241 lines
7.4 KiB
Go
241 lines
7.4 KiB
Go
/*
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Copyright 2014 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package kubectl
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import (
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"bufio"
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"bytes"
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"fmt"
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"io"
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"reflect"
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"regexp"
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"strings"
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"text/tabwriter"
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"k8s.io/apimachinery/pkg/api/meta"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/client-go/util/jsonpath"
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)
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const (
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columnwidth = 10
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tabwidth = 4
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padding = 3
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padding_character = ' '
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flags = 0
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)
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var jsonRegexp = regexp.MustCompile("^\\{\\.?([^{}]+)\\}$|^\\.?([^{}]+)$")
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// MassageJSONPath attempts to be flexible with JSONPath expressions, it accepts:
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// * metadata.name (no leading '.' or curly brances '{...}'
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// * {metadata.name} (no leading '.')
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// * .metadata.name (no curly braces '{...}')
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// * {.metadata.name} (complete expression)
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// And transforms them all into a valid jsonpat expression:
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// {.metadata.name}
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func massageJSONPath(pathExpression string) (string, error) {
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if len(pathExpression) == 0 {
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return pathExpression, nil
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}
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submatches := jsonRegexp.FindStringSubmatch(pathExpression)
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if submatches == nil {
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return "", fmt.Errorf("unexpected path string, expected a 'name1.name2' or '.name1.name2' or '{name1.name2}' or '{.name1.name2}'")
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}
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if len(submatches) != 3 {
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return "", fmt.Errorf("unexpected submatch list: %v", submatches)
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}
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var fieldSpec string
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if len(submatches[1]) != 0 {
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fieldSpec = submatches[1]
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} else {
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fieldSpec = submatches[2]
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}
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return fmt.Sprintf("{.%s}", fieldSpec), nil
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}
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// NewCustomColumnsPrinterFromSpec creates a custom columns printer from a comma separated list of <header>:<jsonpath-field-spec> pairs.
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// e.g. NAME:metadata.name,API_VERSION:apiVersion creates a printer that prints:
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//
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// NAME API_VERSION
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// foo bar
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func NewCustomColumnsPrinterFromSpec(spec string, decoder runtime.Decoder, noHeaders bool) (*CustomColumnsPrinter, error) {
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if len(spec) == 0 {
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return nil, fmt.Errorf("custom-columns format specified but no custom columns given")
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}
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parts := strings.Split(spec, ",")
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columns := make([]Column, len(parts))
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for ix := range parts {
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colSpec := strings.Split(parts[ix], ":")
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if len(colSpec) != 2 {
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return nil, fmt.Errorf("unexpected custom-columns spec: %s, expected <header>:<json-path-expr>", parts[ix])
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}
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spec, err := massageJSONPath(colSpec[1])
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if err != nil {
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return nil, err
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}
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columns[ix] = Column{Header: colSpec[0], FieldSpec: spec}
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}
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return &CustomColumnsPrinter{Columns: columns, Decoder: decoder, NoHeaders: noHeaders}, nil
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}
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func splitOnWhitespace(line string) []string {
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lineScanner := bufio.NewScanner(bytes.NewBufferString(line))
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lineScanner.Split(bufio.ScanWords)
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result := []string{}
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for lineScanner.Scan() {
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result = append(result, lineScanner.Text())
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}
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return result
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}
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// NewCustomColumnsPrinterFromTemplate creates a custom columns printer from a template stream. The template is expected
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// to consist of two lines, whitespace separated. The first line is the header line, the second line is the jsonpath field spec
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// For example, the template below:
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// NAME API_VERSION
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// {metadata.name} {apiVersion}
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func NewCustomColumnsPrinterFromTemplate(templateReader io.Reader, decoder runtime.Decoder) (*CustomColumnsPrinter, error) {
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scanner := bufio.NewScanner(templateReader)
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if !scanner.Scan() {
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return nil, fmt.Errorf("invalid template, missing header line. Expected format is one line of space separated headers, one line of space separated column specs.")
