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Hide the mutex in formatter.ContainerStats 

The formatter.ContainerStats struct exposes its Mutex.
This is a bad design and should be fixed.

To fix that, I separated the statistics
attributes from ContainerStats to StatsEntry and
hid the mutex. Notice that the mutex protects both
the `err` field and the statistics attributes.

Then, implemented SetStatistics, SetError, GetStatistics
and GetError to avoid races.

Moreover, to make this less granular, I decided to
replace the read-write mutex with the regular mutex and
to pass a StatsEntry slice to formatter.ContainerStatsWrite

Signed-off-by: Boaz Shuster <ripcurld.github@gmail.com>
This commit is contained in:
Boaz Shuster 2016-09-22 15:54:41 +03:00
parent bfbdb15f55
commit 3bc50c45ba
3 changed files with 132 additions and 81 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
command/container/stats.go
View File

@ -166,11 +166,10 @@ func runStats(dockerCli *command.DockerCli, opts *statsOptions) error {
var errs []string
cStats.mu.Lock()
for _, c := range cStats.cs {
c.Mu.Lock()
if c.Err != nil {
errs = append(errs, fmt.Sprintf("%s: %v", c.Name, c.Err))
cErr := c.GetError()
if cErr != nil {
errs = append(errs, fmt.Sprintf("%s: %v", c.Name, cErr))
}
c.Mu.Unlock()
}
cStats.mu.Unlock()
if len(errs) > 0 {
@ -189,7 +188,7 @@ func runStats(dockerCli *command.DockerCli, opts *statsOptions) error {
Format: formatter.NewStatsFormat(f, daemonOSType),
}
cleanHeader := func() {
cleanScreen := func() {
if !opts.noStream {
fmt.Fprint(dockerCli.Out(), "\033[2J")
fmt.Fprint(dockerCli.Out(), "\033[H")
@ -198,14 +197,17 @@ func runStats(dockerCli *command.DockerCli, opts *statsOptions) error {
var err error
for range time.Tick(500 * time.Millisecond) {
cleanHeader()
cStats.mu.RLock()
csLen := len(cStats.cs)
if err = formatter.ContainerStatsWrite(statsCtx, cStats.cs); err != nil {
cleanScreen()
ccstats := []formatter.StatsEntry{}
cStats.mu.Lock()
for _, c := range cStats.cs {
ccstats = append(ccstats, c.GetStatistics())
}
cStats.mu.Unlock()
if err = formatter.ContainerStatsWrite(statsCtx, ccstats); err != nil {
break
}
cStats.mu.RUnlock()
if csLen == 0 && !showAll {
if len(cStats.cs) == 0 && !showAll {
break
}
if opts.noStream {

57
command/container/stats_helpers.go
View File

@ -17,7 +17,7 @@ import (
type stats struct {
ostype string
mu sync.RWMutex
mu sync.Mutex
cs []*formatter.ContainerStats
}
@ -72,9 +72,7 @@ func collect(s *formatter.ContainerStats, ctx context.Context, cli client.APICli
response, err := cli.ContainerStats(ctx, s.Name, streamStats)
if err != nil {
s.Mu.Lock()
s.Err = err
s.Mu.Unlock()
s.SetError(err)
return
}
defer response.Body.Close()
@ -88,6 +86,9 @@ func collect(s *formatter.ContainerStats, ctx context.Context, cli client.APICli
cpuPercent = 0.0
blkRead, blkWrite uint64 // Only used on Linux
mem = 0.0
memLimit = 0.0
memPerc = 0.0
pidsStatsCurrent uint64
)
if err := dec.Decode(&v); err != nil {
@ -113,26 +114,27 @@ func collect(s *formatter.ContainerStats, ctx context.Context, cli client.APICli
cpuPercent = calculateCPUPercentUnix(previousCPU, previousSystem, v)
blkRead, blkWrite = calculateBlockIO(v.BlkioStats)
mem = float64(v.MemoryStats.Usage)
memLimit = float64(v.MemoryStats.Limit)
memPerc = memPercent
pidsStatsCurrent = v.PidsStats.Current
} else {
cpuPercent = calculateCPUPercentWindows(v)
blkRead = v.StorageStats.ReadSizeBytes
blkWrite = v.StorageStats.WriteSizeBytes
mem = float64(v.MemoryStats.PrivateWorkingSet)
}
s.Mu.Lock()
s.CPUPercentage = cpuPercent
s.Memory = mem
s.NetworkRx, s.NetworkTx = calculateNetwork(v.Networks)
s.BlockRead = float64(blkRead)
s.BlockWrite = float64(blkWrite)
if daemonOSType != "windows" {
s.MemoryLimit = float64(v.MemoryStats.Limit)
s.MemoryPercentage = memPercent
s.PidsCurrent = v.PidsStats.Current
}
s.Mu.Unlock()
netRx, netTx := calculateNetwork(v.Networks)
s.SetStatistics(formatter.StatsEntry{
CPUPercentage: cpuPercent,
Memory: mem,
MemoryPercentage: memPerc,
MemoryLimit: memLimit,
NetworkRx: netRx,
NetworkTx: netTx,
BlockRead: float64(blkRead),
BlockWrite: float64(blkWrite),
PidsCurrent: pidsStatsCurrent,
})
u <- nil
if !streamStats {
return
@ -144,18 +146,7 @@ func collect(s *formatter.ContainerStats, ctx context.Context, cli client.APICli
case <-time.After(2 * time.Second):
// zero out the values if we have not received an update within
// the specified duration.
s.Mu.Lock()
s.CPUPercentage = 0
s.Memory = 0
s.MemoryPercentage = 0
s.MemoryLimit = 0
s.NetworkRx = 0
s.NetworkTx = 0
s.BlockRead = 0
s.BlockWrite = 0
s.PidsCurrent = 0
s.Err = errors.New("timeout waiting for stats")
s.Mu.Unlock()
s.SetErrorAndReset(errors.New("timeout waiting for stats"))
// if this is the first stat you get, release WaitGroup
if !getFirst {
getFirst = true
@ -163,12 +154,10 @@ func collect(s *formatter.ContainerStats, ctx context.Context, cli client.APICli
}
case err := <-u:
if err != nil {
s.Mu.Lock()
s.Err = err
s.Mu.Unlock()
s.SetError(err)
continue
}
s.Err = nil
s.SetError(nil)
// if this is the first stat you get, release WaitGroup
if !getFirst {
getFirst = true

