f10a54653a1b177da9f9466be1d1c893b50 Mon Sep 17 00:00:00 2001
From: Sandeep Rajan <srajan@infoblox.com>
Date: Thu, 18 Apr 2019 16:02:48 -0400
Subject: [PATCH 3/5] nit

---
 kubernetes/corefile-tool/cmd/migrate.go     | 2 +-
 kubernetes/corefile-tool/cmd/root.go        | 2 +-
 kubernetes/corefile-tool/cmd/unsupported.go | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kubernetes/corefile-tool/cmd/migrate.go b/kubernetes/corefile-tool/cmd/migrate.go
index 83e0b40..2f09f28 100644
--- a/kubernetes/corefile-tool/cmd/migrate.go
+++ b/kubernetes/corefile-tool/cmd/migrate.go
@@ -10,7 +10,7 @@ import (
 	"github.com/spf13/cobra"
 )
 
-// migrateCmd represents the migrate command
+// NewMigrateCmd represents the migrate command
 func NewMigrateCmd() *cobra.Command {
 	var migrateCmd = &cobra.Command{
 		Use:   "migrate",
diff --git a/kubernetes/corefile-tool/cmd/root.go b/kubernetes/corefile-tool/cmd/root.go
index 2c85b28..f6cc268 100644
--- a/kubernetes/corefile-tool/cmd/root.go
+++ b/kubernetes/corefile-tool/cmd/root.go
@@ -8,7 +8,7 @@ import (
 	"github.com/spf13/cobra"
 )
 
-// rootCmd represents the base command for the corefile-tool.
+// CorefileTool represents the base command for the corefile-tool.
 func CorefileTool() *cobra.Command {
 	rootCmd := &cobra.Command{
 		Use:   "corefile-tool",
diff --git a/kubernetes/corefile-tool/cmd/unsupported.go b/kubernetes/corefile-tool/cmd/unsupported.go
index 39d8204..ccd60d2 100644
--- a/kubernetes/corefile-tool/cmd/unsupported.go
+++ b/kubernetes/corefile-tool/cmd/unsupported.go
@@ -9,7 +9,7 @@ import (
 	"github.com/spf13/cobra"
 )
 
-// unsupportedCmd represents the unsupported command
+// NewUnsupportedCmd represents the unsupported command
 func NewUnsupportedCmd() *cobra.Command {
 	unsupportedCmd := &cobra.Command{
 		Use:   "unsupported",

From d7c652ee2d562ff110ccd4c73eca915557b75269 Mon Sep 17 00:00:00 2001
From: Sandeep Rajan <srajan@infoblox.com>
Date: Tue, 23 Apr 2019 10:50:42 -0400
Subject: [PATCH 4/5] add fn to get corefile path

---
 kubernetes/corefile-tool/.gitignore         |  2 +-
 kubernetes/corefile-tool/cmd/default.go     | 10 ++--------
 kubernetes/corefile-tool/cmd/deprecated.go  |  8 +-------
 kubernetes/corefile-tool/cmd/migrate.go     |  8 +-------
 kubernetes/corefile-tool/cmd/removed.go     |  8 +-------
 kubernetes/corefile-tool/cmd/root.go        | 14 ++++++++++++++
 kubernetes/corefile-tool/cmd/unsupported.go |  9 ++-------
 7 files changed, 22 insertions(+), 37 deletions(-)

diff --git a/kubernetes/corefile-tool/.gitignore b/kubernetes/corefile-tool/.gitignore
index adefe92..50d0b69 100644
--- a/kubernetes/corefile-tool/.gitignore
+++ b/kubernetes/corefile-tool/.gitignore
@@ -1,3 +1,3 @@
 Corefile
 corefile-tool
-*.yaml
\ No newline at end of file
+*.yaml
diff --git a/kubernetes/corefile-tool/cmd/default.go b/kubernetes/corefile-tool/cmd/default.go
index a9d2173..da20ec4 100644
--- a/kubernetes/corefile-tool/cmd/default.go
+++ b/kubernetes/corefile-tool/cmd/default.go
@@ -2,8 +2,6 @@ package cmd
 
 import (
 	"fmt"
-	"io/ioutil"
-	"os"
 
 	"github.com/coredns/deployment/kubernetes/migration"
 
@@ -38,13 +36,9 @@ corefile-tool default --k8sversion 1.4.0 --corefile /path/to/Corefile`,
 }
 