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}
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headers := splitOnWhitespace(scanner.Text())
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if !scanner.Scan() {
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return nil, fmt.Errorf("invalid template, missing spec line. Expected format is one line of space separated headers, one line of space separated column specs.")
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}
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specs := splitOnWhitespace(scanner.Text())
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if len(headers) != len(specs) {
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return nil, fmt.Errorf("number of headers (%d) and field specifications (%d) don't match", len(headers), len(specs))
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}
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columns := make([]Column, len(headers))
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for ix := range headers {
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spec, err := massageJSONPath(specs[ix])
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if err != nil {
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return nil, err
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}
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columns[ix] = Column{
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Header: headers[ix],
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FieldSpec: spec,
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}
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}
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return &CustomColumnsPrinter{Columns: columns, Decoder: decoder, NoHeaders: false}, nil
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}
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// Column represents a user specified column
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type Column struct {
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// The header to print above the column, general style is ALL_CAPS
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Header string
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// The pointer to the field in the object to print in JSONPath form
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// e.g. {.ObjectMeta.Name}, see pkg/util/jsonpath for more details.
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FieldSpec string
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}
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// CustomColumnPrinter is a printer that knows how to print arbitrary columns
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// of data from templates specified in the `Columns` array
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type CustomColumnsPrinter struct {
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Columns []Column
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Decoder runtime.Decoder
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NoHeaders bool
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}
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func (s *CustomColumnsPrinter) AfterPrint(w io.Writer, res string) error {
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return nil
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}
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func (s *CustomColumnsPrinter) PrintObj(obj runtime.Object, out io.Writer) error {
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w := tabwriter.NewWriter(out, columnwidth, tabwidth, padding, padding_character, flags)
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if !s.NoHeaders {
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headers := make([]string, len(s.Columns))
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for ix := range s.Columns {
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headers[ix] = s.Columns[ix].Header
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}
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fmt.Fprintln(w, strings.Join(headers, "\t"))
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}
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parsers := make([]*jsonpath.JSONPath, len(s.Columns))
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for ix := range s.Columns {
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parsers[ix] = jsonpath.New(fmt.Sprintf("column%d", ix))
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if err := parsers[ix].Parse(s.Columns[ix].FieldSpec); err != nil {
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return err
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}
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}
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if meta.IsListType(obj) {
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objs, err := meta.ExtractList(obj)
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if err != nil {
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return err
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}
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for ix := range objs {
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if err := s.printOneObject(objs[ix], parsers, w); err != nil {
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return err
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}
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}
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} else {
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if err := s.printOneObject(obj, parsers, w); err != nil {
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return err
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}
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}
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return w.Flush()
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}
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func (s *CustomColumnsPrinter) printOneObject(obj runtime.Object, parsers []*jsonpath.JSONPath, out io.Writer) error {
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columns := make([]string, len(parsers))
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switch u := obj.(type) {
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case *runtime.Unknown:
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if len(u.Raw) > 0 {
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var err error
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if obj, err = runtime.Decode(s.Decoder, u.Raw); err != nil {
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return fmt.Errorf("can't decode object for printing: %v (%s)", err, u.Raw)
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}
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}
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}
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for ix := range parsers {
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parser := parsers[ix]
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var values [][]reflect.Value
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var err error
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if unstructured, ok := obj.(runtime.Unstructured); ok {
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values, err = parser.FindResults(unstructured.UnstructuredContent())
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} else {
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values, err = parser.FindResults(reflect.ValueOf(obj).Elem().Interface())
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}
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if err != nil {
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return err
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}
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if len(values) == 0 || len(values[0]) == 0 {
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fmt.Fprintf(out, "<none>\t")
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}
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valueStrings := []string{}
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for arrIx := range values {
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for valIx := range values[arrIx] {
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valueStrings = append(valueStrings, fmt.Sprintf("%v", values[arrIx][valIx].Interface()))
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}
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}
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columns[ix] = strings.Join(valueStrings, ",")
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}
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fmt.Fprintln(out, strings.Join(columns, "\t"))
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return nil
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}
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func (s *CustomColumnsPrinter) HandledResources() []string {
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return []string{}
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}
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