api: Service Logs support

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

interface.go

@@ -111,6 +111,7 @@ type ServiceAPIClient interface {
 	ServiceList(ctx context.Context, options types.ServiceListOptions) ([]swarm.Service, error)
 	ServiceRemove(ctx context.Context, serviceID string) error
 	ServiceUpdate(ctx context.Context, serviceID string, version swarm.Version, service swarm.ServiceSpec, options types.ServiceUpdateOptions) error
+	ServiceLogs(ctx context.Context, serviceID string, options types.ContainerLogsOptions) (io.ReadCloser, error)
 	TaskInspectWithRaw(ctx context.Context, taskID string) (swarm.Task, []byte, error)
 	TaskList(ctx context.Context, options types.TaskListOptions) ([]swarm.Task, error)
 }

service_logs.go

@@ -0,0 +1,52 @@
+package client
+
+import (
+	"io"
+	"net/url"
+	"time"
+
+	"golang.org/x/net/context"
+
+	"github.com/docker/docker/api/types"
+	timetypes "github.com/docker/docker/api/types/time"
+)
+
+// ServiceLogs returns the logs generated by a service in an io.ReadCloser.
+// It's up to the caller to close the stream.
+func (cli *Client) ServiceLogs(ctx context.Context, serviceID string, options types.ContainerLogsOptions) (io.ReadCloser, error) {
+	query := url.Values{}
+	if options.ShowStdout {
+		query.Set("stdout", "1")
+	}
+
+	if options.ShowStderr {
+		query.Set("stderr", "1")
+	}
+
+	if options.Since != "" {
+		ts, err := timetypes.GetTimestamp(options.Since, time.Now())
+		if err != nil {
+			return nil, err
+		}
+		query.Set("since", ts)
+	}
+
+	if options.Timestamps {
+		query.Set("timestamps", "1")
+	}
+
+	if options.Details {
+		query.Set("details", "1")
+	}
+
+	if options.Follow {
+		query.Set("follow", "1")
+	}
+	query.Set("tail", options.Tail)
+
+	resp, err := cli.get(ctx, "/services/"+serviceID+"/logs", query, nil)
+	if err != nil {
+		return nil, err
+	}
+	return resp.body, nil
+}

service_logs_test.go

@@ -0,0 +1,133 @@
+package client
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/docker/docker/api/types"
+
+	"golang.org/x/net/context"
+)
+
+func TestServiceLogsError(t *testing.T) {
+	client := &Client{
+		client: newMockClient(errorMock(http.StatusInternalServerError, "Server error")),
+	}
+	_, err := client.ServiceLogs(context.Background(), "service_id", types.ContainerLogsOptions{})
+	if err == nil || err.Error() != "Error response from daemon: Server error" {
+		t.Fatalf("expected a Server Error, got %v", err)
+	}
+	_, err = client.ServiceLogs(context.Background(), "service_id", types.ContainerLogsOptions{
+		Since: "2006-01-02TZ",
+	})
+	if err == nil || !strings.Contains(err.Error(), `parsing time "2006-01-02TZ"`) {
+		t.Fatalf("expected a 'parsing time' error, got %v", err)
+	}
+}
+
+func TestServiceLogs(t *testing.T) {
+	expectedURL := "/services/service_id/logs"
+	cases := []struct {
+		options             types.ContainerLogsOptions
+		expectedQueryParams map[string]string
+	}{
+		{
+			expectedQueryParams: map[string]string{
+				"tail": "",
+			},
+		},
+		{
+			options: types.ContainerLogsOptions{
+				Tail: "any",
+			},
+			expectedQueryParams: map[string]string{
+				"tail": "any",
+			},
+		},
+		{
+			options: types.ContainerLogsOptions{
+				ShowStdout: true,
+				ShowStderr: true,
+				Timestamps: true,
+				Details:    true,
+				Follow:     true,
+			},
+			expectedQueryParams: map[string]string{
+				"tail":       "",
+				"stdout":     "1",
+				"stderr":     "1",
+				"timestamps": "1",
+				"details":    "1",
+				"follow":     "1",
+			},
+		},
+		{
+			options: types.ContainerLogsOptions{
+				// An complete invalid date, timestamp or go duration will be
+				// passed as is
+				Since: "invalid but valid",
+			},
+			expectedQueryParams: map[string]string{
+				"tail":  "",
+				"since": "invalid but valid",
+			},
+		},
+	}
+	for _, logCase := range cases {
+		client := &Client{
+			client: newMockClient(func(r *http.Request) (*http.Response, error) {
+				if !strings.HasPrefix(r.URL.Path, expectedURL) {
+					return nil, fmt.Errorf("Expected URL '%s', got '%s'", expectedURL, r.URL)
+				}
+				// Check query parameters
+				query := r.URL.Query()
+				for key, expected := range logCase.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)
+					}
+				}
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Body:       ioutil.NopCloser(bytes.NewReader([]byte("response"))),
+				}, nil
+			}),
+		}
+		body, err := client.ServiceLogs(context.Background(), "service_id", logCase.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))
+		}
+	}
+}
+
+func ExampleClient_ServiceLogs_withTimeout() {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	client, _ := NewEnvClient()
+	reader, err := client.ServiceLogs(ctx, "service_id", types.ContainerLogsOptions{})
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	_, err = io.Copy(os.Stdout, reader)
+	if err != nil && err != io.EOF {
+		log.Fatal(err)
+	}
+}