 // defaultCorefileFromPath takes the path where the Corefile is located and checks
-// if the Corefile is the default for a that version of Kubernetes.
+// if the Corefile is the default for that version of Kubernetes.
 func defaultCorefileFromPath(k8sVersion, corefilePath string) (bool, error) {
-	if _, err := os.Stat(corefilePath); os.IsNotExist(err) {
-		return false, err
-	}
-
-	fileBytes, err := ioutil.ReadFile(corefilePath)
+	fileBytes, err := getCorefileFromPath(corefilePath)
 	if err != nil {
 		return false, err
 	}
diff --git a/kubernetes/corefile-tool/cmd/deprecated.go b/kubernetes/corefile-tool/cmd/deprecated.go
index 3f03fd5..00a59e3 100644
--- a/kubernetes/corefile-tool/cmd/deprecated.go
+++ b/kubernetes/corefile-tool/cmd/deprecated.go
@@ -2,8 +2,6 @@ package cmd
 
 import (
 	"fmt"
-	"io/ioutil"
-	"os"
 
 	"github.com/coredns/deployment/kubernetes/migration"
 
@@ -44,11 +42,7 @@ corefile-tool deprecated --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile`,
 // deprecatedCorefileFromPath takes the path where the Corefile is located and returns the deprecated plugins or directives
 // present in the Corefile.
 func deprecatedCorefileFromPath(fromCoreDNSVersion, toCoreDNSVersion, corefilePath string) ([]migration.Notice, error) {
-	if _, err := os.Stat(corefilePath); os.IsNotExist(err) {
-		return nil, err
-	}
-
-	fileBytes, err := ioutil.ReadFile(corefilePath)
+	fileBytes, err := getCorefileFromPath(corefilePath)
 	if err != nil {
 		return nil, err
 	}
diff --git a/kubernetes/corefile-tool/cmd/migrate.go b/kubernetes/corefile-tool/cmd/migrate.go
index 2f09f28..eeba020 100644
--- a/kubernetes/corefile-tool/cmd/migrate.go
+++ b/kubernetes/corefile-tool/cmd/migrate.go
@@ -2,8 +2,6 @@ package cmd
 
 import (
 	"fmt"
-	"io/ioutil"
-	"os"
 
 	"github.com/coredns/deployment/kubernetes/migration"
 
@@ -49,11 +47,7 @@ corefile-tool migrate --from 1.2.2 --to 1.3.1 --corefile /path/to/Corefile  --de
 // migrateCorefileFromPath takes the path where the Corefile is located and returns the deprecated plugins or directives
 // present in the Corefile.
 func migrateCorefileFromPath(fromCoreDNSVersion, toCoreDNSVersion, corefilePath string, deprecations bool) (string, error) {
-	if _, err := os.Stat(corefilePath); os.IsNotExist(err) {
-		return "", err
-	}
-
-	fileBytes, err := ioutil.ReadFile(corefilePath)
+	fileBytes, err := getCorefileFromPath(corefilePath)
 	if err != nil {
 		return "", err
 	}
diff --git a/kubernetes/corefile-tool/cmd/removed.go b/kubernetes/corefile-tool/cmd/removed.go
index d77efc8..ab19c37 100644
--- a/kubernetes/corefile-tool/cmd/removed.go
+++ b/kubernetes/corefile-tool/cmd/removed.go
@@ -2,8 +2,6 @@ package cmd
 
 import (
 	"fmt"
-	"io/ioutil"
-	"os"
 
 	"github.com/coredns/deployment/kubernetes/migration"
 
@@ -45,11 +43,7 @@ corefile-tool removed --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile`,
 // removedCorefileFromPath takes the path where the Corefile is located and returns the plugins or directives
 // that have been removed.
 func removedCorefileFromPath(fromCoreDNSVersion, toCoreDNSVersion, corefilePath string) ([]migration.Notice, error) {
-	if _, err := os.Stat(corefilePath); os.IsNotExist(err) {
-		return nil, err
-	}
-
-	fileBytes, err := ioutil.ReadFile(corefilePath)
+	fileBytes, err := getCorefileFromPath(corefilePath)
 	if err != nil {
 		return nil, err
 	}
diff --git a/kubernetes/corefile-tool/cmd/root.go b/kubernetes/corefile-tool/cmd/root.go
index f6cc268..cd884f4 100644
--- a/kubernetes/corefile-tool/cmd/root.go
+++ b/kubernetes/corefile-tool/cmd/root.go
@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"fmt"
+	"io/ioutil"
 	"os"
 
