Moved event stream processing into engine api

Signed-off-by: Joshua Horwitz <[email protected]>

client/events.go

@@ -1,20 +1,70 @@
 package client
 
 import (
-	"io"
+	"encoding/json"
 	"net/url"
 	"time"
 
 	"golang.org/x/net/context"
 
 	"github.com/docker/engine-api/types"
+	"github.com/docker/engine-api/types/events"
 	"github.com/docker/engine-api/types/filters"
 	timetypes "github.com/docker/engine-api/types/time"
 )
 
-// Events returns a stream of events in the daemon in a ReadCloser.
-// It's up to the caller to close the stream.
-func (cli *Client) Events(ctx context.Context, options types.EventsOptions) (io.ReadCloser, error) {
+// 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, 1)
+	errs := make(chan error, 1)
+
+	go func() {
+		defer close(messages)
+		defer close(errs)
+
+		query, err := buildEventsQueryParams(cli.version, options)
+		if err != nil {
+			errs <- err
+			return
+		}
+
+		resp, err := cli.get(ctx, "/events", query, nil)
+		if err != nil {
+			errs <- err
+			return
+		}
+		defer resp.body.Close()
+
+		decoder := json.NewDecoder(resp.body)
+
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			default:
+				var event events.Message
+				if err := decoder.Decode(&event); err != nil {
+					errs <- err
+					return
+				}
+
+				select {
+				case messages <- event:
+				case <-ctx.Done():
+					return
+				}
+			}
+		}
+	}()
+
+	return messages, errs
+}
+
+func buildEventsQueryParams(cliVersion string, options types.EventsOptions) (url.Values, error) {
 	query := url.Values{}
 	ref := time.Now()
 
@@ -25,24 +75,22 @@ func (cli *Client) Events(ctx context.Context, options types.EventsOptions) (io.
 		}
 		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(cli.version, options.Filters)
+		filterJSON, err := filters.ToParamWithVersion(cliVersion, options.Filters)
 		if err != nil {
 			return nil, err
 		}
 		query.Set("filters", filterJSON)
 	}
 
-	serverResponse, err := cli.get(ctx, "/events", query, nil)
-	if err != nil {
-		return nil, err
-	}
-	return serverResponse.body, nil
+	return query, nil
 }

client/events_test.go

@@ -2,7 +2,9 @@ package client
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net/http"
 	"strings"
@@ -11,6 +13,7 @@ import (
 	"golang.org/x/net/context"
 
 	"github.com/docker/engine-api/types"
+	"github.com/docker/engine-api/types/events"
 	"github.com/docker/engine-api/types/filters"
 )
 
@@ -36,7 +39,8 @@ func TestEventsErrorInOptions(t *testing.T) {
 		client := &Client{
 			transport: newMockClient(nil, errorMock(http.StatusInternalServerError, "Server error")),
 		}
-		_, err := client.Events(context.Background(), e.options)
+		_, errs := client.Events(context.Background(), e.options)
+		err := <-errs
 		if err == nil || !strings.Contains(err.Error(), e.expectedError) {
 			t.Fatalf("expected a error %q, got %v", e.expectedError, err)
 		}
@@ -47,39 +51,36 @@ func TestEventsErrorFromServer(t *testing.T) {
 	client := &Client{
 		transport: newMockClient(nil, errorMock(http.StatusInternalServerError, "Server error")),
 	}
-	_, err := client.Events(context.Background(), types.EventsOptions{})
+	_, errs := client.Events(context.Background(), types.EventsOptions{})
+	err := <-errs
 	if err == nil || err.Error() != "Error response from daemon: Server error" {
 		t.Fatalf("expected a Server Error, got %v", err)
 	}
 }
 
 func TestEvents(t *testing.T) {
+
 	expectedURL := "/events"
 
 	filters := filters.NewArgs()
-	filters.Add("label", "label1")
-	filters.Add("label", "label2")
-	expectedFiltersJSON := `{"label":{"label1":true,"label2":true}}`
+	filters.Add("type", events.ContainerEventType)
+	expectedFiltersJSON := fmt.Sprintf(`{"type":{"%s":true}}`, events.ContainerEventType)
 
