Enhance config restore to carry previous set content as well (#8483)

This PR brings support for `history` list to
list in the following agreed format

```
~ mc admin config history list -n 2 myminio
RestoreId: df0ebb1e-69b0-4043-b9dd-ab54508f2897
Date: Mon, 04 Nov 2019 17:27:27 GMT

region name="us-east-1" state="on"
region name="us-east-1" state="on"
region name="us-east-1" state="on"
region name="us-east-1" state="on"

RestoreId: ecc6873a-0ed3-41f9-b03e-a2a1bab48b5f
Date: Mon, 04 Nov 2019 17:28:23 GMT

region name=us-east-1 state=off
```

This PR also moves the help templating and coloring to
fully `mc` side instead than `madmin` API.

cmd/admin-handlers-config-kv.go

@@ -23,6 +23,7 @@ import (
 	"encoding/json"
 	"io"
 	"net/http"
+	"strconv"
 
 	"github.com/gorilla/mux"
 	"github.com/minio/minio/cmd/config"
@@ -236,7 +237,7 @@ func (a adminAPIHandlers) ClearConfigHistoryKVHandler(w http.ResponseWriter, r *
 		return
 	}
 	if restoreID == "all" {
-		chEntries, err := listServerConfigHistory(ctx, objectAPI)
+		chEntries, err := listServerConfigHistory(ctx, objectAPI, false, -1)
 		if err != nil {
 			writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
 			return
@@ -323,7 +324,14 @@ func (a adminAPIHandlers) ListConfigHistoryKVHandler(w http.ResponseWriter, r *h
 		return
 	}
 
-	chEntries, err := listServerConfigHistory(ctx, objectAPI)
+	vars := mux.Vars(r)
+	count, err := strconv.Atoi(vars["count"])
+	if err != nil {
+		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
+		return
+	}
+
+	chEntries, err := listServerConfigHistory(ctx, objectAPI, true, count)
 	if err != nil {
 		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
 		return
@@ -335,7 +343,14 @@ func (a adminAPIHandlers) ListConfigHistoryKVHandler(w http.ResponseWriter, r *h
 		return
 	}
 
-	writeSuccessResponseJSON(w, data)
+	password := globalActiveCred.SecretKey
+	econfigData, err := madmin.EncryptData(password, data)
+	if err != nil {
+		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
+		return
+	}
+
+	writeSuccessResponseJSON(w, econfigData)
 }
 
 // HelpConfigKVHandler - GET /minio/admin/v2/help-config-kv?subSys={subSys}&key={key}

cmd/admin-router.go

@@ -81,7 +81,7 @@ func registerAdminRouter(router *mux.Router, enableConfigOps, enableIAMOps bool)
 		adminRouter.Methods(http.MethodPut).Path(adminAPIVersionPrefix + "/set-config-kv").HandlerFunc(httpTraceHdrs(adminAPI.SetConfigKVHandler))
 		adminRouter.Methods(http.MethodDelete).Path(adminAPIVersionPrefix + "/del-config-kv").HandlerFunc(httpTraceHdrs(adminAPI.DelConfigKVHandler))
 		adminRouter.Methods(http.MethodGet).Path(adminAPIVersionPrefix+"/help-config-kv").HandlerFunc(httpTraceAll(adminAPI.HelpConfigKVHandler)).Queries("subSys", "{subSys:.*}", "key", "{key:.*}")
-		adminRouter.Methods(http.MethodGet).Path(adminAPIVersionPrefix + "/list-config-history-kv").HandlerFunc(httpTraceAll(adminAPI.ListConfigHistoryKVHandler))
+		adminRouter.Methods(http.MethodGet).Path(adminAPIVersionPrefix+"/list-config-history-kv").HandlerFunc(httpTraceAll(adminAPI.ListConfigHistoryKVHandler)).Queries("count", "{count:[0-9]+}")
 		adminRouter.Methods(http.MethodDelete).Path(adminAPIVersionPrefix+"/clear-config-history-kv").HandlerFunc(httpTraceHdrs(adminAPI.ClearConfigHistoryKVHandler)).Queries("restoreId", "{restoreId:.*}")
 		adminRouter.Methods(http.MethodPut).Path(adminAPIVersionPrefix+"/restore-config-history-kv").HandlerFunc(httpTraceHdrs(adminAPI.RestoreConfigHistoryKVHandler)).Queries("restoreId", "{restoreId:.*}")
 	}

cmd/config.go

@@ -34,6 +34,8 @@ import (
 const (
 	minioConfigPrefix = "config"
 
+	kvPrefix = ".kv"
+
 	// Captures all the previous SetKV operations and allows rollback.
 	minioConfigHistoryPrefix = minioConfigPrefix + "/history"
 
