list_units.go

/*
   Copyright 2014 CoreOS, Inc.

   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.
*/

package main

import (
	"fmt"
	"sort"
	"strings"

	"github.com/coreos/fleet/machine"
	"github.com/coreos/fleet/schema"
)

const (
	defaultListUnitsFields = "unit,machine,active,sub"
)

var (
	listUnitsFieldsFlag string
	cmdListUnits        = &Command{
		Name:    "list-units",
		Summary: "List the current state of units in the cluster",
		Usage:   "[--no-legend] [-l|--full] [--fields]",
		Description: `Lists the state of all units in the cluster loaded onto a machine.

For easily parsable output, you can remove the column headers:
	fleetctl list-units --no-legend

Output the list without ellipses:
	fleetctl list-units --full

Or, choose the columns to display:
	fleetctl list-units --fields=unit,machine`,
		Run: runListUnits,
	}

	listUnitsFields = map[string]usToField{
		"unit": func(us *schema.UnitState, full bool) string {
			if us == nil {
				return "-"
			}
			return us.Name
		},
		"load": func(us *schema.UnitState, full bool) string {
			if us == nil {
				return "-"
			}
			return us.SystemdLoadState
		},
		"active": func(us *schema.UnitState, full bool) string {
			if us == nil {
				return "-"
			}
			return us.SystemdActiveState
		},
		"sub": func(us *schema.UnitState, full bool) string {
			if us == nil {
				return "-"
			}
			return us.SystemdSubState
		},
		"machine": func(us *schema.UnitState, full bool) string {
			if us == nil || us.MachineID == "" {
				return "-"
			}
			ms := cachedMachineState(us.MachineID)
			if ms == nil {
				ms = &machine.MachineState{ID: us.MachineID}
			}
			return machineFullLegend(*ms, full)
		},
		"hash": func(us *schema.UnitState, full bool) string {
			if us == nil || us.Hash == "" {
				return "-"
			}
			if !full {
				return us.Hash[:7]
			}
			return us.Hash
		},
	}
)

type usToField func(us *schema.UnitState, full bool) string

func init() {
	cmdListUnits.Flags.BoolVar(&sharedFlags.Full, "full", false, "Do not ellipsize fields on output")
	cmdListUnits.Flags.BoolVar(&sharedFlags.Full, "l", false, "Shorthand for --full")
	cmdListUnits.Flags.BoolVar(&sharedFlags.NoLegend, "no-legend", false, "Do not print a legend (column headers)")
	cmdListUnits.Flags.StringVar(&listUnitsFieldsFlag, "fields", defaultListUnitsFields, fmt.Sprintf("Columns to print for each Unit. Valid fields are %q", strings.Join(usToFieldKeys(listUnitsFields), ",")))
}

func runListUnits(args []string) (exit int) {
	if listUnitsFieldsFlag == "" {
		stderr("Must define output format")
		return 1
	}

	cols := strings.Split(listUnitsFieldsFlag, ",")
	for _, s := range cols {
		if _, ok := listUnitsFields[s]; !ok {
			stderr("Invalid key in output format: %q", s)
			return 1
		}
	}

	states, err := cAPI.UnitStates()
	if err != nil {
		stderr("Error retrieving list of units from repository: %v", err)
		return 1
	}

	if !sharedFlags.NoLegend {
		fmt.Fprintln(out, strings.ToUpper(strings.Join(cols, "\t")))
	}

	for _, us := range states {
		var f []string
		for _, c := range cols {
			f = append(f, listUnitsFields[c](us, sharedFlags.Full))
		}
		fmt.Fprintln(out, strings.Join(f, "\t"))
	}

	out.Flush()
	return
}

func usToFieldKeys(m map[string]usToField) (keys []string) {
	for k := range m {
		keys = append(keys, k)
	}
	sort.Strings(keys)
	return
}