text: package client
  
  import (
  	"encoding/json"
  	"net/url"
  	"time"
  
  	"golang.org/x/net/context"
  
  	"github.com/docker/docker/api/types"
  	"github.com/docker/docker/api/types/events"
  	"github.com/docker/docker/api/types/filters"
  	timetypes "github.com/docker/docker/api/types/time"
  )
  
  // Events returns a stream of events in the daemon. It's up to the caller to close the stream
  // by cancelling the context. Once the stream has been completely read an io.EOF error will
  // be sent over the error channel. If an error is sent all processing will be stopped. It's up
  // to the caller to reopen the stream in the event of an error by reinvoking this method.
  func (cli *Client) Events(ctx context.Context, options types.EventsOptions) (<-chan events.Message, <-chan error) {
  
  	messages := make(chan events.Message)
  	errs := make(chan error, 1)
  
  	started := make(chan struct{})
  	go func() {
  		defer close(errs)
  
  		query, err := buildEventsQueryParams(cli.version, options)
  		if err != nil {
  			close(started)
  			errs <- err
  			return
  		}
  
  		resp, err := cli.get(ctx, "/events", query, nil)
  		if err != nil {
  			close(started)
  			errs <- err
  			return
  		}
  		defer resp.body.Close()
  
  		decoder := json.NewDecoder(resp.body)
  
  		close(started)
  		for {
  			select {
  			case <-ctx.Done():
  				errs <- ctx.Err()
  				return
  			default:
  				var event events.Message
  				if err := decoder.Decode(&event); err != nil {
  					errs <- err
  					return
  				}
  
  				select {
  				case messages <- event:
  				case <-ctx.Done():
  					errs <- ctx.Err()
  					return
  				}
  			}
  		}
  	}()
  	<-started
  
  	return messages, errs
  }
  
  func buildEventsQueryParams(cliVersion string, options types.EventsOptions) (url.Values, error) {
  	query := url.Values{}
  	ref := time.Now()
  
  	if options.Since != "" {
  		ts, err := timetypes.GetTimestamp(options.Since, ref)
  		if err != nil {
  			return nil, err
  		}
  		query.Set("since", ts)
  	}
  
  	if options.Until != "" {
  		ts, err := timetypes.GetTimestamp(options.Until, ref)
  		if err != nil {
  			return nil, err
  		}
  		query.Set("until", ts)
  	}
  
  	if options.Filters.Len() > 0 {
  		filterJSON, err := filters.ToParamWithVersion(cliVersion, options.Filters)
  		if err != nil {
  			return nil, err
  		}
  		query.Set("filters", filterJSON)
  	}
  
  	return query, nil
  }
  