71 lines
2.1 KiB
Go
71 lines
2.1 KiB
Go
/*
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Copyright 2020 VMware, Inc.
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SPDX-License-Identifier: Apache-2.0
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*/
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// Package downward implements a client interface for interacting with Kubernetes "downwardAPI" volumes.
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// See https://kubernetes.io/docs/tasks/inject-data-application/downward-api-volume-expose-pod-information/.
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package downward
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import (
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"bytes"
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"fmt"
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"io"
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"io/ioutil"
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"path/filepath"
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"strconv"
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"strings"
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)
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// PodInfo contains pod metadata about the current pod.
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type PodInfo struct {
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// Namespace where the current pod is running.
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Namespace string
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// Labels of the current pod.
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Labels map[string]string
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}
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// Load pod metadata from a downwardAPI volume directory.
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func Load(directory string) (*PodInfo, error) {
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var result PodInfo
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ns, err := ioutil.ReadFile(filepath.Join(directory, "namespace"))
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if err != nil {
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return nil, fmt.Errorf("could not load namespace: %w", err)
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}
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result.Namespace = strings.TrimSpace(string(ns))
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labels, err := ioutil.ReadFile(filepath.Join(directory, "labels"))
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if err != nil {
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return nil, fmt.Errorf("could not load labels: %w", err)
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}
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result.Labels, err = parseMap(labels)
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if err != nil {
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return nil, fmt.Errorf("could not parse labels: %w", err)
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}
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return &result, nil
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}
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// parseMap parses the key/value format emitted by the Kubernetes Downward API for pod labels and annotations.
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// See https://kubernetes.io/docs/tasks/inject-data-application/downward-api-volume-expose-pod-information/.
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// See https://github.com/kubernetes/kubernetes/blob/4b2cb072dba10227083b16731f019f096c581787/pkg/fieldpath/fieldpath.go#L28.
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func parseMap(input []byte) (map[string]string, error) {
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result := map[string]string{}
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for _, line := range bytes.Split(input, []byte("\n")) {
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line = bytes.TrimSpace(line)
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if len(line) == 0 {
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continue
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}
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parts := bytes.SplitN(line, []byte("="), 2)
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if len(parts) != 2 {
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return nil, fmt.Errorf("expected 2 parts, found %d: %w", len(parts), io.ErrShortBuffer)
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}
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value, err := strconv.Unquote(string(parts[1]))
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if err != nil {
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return nil, fmt.Errorf("invalid quoted value: %w", err)
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}
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result[string(parts[0])] = value
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}
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return result, nil
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}
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