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moby--moby/cli/command/system/events.go

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package system
import (
"fmt"
"io"
"io/ioutil"
"sort"
"strings"
"text/template"
"time"
"golang.org/x/net/context"
"github.com/docker/docker/api/types"
eventtypes "github.com/docker/docker/api/types/events"
"github.com/docker/docker/cli"
"github.com/docker/docker/cli/command"
"github.com/docker/docker/opts"
"github.com/docker/docker/pkg/jsonlog"
"github.com/docker/docker/utils/templates"
"github.com/spf13/cobra"
)
type eventsOptions struct {
since string
until string
filter opts.FilterOpt
format string
}
// NewEventsCommand creates a new cobra.Command for `docker events`
func NewEventsCommand(dockerCli *command.DockerCli) *cobra.Command {
opts := eventsOptions{filter: opts.NewFilterOpt()}
cmd := &cobra.Command{
Use: "events [OPTIONS]",
Short: "Get real time events from the server",
Args: cli.NoArgs,
RunE: func(cmd *cobra.Command, args []string) error {
return runEvents(dockerCli, &opts)
},
}
flags := cmd.Flags()
flags.StringVar(&opts.since, "since", "", "Show all events created since timestamp")
flags.StringVar(&opts.until, "until", "", "Stream events until this timestamp")
flags.VarP(&opts.filter, "filter", "f", "Filter output based on conditions provided")
flags.StringVar(&opts.format, "format", "", "Format the output using the given Go template")
return cmd
}
func runEvents(dockerCli *command.DockerCli, opts *eventsOptions) error {
tmpl, err := makeTemplate(opts.format)
if err != nil {
return cli.StatusError{
StatusCode: 64,
Status: "Error parsing format: " + err.Error()}
}
options := types.EventsOptions{
Since: opts.since,
Until: opts.until,
Filters: opts.filter.Value(),
}
ctx, cancel := context.WithCancel(context.Background())
events, errs := dockerCli.Client().Events(ctx, options)
defer cancel()
out := dockerCli.Out()
for {
select {
case event := <-events:
if err := handleEvent(out, event, tmpl); err != nil {
return err
}
case err := <-errs:
if err == io.EOF {
return nil
}
return err
}
}
}
func handleEvent(out io.Writer, event eventtypes.Message, tmpl *template.Template) error {
if tmpl == nil {
return prettyPrintEvent(out, event)
}
return formatEvent(out, event, tmpl)
}
func makeTemplate(format string) (*template.Template, error) {
if format == "" {
return nil, nil
}
tmpl, err := templates.Parse(format)
if err != nil {
return tmpl, err
}
// we execute the template for an empty message, so as to validate
// a bad template like "{{.badFieldString}}"
return tmpl, tmpl.Execute(ioutil.Discard, &eventtypes.Message{})
}
// prettyPrintEvent prints all types of event information.
// Each output includes the event type, actor id, name and action.
// Actor attributes are printed at the end if the actor has any.
func prettyPrintEvent(out io.Writer, event eventtypes.Message) error {
if event.TimeNano != 0 {
fmt.Fprintf(out, "%s ", time.Unix(0, event.TimeNano).Format(jsonlog.RFC3339NanoFixed))
} else if event.Time != 0 {
fmt.Fprintf(out, "%s ", time.Unix(event.Time, 0).Format(jsonlog.RFC3339NanoFixed))
}
fmt.Fprintf(out, "%s %s %s", event.Type, event.Action, event.Actor.ID)
if len(event.Actor.Attributes) > 0 {
var attrs []string
var keys []string
for k := range event.Actor.Attributes {
keys = append(keys, k)
}
sort.Strings(keys)
for _, k := range keys {
v := event.Actor.Attributes[k]
attrs = append(attrs, fmt.Sprintf("%s=%s", k, v))
}
fmt.Fprintf(out, " (%s)", strings.Join(attrs, ", "))
}
fmt.Fprint(out, "\n")
return nil
}
func formatEvent(out io.Writer, event eventtypes.Message, tmpl *template.Template) error {
defer out.Write([]byte{'\n'})
return tmpl.Execute(out, event)
}