mirror of https://github.com/tailscale/tailscale/
util/syspolicy: implement a syspolicy store that reads settings from environment variables
In this PR, we implement (but do not use yet, pending #13727 review) a syspolicy/source.Store that reads policy settings from environment variables. It converts a CamelCase setting.Key, such as AuthKey or ExitNodeID, to a SCREAMING_SNAKE_CASE, TS_-prefixed environment variable name, such as TS_AUTH_KEY and TS_EXIT_NODE_ID. It then looks up the variable and attempts to parse it according to the expected value type. If the environment variable is not set, the policy setting is considered not configured in this store (the syspolicy package will still read it from other sources). Similarly, if the environment variable has an invalid value for the setting type, it won't be used (though the reported/logged error will differ). Updates #13193 Updates #12687 Signed-off-by: Nick Khyl <nickk@tailscale.com>pull/13968/head
Nick Khyl
1 month ago
committed by
Nick Khyl
parent
1103044598
commit
2336c340c4
@ -0,0 +1,159 @@
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// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package source
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import (
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"fmt"
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"os"
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"strconv"
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"strings"
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"unicode/utf8"
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"github.com/pkg/errors"
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"tailscale.com/util/syspolicy/setting"
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)
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var lookupEnv = os.LookupEnv // test hook
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var _ Store = (*EnvPolicyStore)(nil)
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// EnvPolicyStore is a [Store] that reads policy settings from environment variables.
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type EnvPolicyStore struct{}
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// ReadString implements [Store].
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func (s *EnvPolicyStore) ReadString(key setting.Key) (string, error) {
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_, str, err := s.lookupSettingVariable(key)
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if err != nil {
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return "", err
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}
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return str, nil
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}
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// ReadUInt64 implements [Store].
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func (s *EnvPolicyStore) ReadUInt64(key setting.Key) (uint64, error) {
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name, str, err := s.lookupSettingVariable(key)
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if err != nil {
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return 0, err
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}
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if str == "" {
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return 0, setting.ErrNotConfigured
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}
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value, err := strconv.ParseUint(str, 0, 64)
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if err != nil {
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return 0, fmt.Errorf("%s: %w: %q is not a valid uint64", name, setting.ErrTypeMismatch, str)
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}
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return value, nil
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}
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// ReadBoolean implements [Store].
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func (s *EnvPolicyStore) ReadBoolean(key setting.Key) (bool, error) {
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name, str, err := s.lookupSettingVariable(key)
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if err != nil {
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return false, err
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}
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if str == "" {
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return false, setting.ErrNotConfigured
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}
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value, err := strconv.ParseBool(str)
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if err != nil {
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return false, fmt.Errorf("%s: %w: %q is not a valid bool", name, setting.ErrTypeMismatch, str)
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}
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return value, nil
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}
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// ReadStringArray implements [Store].
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func (s *EnvPolicyStore) ReadStringArray(key setting.Key) ([]string, error) {
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_, str, err := s.lookupSettingVariable(key)
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if err != nil || str == "" {
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return nil, err
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}
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var dst int
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res := strings.Split(str, ",")
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for src := range res {
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res[dst] = strings.TrimSpace(res[src])
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if res[dst] != "" {
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dst++
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}
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}
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return res[0:dst], nil
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}
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func (s *EnvPolicyStore) lookupSettingVariable(key setting.Key) (name, value string, err error) {
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name, err = keyToEnvVarName(key)
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if err != nil {
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return "", "", err
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}
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value, ok := lookupEnv(name)
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if !ok {
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return name, "", setting.ErrNotConfigured
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}
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return name, value, nil
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}
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var (
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errEmptyKey = errors.New("key must not be empty")
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errInvalidKey = errors.New("key must consist of alphanumeric characters and slashes")
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)
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// keyToEnvVarName returns the environment variable name for a given policy
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// setting key, or an error if the key is invalid. It converts CamelCase keys into
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// underscore-separated words and prepends the variable name with the TS prefix.
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// For example: AuthKey => TS_AUTH_KEY, ExitNodeAllowLANAccess => TS_EXIT_NODE_ALLOW_LAN_ACCESS, etc.
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//
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// It's fine to use this in [EnvPolicyStore] without caching variable names since it's not a hot path.
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// [EnvPolicyStore] is not a [Changeable] policy store, so the conversion will only happen once.
