Move admin APIs to new path and add redesigned heal APIs (#5351)

- Changes related to moving admin APIs
   - admin APIs now have an endpoint under /minio/admin
   - admin APIs are now versioned - a new API to server the version is
     added at "GET /minio/admin/version" and all API operations have the
     path prefix /minio/admin/v1/<operation>
   - new service stop API added
   - credentials change API is moved to /minio/admin/v1/config/credential
   - credentials change API and configuration get/set API now require TLS
     so that credentials are protected
   - all API requests now receive JSON
   - heal APIs are disabled as they will be changed substantially

- Heal API changes
   Heal API is now provided at a single endpoint with the ability for a
   client to start a heal sequence on all the data in the server, a
   single bucket, or under a prefix within a bucket.

   When a heal sequence is started, the server returns a unique token
   that needs to be used for subsequent 'status' requests to fetch heal
   results.

   On each status request from the client, the server returns heal result
   records that it has accumulated since the previous status request. The
   server accumulates upto 1000 records and pauses healing further
   objects until the client requests for status. If the client does not
   request any further records for a long time, the server aborts the
   heal sequence automatically.

   A heal result record is returned for each entity healed on the server,
   such as system metadata, object metadata, buckets and objects, and has
   information about the before and after states on each disk.

   A client may request to force restart a heal sequence - this causes
   the running heal sequence to be aborted at the next safe spot and
   starts a new heal sequence.

cmd/api-errors.go

@@ -41,8 +41,8 @@ type APIErrorResponse struct {
 	Key        string
 	BucketName string
 	Resource   string
-	RequestID  string `xml:"RequestId"`
-	HostID     string `xml:"HostId"`
+	RequestID  string `xml:"RequestId" json:"RequestId"`
+	HostID     string `xml:"HostId" json:"HostId"`
 }
 
 // APIErrorCode type of error status.
@@ -158,6 +158,7 @@ const (
 	ErrReadQuorum
 	ErrWriteQuorum
 	ErrStorageFull
+	ErrRequestBodyParse
 	ErrObjectExistsAsDirectory
 	ErrPolicyNesting
 	ErrInvalidObjectName
@@ -174,6 +175,7 @@ const (
 	// Please open a https://github.com/minio/minio/issues before adding
 	// new error codes here.
 
+	ErrMalformedJSON
 	ErrAdminInvalidAccessKey
 	ErrAdminInvalidSecretKey
 	ErrAdminConfigNoQuorum
@@ -183,6 +185,11 @@ const (
 	ErrInsecureClientRequest
 	ErrObjectTampered
 	ErrHealNotImplemented
+	ErrHealNoSuchProcess
+	ErrHealInvalidClientToken
+	ErrHealMissingBucket
+	ErrHealAlreadyRunning
+	ErrHealOverlappingPaths
 )
 
 // error code to APIError structure, these fields carry respective
@@ -673,6 +680,11 @@ var errorCodeResponse = map[APIErrorCode]APIError{
 		Description:    "Storage backend has reached its minimum free disk threshold. Please delete a few objects to proceed.",
 		HTTPStatusCode: http.StatusInternalServerError,
 	},
+	ErrRequestBodyParse: {
+		Code:           "XMinioRequestBodyParse",
+		Description:    "The request body failed to parse.",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
 	ErrObjectExistsAsDirectory: {
 		Code:           "XMinioObjectExistsAsDirectory",
 		Description:    "Object name already exists as a directory.",
@@ -708,6 +720,11 @@ var errorCodeResponse = map[APIErrorCode]APIError{
 		Description:    "Server not initialized, please try again.",
 		HTTPStatusCode: http.StatusServiceUnavailable,
 	},
+	ErrMalformedJSON: {
+		Code:           "XMinioMalformedJSON",
+		Description:    "The JSON you provided was not well-formed or did not validate against our published format.",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
 	ErrAdminInvalidAccessKey: {
 		Code:           "XMinioAdminInvalidAccessKey",
 		Description:    "The access key is invalid.",
@@ -764,11 +781,6 @@ var errorCodeResponse = map[APIErrorCode]APIError{
 		Description:    errObjectTampered.Error(),
 		HTTPStatusCode: http.StatusPartialContent,
 	},
-	ErrHealNotImplemented: {
-		Code:           "XMinioHealNotImplemented",
-		Description:    "This server does not implement heal functionality.",
-		HTTPStatusCode: http.StatusBadRequest,
-	},
 	ErrMaximumExpires: {
 		Code:           "AuthorizationQueryParametersError",
 		Description:    "X-Amz-Expires must be less than a week (in seconds); that is, the given X-Amz-Expires must be less than 604800 seconds",
@@ -782,6 +794,36 @@ var errorCodeResponse = map[APIErrorCode]APIError{
 		Description:    "Invalid Request",
 		HTTPStatusCode: http.StatusBadRequest,
 	},
+	ErrHealNotImplemented: {
+		Code:           "XMinioHealNotImplemented",
+		Description:    "This server does not implement heal functionality.",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
+	ErrHealNoSuchProcess: {
+		Code:           "XMinioHealNoSuchProcess",
+		Description:    "No such heal process is running on the server",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
+	ErrHealInvalidClientToken: {
+		Code:           "XMinioHealInvalidClientToken",
+		Description:    "Client token mismatch",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
+	ErrHealMissingBucket: {
+		Code:           "XMinioHealMissingBucket",
+		Description:    "A heal start request with a non-empty object-prefix parameter requires a bucket to be specified.",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
+	ErrHealAlreadyRunning: {
+		Code:           "XMinioHealAlreadyRunning",
+		Description:    "",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
+	ErrHealOverlappingPaths: {
+		Code:           "XMinioHealOverlappingPaths",
+		Description:    "",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
 
 	// Add your error structure here.
 }