95aea39348
This commit moves one-shot stats processing out of the publishing channels, i.e. collect stats directly. Also changes the method of getSystemCPUUsage() on Linux to return number of online CPUs also. Signed-off-by: Xinfeng Liu <XinfengLiu@icloud.com>
118 lines
3 KiB
Go
118 lines
3 KiB
Go
package stats // import "github.com/docker/docker/daemon/stats"
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import (
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"sync"
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"time"
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"github.com/docker/docker/api/types"
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"github.com/docker/docker/container"
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"github.com/moby/pubsub"
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)
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// Collector manages and provides container resource stats
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type Collector struct {
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m sync.Mutex
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cond *sync.Cond
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supervisor supervisor
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interval time.Duration
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publishers map[*container.Container]*pubsub.Publisher
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}
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// NewCollector creates a stats collector that will poll the supervisor with the specified interval
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func NewCollector(supervisor supervisor, interval time.Duration) *Collector {
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s := &Collector{
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interval: interval,
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supervisor: supervisor,
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publishers: make(map[*container.Container]*pubsub.Publisher),
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}
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s.cond = sync.NewCond(&s.m)
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return s
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}
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type supervisor interface {
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// GetContainerStats collects all the stats related to a container
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GetContainerStats(container *container.Container) (*types.StatsJSON, error)
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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 *Collector) Collect(c *container.Container) chan interface{} {
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s.cond.L.Lock()
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defer s.cond.L.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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s.cond.Broadcast()
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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 *Collector) StopCollection(c *container.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 *Collector) Unsubscribe(c *container.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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// Run starts the collectors and will indefinitely collect stats from the supervisor
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func (s *Collector) Run() {
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type publishersPair struct {
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container *container.Container
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publisher *pubsub.Publisher
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}
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// we cannot determine the capacity here.
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// it will grow enough in first iteration
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var pairs []publishersPair
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for {
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s.cond.L.Lock()
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for len(s.publishers) == 0 {
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s.cond.Wait()
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}
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// it does not make sense in the first iteration,
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// but saves allocations in further iterations
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pairs = pairs[:0]
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for container, publisher := range s.publishers {
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// copy pointers here to release the lock ASAP
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pairs = append(pairs, publishersPair{container, publisher})
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}
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s.cond.L.Unlock()
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for _, pair := range pairs {
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stats, err := s.supervisor.GetContainerStats(pair.container)
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if err != nil {
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stats = &types.StatsJSON{
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Name: pair.container.Name,
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ID: pair.container.ID,
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}
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}
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pair.publisher.Publish(*stats)
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}
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time.Sleep(s.interval)
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}
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}
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