 	"github.com/lithammer/dedent"
@@ -42,3 +43,16 @@ func Execute() {
 		os.Exit(1)
 	}
 }
+
+func getCorefileFromPath(corefilePath string) ([]byte, error) {
+	if _, err := os.Stat(corefilePath); os.IsNotExist(err) {
+		return nil, err
+	}
+
+	fileBytes, err := ioutil.ReadFile(corefilePath)
+	if err != nil {
+		return nil, err
+	}
+
+	return fileBytes, nil
+}
diff --git a/kubernetes/corefile-tool/cmd/unsupported.go b/kubernetes/corefile-tool/cmd/unsupported.go
index ccd60d2..f82fbe6 100644
--- a/kubernetes/corefile-tool/cmd/unsupported.go
+++ b/kubernetes/corefile-tool/cmd/unsupported.go
@@ -2,9 +2,8 @@ package cmd
 
 import (
 	"fmt"
+
 	"github.com/coredns/deployment/kubernetes/migration"
-	"io/ioutil"
-	"os"
 
 	"github.com/spf13/cobra"
 )
@@ -44,11 +43,7 @@ corefile-tool unsupported --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile`,
 // unsupportedCorefileFromPath takes the path where the Corefile is located and returns a list of  plugins
 // that have been removed.
 func unsupportedCorefileFromPath(fromCoreDNSVersion, toCoreDNSVersion, corefilePath string) ([]migration.Notice, error) {
-	if _, err := os.Stat(corefilePath); os.IsNotExist(err) {
-		return nil, err
-	}
-
-	fileBytes, err := ioutil.ReadFile(corefilePath)
+	fileBytes, err := getCorefileFromPath(corefilePath)
 	if err != nil {
 		return nil, err
 	}

From 54235738e77883ec23918d3a8e5f0f3930f91135 Mon Sep 17 00:00:00 2001
From: Sandeep Rajan <srajan@infoblox.com>
Date: Wed, 24 Apr 2019 11:16:26 -0400
Subject: [PATCH 5/5] add released command and improve readme

---
 kubernetes/corefile-tool/README.md       | 51 ++++++++++++++++++++++--
 kubernetes/corefile-tool/cmd/default.go  |  2 +-
 kubernetes/corefile-tool/cmd/released.go | 32 +++++++++++++++
 kubernetes/corefile-tool/cmd/root.go     |  1 +
 4 files changed, 82 insertions(+), 4 deletions(-)
 create mode 100644 kubernetes/corefile-tool/cmd/released.go

diff --git a/kubernetes/corefile-tool/README.md b/kubernetes/corefile-tool/README.md
index 9d488ac..d93dd4c 100644
--- a/kubernetes/corefile-tool/README.md
+++ b/kubernetes/corefile-tool/README.md
@@ -17,14 +17,57 @@ where `command`, `flags` are:
 
 ### Operations
 
-The following operations are supported:
+The following commands are supported:
+
 - `default`: Default returns true if the Corefile is the default for a that version of Kubernetes. 
 If the Kubernetes version is omitted, returns true if the Corefile is the default for any version.
 
+    The following flags are accepted by the `default` command:
+     
+     - `k8sversion`: The Kubernetes version for which you are checking the default. 
+     If the Kubernetes version is omitted, returns true if the Corefile is the default for any version.
+     - `corefile`  : The path where your Corefile is located. This flag is mandatory. 
+
 - `deprecated`    : Deprecated returns a list of deprecated plugins or directives present in the Corefile.
+    
+    The following flags are accepted and mandatory for the `deprecated` command:
+    
+    - `from`: The CoreDNS version you are migrating from.
+    - `to`  : The CoreDNS version you are migrating to.
+    - `corefile`  : The path where your Corefile is located.
+    
 - `migrate`       : Migrate your CoreDNS corefile.
+
+    The following flags are accepted and mandatory for the `migrate` command:
+        
+    - `from`        : The CoreDNS version you are migrating from.
+    - `to`          : The CoreDNS version you are migrating to. This flag is mandatory.
+    - `corefile`    : The path where your Corefile is located. This flag is mandatory. 
+    - `deprecations`: Specify whether you want to migrate all the deprecations that are present in the current Corefile.
+    Specifying `false` will result in the `migrate` command not migrating the deprecated plugins present in the Corefile.
+        
+- `released`      : Released determines whether your Docker Image ID of a CoreDNS release is valid or not.
+
+    The following flags are accepted and mandatory for the `released` command:
+    
+    - `dockerImageID` : The docker image ID you want to check.
+    
 - `removed`       : Removed returns a list of removed plugins or directives present in the Corefile.
+
+    The following flags are accepted and mandatory for the `removed` command:
+        
+    - `from`        : The CoreDNS version you are migrating from.
+    - `to`          : The CoreDNS version you are migrating to. This flag is mandatory.
+    - `corefile`    : The path where your Corefile is located. This flag is mandatory. 
+    
 - `unsupported`   : Unsupported returns a list of plugins that are not recognized/supported by the migration tool (but may still be valid in CoreDNS).
+
+    The following flags are accepted and mandatory for the `unsupported` command:
+        
+    - `from`        : The CoreDNS version you are migrating from.
+    - `to`          : The CoreDNS version you are migrating to. This flag is mandatory.
+    - `corefile`    : The path where your Corefile is located. This flag is mandatory. 
+    
 - `validversions` : Shows valid versions of CoreDNS.
 