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func keyToEnvVarName(key setting.Key) (string, error) {
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if len(key) == 0 {
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return "", errEmptyKey
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}
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isLower := func(c byte) bool { return 'a' <= c && c <= 'z' }
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isUpper := func(c byte) bool { return 'A' <= c && c <= 'Z' }
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isLetter := func(c byte) bool { return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') }
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isDigit := func(c byte) bool { return '0' <= c && c <= '9' }
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words := make([]string, 0, 8)
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words = append(words, "TS")
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var currentWord strings.Builder
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for i := 0; i < len(key); i++ {
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c := key[i]
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if c >= utf8.RuneSelf {
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return "", errInvalidKey
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}
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var split bool
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switch {
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case isLower(c):
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c -= 'a' - 'A' // make upper
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split = currentWord.Len() > 0 && !isLetter(key[i-1])
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case isUpper(c):
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if currentWord.Len() > 0 {
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prevUpper := isUpper(key[i-1])
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nextLower := i < len(key)-1 && isLower(key[i+1])
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split = !prevUpper || nextLower // split on case transition
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}
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case isDigit(c):
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split = currentWord.Len() > 0 && !isDigit(key[i-1])
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case c == setting.KeyPathSeparator:
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words = append(words, currentWord.String())
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currentWord.Reset()
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continue
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default:
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return "", errInvalidKey
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}
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if split {
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words = append(words, currentWord.String())
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currentWord.Reset()
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}
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currentWord.WriteByte(c)
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}
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if currentWord.Len() > 0 {
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words = append(words, currentWord.String())
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}
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return strings.Join(words, "_"), nil
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}
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@ -0,0 +1,354 @@
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// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package source
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import (
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"cmp"
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"errors"
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"math"
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"reflect"
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"strconv"
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"testing"
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"tailscale.com/util/syspolicy/setting"
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)
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func TestKeyToVariableName(t *testing.T) {
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tests := []struct {
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name string
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key setting.Key
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want string
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wantErr error
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}{
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{
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name: "empty",
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key: "",
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wantErr: errEmptyKey,
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},
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{
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name: "lowercase",
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key: "tailnet",
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want: "TS_TAILNET",
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},
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{
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name: "CamelCase",
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key: "AuthKey",
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want: "TS_AUTH_KEY",
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},
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{
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name: "LongerCamelCase",
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key: "ManagedByOrganizationName",
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want: "TS_MANAGED_BY_ORGANIZATION_NAME",
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},
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{
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name: "UPPERCASE",
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key: "UPPERCASE",
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want: "TS_UPPERCASE",
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},
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{
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name: "WithAbbrev/Front",
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key: "DNSServer",
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want: "TS_DNS_SERVER",
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},
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{
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name: "WithAbbrev/Middle",
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key: "ExitNodeAllowLANAccess",
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want: "TS_EXIT_NODE_ALLOW_LAN_ACCESS",
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},
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{
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name: "WithAbbrev/Back",
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key: "ExitNodeID",
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want: "TS_EXIT_NODE_ID",
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},
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{
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name: "WithDigits/Single/Front",
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key: "0TestKey",
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want: "TS_0_TEST_KEY",
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},
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{
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name: "WithDigits/Multi/Front",
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key: "64TestKey",
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want: "TS_64_TEST_KEY",
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},
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{
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name: "WithDigits/Single/Middle",
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key: "Test0Key",
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want: "TS_TEST_0_KEY",
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},
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{
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name: "WithDigits/Multi/Middle",
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key: "Test64Key",
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want: "TS_TEST_64_KEY",
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},
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{
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name: "WithDigits/Single/Back",
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key: "TestKey0",
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want: "TS_TEST_KEY_0",
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},
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{
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name: "WithDigits/Multi/Back",
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key: "TestKey64",
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want: "TS_TEST_KEY_64",
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},
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{
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name: "WithDigits/Multi/Back",
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key: "TestKey64",
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want: "TS_TEST_KEY_64",
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},
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{
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name: "WithPathSeparators/Single",
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key: "Key/Subkey",
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want: "TS_KEY_SUBKEY",
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},
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{
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name: "WithPathSeparators/Multi",
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key: "Root/Level1/Level2",
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want: "TS_ROOT_LEVEL_1_LEVEL_2",
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},
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{
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name: "Mixed",
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key: "Network/DNSServer/IPAddress",
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want: "TS_NETWORK_DNS_SERVER_IP_ADDRESS",
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},
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{
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name: "Non-Alphanumeric/NonASCII/1",
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key: "ж",
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wantErr: errInvalidKey,
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},
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{
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name: "Non-Alphanumeric/NonASCII/2",
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key: "KeyжName",
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wantErr: errInvalidKey,
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},
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{
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name: "Non-Alphanumeric/Space",
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key: "Key Name",
