Merge pull request moby#49894 from thaJeztah/daemon_less_output_vars

daemon/*: reduce named (error)-returns, naked returns, and some minor linting-fixes

Author: thaJeztah

daemon/archive.go

@@ -10,13 +10,13 @@ import (
 
 // ContainerStatPath stats the filesystem resource at the specified path in the
 // container identified by the given name.
-func (daemon *Daemon) ContainerStatPath(name string, path string) (stat *container.PathStat, err error) {
+func (daemon *Daemon) ContainerStatPath(name string, path string) (*container.PathStat, error) {
 	ctr, err := daemon.GetContainer(name)
 	if err != nil {
 		return nil, err
 	}
 
-	stat, err = daemon.containerStatPath(ctr, path)
+	stat, err := daemon.containerStatPath(ctr, path)
 	if err != nil {
 		if os.IsNotExist(err) {
 			return nil, containerFileNotFound{path, name}
@@ -33,7 +33,7 @@ func (daemon *Daemon) ContainerStatPath(name string, path string) (stat *contain
 // ContainerArchivePath creates an archive of the filesystem resource at the
 // specified path in the container identified by the given name. Returns a
 // tar archive of the resource and whether it was a directory or a single file.
-func (daemon *Daemon) ContainerArchivePath(name string, path string) (content io.ReadCloser, stat *container.PathStat, err error) {
+func (daemon *Daemon) ContainerArchivePath(name string, path string) (content io.ReadCloser, stat *container.PathStat, _ error) {
 	ctr, err := daemon.GetContainer(name)
 	if err != nil {
 		return nil, nil, err

daemon/archive_unix.go

@@ -20,7 +20,7 @@ import (
 
 // containerStatPath stats the filesystem resource at the specified path in this
 // container. Returns stat info about the resource.
-func (daemon *Daemon) containerStatPath(container *container.Container, path string) (stat *containertypes.PathStat, err error) {
+func (daemon *Daemon) containerStatPath(container *container.Container, path string) (*containertypes.PathStat, error) {
 	container.Lock()
 	defer container.Unlock()
 
@@ -36,11 +36,11 @@ func (daemon *Daemon) containerStatPath(container *container.Container, path str
 // containerArchivePath creates an archive of the filesystem resource at the specified
 // path in this container. Returns a tar archive of the resource and stat info
 // about the resource.
-func (daemon *Daemon) containerArchivePath(container *container.Container, path string) (content io.ReadCloser, stat *containertypes.PathStat, err error) {
+func (daemon *Daemon) containerArchivePath(container *container.Container, path string) (content io.ReadCloser, stat *containertypes.PathStat, retErr error) {
 	container.Lock()
 
 	defer func() {
-		if err != nil {
+		if retErr != nil {
 			// Wait to unlock the container until the archive is fully read
 			// (see the ReadCloseWrapper func below) or if there is an error
 			// before that occurs.
@@ -54,8 +54,8 @@ func (daemon *Daemon) containerArchivePath(container *container.Container, path
 	}
 
 	defer func() {
-		if err != nil {
-			cfs.Close()
+		if retErr != nil {
+			_ = cfs.Close()
 		}
 	}()
 

daemon/archive_windows.go

@@ -17,7 +17,7 @@ import (
 
 // containerStatPath stats the filesystem resource at the specified path in this
 // container. Returns stat info about the resource.
-func (daemon *Daemon) containerStatPath(container *container.Container, path string) (stat *containertypes.PathStat, err error) {
+func (daemon *Daemon) containerStatPath(container *container.Container, path string) (*containertypes.PathStat, error) {
 	container.Lock()
 	defer container.Unlock()
 
@@ -26,12 +26,12 @@ func (daemon *Daemon) containerStatPath(container *container.Container, path str
 		return nil, err
 	}
 
-	if err = daemon.Mount(container); err != nil {
+	if err := daemon.Mount(container); err != nil {
 		return nil, err
 	}
 	defer daemon.Unmount(container)
 
-	err = daemon.mountVolumes(container)
+	err := daemon.mountVolumes(container)
 	defer container.DetachAndUnmount(daemon.LogVolumeEvent)
 	if err != nil {
 		return nil, err
@@ -51,11 +51,11 @@ func (daemon *Daemon) containerStatPath(container *container.Container, path str
 // containerArchivePath creates an archive of the filesystem resource at the specified
 // path in this container. Returns a tar archive of the resource and stat info
 // about the resource.
-func (daemon *Daemon) containerArchivePath(container *container.Container, path string) (content io.ReadCloser, stat *containertypes.PathStat, err error) {
+func (daemon *Daemon) containerArchivePath(container *container.Container, path string) (content io.ReadCloser, stat *containertypes.PathStat, retErr error) {
 	container.Lock()
 
 	defer func() {
-		if err != nil {
+		if retErr != nil {
 			// Wait to unlock the container until the archive is fully read
 			// (see the ReadCloseWrapper func below) or if there is an error
 			// before that occurs.
@@ -68,20 +68,20 @@ func (daemon *Daemon) containerArchivePath(container *container.Container, path
 		return nil, nil, err
 	}
 
