kpod top

Display information about processes in a running container.

Signed-off-by: baude <bbaude@redhat.com>

Closes: #121
Approved by: rhatdan

README.md

@@ -61,6 +61,7 @@ libpod is currently in active development.
 | [kpod-stats(1)](/docs/kpod-stats.1.md)               | Display a live stream of one or more containers' resource usage statistics||
 | [kpod-stop(1)](/docs/kpod-stop.1.md)                 | Stops one or more running containers                                      ||
 | [kpod-tag(1)](/docs/kpod-tag.1.md)                   | Add an additional name to a local image                                   |[![...](/docs/play.png)](https://asciinema.org/a/133803)|
+| [kpod-top(1)](/docs/kpod-top.1.md)                   | Display the running processes of a container
 | [kpod-umount(1)](/docs/kpod-umount.1.md)             | Unmount a working container's root filesystem                             ||
 | [kpod-unpause(1)](/docs/kpod-unpause.1.md)           | Unpause one or more running containers                                    |[![...](/docs/play.png)](https://asciinema.org/a/141292)|
 | [kpod-version(1)](/docs/kpod-version.1.md)           | Display the version information                                           |[![...](/docs/play.png)](https://asciinema.org/a/mfrn61pjZT9Fc8L4NbfdSqfgu)|

cmd/kpod/images.go

@@ -155,8 +155,13 @@ func genImagesFormat(format string, quiet, noHeading, digests bool) string {
 func imagesToGeneric(templParams []imagesTemplateParams, JSONParams []imagesJSONParams) (genericParams []interface{}) {
 	if len(templParams) > 0 {
 		for _, v := range templParams {
+			fmt.Println(v)
+			fmt.Printf("%T\n", v)
 			genericParams = append(genericParams, interface{}(v))
 		}
+		fmt.Println("###")
+		fmt.Println(genericParams)
+		fmt.Println("###")
 		return
 	}
 	for _, v := range JSONParams {
@@ -178,6 +183,9 @@ func (i *imagesTemplateParams) headerMap() map[string]string {
 		}
 		values[key] = strings.ToUpper(splitCamelCase(value))
 	}
+	fmt.Println("!!!")
+	fmt.Printf("%+v\n", values)
+	fmt.Println("!!!")
 	return values
 }
 

cmd/kpod/main.go

@@ -62,6 +62,7 @@ func main() {
 		statsCommand,
 		stopCommand,
 		tagCommand,
+		topCommand,
 		umountCommand,
 		unpauseCommand,
 		versionCommand,

