NET 1594 - Snapshot Agent Filename Should Include Consul Version / Datacenter (#18625)

* init

* tests added and few fixes

* revert arg message

* changelog added

* removed var declaration

* fix CI

* fix test

* added node name and status

* updated save.mdx

* added example

* fix tense

* fix description

.changelog/18625.txt

@@ -0,0 +1,5 @@
+```release-note:improvement
+Adds flag -append-filename (which works on values version, dc, node and status) to consul snapshot save command.
+Adding the flag -append-filename version,dc,node,status will add consul version, consul datacenter, node name and leader/follower
+(status) in the file name given in the snapshot save command before the file extension.
+```

command/snapshot/save/snapshot_save.go

@@ -3,7 +3,10 @@ package save
 import (
 	"flag"
 	"fmt"
+	"golang.org/x/exp/slices"
 	"os"
+	"path/filepath"
+	"strings"
 
 	"github.com/mitchellh/cli"
 	"github.com/rboyer/safeio"
@@ -20,10 +23,18 @@ func New(ui cli.Ui) *cmd {
 }
 
 type cmd struct {
-	UI    cli.Ui
-	flags *flag.FlagSet
-	http  *flags.HTTPFlags
-	help  string
+	UI                 cli.Ui
+	flags              *flag.FlagSet
+	http               *flags.HTTPFlags
+	help               string
+	appendFileNameFlag flags.StringValue
+}
+
+func (c *cmd) getAppendFileNameFlag() *flag.FlagSet {
+	fs := flag.NewFlagSet("", flag.ContinueOnError)
+	fs.Var(&c.appendFileNameFlag, "append-filename", "Append filename flag supports the following "+
+		"comma-separated arguments. 1. version, 2. dc. 3. node 4. status. It appends these values to the filename provided in the command")
+	return fs
 }
 
 func (c *cmd) init() {
@@ -31,6 +42,7 @@ func (c *cmd) init() {
 	c.http = &flags.HTTPFlags{}
 	flags.Merge(c.flags, c.http.ClientFlags())
 	flags.Merge(c.flags, c.http.ServerFlags())
+	flags.Merge(c.flags, c.getAppendFileNameFlag())
 	c.help = flags.Usage(help, c.flags)
 }
 
@@ -55,6 +67,62 @@ func (c *cmd) Run(args []string) int {
 
 	// Create and test the HTTP client
 	client, err := c.http.APIClient()
+
+	appendFileNameFlags := strings.Split(c.appendFileNameFlag.String(), ",")
+
+	if len(appendFileNameFlags) != 0 && len(c.appendFileNameFlag.String()) > 0 {
+		agentSelfResponse, err := client.Agent().Self()
+		if err != nil {
+			c.UI.Error(fmt.Sprintf("Error connecting to Consul agent and fetching datacenter/version: %s", err))
+			return 1
+		}
+
+		fileExt := filepath.Ext(file)
+		fileNameWithoutExt := strings.TrimSuffix(file, fileExt)
+
+		if slices.Contains(appendFileNameFlags, "version") {
+			if config, ok := agentSelfResponse["Config"]; ok {
+				if version, ok := config["Version"]; ok {
+					fileNameWithoutExt = fileNameWithoutExt + "-" + version.(string)
+				}
+			}
+		}
+
+		if slices.Contains(appendFileNameFlags, "dc") {
+			if config, ok := agentSelfResponse["Config"]; ok {
+				if datacenter, ok := config["Datacenter"]; ok {
+					fileNameWithoutExt = fileNameWithoutExt + "-" + datacenter.(string)
+				}
+			}
+		}
+
+		if slices.Contains(appendFileNameFlags, "node") {
+			if config, ok := agentSelfResponse["Config"]; ok {
+				if nodeName, ok := config["NodeName"]; ok {
+					fileNameWithoutExt = fileNameWithoutExt + "-" + nodeName.(string)
+				}
+			}
+		}
+
+		if slices.Contains(appendFileNameFlags, "status") {
+			if status, ok := agentSelfResponse["Stats"]; ok {
+				if config, ok := status["consul"]; ok {
+					configMap := config.(map[string]interface{})
+					if leader, ok := configMap["leader"]; ok {
+						if leader == "true" {
+							fileNameWithoutExt = fileNameWithoutExt + "-" + "leader"
+						} else {
+							fileNameWithoutExt = fileNameWithoutExt + "-" + "follower"
+						}
+					}
+				}
+			}
+		}
+
+		//adding extension back
+		file = fileNameWithoutExt + fileExt
+	}
+
 	if err != nil {
 		c.UI.Error(fmt.Sprintf("Error connecting to Consul agent: %s", err))
 		return 1

command/snapshot/save/snapshot_save_test.go

@@ -69,6 +69,58 @@ func TestSnapshotSaveCommand_Validation(t *testing.T) {
 	}
 }
 
+func TestSnapshotSaveCommandWithAppendFileNameFlag(t *testing.T) {
+	if testing.Short() {
+		t.Skip("too slow for testing.Short")
+	}
+
+	t.Parallel()
+	a := agent.NewTestAgent(t, ``)
+	defer a.Shutdown()
+	client := a.Client()
+
+	ui := cli.NewMockUi()
+	c := New(ui)
+
+	dir := testutil.TempDir(t, "snapshot")
+	file := filepath.Join(dir, "backup.tgz")
+	args := []string{
+		"-append-filename=version,dc,node,status",
+		"-http-addr=" + a.HTTPAddr(),
+		file,
+	}
+
+	stats := a.Stats()
+
+	status := "follower"
+
+	if stats["consul"]["leader"] == "true" {
+		status = "leader"
+	}
+
+	newFilePath := filepath.Join(dir, "backup"+"-"+a.Config.Version+"-"+a.Config.Datacenter+
+		"-"+a.Config.NodeName+"-"+status+".tgz")
+
+	code := c.Run(args)
+	if code != 0 {
+		t.Fatalf("bad: %d. %#v", code, ui.ErrorWriter.String())
+	}
+
+	fi, err := os.Stat(newFilePath)
+	require.NoError(t, err)
+	require.Equal(t, fi.Mode(), os.FileMode(0600))
+
+	f, err := os.Open(newFilePath)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	defer f.Close()
+
+	if err := client.Snapshot().Restore(nil, f); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+}
+
 func TestSnapshotSaveCommand(t *testing.T) {
 	if testing.Short() {
 		t.Skip("too slow for testing.Short")

website/content/commands/snapshot/save.mdx

@@ -47,6 +47,10 @@ Usage: `consul snapshot save [options] FILE`
 
 @include 'http_api_options_server.mdx'
 
+- `-append-filename=<value>` - Value can be - version,dc,node,status
+Adds consul version, datacenter name, node name, and status (leader/follower)
+to the file name before the extension separated by `-`
+
 ## Examples
 
 To create a snapshot from the leader server and save it to "backup.snap":
@@ -71,6 +75,17 @@ $ consul snapshot save -stale backup.snap
 # ...
 ```
 
+To create snapshot file with consul version, datacenter, node name and leader/follower info,
+run
+
+```shell-session
+$ consul snapshot save -append-filename node,status,version,dc backup.snap
+#...
+```
+
+File name created will be like backup-%CONSUL_VERSION%-%DC_NAME%-%NODE_NAME%-%STATUS.snap
+example - backup-1.17.0-dc1-local-machine-leader.tgz
+
 This is useful for situations where a cluster is in a degraded state and no
 leader is available. To target a specific server for a snapshot, you can run
 the `consul snapshot save` command on that specific server.