Lint on pkg/* packages

- pkg/useragent
- pkg/units
- pkg/ulimit
- pkg/truncindex
- pkg/timeoutconn
- pkg/term
- pkg/tarsum
- pkg/tailfile
- pkg/systemd
- pkg/stringutils
- pkg/stringid
- pkg/streamformatter
- pkg/sockets
- pkg/signal
- pkg/proxy
- pkg/progressreader
- pkg/pools
- pkg/plugins
- pkg/pidfile
- pkg/parsers
- pkg/parsers/filters
- pkg/parsers/kernel
- pkg/parsers/operatingsystem

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

tarsum/builder_context.go

@@ -1,9 +1,10 @@
 package tarsum
 
-// This interface extends TarSum by adding the Remove method.  In general
-// there was concern about adding this method to TarSum itself so instead
-// it is being added just to "BuilderContext" which will then only be used
-// during the .dockerignore file processing - see builder/evaluator.go
+// BuilderContext is an interface extending TarSum by adding the Remove method.
+// In general there was concern about adding this method to TarSum itself
+// so instead it is being added just to "BuilderContext" which will then
+// only be used during the .dockerignore file processing
+// - see builder/evaluator.go
 type BuilderContext interface {
 	TarSum
 	Remove(string)

tarsum/fileinfosums.go

@@ -2,7 +2,9 @@ package tarsum
 
 import "sort"
 
-// This info will be accessed through interface so the actual name and sum cannot be medled with
+// FileInfoSumInterface provides an interface for accessing file checksum
+// information within a tar file. This info is accessed through interface
+// so the actual name and sum cannot be medled with.
 type FileInfoSumInterface interface {
 	// File name
 	Name() string
@@ -28,9 +30,10 @@ func (fis fileInfoSum) Pos() int64 {
 	return fis.pos
 }
 
+// FileInfoSums provides a list of FileInfoSumInterfaces.
 type FileInfoSums []FileInfoSumInterface
 
-// GetFile returns the first FileInfoSumInterface with a matching name
+// GetFile returns the first FileInfoSumInterface with a matching name.
 func (fis FileInfoSums) GetFile(name string) FileInfoSumInterface {
 	for i := range fis {
 		if fis[i].Name() == name {
@@ -40,7 +43,7 @@ func (fis FileInfoSums) GetFile(name string) FileInfoSumInterface {
 	return nil
 }
 
-// GetAllFile returns a FileInfoSums with all matching names
+// GetAllFile returns a FileInfoSums with all matching names.
 func (fis FileInfoSums) GetAllFile(name string) FileInfoSums {
 	f := FileInfoSums{}
 	for i := range fis {
@@ -51,6 +54,7 @@ func (fis FileInfoSums) GetAllFile(name string) FileInfoSums {
 	return f
 }
 
+// GetDuplicatePaths returns a FileInfoSums with all duplicated paths.
 func (fis FileInfoSums) GetDuplicatePaths() (dups FileInfoSums) {
 	seen := make(map[string]int, len(fis)) // allocate earl. no need to grow this map.
 	for i := range fis {
@@ -64,17 +68,23 @@ func (fis FileInfoSums) GetDuplicatePaths() (dups FileInfoSums) {
 	return dups
 }
 
-func (fis FileInfoSums) Len() int      { return len(fis) }
+// Len returns the size of the FileInfoSums.
+func (fis FileInfoSums) Len() int { return len(fis) }
+
+// Swap swaps two FileInfoSum values if a FileInfoSums list.
 func (fis FileInfoSums) Swap(i, j int) { fis[i], fis[j] = fis[j], fis[i] }
 
+// SortByPos sorts FileInfoSums content by position.
 func (fis FileInfoSums) SortByPos() {
 	sort.Sort(byPos{fis})
 }
 
+// SortByNames sorts FileInfoSums content by name.
 func (fis FileInfoSums) SortByNames() {
 	sort.Sort(byName{fis})
 }
 
