Implement mc ready to check if the cluster is ready or not (#4101)

Also adds option to check if the cluster has enough read quorum and if
the cluster is taken down for any maintenance.

Uses madmin.AnonymousClient for invoking the requests

cmd/auto-complete.go

@@ -425,6 +425,7 @@ var completeCmds = map[string]complete.Predictor{
 	"/support/status":       aliasCompleter,
 
 	"/update": nil,
+	"/ready":  nil,
 }
 
 // flagsToCompleteFlags transforms a cli.Flag to complete.Flags

cmd/client-admin.go

@@ -155,6 +155,77 @@ func newAdminClient(aliasedURL string) (*madmin.AdminClient, *probe.Error) {
 	return s3Client, nil
 }
 
+func newAnonymousClient(aliasedURL string) (*madmin.AnonymousClient, *probe.Error) {
+	_, urlStrFull, aliasCfg, err := expandAlias(aliasedURL)
+	if err != nil {
+		return nil, err.Trace(aliasedURL)
+	}
+	// Verify if the aliasedURL is a real URL, fail in those cases
+	// indicating the user to add alias.
+	if aliasCfg == nil && urlRgx.MatchString(aliasedURL) {
+		return nil, errInvalidAliasedURL(aliasedURL).Trace(aliasedURL)
+	}
+	if aliasCfg == nil {
+		return nil, probe.NewError(fmt.Errorf("No valid configuration found for '%s' host alias", urlStrFull))
+	}
+
+	// Creates a parsed URL.
+	targetURL, e := url.Parse(urlStrFull)
+	if e != nil {
+		return nil, probe.NewError(e)
+	}
+
+	// By default enable HTTPs.
+	useTLS := true
+	if targetURL.Scheme == "http" {
+		useTLS = false
+	}
+
+	// Construct an anonymous client
+	anonClient, e := madmin.NewAnonymousClient(targetURL.Host, useTLS)
+	if e != nil {
+		return nil, probe.NewError(e)
+	}
+
+	// Keep TLS config.
+	tlsConfig := &tls.Config{
+		RootCAs: globalRootCAs,
+		// Can't use SSLv3 because of POODLE and BEAST
+		// Can't use TLSv1.0 because of POODLE and BEAST using CBC cipher
+		// Can't use TLSv1.1 because of RC4 cipher usage
+		MinVersion: tls.VersionTLS12,
+	}
+	if globalInsecure {
+		tlsConfig.InsecureSkipVerify = true
+	}
+	// Set custom transport
+	var transport http.RoundTripper = &http.Transport{
+		Proxy: ieproxy.GetProxyFunc(),
+		DialContext: (&net.Dialer{
+			Timeout:   10 * time.Second,
+			KeepAlive: 15 * time.Second,
+		}).DialContext,
+		MaxIdleConnsPerHost:   256,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 10 * time.Second,
+		TLSClientConfig:       tlsConfig,
+		// Set this value so that the underlying transport round-tripper
+		// doesn't try to auto decode the body of objects with
+		// content-encoding set to `gzip`.
+		//
+		// Refer:
+		//    https://golang.org/src/net/http/transport.go?h=roundTrip#L1843
+		DisableCompression: true,
+	}
+	if globalDebug {
+		transport = httptracer.GetNewTraceTransport(newTraceV4(), transport)
+	}
+	anonClient.SetCustomTransport(transport)
+
+	return anonClient, nil
+}
+
 // s3AdminNew returns an initialized minioAdmin structure. If debug is enabled,
 // it also enables an internal trace transport.
 var s3AdminNew = NewAdminFactory()

cmd/main.go

@@ -450,6 +450,7 @@ var appCmds = []cli.Command{
 	adminCmd,
 	configCmd,
 	updateCmd,
+	readyCmd,
 }
 