132
command/formatter/stats.go
View File

@ -4,27 +4,27 @@ import (
"fmt"
"sync"
"github.com/docker/go-units"
units "src/github.com/docker/go-units"
)
const (
defaultStatsTableFormat = "table {{.Container}}\t{{.CPUPrec}}\t{{.MemUsage}}\t{{.MemPrec}}\t{{.NetIO}}\t{{.BlockIO}}\t{{.PIDs}}"
winDefaultStatsTableFormat = "table {{.Container}}\t{{.CPUPrec}}\t{{{.MemUsage}}\t{.NetIO}}\t{{.BlockIO}}"
winOSType = "windows"
defaultStatsTableFormat = "table {{.Container}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.MemPerc}}\t{{.NetIO}}\t{{.BlockIO}}\t{{.PIDs}}"
winDefaultStatsTableFormat = "table {{.Container}}\t{{.CPUPerc}}\t{{{.MemUsage}}\t{.NetIO}}\t{{.BlockIO}}"
emptyStatsTableFormat = "Waiting for statistics..."
containerHeader = "CONTAINER"
cpuPrecHeader = "CPU %"
cpuPercHeader = "CPU %"
netIOHeader = "NET I/O"
blockIOHeader = "BLOCK I/O"
winMemPrecHeader = "PRIV WORKING SET" // Used only on Window
memPrecHeader = "MEM %" // Used only on Linux
winMemPercHeader = "PRIV WORKING SET" // Used only on Window
memPercHeader = "MEM %" // Used only on Linux
memUseHeader = "MEM USAGE / LIMIT" // Used only on Linux
pidsHeader = "PIDS" // Used only on Linux
)
// ContainerStatsAttrs represents the statistics data collected from a container.
type ContainerStatsAttrs struct {
Windows bool
// StatsEntry represents represents the statistics data collected from a container
type StatsEntry struct {
Name string
CPUPercentage float64
Memory float64 // On Windows this is the private working set
@ -35,19 +35,73 @@ type ContainerStatsAttrs struct {
BlockRead float64
BlockWrite float64
PidsCurrent uint64 // Not used on Windows
IsInvalid bool
OSType string
}
// ContainerStats represents the containers statistics data.
// ContainerStats represents an entity to store containers statistics synchronously
type ContainerStats struct {
Mu sync.RWMutex
ContainerStatsAttrs
Err error
mutex sync.Mutex
StatsEntry
err error
}
// GetError returns the container statistics error.
// This is used to determine whether the statistics are valid or not
func (cs *ContainerStats) GetError() error {
cs.mutex.Lock()
defer cs.mutex.Unlock()
return cs.err
}
// SetErrorAndReset zeroes all the container statistics and store the error.
// It is used when receiving time out error during statistics collecting to reduce lock overhead
func (cs *ContainerStats) SetErrorAndReset(err error) {
cs.mutex.Lock()
defer cs.mutex.Unlock()
cs.CPUPercentage = 0
cs.Memory = 0
cs.MemoryPercentage = 0
cs.MemoryLimit = 0
cs.NetworkRx = 0
cs.NetworkTx = 0
cs.BlockRead = 0
cs.BlockWrite = 0
cs.PidsCurrent = 0
cs.err = err
cs.IsInvalid = true
}
// SetError sets container statistics error
func (cs *ContainerStats) SetError(err error) {
cs.mutex.Lock()
defer cs.mutex.Unlock()
cs.err = err
if err != nil {
cs.IsInvalid = true
}
}
// SetStatistics set the container statistics
func (cs *ContainerStats) SetStatistics(s StatsEntry) {
cs.mutex.Lock()
defer cs.mutex.Unlock()
s.Name = cs.Name
s.OSType = cs.OSType
cs.StatsEntry = s
}
// GetStatistics returns container statistics with other meta data such as the container name
func (cs *ContainerStats) GetStatistics() StatsEntry {
cs.mutex.Lock()
defer cs.mutex.Unlock()
return cs.StatsEntry
}
// NewStatsFormat returns a format for rendering an CStatsContext