-	if err = daemon.Mount(container); err != nil {
+	if err := daemon.Mount(container); err != nil {
 		return nil, nil, err
 	}
 
 	defer func() {
-		if err != nil {
+		if retErr != nil {
 			// unmount any volumes
 			container.DetachAndUnmount(daemon.LogVolumeEvent)
 			// unmount the container's rootfs
 			daemon.Unmount(container)
 		}
 	}()
 
-	if err = daemon.mountVolumes(container); err != nil {
+	if err := daemon.mountVolumes(container); err != nil {
 		return nil, nil, err
 	}
 
@@ -223,14 +223,14 @@ func (daemon *Daemon) containerExtractToDir(container *container.Container, path
 	return nil
 }
 
-func (daemon *Daemon) containerCopy(container *container.Container, resource string) (rc io.ReadCloser, err error) {
+func (daemon *Daemon) containerCopy(container *container.Container, resource string) (_ io.ReadCloser, retErr error) {
 	if resource[0] == '/' || resource[0] == '\\' {
 		resource = resource[1:]
 	}
 	container.Lock()
 
 	defer func() {
-		if err != nil {
+		if retErr != nil {
 			// Wait to unlock the container until the archive is fully read
 			// (see the ReadCloseWrapper func below) or if there is an error
 			// before that occurs.
@@ -248,7 +248,7 @@ func (daemon *Daemon) containerCopy(container *container.Container, resource str
 	}
 
 	defer func() {
-		if err != nil {
+		if retErr != nil {
 			// unmount any volumes
 			container.DetachAndUnmount(daemon.LogVolumeEvent)
 			// unmount the container's rootfs

daemon/cluster/controllers/plugin/controller.go

@@ -87,7 +87,7 @@ func (p *Controller) Update(ctx context.Context, t *api.Task) error {
 }
 
 // Prepare is the prepare phase from swarmkit
-func (p *Controller) Prepare(ctx context.Context) (err error) {
+func (p *Controller) Prepare(ctx context.Context) (retErr error) {
 	p.logger.Debug("Prepare")
 
 	remote, err := reference.ParseNormalizedNamed(p.spec.Remote)
@@ -105,7 +105,7 @@ func (p *Controller) Prepare(ctx context.Context) (err error) {
 	pl, err := p.backend.Get(p.spec.Name)
 
 	defer func() {
-		if pl != nil && err == nil {
+		if pl != nil && retErr == nil {
 			pl.Acquire()
 		}
 	}()

daemon/container.go

@@ -226,10 +226,10 @@ func (daemon *Daemon) setHostConfig(container *container.Container, hostConfig *
 
 // verifyContainerSettings performs validation of the hostconfig and config
 // structures.
-func (daemon *Daemon) verifyContainerSettings(daemonCfg *configStore, hostConfig *containertypes.HostConfig, config *containertypes.Config, update bool) (warnings []string, err error) {
+func (daemon *Daemon) verifyContainerSettings(daemonCfg *configStore, hostConfig *containertypes.HostConfig, config *containertypes.Config, update bool) (warnings []string, _ error) {
 	// First perform verification of settings common across all platforms.
-	if err = validateContainerConfig(config); err != nil {
-		return warnings, err
+	if err := validateContainerConfig(config); err != nil {
+		return nil, err
 	}
 
 	warns, err := validateHostConfig(hostConfig)

daemon/container_operations.go

@@ -761,12 +761,12 @@ func (daemon *Daemon) connectToNetwork(ctx context.Context, cfg *config.Config,
 	if !ctr.Managed {
 		// add container name/alias to DNS
 		if err := daemon.ActivateContainerServiceBinding(ctr.Name); err != nil {
-			return fmt.Errorf("Activate container service binding for %s failed: %v", ctr.Name, err)
+			return fmt.Errorf("activate container service binding for %s failed: %v", ctr.Name, err)
 		}
 	}
 
 	if err := updateJoinInfo(ctr.NetworkSettings, n, ep); err != nil {
-		return fmt.Errorf("Updating join info failed: %v", err)
+		return fmt.Errorf("updating join info failed: %v", err)
 	}
 
 	ctr.NetworkSettings.Ports = getPortMapInfo(sb)