 
@@ -53,10 +96,12 @@ corefile-tool removed --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile
 ```
 
 ```bash
-# Migrate CoreDNS from v1.4.0 to v1.5.0 and handle deprecations . 
+# Migrate CoreDNS from v1.4.0 to v1.5.0 and also migrate all the deprecations 
+# that are present in the current Corefile. 
 corefile-tool migrate --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile  --deprecations true
 
-# Migrate CoreDNS from v1.2.2 to v1.3.1 and do not handle deprecations .
+# Migrate CoreDNS from v1.2.2 to v1.3.1 and do not also migrate all the deprecations 
+# that are present in the current Corefile.
 corefile-tool migrate --from 1.2.2 --to 1.3.1 --corefile /path/to/Corefile  --deprecations false
 ```
 
diff --git a/kubernetes/corefile-tool/cmd/default.go b/kubernetes/corefile-tool/cmd/default.go
index da20ec4..c719ac7 100644
--- a/kubernetes/corefile-tool/cmd/default.go
+++ b/kubernetes/corefile-tool/cmd/default.go
@@ -28,7 +28,7 @@ corefile-tool default --k8sversion 1.4.0 --corefile /path/to/Corefile`,
 			return nil
 		},
 	}
-	defaultCmd.Flags().String("k8sversion", "", "The Kuberenetes version for which you are checking the default.")
+	defaultCmd.Flags().String("k8sversion", "", "The Kubernetes version for which you are checking the default.")
 	defaultCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
 	defaultCmd.MarkFlagRequired("corefile")
 
diff --git a/kubernetes/corefile-tool/cmd/released.go b/kubernetes/corefile-tool/cmd/released.go
new file mode 100644
index 0000000..d8db04c
--- /dev/null
+++ b/kubernetes/corefile-tool/cmd/released.go
@@ -0,0 +1,32 @@
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/coredns/deployment/kubernetes/migration"
+
+	"github.com/spf13/cobra"
+)
+
+// NewReleasedCmd represents the released command
+func NewReleasedCmd() *cobra.Command {
+	releasedCmd := &cobra.Command{
+		Use:   "released",
+		Short: "Determines whether your Docker Image ID of a CoreDNS release is valid or not",
+		Run: func(cmd *cobra.Command, args []string) {
+			image, _ := cmd.Flags().GetString("dockerImageID")
+			result := migration.Released(image)
+
+			if result {
+				fmt.Println("The docker image ID is valid")
+			} else {
+				fmt.Println("The docker image ID is invalid")
+			}
+		},
+	}
+
+	releasedCmd.Flags().String("dockerImageID", "", "Required: The docker image ID you want to check. ")
+	releasedCmd.MarkFlagRequired("dockerImageID")
+
+	return releasedCmd
+}
diff --git a/kubernetes/corefile-tool/cmd/root.go b/kubernetes/corefile-tool/cmd/root.go
index cd884f4..64dbb04 100644
--- a/kubernetes/corefile-tool/cmd/root.go
+++ b/kubernetes/corefile-tool/cmd/root.go
@@ -32,6 +32,7 @@ func CorefileTool() *cobra.Command {
 	rootCmd.AddCommand(NewDeprecatedCmd())
 	rootCmd.AddCommand(NewUnsupportedCmd())
 	rootCmd.AddCommand(NewValidVersionsCmd())
+	rootCmd.AddCommand(NewReleasedCmd())
 
 	return rootCmd
 }