func NewStatsFormat(source, osType string) Format {
if source == TableFormatKey {
if osType == "windows" {
if osType == winOSType {
return Format(winDefaultStatsTableFormat)
}
return Format(defaultStatsTableFormat)
@ -58,22 +112,16 @@ func NewStatsFormat(source, osType string) Format {
// NewContainerStats returns a new ContainerStats entity and sets in it the given name
func NewContainerStats(name, osType string) *ContainerStats {
return &ContainerStats{
ContainerStatsAttrs: ContainerStatsAttrs{
Name: name,
Windows: (osType == "windows"),
},
StatsEntry: StatsEntry{Name: name, OSType: osType},
}
}
// ContainerStatsWrite renders the context for a list of containers statistics
func ContainerStatsWrite(ctx Context, containerStats []*ContainerStats) error {
func ContainerStatsWrite(ctx Context, containerStats []StatsEntry) error {
render := func(format func(subContext subContext) error) error {
for _, cstats := range containerStats {
cstats.Mu.RLock()
cstatsAttrs := cstats.ContainerStatsAttrs
cstats.Mu.RUnlock()
containerStatsCtx := &containerStatsContext{
s: cstatsAttrs,
s: cstats,
}
if err := format(containerStatsCtx); err != nil {
return err
@ -86,7 +134,7 @@ func ContainerStatsWrite(ctx Context, containerStats []*ContainerStats) error {
type containerStatsContext struct {
HeaderContext
s ContainerStatsAttrs
s StatsEntry
}
func (c *containerStatsContext) Container() string {
@ -94,42 +142,54 @@ func (c *containerStatsContext) Container() string {
return c.s.Name
}
func (c *containerStatsContext) CPUPrec() string {
c.AddHeader(cpuPrecHeader)
func (c *containerStatsContext) CPUPerc() string {
c.AddHeader(cpuPercHeader)
if c.s.IsInvalid {
return fmt.Sprintf("--")
}
return fmt.Sprintf("%.2f%%", c.s.CPUPercentage)
}
func (c *containerStatsContext) MemUsage() string {
c.AddHeader(memUseHeader)
if !c.s.Windows {
return fmt.Sprintf("%s / %s", units.BytesSize(c.s.Memory), units.BytesSize(c.s.MemoryLimit))
if c.s.IsInvalid || c.s.OSType == winOSType {
return fmt.Sprintf("-- / --")
}
return fmt.Sprintf("-- / --")
return fmt.Sprintf("%s / %s", units.BytesSize(c.s.Memory), units.BytesSize(c.s.MemoryLimit))
}
func (c *containerStatsContext) MemPrec() string {
header := memPrecHeader
if c.s.Windows {
header = winMemPrecHeader
func (c *containerStatsContext) MemPerc() string {
header := memPercHeader
if c.s.OSType == winOSType {
header = winMemPercHeader
}
c.AddHeader(header)
if c.s.IsInvalid {
return fmt.Sprintf("--")
}
return fmt.Sprintf("%.2f%%", c.s.MemoryPercentage)
}
func (c *containerStatsContext) NetIO() string {
c.AddHeader(netIOHeader)
if c.s.IsInvalid {
return fmt.Sprintf("--")
}
return fmt.Sprintf("%s / %s", units.HumanSizeWithPrecision(c.s.NetworkRx, 3), units.HumanSizeWithPrecision(c.s.NetworkTx, 3))
}
func (c *containerStatsContext) BlockIO() string {
c.AddHeader(blockIOHeader)
if c.s.IsInvalid {
return fmt.Sprintf("--")
}
return fmt.Sprintf("%s / %s", units.HumanSizeWithPrecision(c.s.BlockRead, 3), units.HumanSizeWithPrecision(c.s.BlockWrite, 3))
}
func (c *containerStatsContext) PIDs() string {
c.AddHeader(pidsHeader)
if !c.s.Windows {
return fmt.Sprintf("%d", c.s.PidsCurrent)
if c.s.IsInvalid || c.s.OSType == winOSType {
return fmt.Sprintf("--")
}
return fmt.Sprintf("-")
return fmt.Sprintf("%d", c.s.PidsCurrent)
}