cmd/kpod/top.go

@@ -0,0 +1,258 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/pkg/errors"
+	"github.com/projectatomic/libpod/cmd/kpod/formats"
+	"github.com/projectatomic/libpod/libpod"
+	"github.com/urfave/cli"
+)
+
+var (
+	topFlags = []cli.Flag{
+		cli.StringFlag{
+			Name:  "format",
+			Usage: "Change the output to JSON",
+		},
+	}
+	topDescription = `
+   kpod top
+
+	Display the running processes of the container.
+`
+
+	topCommand = cli.Command{
+		Name:           "top",
+		Usage:          "Display the running processes of a container",
+		Description:    topDescription,
+		Flags:          topFlags,
+		Action:         topCmd,
+		ArgsUsage:      "CONTAINER-NAME",
+		SkipArgReorder: true,
+	}
+)
+
+func topCmd(c *cli.Context) error {
+	doJSON := false
+	if c.IsSet("format") {
+		if strings.ToUpper(c.String("format")) == "JSON" {
+			doJSON = true
+		} else {
+			return errors.Errorf("only 'json' is supported for a format option")
+		}
+	}
+	args := c.Args()
+	var psArgs []string
+	psOpts := []string{"-o", "uid,pid,ppid,c,stime,tname,time,cmd"}
+	if len(args) < 1 {
+		return errors.Errorf("you must provide the name or id of a running container")
+	}
+	if err := validateFlags(c, topFlags); err != nil {
+		return err
+	}
+
+	runtime, err := getRuntime(c)
+	if err != nil {
+		return errors.Wrapf(err, "error creating libpod runtime")
+	}
+	defer runtime.Shutdown(false)
+	if len(args) > 1 {
+		psOpts = args[1:]
+	}
+
+	container, err := runtime.LookupContainer(args[0])
+	if err != nil {
+		return errors.Wrapf(err, "unable to lookup %s", args[0])
+	}
+	conStat, err := container.State()
+	if err != nil {
+		return errors.Wrapf(err, "unable to look up state for %s", args[0])
+	}
+	if conStat != libpod.ContainerStateRunning {
+		return errors.Errorf("top can only be used on running containers")
+	}
+
+	psArgs = append(psArgs, psOpts...)
+
+	results, err := container.GetContainerPidInformation(psArgs)
+	if err != nil {
+		return err
+	}
+	headers := getHeaders(results[0])
+	format := genTopFormat(headers)
+	var out formats.Writer
+	psParams, err := psDataToPSParams(results[1:], headers)
+	if err != nil {
+		return errors.Wrap(err, "unable to convert ps data to proper structure")
+	}
+	if doJSON {
+		out = formats.JSONStructArray{Output: topToGeneric(psParams)}
+	} else {
+		out = formats.StdoutTemplateArray{Output: topToGeneric(psParams), Template: format, Fields: createTopHeaderMap(headers)}
+	}
+	formats.Writer(out).Out()
+	return nil
+}
+
+func getHeaders(s string) []string {
+	var headers []string
+	tmpHeaders := strings.Fields(s)
+	for _, header := range tmpHeaders {
+		headers = append(headers, strings.Replace(header, "%", "", -1))
+	}
+	return headers
+}
+
+func genTopFormat(headers []string) string {
+	format := "table "
+	for _, header := range headers {
+		format = fmt.Sprintf("%s{{.%s}}\t", format, header)
+	}
+	return format
+}
+
+// imagesToGeneric creates an empty array of interfaces for output
+func topToGeneric(templParams []PSParams) (genericParams []interface{}) {
+	for _, v := range templParams {
+		genericParams = append(genericParams, interface{}(v))
+	}
+	return
+}
+
+// generate the header based on the template provided
+func createTopHeaderMap(v []string) map[string]string {
+	values := make(map[string]string)
+	for _, key := range v {
+		value := key
+		if value == "CPU" {
+			value = "%CPU"
+		} else if value == "MEM" {
+			value = "%MEM"
+		}
+		values[key] = strings.ToUpper(splitCamelCase(value))
+	}
+	return values
+}
+
+// PSDataToParams converts a string array of data and its headers to an
+// arra if PSParams
+func psDataToPSParams(data []string, headers []string) ([]PSParams, error) {
+	var params []PSParams
+	for _, line := range data {
+		tmpMap := make(map[string]string)
+		tmpArray := strings.Fields(line)
+		if len(tmpArray) == 0 {
+			continue
+		}
+		for index, v := range tmpArray {
+			header := headers[index]
+			tmpMap[header] = v
+		}
+		jsonData, _ := json.Marshal(tmpMap)
+		var r PSParams
+		err := json.Unmarshal(jsonData, &r)
+		if err != nil {
+			return []PSParams{}, err
+		}
+		params = append(params, r)
+	}
+	return params, nil
+}
+
+//PSParams is a list of options that the command line ps recognizes
+type PSParams struct {
+	CPU     string `json: "%CPU"`
+	MEM     string `json: "%MEM"`
+	COMMAND string
+	BLOCKED string
+	START   string
+	TIME    string
+	C       string
+	CAUGHT  string
+	CGROUP  string
+	CLSCLS  string
+	CLS     string
+	CMD     string
+	CP      string
+	DRS     string
+	EGID    string
+	EGROUP  string
+	EIP     string
+	ESP     string
+	ELAPSED string
+	EUIDE   string
+	USER    string
+	F       string
+	FGID    string
+	FGROUP  string
+	FUID    string
+	FUSER   string
+	GID     string
+	GROUP   string
+	IGNORED string
+	IPCNS   string
+	LABEL   string
+	STARTED string
+	SESSION string
+	LWP     string
+	MACHINE string
+	MAJFLT  string
+	MINFLT  string
+	MNTNS   string
+	NETNS   string
+	NI      string
+	NLWP    string
+	OWNER   string
+	PENDING string
+	PGID    string
+	PGRP    string
+	PID     string
+	PIDNS   string
+	POL     string
+	PPID    string
+	PRI     string
+	PSR     string
+	RGID    string
+	RGROUP  string
+	RSS     string
+	RSZ     string
+	RTPRIO  string
+	RUID    string
+	RUSER   string
+	S       string
+	SCH     string
+	SEAT    string
+	SESS    string
+	P       string
+	SGID    string
+	SGROUP  string
+	SID     string
+	SIZE    string
+	SLICE   string
+	SPID    string
+	STACKP  string
+	STIME   string
+	SUID    string
+	SUPGID  string
+	SUPGRP  string
+	SUSER   string
+	SVGID   string
+	SZ      string
+	TGID    string
+	THCNT   string
+	TID     string
+	TTY     string
+	TPGID   string
+	TRS     string
+	TT      string
+	UID     string
+	UNIT    string
+	USERNS  string
+	UTSNS   string
+	UUNIT   string
+	VSZ     string
+	WCHAN   string
+}

