github.com/coreos/rocket@v1.30.1-0.20200224141603-171c416fac02/rkt/status.go

// Copyright 2014 The rkt Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//+build linux

package main

import (
	"encoding/json"
	"fmt"
	"strconv"
	"time"

	lib "github.com/rkt/rkt/lib"
	pkgPod "github.com/rkt/rkt/pkg/pod"
	"github.com/spf13/cobra"
	"golang.org/x/net/context"
)

var (
	cmdStatus = &cobra.Command{
		Use:   "status [--wait=bool|timeout] [--wait-ready=bool|timeout] --uuid-file=FILE | UUID",
		Short: "Check the status of a rkt pod",
		Long: `Prints assorted information about the pod such as its state, pid and exit status.

The --wait and --wait-ready flags accept boolean or timeout values. If set to true, wait indefinitely. If set to false, don't wait at all.
They can also be set to a duration. If the duration is less than zero, wait indefinitely. If the duration is zero, don't wait at all.`,
		Run: runWrapper(runStatus),
	}
	flagWait      string
	flagWaitReady string
)

const (
	regularStatusDir = "stage1/rootfs/rkt/status"
	cmdStatusName    = "status"
)

func init() {
	cmdRkt.AddCommand(cmdStatus)
	cmdStatus.Flags().StringVar(&flagWait, "wait", "false", `toggles waiting for the pod to finish. Use the output to determine the actual terminal state.`)
	cmdStatus.Flags().StringVar(&flagWaitReady, "wait-ready", "false", `toggles waiting until the pod is ready.`)
	cmdStatus.Flags().Var(&flagFormat, "format", `choose the output format. Allowed format includes 'json', 'json-pretty'. If empty, then the result is printed as key value pairs`)

	cmdStatus.Flags().Lookup("wait").NoOptDefVal = "true"
	cmdStatus.Flags().Lookup("wait-ready").NoOptDefVal = "true"
	cmdStatus.Flags().StringVar(&flagUUIDFile, "uuid-file", "", "read pod UUID from file instead of argument")
}

func runStatus(cmd *cobra.Command, args []string) (exit int) {
	var podUUID string

	switch {
	case len(args) == 0 && flagUUIDFile != "":
		UUID, err := pkgPod.ReadUUIDFromFile(flagUUIDFile)
		if err != nil {
			stderr.PrintE("unable to resolve UUID from file", err)
			return 1
		}
		podUUID = UUID

	case len(args) == 1 && flagUUIDFile == "":
		podUUID = args[0]

	default:
		cmd.Usage()
		return 254
	}

	dWait, err := parseDuration(flagWait)
	if err != nil {
		cmd.Usage()
		return 254
	}

	dReady, err := parseDuration(flagWaitReady)
	if err != nil {
		cmd.Usage()
		return 254
	}
	p, err := pkgPod.PodFromUUIDString(getDataDir(), podUUID)
	if err != nil {
		stderr.PrintE("problem retrieving pod", err)
		return 254
	}
	defer p.Close()

	if dReady != 0 {
		if err := p.WaitReady(newContext(dReady)); err != nil {
			stderr.PrintE("error waiting for pod readiness", err)
			return 254
		}
	}

	if dWait != 0 {
		if err := p.WaitFinished(newContext(dWait)); err != nil {
			stderr.PrintE("error waiting for pod to finish", err)
			return 254
		}
	}

	if err = printStatus(p); err != nil {
		stderr.PrintE("unable to print status", err)
		return 254
	}

	return 0
}

// parseDuration converts the given string s to a duration value.
// If it is empty string or a true boolean value according to strconv.ParseBool, a negative duration is returned.
// If the boolean value is false, a 0 duration is returned.
// If the string s is a duration value, then it is returned.
// It returns an error if the duration conversion failed.
func parseDuration(s string) (time.Duration, error) {
	if s == "" {
		return time.Duration(-1), nil
	}

	b, err := strconv.ParseBool(s)

	switch {
	case err != nil:
		return time.ParseDuration(s)
	case b:
		return time.Duration(-1), nil
	}

	return time.Duration(0), nil
}

// newContext returns a new context with timeout t if t > 0.
func newContext(t time.Duration) context.Context {
	ctx := context.Background()
	if t > 0 {
		ctx, _ = context.WithTimeout(ctx, t)
	}
	return ctx
}

// getExitStatuses returns a map of the statuses of the pod.
func getExitStatuses(p *pkgPod.Pod) (map[string]int, error) {
	_, manifest, err := p.PodManifest()
	if err != nil {
		return nil, err
	}

	stats := make(map[string]int)
	for _, app := range manifest.Apps {
		exitCode, err := p.AppExitCode(app.Name.String())
		if err != nil {
			continue
		}
		stats[app.Name.String()] = exitCode
	}
	return stats, nil
}

// printStatus prints the pod's pid and per-app status codes
func printStatus(p *pkgPod.Pod) error {
	if flagFormat != outputFormatTabbed {
		pod, err := lib.NewPodFromInternalPod(p)
		if err != nil {
			return fmt.Errorf("error converting pod: %v", err)
		}
		switch flagFormat {
		case outputFormatJSON:
			result, err := json.Marshal(pod)
			if err != nil {
				return fmt.Errorf("error marshaling the pod: %v", err)
			}
			stdout.Print(string(result))
		case outputFormatPrettyJSON:
			result, err := json.MarshalIndent(pod, "", "\t")
			if err != nil {
				return fmt.Errorf("error marshaling the pod: %v", err)
			}
			stdout.Print(string(result))
		}
		return nil
	}

	state := p.State()
	stdout.Printf("state=%s", state)

	created, err := p.CreationTime()
	if err != nil {
		return fmt.Errorf("unable to get creation time for pod %q: %v", p.UUID, err)
	}
	createdStr := created.Format(defaultTimeLayout)

	stdout.Printf("created=%s", createdStr)

	started, err := p.StartTime()
	if err != nil {
		return fmt.Errorf("unable to get start time for pod %q: %v", p.UUID, err)
	}
	var startedStr string
	if !started.IsZero() {
		startedStr = started.Format(defaultTimeLayout)
		stdout.Printf("started=%s", startedStr)
	}

	if state == pkgPod.Running || state == pkgPod.Exited {
		stdout.Printf("networks=%s", fmtNets(p.Nets))
	}

	if !(state == pkgPod.Running || state == pkgPod.Deleting || state == pkgPod.ExitedDeleting || state == pkgPod.Exited || state == pkgPod.ExitedGarbage) {
		return nil
	}

	if pid, err := p.Pid(); err == nil {
		// the pid file might not be written yet when the state changes to 'Running'
		// it may also never be written if systemd never executes (e.g.: a bad command)
		stdout.Printf("pid=%d", pid)
	}
	stdout.Printf("exited=%t", (state == pkgPod.Exited || state == pkgPod.ExitedGarbage))

	if state != pkgPod.Running {
		stats, err := getExitStatuses(p)
		if err != nil {
			return fmt.Errorf("unable to get exit statuses for pod %q: %v", p.UUID, err)
		}
		for app, stat := range stats {
			stdout.Printf("app-%s=%d", app, stat)
		}
	}
	return nil
}