 func printMCVersion(c *cli.Context) {

cmd/ready.go

@@ -0,0 +1,153 @@
+// Copyright (c) 2015-2022 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package cmd
+
+import (
+	"context"
+	"time"
+
+	"github.com/fatih/color"
+	"github.com/minio/cli"
+	json "github.com/minio/colorjson"
+	"github.com/minio/madmin-go"
+	"github.com/minio/mc/pkg/probe"
+)
+
+const (
+	healthCheckInterval = 5 * time.Second
+)
+
+var readyFlags = []cli.Flag{
+	cli.BoolFlag{
+		Name:  "cluster-read",
+		Usage: "check if the cluster has enough read quorum",
+	},
+	cli.BoolFlag{
+		Name:  "maintenance",
+		Usage: "check if the cluster is taken down for maintenance",
+	},
+}
+
+// Checks if the cluster is ready or not
+var readyCmd = cli.Command{
+	Name:         "ready",
+	Usage:        "checks if the cluster is ready or not",
+	Action:       mainReady,
+	OnUsageError: onUsageError,
+	Before:       setGlobalsFromContext,
+	Flags:        append(readyFlags, globalFlags...),
+	CustomHelpTemplate: `NAME:
+  {{.HelpName}} - {{.Usage}}
+
+USAGE:
+  {{.HelpName}} [FLAGS] TARGET
+{{if .VisibleFlags}}
+FLAGS:
+  {{range .VisibleFlags}}{{.}}
+  {{end}}{{end}}
+EXAMPLES:
+  1. Check if the cluster is ready or not
+     {{.Prompt}} {{.HelpName}} myminio
+
+  2. Check if the cluster has enough read quorum
+     {{.Prompt}} {{.HelpName}} myminio --cluster-read
+
+  3. Check if the cluster is taken down for maintenance
+     {{.Prompt}} {{.HelpName}} myminio --maintenance
+`,
+}
+
+type readyMessage struct {
+	Healthy         bool `json:"healthy"`
+	MaintenanceMode bool `json:"maintenanceMode"`
+	WriteQuorum     int  `json:"writeQuorum"`
+	HealingDrives   int  `json:"healingDrives"`
+}
+
+func (r readyMessage) String() string {
+	if r.Healthy {
+		return color.GreenString("The cluster is ready")
+	}
+	return color.RedString("The cluster is not ready")
+}
+
+// JSON jsonified ready result
+func (r readyMessage) JSON() string {
+	jsonMessageBytes, e := json.MarshalIndent(r, "", " ")
+	fatalIf(probe.NewError(e), "Unable to marshal into JSON.")
+	return string(jsonMessageBytes)
+}
+
+// mainReady - main handler for mc ready command.
+func mainReady(cliCtx *cli.Context) error {
+	if !cliCtx.Args().Present() {
+		exitCode := 1
+		cli.ShowCommandHelpAndExit(cliCtx, "ready", exitCode)
+	}
+
+	// Set command flags from context.
+	clusterRead := cliCtx.Bool("cluster-read")
+	maintenance := cliCtx.Bool("maintenance")
+
+	ctx, cancelClusterReady := context.WithCancel(globalContext)
+	defer cancelClusterReady()
+	aliasedURL := cliCtx.Args().Get(0)
+
+	anonClient, err := newAnonymousClient(aliasedURL)
+	fatalIf(err.Trace(aliasedURL), "Couldn't construct anonymous client for `"+aliasedURL+"`.")
+
+	healthOpts := madmin.HealthOpts{
+		ClusterRead: clusterRead,
+		Maintenance: maintenance,
+	}
+
+	healthResult, hErr := anonClient.Healthy(ctx, healthOpts)
+	fatalIf(probe.NewError(hErr).Trace(aliasedURL), "Couldn't get the health status for `"+aliasedURL+"`.")
+
+	if healthResult.Healthy {
+		printMsg(readyMessage{
+			Healthy:         healthResult.Healthy,
+			MaintenanceMode: healthResult.MaintenanceMode,
+			WriteQuorum:     healthResult.WriteQuorum,
+			HealingDrives:   healthResult.HealingDrives,
+		})
+		return nil
+	}
+
+	timer := time.NewTimer(healthCheckInterval)
+	defer timer.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return nil
+		case <-timer.C:
+			timer.Reset(healthCheckInterval)
+			healthResult, hErr := anonClient.Healthy(ctx, healthOpts)
+			fatalIf(probe.NewError(hErr).Trace(aliasedURL), "Couldn't get the health status for `"+aliasedURL+"`.")
+			printMsg(readyMessage{
+				Healthy:         healthResult.Healthy,
+				MaintenanceMode: healthResult.MaintenanceMode,
+				WriteQuorum:     healthResult.WriteQuorum,
+				HealingDrives:   healthResult.HealingDrives,
+			})
+			if healthResult.Healthy {
+				return nil
+			}
+		}
+	}
+}

cmd/utils.go

@@ -151,8 +151,8 @@ func NewS3Config(urlStr string, aliasCfg *aliasConfigV10) *Config {
 		s3Config.SecretKey = aliasCfg.SecretKey
 		s3Config.SessionToken = aliasCfg.SessionToken
 		s3Config.Signature = aliasCfg.API
-	}
 		s3Config.Lookup = getLookupType(aliasCfg.Path)
+	}
 	return s3Config
 }
 

go.mod

@@ -19,7 +19,7 @@ require (
 	github.com/minio/cli v1.22.0
 	github.com/minio/colorjson v1.0.2
 	github.com/minio/filepath v1.0.0
-	github.com/minio/madmin-go v1.3.19
+	github.com/minio/madmin-go v1.3.20
 	github.com/minio/md5-simd v1.1.2 // indirect
 	github.com/minio/minio-go/v7 v7.0.30
 	github.com/minio/pkg v1.1.22

go.sum

@@ -342,6 +342,8 @@ github.com/minio/filepath v1.0.0/go.mod h1:/nRZA2ldl5z6jT9/KQuvZcQlxZIMQoFFQPvEX
 github.com/minio/madmin-go v1.3.5/go.mod h1:vGKGboQgGIWx4DuDUaXixjlIEZOCIp6ivJkQoiVaACc=
 github.com/minio/madmin-go v1.3.19 h1:X/L4MTnDoR1VG1wwkeaQOBIQQohMTp5k8mjKNBbxGkE=
 github.com/minio/madmin-go v1.3.19/go.mod h1:ez87VmMtsxP7DRxjKJKD4RDNW+nhO2QF9KSzwxBDQ98=
+github.com/minio/madmin-go v1.3.20 h1:XHlIdewxAEEd/poI43CPiSmHGgJplkbFKFXZ1vZ6zMY=
+github.com/minio/madmin-go v1.3.20/go.mod h1:ez87VmMtsxP7DRxjKJKD4RDNW+nhO2QF9KSzwxBDQ98=
 github.com/minio/md5-simd v1.1.0/go.mod h1:XpBqgZULrMYD3R+M28PcmP0CkI7PEMzB3U77ZrKZ0Gw=
 github.com/minio/md5-simd v1.1.2 h1:Gdi1DZK69+ZVMoNHRXJyNcxrMA4dSxoYHZSQbirFg34=
 github.com/minio/md5-simd v1.1.2/go.mod h1:MzdKDxYpY2BT9XQFocsiZf/NKVtR7nkE4RoEpN+20RM=