Add a package for loading Downward API metadata.
Signed-off-by: Matt Moyer <moyerm@vmware.com>
This commit is contained in:
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70
internal/downward/downward.go
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70
internal/downward/downward.go
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/*
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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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111
internal/downward/downward_test.go
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111
internal/downward/downward_test.go
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/*
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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
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import (
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"testing"
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"github.com/stretchr/testify/require"
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)
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func TestLoad(t *testing.T) {
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t.Parallel()
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tests := []struct {
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name string
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inputDir string
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wantErr string
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want *PodInfo
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}{
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{
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name: "missing directory",
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inputDir: "./testdata/no-such-directory",
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wantErr: "could not load namespace: open testdata/no-such-directory/namespace: no such file or directory",
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},
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{
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name: "missing labels file",
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inputDir: "./testdata/missinglabels",
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wantErr: "could not load labels: open testdata/missinglabels/labels: no such file or directory",
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},
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{
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name: "invalid labels file",
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inputDir: "./testdata/invalidlabels",
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wantErr: "could not parse labels: expected 2 parts, found 1: short buffer",
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},
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{
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name: "valid",
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inputDir: "./testdata/valid",
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want: &PodInfo{
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Namespace: "test-namespace",
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Labels: map[string]string{"foo": "bar", "bat": "baz"},
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},
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},
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}
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for _, tt := range tests {
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tt := tt
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t.Run(tt.name, func(t *testing.T) {
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got, err := Load(tt.inputDir)
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if tt.wantErr != "" {
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require.EqualError(t, err, tt.wantErr)
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require.Empty(t, got)
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return
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}
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require.NoError(t, err)
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require.Equal(t, tt.want, got)
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})
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}
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}
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func TestParseMap(t *testing.T) {
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t.Parallel()
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tests := []struct {
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name string
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input []byte
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wantErr string
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want map[string]string
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}{
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{
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name: "empty",
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want: map[string]string{},
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},
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{
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name: "missing equal",
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input: []byte(`akjhlakjh`),
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wantErr: "expected 2 parts, found 1: short buffer",
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},
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{
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name: "missing invalid value",
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input: []byte(`akjhlakjh="foo\qbar"`),
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wantErr: "invalid quoted value: invalid syntax",
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},
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{
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name: "success",
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input: []byte(`
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fooTime="2020-07-15T19:35:12.027636555Z"
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example.com/config.source="api"
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example.com/bar="baz\x01"
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`),
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want: map[string]string{
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"fooTime": "2020-07-15T19:35:12.027636555Z",
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"example.com/config.source": "api",
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"example.com/bar": "baz\x01",
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},
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},
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}
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for _, tt := range tests {
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tt := tt
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t.Run(tt.name, func(t *testing.T) {
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got, err := parseMap(tt.input)
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if tt.wantErr != "" {
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require.EqualError(t, err, tt.wantErr)
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require.Empty(t, got)
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return
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}
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require.NoError(t, err)
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require.Equal(t, tt.want, got)
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})
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}
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}
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1
internal/downward/testdata/invalidlabels/labels
vendored
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1
internal/downward/testdata/invalidlabels/labels
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invalid
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1
internal/downward/testdata/invalidlabels/namespace
vendored
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1
internal/downward/testdata/invalidlabels/namespace
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test-namespace
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1
internal/downward/testdata/missinglabels/namespace
vendored
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1
internal/downward/testdata/missinglabels/namespace
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test-namespace
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2
internal/downward/testdata/valid/labels
vendored
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2
internal/downward/testdata/valid/labels
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foo="bar"
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bat="baz"
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1
internal/downward/testdata/valid/namespace
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1
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test-namespace
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