 	eventsCases := []struct {
 		options             types.EventsOptions
+		events              []events.Message
+		expectedEvents      map[string]bool
 		expectedQueryParams map[string]string
 	}{
 		{
 			options: types.EventsOptions{
-				Since: "invalid but valid",
-			},
-			expectedQueryParams: map[string]string{
-				"since": "invalid but valid",
-			},
-		},
-		{
-			options: types.EventsOptions{
-				Until: "invalid but valid",
+				Filters: filters,
 			},
 			expectedQueryParams: map[string]string{
-				"until": "invalid but valid",
+				"filters": expectedFiltersJSON,
 			},
+			events:         []events.Message{},
+			expectedEvents: make(map[string]bool),
 		},
 		{
 			options: types.EventsOptions{
@@ -88,6 +89,28 @@ func TestEvents(t *testing.T) {
 			expectedQueryParams: map[string]string{
 				"filters": expectedFiltersJSON,
 			},
+			events: []events.Message{
+				events.Message{
+					Type:   "container",
+					ID:     "1",
+					Action: "create",
+				},
+				events.Message{
+					Type:   "container",
+					ID:     "2",
+					Action: "die",
+				},
+				events.Message{
+					Type:   "container",
+					ID:     "3",
+					Action: "create",
+				},
+			},
+			expectedEvents: map[string]bool{
+				"1": true,
+				"2": true,
+				"3": true,
+			},
 		},
 	}
 
@@ -98,29 +121,45 @@ func TestEvents(t *testing.T) {
 					return nil, fmt.Errorf("Expected URL '%s', got '%s'", expectedURL, req.URL)
 				}
 				query := req.URL.Query()
+
 				for key, expected := range eventsCase.expectedQueryParams {
 					actual := query.Get(key)
 					if actual != expected {
 						return nil, fmt.Errorf("%s not set in URL query properly. Expected '%s', got %s", key, expected, actual)
 					}
 				}
+
+				buffer := new(bytes.Buffer)
+
+				for _, e := range eventsCase.events {
+					b, _ := json.Marshal(e)
+					buffer.Write(b)
+				}
+
 				return &http.Response{
 					StatusCode: http.StatusOK,
-					Body:       ioutil.NopCloser(bytes.NewReader([]byte("response"))),
+					Body:       ioutil.NopCloser(buffer),
 				}, nil
 			}),
 		}
-		body, err := client.Events(context.Background(), eventsCase.options)
-		if err != nil {
-			t.Fatal(err)
-		}
-		defer body.Close()
-		content, err := ioutil.ReadAll(body)
-		if err != nil {
-			t.Fatal(err)
-		}
-		if string(content) != "response" {
-			t.Fatalf("expected response to contain 'response', got %s", string(content))
+
+		messages, errs := client.Events(context.Background(), eventsCase.options)
+
+	loop:
+		for {
+			select {
+			case err := <-errs:
+				if err != nil && err != io.EOF {
+					t.Fatal(err)
+				}
+
+				break loop
+			case e := <-messages:
+				_, ok := eventsCase.expectedEvents[e.ID]
+				if !ok {
+					t.Fatalf("event received not expected with action %s & id %s", e.Action, e.ID)
+				}
+			}
 		}
 	}
 }

client/interface.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/docker/engine-api/types"
 	"github.com/docker/engine-api/types/container"
+	"github.com/docker/engine-api/types/events"
 	"github.com/docker/engine-api/types/filters"
 	"github.com/docker/engine-api/types/network"
 	"github.com/docker/engine-api/types/registry"
@@ -120,7 +121,7 @@ type SwarmAPIClient interface {
 
 // SystemAPIClient defines API client methods for the system
 type SystemAPIClient interface {
-	Events(ctx context.Context, options types.EventsOptions) (io.ReadCloser, error)
+	Events(ctx context.Context, options types.EventsOptions) (<-chan events.Message, <-chan error)
 	Info(ctx context.Context) (types.Info, error)
 	RegistryLogin(ctx context.Context, auth types.AuthConfig) (types.AuthResponse, error)
 }