completions/bash/kpod

@@ -1288,6 +1288,14 @@ kpod_tag() {
     _complete_ "$options_with_args" "$boolean_options"
 }
 
+kpod_top() {
+    local options_with_args="
+    "
+    local boolean_options="
+    "
+    _complete_ "$options_with_args" "$boolean_options"
+}
+
 _kpod_version() {
      local options_with_args="
      "

docs/kpod-top.1.md

@@ -0,0 +1,59 @@
+% kpod(1) kpod-top - display the running processes of a container
+% Brent Baude
+
+## NAME
+kpod top - Display the running processes of a container
+
+## SYNOPSIS
+**kpod top**
+[**--help**|**-h**]
+
+## DESCRIPTION
+Display the running process of the container. ps-OPTION can be any of the options you would pass to a Linux ps command
+
+**kpod [GLOBAL OPTIONS] top [OPTIONS]**
+
+## OPTIONS
+
+**--help, -h**
+  Print usage statement
+
+**--format**
+  Display the output in an alternate format.  The only supported format is **JSON**.
+
+## EXAMPLES
+
+```
+# kpod top f5a62a71b07
+  UID   PID  PPID %CPU STIME TT           TIME CMD
+    0 18715 18705  0.0 10:35 pts/0    00:00:00 /bin/bash
+    0 18741 18715  0.0 10:35 pts/0    00:00:00 vi
+#
+```
+
+```
+#kpod --log-level=debug top f5a62a71b07 -o fuser,f,comm,label
+FUSER    F COMMAND         LABEL
+root     4 bash            system_u:system_r:container_t:s0:c429,c1016
+root     0 vi              system_u:system_r:container_t:s0:c429,c1016
+#
+```
+```
+# kpod top --format=json f5a62a71b07b -o %cpu,%mem,command,blocked
+[
+    {
+        "CPU": "0.0",
+        "MEM": "0.0",
+        "COMMAND": "vi",
+        "BLOCKED": "0000000000000000",
+        "START": "",
+        "TIME": "",
+        "C": "",
+        "CAUGHT": "",
+        ...
+```
+## SEE ALSO
+kpod(1), ps(1)
+
+## HISTORY
+December 2017, Originally compiled by Brent Baude<bbaude@redhat.com>

docs/kpod.1.md

@@ -136,6 +136,9 @@ Stops one or more running containers.
 ### tag
 Add an additional name to a local image
 
