dotcloud/docker

package client // import "github.com/docker/docker/client"

import (
    "context"
    "encoding/json"
    "net/url"
    "time"

    "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 events.ListOptions) (<-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 events.ListOptions) (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 {
        //nolint:staticcheck // ignore SA1019 for old code
        filterJSON, err := filters.ToParamWithVersion(cliVersion, options.Filters)
        if err != nil {
            return nil, err
        }
        query.Set("filters", filterJSON)
    }

    return query, nil
}