daemon/containerd/image_delete.go

@@ -203,7 +203,7 @@ func (i *ImageService) ImageDelete(ctx context.Context, imageRef string, force,
 // also deletes dangling parents if there is no conflict in doing so.
 // Parent images are removed quietly, and if there is any issue/conflict
 // it is logged but does not halt execution/an error is not returned.
-func (i *ImageService) deleteAll(ctx context.Context, imgID image.ID, all []c8dimages.Image, c conflictType, prune bool) (records []imagetypes.DeleteResponse, err error) {
+func (i *ImageService) deleteAll(ctx context.Context, imgID image.ID, all []c8dimages.Image, c conflictType, prune bool) (records []imagetypes.DeleteResponse, _ error) {
 	// Workaround for: https://github.com/moby/buildkit/issues/3797
 	possiblyDeletedConfigs := map[digest.Digest]struct{}{}
 	if len(all) > 0 && i.content != nil {
@@ -236,6 +236,7 @@ func (i *ImageService) deleteAll(ctx context.Context, imgID image.ID, all []c8di
 	var parents []c8dimages.Image
 	if prune {
 		// TODO(dmcgowan): Consider using GC labels to walk for deletion
+		var err error
 		parents, err = i.parents(ctx, imgID)
 		if err != nil {
 			log.G(ctx).WithError(err).Warn("failed to get image parents")
@@ -254,8 +255,7 @@ func (i *ImageService) deleteAll(ctx context.Context, imgID image.ID, all []c8di
 		if !isDanglingImage(parent) {
 			break
 		}
-		err = i.imageDeleteHelper(ctx, parent, all, &records, conflictSoft)
-		if err != nil {
+		if err := i.imageDeleteHelper(ctx, parent, all, &records, conflictSoft); err != nil {
 			log.G(ctx).WithError(err).Warn("failed to remove image parent")
 			break
 		}

daemon/containerd/image_list.go

@@ -654,7 +654,7 @@ func setupLabelFilter(ctx context.Context, store content.Store, fltrs filters.Ar
 		// It will be returned once a matching config is found.
 		errFoundConfig := errors.New("success, found matching config")
 
-		err := c8dimages.Dispatch(ctx, presentChildrenHandler(store, c8dimages.HandlerFunc(func(ctx context.Context, desc ocispec.Descriptor) (subdescs []ocispec.Descriptor, err error) {
+		err := c8dimages.Dispatch(ctx, presentChildrenHandler(store, c8dimages.HandlerFunc(func(ctx context.Context, desc ocispec.Descriptor) (subdescs []ocispec.Descriptor, _ error) {
 			if !c8dimages.IsConfigType(desc.MediaType) {
 				return nil, nil
 			}

daemon/daemon.go

@@ -760,7 +760,7 @@ func (daemon *Daemon) IsSwarmCompatible() error {
 
 // NewDaemon sets up everything for the daemon to be able to service
 // requests from the webserver.
-func NewDaemon(ctx context.Context, config *config.Config, pluginStore *plugin.Store, authzMiddleware *authorization.Middleware) (daemon *Daemon, err error) {
+func NewDaemon(ctx context.Context, config *config.Config, pluginStore *plugin.Store, authzMiddleware *authorization.Middleware) (_ *Daemon, retErr error) {
 	// Verify platform-specific requirements.
 	// TODO(thaJeztah): this should be called before we try to create the daemon; perhaps together with the config validation.
 	if err := checkSystem(); err != nil {
@@ -841,7 +841,7 @@ func NewDaemon(ctx context.Context, config *config.Config, pluginStore *plugin.S
 	// Ensure the daemon is properly shutdown if there is a failure during
 	// initialization
 	defer func() {
-		if err != nil {
+		if retErr != nil {
 			// Use a fresh context here. Passed context could be cancelled.
 			if err := d.Shutdown(context.Background()); err != nil {
 				log.G(ctx).Error(err)

daemon/daemon_unix.go

@@ -413,7 +413,7 @@ func adaptSharedNamespaceContainer(daemon containerGetter, hostConfig *container
 }
 
 // verifyPlatformContainerResources performs platform-specific validation of the container's resource-configuration
-func verifyPlatformContainerResources(resources *containertypes.Resources, sysInfo *sysinfo.SysInfo, update bool) (warnings []string, err error) {
+func verifyPlatformContainerResources(resources *containertypes.Resources, sysInfo *sysinfo.SysInfo, update bool) (warnings []string, _ error) {
 	fixMemorySwappiness(resources)
 
 	// memory subsystem checks and adjustments
@@ -650,7 +650,7 @@ func isRunningSystemd() bool {
 
 // verifyPlatformContainerSettings performs platform-specific validation of the
 // hostconfig and config structures.
-func verifyPlatformContainerSettings(daemon *Daemon, daemonCfg *configStore, hostConfig *containertypes.HostConfig, update bool) (warnings []string, err error) {
+func verifyPlatformContainerSettings(daemon *Daemon, daemonCfg *configStore, hostConfig *containertypes.HostConfig, update bool) (warnings []string, _ error) {
 	if hostConfig == nil {
 		return nil, nil
 	}