client: Client.ServiceLogs: close reader on context cancellation

Use a cancelReadCloser to automatically close the reader when the context
is cancelled. Consumers are still recommended to manually close the reader,
but the cancelReadCloser makes the Close idempotent.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

client/service_logs.go

@@ -29,8 +29,14 @@ type ServiceLogsResult interface {
 	io.ReadCloser
 }
 
-// ServiceLogs returns the logs generated by a service in an [ServiceLogsResult].
+// ServiceLogs returns the logs generated by a service in a [ServiceLogsResult].
+// as an [io.ReadCloser]. Callers should close the stream.
+//
+// The underlying [io.ReadCloser] is automatically closed if the context is canceled,
 func (cli *Client) ServiceLogs(ctx context.Context, serviceID string, options ServiceLogsOptions) (ServiceLogsResult, error) {
+	// TODO(thaJeztah): this function needs documentation about the format of ths stream (similar to for container logs)
+	// TODO(thaJeztah): migrate CLI utilities to the client where suitable; https://github.com/docker/cli/blob/v29.0.0-rc.1/cli/command/service/logs.go#L73-L348
+
 	serviceID, err := trimID("service", serviceID)
 	if err != nil {
 		return nil, err
@@ -71,30 +77,15 @@ func (cli *Client) ServiceLogs(ctx context.Context, serviceID string, options Se
 		return nil, err
 	}
 	return &serviceLogsResult{
-		body: resp.Body,
+		ReadCloser: newCancelReadCloser(ctx, resp.Body),
 	}, nil
 }
 
 type serviceLogsResult struct {
-	// body must be closed to avoid a resource leak
+	io.ReadCloser
-	body io.ReadCloser
 }
 
 var (
 	_ io.ReadCloser     = (*serviceLogsResult)(nil)
 	_ ServiceLogsResult = (*serviceLogsResult)(nil)
 )
-
-func (r *serviceLogsResult) Read(p []byte) (int, error) {
-	if r == nil || r.body == nil {
-		return 0, io.EOF
-	}
-	return r.body.Read(p)
-}
-
-func (r *serviceLogsResult) Close() error {
-	if r == nil || r.body == nil {
-		return nil
-	}
-	return r.body.Close()
-}

integration/service/create_test.go

@@ -232,14 +232,14 @@ func TestCreateServiceSecretFileMode(t *testing.T) {
 
 	poll.WaitOn(t, swarm.RunningTasksCount(ctx, apiClient, serviceID, instances), swarm.ServicePoll)
 
-	body, err := apiClient.ServiceLogs(ctx, serviceID, client.ServiceLogsOptions{
+	res, err := apiClient.ServiceLogs(ctx, serviceID, client.ServiceLogsOptions{
 		Tail:       "1",
 		ShowStdout: true,
 	})
 	assert.NilError(t, err)
-	defer body.Close()
+	defer func() { _ = res.Close() }()
 
-	content, err := io.ReadAll(body)
+	content, err := io.ReadAll(res)
 	assert.NilError(t, err)
 	assert.Check(t, is.Contains(string(content), "-rwxrwxrwx"))
 
@@ -291,14 +291,14 @@ func TestCreateServiceConfigFileMode(t *testing.T) {
 
 	poll.WaitOn(t, swarm.RunningTasksCount(ctx, apiClient, serviceID, instances))
 
-	body, err := apiClient.ServiceLogs(ctx, serviceID, client.ServiceLogsOptions{
+	res, err := apiClient.ServiceLogs(ctx, serviceID, client.ServiceLogsOptions{
 		Tail:       "1",
 		ShowStdout: true,
 	})
 	assert.NilError(t, err)
-	defer body.Close()
+	defer func() { _ = res.Close() }()
 
-	content, err := io.ReadAll(body)
+	content, err := io.ReadAll(res)
 	assert.NilError(t, err)
 	assert.Check(t, is.Contains(string(content), "-rwxrwxrwx"))
 

vendor/github.com/moby/moby/client/service_logs.go

@@ -29,8 +29,14 @@ type ServiceLogsResult interface {
 	io.ReadCloser
 }
 
-// ServiceLogs returns the logs generated by a service in an [ServiceLogsResult].
+// ServiceLogs returns the logs generated by a service in a [ServiceLogsResult].
+// as an [io.ReadCloser]. Callers should close the stream.
+//
+// The underlying [io.ReadCloser] is automatically closed if the context is canceled,
 func (cli *Client) ServiceLogs(ctx context.Context, serviceID string, options ServiceLogsOptions) (ServiceLogsResult, error) {
+	// TODO(thaJeztah): this function needs documentation about the format of ths stream (similar to for container logs)
+	// TODO(thaJeztah): migrate CLI utilities to the client where suitable; https://github.com/docker/cli/blob/v29.0.0-rc.1/cli/command/service/logs.go#L73-L348
+
 	serviceID, err := trimID("service", serviceID)
 	if err != nil {
 		return nil, err
@@ -71,30 +77,15 @@ func (cli *Client) ServiceLogs(ctx context.Context, serviceID string, options Se
 		return nil, err
 	}
 	return &serviceLogsResult{
-		body: resp.Body,
+		ReadCloser: newCancelReadCloser(ctx, resp.Body),
 	}, nil
 }
 
 type serviceLogsResult struct {
-	// body must be closed to avoid a resource leak
+	io.ReadCloser
-	body io.ReadCloser
 }
 
 var (
 	_ io.ReadCloser     = (*serviceLogsResult)(nil)
 	_ ServiceLogsResult = (*serviceLogsResult)(nil)
 )
-
-func (r *serviceLogsResult) Read(p []byte) (int, error) {
-	if r == nil || r.body == nil {
-		return 0, io.EOF
-	}
-	return r.body.Read(p)
-}
-
-func (r *serviceLogsResult) Close() error {
-	if r == nil || r.body == nil {
-		return nil
-	}
-	return r.body.Close()
-}