@@ -44,7 +46,9 @@ const (
 	minioConfigBackupFile = minioConfigFile + ".backup"
 )
 
-func listServerConfigHistory(ctx context.Context, objAPI ObjectLayer) ([]madmin.ConfigHistoryEntry, error) {
+func listServerConfigHistory(ctx context.Context, objAPI ObjectLayer, withData bool, count int) (
+	[]madmin.ConfigHistoryEntry, error) {
+
 	var configHistory []madmin.ConfigHistoryEntry
 
 	// List all kvs
@@ -55,10 +59,28 @@ func listServerConfigHistory(ctx context.Context, objAPI ObjectLayer) ([]madmin.
 			return nil, err
 		}
 		for _, obj := range res.Objects {
-			configHistory = append(configHistory, madmin.ConfigHistoryEntry{
-				RestoreID:  path.Base(obj.Name),
+			cfgEntry := madmin.ConfigHistoryEntry{
+				RestoreID:  strings.TrimSuffix(path.Base(obj.Name), kvPrefix),
 				CreateTime: obj.ModTime, // ModTime is createTime for config history entries.
-			})
+			}
+			if withData {
+				data, err := readConfig(ctx, objAPI, obj.Name)
+				if err != nil {
+					return nil, err
+				}
+				if globalConfigEncrypted {
+					data, err = madmin.DecryptData(globalActiveCred.String(), bytes.NewReader(data))
+					if err != nil {
+						return nil, err
+					}
+				}
+				cfgEntry.Data = string(data)
+			}
+			configHistory = append(configHistory, cfgEntry)
+			count--
+			if count == 0 {
+				break
+			}
 		}
 		if !res.IsTruncated {
 			// We are done here
@@ -73,12 +95,12 @@ func listServerConfigHistory(ctx context.Context, objAPI ObjectLayer) ([]madmin.
 }
 
 func delServerConfigHistory(ctx context.Context, objAPI ObjectLayer, uuidKV string) error {
-	historyFile := pathJoin(minioConfigHistoryPrefix, uuidKV)
+	historyFile := pathJoin(minioConfigHistoryPrefix, uuidKV+kvPrefix)
 	return objAPI.DeleteObject(ctx, minioMetaBucket, historyFile)
 }
 
 func readServerConfigHistory(ctx context.Context, objAPI ObjectLayer, uuidKV string) ([]byte, error) {
-	historyFile := pathJoin(minioConfigHistoryPrefix, uuidKV)
+	historyFile := pathJoin(minioConfigHistoryPrefix, uuidKV+kvPrefix)
 	data, err := readConfig(ctx, objAPI, historyFile)
 	if err != nil {
 		return nil, err
@@ -92,7 +114,7 @@ func readServerConfigHistory(ctx context.Context, objAPI ObjectLayer, uuidKV str
 }
 
 func saveServerConfigHistory(ctx context.Context, objAPI ObjectLayer, kv []byte) error {
-	uuidKV := mustGetUUID() + ".kv"
+	uuidKV := mustGetUUID() + kvPrefix
 	historyFile := pathJoin(minioConfigHistoryPrefix, uuidKV)
 
 	var err error

cmd/config/config.go

@@ -24,6 +24,7 @@ import (
 	"github.com/minio/minio-go/pkg/set"
 	"github.com/minio/minio/pkg/auth"
 	"github.com/minio/minio/pkg/env"
+	"github.com/minio/minio/pkg/madmin"
 )
 
 // Error config error type
@@ -41,7 +42,7 @@ func (e Error) Error() string {
 
 // Default keys
 const (
-	Default = `_`
+	Default = madmin.Default
 	State   = "state"
 	Comment = "comment"
 
@@ -133,13 +134,13 @@ var SubSystemsSingleTargets = set.CreateStringSet([]string{
 
 // Constant separators
 const (
-	SubSystemSeparator = `:`
-	KvSeparator        = `=`
-	KvSpaceSeparator   = ` `
-	KvComment          = `#`
-	KvNewline          = "\n"
-	KvDoubleQuote      = `"`
-	KvSingleQuote      = `'`
+	SubSystemSeparator = madmin.SubSystemSeparator
+	KvSeparator        = madmin.KvSeparator
+	KvSpaceSeparator   = madmin.KvSpaceSeparator
+	KvComment          = madmin.KvComment
+	KvNewline          = madmin.KvNewline
+	KvDoubleQuote      = madmin.KvDoubleQuote
+	KvSingleQuote      = madmin.KvSingleQuote
 
 	// Env prefix used for all envs in MinIO
 	EnvPrefix        = "MINIO_"