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>

parsers/filters/parse.go

@@ -1,3 +1,5 @@
+// Package filters provides helper function to parse and handle command line
+// filter, used for example in docker ps or docker images commands.
 package filters
 
 import (
@@ -7,16 +9,22 @@ import (
 	"strings"
 )
 
+// Args stores filter arguments as map key:{array of values}.
+// It contains a aggregation of the list of arguments (which are in the form
+// of -f 'key=value') based on the key, and store values for the same key
+// in an slice.
+// e.g given -f 'label=label1=1' -f 'label=label2=2' -f 'image.name=ubuntu'
+// the args will be {'label': {'label1=1','label2=2'}, 'image.name', {'ubuntu'}}
 type Args map[string][]string
 
-// Parse the argument to the filter flag. Like
+// ParseFlag parses the argument to the filter flag. Like
 //
 //   `docker ps -f 'created=today' -f 'image.name=ubuntu*'`
 //
 // If prev map is provided, then it is appended to, and returned. By default a new
 // map is created.
 func ParseFlag(arg string, prev Args) (Args, error) {
-	var filters Args = prev
+	filters := prev
 	if prev == nil {
 		filters = Args{}
 	}
@@ -25,7 +33,7 @@ func ParseFlag(arg string, prev Args) (Args, error) {
 	}
 
 	if !strings.Contains(arg, "=") {
-		return filters, ErrorBadFormat
+		return filters, ErrBadFormat
 	}
 
 	f := strings.SplitN(arg, "=", 2)
@@ -36,9 +44,10 @@ func ParseFlag(arg string, prev Args) (Args, error) {
 	return filters, nil
 }
 
-var ErrorBadFormat = errors.New("bad format of filter (expected name=value)")
+// ErrBadFormat is an error returned in case of bad format for a filter.
+var ErrBadFormat = errors.New("bad format of filter (expected name=value)")
 
-// packs the Args into an string for easy transport from client to server
+// ToParam packs the Args into an string for easy transport from client to server.
 func ToParam(a Args) (string, error) {
 	// this way we don't URL encode {}, just empty space
 	if len(a) == 0 {
@@ -52,7 +61,7 @@ func ToParam(a Args) (string, error) {
 	return string(buf), nil
 }
 
-// unpacks the filter Args
+// FromParam unpacks the filter Args.
 func FromParam(p string) (Args, error) {
 	args := Args{}
 	if len(p) == 0 {
@@ -64,6 +73,11 @@ func FromParam(p string) (Args, error) {
 	return args, nil
 }
 
+// MatchKVList returns true if the values for the specified field maches the ones
+// from the sources.
+// e.g. given Args are {'label': {'label1=1','label2=1'}, 'image.name', {'ubuntu'}},
+//      field is 'label' and sources are {'label':{'label1=1','label2=2','label3=3'}}
+//      it returns true.
 func (filters Args) MatchKVList(field string, sources map[string]string) bool {
 	fieldValues := filters[field]
 
@@ -96,6 +110,10 @@ outer:
 	return true
 }
 
+// Match returns true if the values for the specified field matches the source string
+// e.g. given Args are {'label': {'label1=1','label2=1'}, 'image.name', {'ubuntu'}},
+//      field is 'image.name' and source is 'ubuntu'
+//      it returns true.
 func (filters Args) Match(field, source string) bool {
 	fieldValues := filters[field]
 

parsers/filters/parse_test.go

@@ -39,8 +39,8 @@ func TestParseArgsEdgeCase(t *testing.T) {
 	if args == nil || len(args) != 0 {
 		t.Fatalf("Expected an empty Args (map), got %v", args)
 	}
-	if args, err = ParseFlag("anything", args); err == nil || err != ErrorBadFormat {
-		t.Fatalf("Expected ErrorBadFormat, got %v", err)
+	if args, err = ParseFlag("anything", args); err == nil || err != ErrBadFormat {
+		t.Fatalf("Expected ErrBadFormat, got %v", err)
 	}
 }