+// SortBySums sorts FileInfoSums content by sums.
 func (fis FileInfoSums) SortBySums() {
 	dups := fis.GetDuplicatePaths()
 	if len(dups) > 0 {

tarsum/tarsum.go

@@ -1,3 +1,20 @@
+// Package tarsum provides algorithms to perform checksum calculation on
+// filesystem layers.
+//
+// The transportation of filesystems, regarding Docker, is done with tar(1)
+// archives. There are a variety of tar serialization formats [2], and a key
+// concern here is ensuring a repeatable checksum given a set of inputs from a
+// generic tar archive. Types of transportation include distribution to and from a
+// registry endpoint, saving and loading through commands or Docker daemon APIs,
+// transferring the build context from client to Docker daemon, and committing the
+// filesystem of a container to become an image.
+//
+// As tar archives are used for transit, but not preserved in many situations, the
+// focus of the algorithm is to ensure the integrity of the preserved filesystem,
+// while maintaining a deterministic accountability. This includes neither
+// constraining the ordering or manipulation of the files during the creation or
+// unpacking of the archive, nor include additional metadata state about the file
+// system attributes.
 package tarsum
 
 import (
@@ -30,7 +47,8 @@ func NewTarSum(r io.Reader, dc bool, v Version) (TarSum, error) {
 	return NewTarSumHash(r, dc, v, DefaultTHash)
 }
 
-// Create a new TarSum, providing a THash to use rather than the DefaultTHash
+// NewTarSumHash creates a new TarSum, providing a THash to use rather than
+// the DefaultTHash.
 func NewTarSumHash(r io.Reader, dc bool, v Version, tHash THash) (TarSum, error) {
 	headerSelector, err := getTarHeaderSelector(v)
 	if err != nil {
@@ -41,7 +59,7 @@ func NewTarSumHash(r io.Reader, dc bool, v Version, tHash THash) (TarSum, error)
 	return ts, err
 }
 
-// Create a new TarSum using the provided TarSum version+hash label.
+// NewTarSumForLabel creates a new TarSum using the provided TarSum version+hash label.
 func NewTarSumForLabel(r io.Reader, disableCompression bool, label string) (TarSum, error) {
 	parts := strings.SplitN(label, "+", 2)
 	if len(parts) != 2 {
@@ -66,7 +84,7 @@ func NewTarSumForLabel(r io.Reader, disableCompression bool, label string) (TarS
 }
 
 // TarSum is the generic interface for calculating fixed time
-// checksums of a tar archive
+// checksums of a tar archive.
 type TarSum interface {
 	io.Reader
 	GetSums() FileInfoSums
@@ -75,7 +93,7 @@ type TarSum interface {
 	Hash() THash
 }
 
-// tarSum struct is the structure for a Version0 checksum calculation
+// tarSum struct is the structure for a Version0 checksum calculation.
 type tarSum struct {
 	io.Reader
 	tarR               *tar.Reader
@@ -104,13 +122,13 @@ func (ts tarSum) Version() Version {
 	return ts.tarSumVersion
 }
 
-// A hash.Hash type generator and its name
+// THash provides a hash.Hash type generator and its name.
 type THash interface {
 	Hash() hash.Hash
 	Name() string
 }
 
-// Convenience method for creating a THash
+// NewTHash is a convenience method for creating a THash.
 func NewTHash(name string, h func() hash.Hash) THash {
 	return simpleTHash{n: name, h: h}
 }

tarsum/versioning.go

@@ -8,7 +8,7 @@ import (
 	"strings"
 )
 
-// versioning of the TarSum algorithm
+// Version is used for versioning of the TarSum algorithm
 // based on the prefix of the hash used
 // i.e. "tarsum+sha256:e58fcf7418d4390dec8e8fb69d88c06ec07039d651fedd3aa72af9972e7d046b"
 type Version int
@@ -17,7 +17,7 @@ type Version int
 const (
 	Version0 Version = iota
 	Version1
-	// NOTE: this variable will be either the latest or an unsettled next-version of the TarSum calculation
+	// VersionDev this constant will be either the latest or an unsettled next-version of the TarSum calculation
 	VersionDev
 )
 
@@ -33,7 +33,7 @@ func VersionLabelForChecksum(checksum string) string {
 	return checksum[:sepIndex]
 }
 
-// Get a list of all known tarsum Version
+// GetVersions gets a list of all known tarsum versions.
 func GetVersions() []Version {
 	v := []Version{}
 	for k := range tarSumVersions {
@@ -59,7 +59,7 @@ func (tsv Version) String() string {
 	return tarSumVersions[tsv]
 }
 
-// GetVersionFromTarsum returns the Version from the provided string
+// GetVersionFromTarsum returns the Version from the provided string.
 func GetVersionFromTarsum(tarsum string) (Version, error) {
 	tsv := tarsum
 	if strings.Contains(tarsum, "+") {