129 lines
3.4 KiB
Go
129 lines
3.4 KiB
Go
package daemon
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import (
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"bufio"
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"fmt"
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"os"
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"strconv"
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"strings"
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"sync"
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"time"
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"github.com/Sirupsen/logrus"
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"github.com/docker/docker/daemon/execdriver"
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"github.com/docker/docker/pkg/pubsub"
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"github.com/docker/libcontainer/system"
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)
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// newStatsCollector returns a new statsCollector that collections
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// network and cgroup stats for a registered container at the specified
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// interval. The collector allows non-running containers to be added
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// and will start processing stats when they are started.
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func newStatsCollector(interval time.Duration) *statsCollector {
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s := &statsCollector{
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interval: interval,
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publishers: make(map[*Container]*pubsub.Publisher),
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clockTicks: uint64(system.GetClockTicks()),
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}
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go s.run()
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return s
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}
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// statsCollector manages and provides container resource stats
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type statsCollector struct {
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m sync.Mutex
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interval time.Duration
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clockTicks uint64
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publishers map[*Container]*pubsub.Publisher
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}
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// collect registers the container with the collector and adds it to
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// the event loop for collection on the specified interval returning
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// a channel for the subscriber to receive on.
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func (s *statsCollector) collect(c *Container) chan interface{} {
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s.m.Lock()
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defer s.m.Unlock()
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publisher, exists := s.publishers[c]
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if !exists {
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publisher = pubsub.NewPublisher(100*time.Millisecond, 1024)
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s.publishers[c] = publisher
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}
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return publisher.Subscribe()
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}
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// stopCollection closes the channels for all subscribers and removes
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// the container from metrics collection.
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func (s *statsCollector) stopCollection(c *Container) {
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s.m.Lock()
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if publisher, exists := s.publishers[c]; exists {
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publisher.Close()
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delete(s.publishers, c)
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}
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s.m.Unlock()
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}
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// unsubscribe removes a specific subscriber from receiving updates for a container's stats.
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func (s *statsCollector) unsubscribe(c *Container, ch chan interface{}) {
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s.m.Lock()
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publisher := s.publishers[c]
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if publisher != nil {
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publisher.Evict(ch)
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if publisher.Len() == 0 {
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delete(s.publishers, c)
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}
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}
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s.m.Unlock()
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}
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func (s *statsCollector) run() {
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for _ = range time.Tick(s.interval) {
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for container, publisher := range s.publishers {
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systemUsage, err := s.getSystemCpuUsage()
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if err != nil {
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logrus.Errorf("collecting system cpu usage for %s: %v", container.ID, err)
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continue
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}
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stats, err := container.Stats()
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if err != nil {
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if err != execdriver.ErrNotRunning {
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logrus.Errorf("collecting stats for %s: %v", container.ID, err)
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}
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continue
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}
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stats.SystemUsage = systemUsage
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publisher.Publish(stats)
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}
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}
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}
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const nanoSeconds = 1e9
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// getSystemCpuUSage returns the host system's cpu usage in nanoseconds
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// for the system to match the cgroup readings are returned in the same format.
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func (s *statsCollector) getSystemCpuUsage() (uint64, error) {
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f, err := os.Open("/proc/stat")
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if err != nil {
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return 0, err
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}
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defer f.Close()
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sc := bufio.NewScanner(f)
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for sc.Scan() {
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parts := strings.Fields(sc.Text())
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switch parts[0] {
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case "cpu":
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if len(parts) < 8 {
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return 0, fmt.Errorf("invalid number of cpu fields")
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}
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var sum uint64
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for _, i := range parts[1:8] {
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v, err := strconv.ParseUint(i, 10, 64)
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if err != nil {
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return 0, fmt.Errorf("Unable to convert value %s to int: %s", i, err)
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}
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sum += v
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}
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return (sum * nanoSeconds) / s.clockTicks, nil
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}
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}
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return 0, fmt.Errorf("invalid stat format")
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}
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