+### top
+Display the running processes of a container
+
 ### umount
 Unmount a working container's root file system
 

libpod/container_top.go

@@ -0,0 +1,57 @@
+package libpod
+
+import (
+	"fmt"
+	"io/ioutil"
+	"path/filepath"
+	"strings"
+
+	"github.com/pkg/errors"
+	"github.com/projectatomic/libpod/utils"
+	"github.com/sirupsen/logrus"
+)
+
+// GetContainerPids reads sysfs to obtain the pids associated with the container's cgroup
+// and uses locking
+func (c *Container) GetContainerPids() ([]string, error) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	if err := c.syncContainer(); err != nil {
+		return []string{}, errors.Wrapf(err, "error updating container %s state", c.ID())
+	}
+	return c.getContainerPids()
+}
+
+// Gets the pids for a container without locking.  should only be called from a func where
+// locking has already been established.
+func (c *Container) getContainerPids() ([]string, error) {
+	taskFile := filepath.Join("/sys/fs/cgroup/pids", CGroupParent, fmt.Sprintf("libpod-conmon-%s", c.ID()), c.ID(), "tasks")
+	logrus.Debug("reading pids from ", taskFile)
+	content, err := ioutil.ReadFile(taskFile)
+	if err != nil {
+		return []string{}, errors.Wrapf(err, "unable to read pids from %s", taskFile)
+	}
+	return strings.Fields(string(content)), nil
+
+}
+
+// GetContainerPidInformation calls ps with the appropriate options and returns
+// the results as a string
+func (c *Container) GetContainerPidInformation(args []string) ([]string, error) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	if err := c.syncContainer(); err != nil {
+		return []string{}, errors.Wrapf(err, "error updating container %s state", c.ID())
+	}
+	pids, err := c.getContainerPids()
+	if err != nil {
+		return []string{}, errors.Wrapf(err, "unable to obtain pids for ", c.ID())
+	}
+	args = append(args, "-p", strings.Join(pids, ","))
+	logrus.Debug("Executing: ", strings.Join(args, " "))
+	results, err := utils.ExecCmd("ps", args...)
+	if err != nil {
+		return []string{}, errors.Wrapf(err, "unable to obtain information about pids")
+	}
+	return strings.Split(results, "\n"), nil
+}

test/kpod_top.bats

@@ -0,0 +1,51 @@
+#!/usr/bin/env bats
+
+load helpers
+
+function teardown() {
+    cleanup_test
+}
+
+function setup() {
+    copy_images
+}
+
+@test "top without container name or id" {
+    run ${KPOD_BINARY} ${KPOD_OPTIONS} top
+    echo "$output"
+    [ "$status" -eq 1 ]
+}
+
+@test "top a bogus container" {
+    run ${KPOD_BINARY} ${KPOD_OPTIONS} top foobar
+    echo "$output"
+    [ "$status" -eq 1 ]
+}
+
+@test "top non-running container by id with defaults" {
+    run ${KPOD_BINARY} ${KPOD_OPTIONS} create -d ${ALPINE} sleep 60
+    [ "$status" -eq 0 ]
+    ctr_id="$output"
+    run bash -c "${KPOD_BINARY} ${KPOD_OPTIONS} top $ctr_id"
+    echo "$output"
+    [ "$status" -eq 1 ]
+}
+
+@test "top running container by id with defaults" {
+    run ${KPOD_BINARY} ${KPOD_OPTIONS} run -dt ${ALPINE} /bin/sh
+    [ "$status" -eq 0 ]
+    ctr_id="$output"
+    echo $ctr_id
+    run bash -c "${KPOD_BINARY} ${KPOD_OPTIONS} top $ctr_id"
+    echo "$output"
+    [ "$status" -eq 0 ]
+}
+
+@test "top running container by id with ps opts" {
+    run ${KPOD_BINARY} ${KPOD_OPTIONS} run -d ${ALPINE} sleep 60
+    [ "$status" -eq 0 ]
+    ctr_id="$output"
+    run bash -c "${KPOD_BINARY} ${KPOD_OPTIONS} top $ctr_id -o fuser,f,comm,label"
+    echo "$output"
+    [ "$status" -eq 0 ]
+}