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wantErr: errInvalidKey,
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},
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{
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name: "Non-Alphanumeric/Punct",
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key: "Key!Name",
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wantErr: errInvalidKey,
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},
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{
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name: "Non-Alphanumeric/Backslash",
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key: `Key\Name`,
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wantErr: errInvalidKey,
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},
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}
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for _, tt := range tests {
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t.Run(cmp.Or(tt.name, string(tt.key)), func(t *testing.T) {
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got, err := keyToEnvVarName(tt.key)
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checkError(t, err, tt.wantErr, true)
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if got != tt.want {
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t.Fatalf("got %q; want %q", got, tt.want)
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}
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})
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}
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}
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func TestEnvPolicyStore(t *testing.T) {
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blankEnv := func(string) (string, bool) { return "", false }
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makeEnv := func(wantName, value string) func(string) (string, bool) {
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return func(gotName string) (string, bool) {
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if gotName != wantName {
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return "", false
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}
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return value, true
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}
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}
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tests := []struct {
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name string
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key setting.Key
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lookup func(string) (string, bool)
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want any
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wantErr error
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}{
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{
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name: "NotConfigured/String",
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key: "AuthKey",
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lookup: blankEnv,
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wantErr: setting.ErrNotConfigured,
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want: "",
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},
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{
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name: "Configured/String/Empty",
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key: "AuthKey",
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lookup: makeEnv("TS_AUTH_KEY", ""),
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want: "",
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},
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{
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name: "Configured/String/NonEmpty",
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key: "AuthKey",
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lookup: makeEnv("TS_AUTH_KEY", "ABC123"),
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want: "ABC123",
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},
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{
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name: "NotConfigured/UInt64",
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key: "IntegerSetting",
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lookup: blankEnv,
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wantErr: setting.ErrNotConfigured,
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want: uint64(0),
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},
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{
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name: "Configured/UInt64/Empty",
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key: "IntegerSetting",
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lookup: makeEnv("TS_INTEGER_SETTING", ""),
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wantErr: setting.ErrNotConfigured,
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want: uint64(0),
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},
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{
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name: "Configured/UInt64/Zero",
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key: "IntegerSetting",
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lookup: makeEnv("TS_INTEGER_SETTING", "0"),
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want: uint64(0),
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},
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{
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name: "Configured/UInt64/NonZero",
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key: "IntegerSetting",
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lookup: makeEnv("TS_INTEGER_SETTING", "12345"),
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want: uint64(12345),
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},
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{
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name: "Configured/UInt64/MaxUInt64",
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key: "IntegerSetting",
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lookup: makeEnv("TS_INTEGER_SETTING", strconv.FormatUint(math.MaxUint64, 10)),
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want: uint64(math.MaxUint64),
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},
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{
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name: "Configured/UInt64/Negative",
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key: "IntegerSetting",
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lookup: makeEnv("TS_INTEGER_SETTING", "-1"),
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wantErr: setting.ErrTypeMismatch,
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want: uint64(0),
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},
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{
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name: "Configured/UInt64/Hex",
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key: "IntegerSetting",
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lookup: makeEnv("TS_INTEGER_SETTING", "0xDEADBEEF"),
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want: uint64(0xDEADBEEF),
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},
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{
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name: "NotConfigured/Bool",
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key: "LogSCMInteractions",
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lookup: blankEnv,
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wantErr: setting.ErrNotConfigured,
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want: false,
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},
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{
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name: "Configured/Bool/Empty",
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key: "LogSCMInteractions",
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lookup: makeEnv("TS_LOG_SCM_INTERACTIONS", ""),
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wantErr: setting.ErrNotConfigured,
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want: false,
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},
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{
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name: "Configured/Bool/True",
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key: "LogSCMInteractions",
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lookup: makeEnv("TS_LOG_SCM_INTERACTIONS", "true"),
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want: true,
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},
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{
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name: "Configured/Bool/False",
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key: "LogSCMInteractions",
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lookup: makeEnv("TS_LOG_SCM_INTERACTIONS", "False"),
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want: false,
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},
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{
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name: "Configured/Bool/1",
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key: "LogSCMInteractions",
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lookup: makeEnv("TS_LOG_SCM_INTERACTIONS", "1"),
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want: true,
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},
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{
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name: "Configured/Bool/0",
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key: "LogSCMInteractions",
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lookup: makeEnv("TS_LOG_SCM_INTERACTIONS", "0"),
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want: false,
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},
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{
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name: "Configured/Bool/Invalid",
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key: "IntegerSetting",
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lookup: makeEnv("TS_INTEGER_SETTING", "NotABool"),
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wantErr: setting.ErrTypeMismatch,
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want: false,
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},
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{
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name: "NotConfigured/StringArray",
|
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key: "AllowedSuggestedExitNodes",
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lookup: blankEnv,
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wantErr: setting.ErrNotConfigured,
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want: []string(nil),
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},
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{
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name: "Configured/StringArray/Empty",
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key: "AllowedSuggestedExitNodes",
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lookup: makeEnv("TS_ALLOWED_SUGGESTED_EXIT_NODES", ""),
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want: []string(nil),
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},
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{
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name: "Configured/StringArray/Spaces",
|
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key: "AllowedSuggestedExitNodes",
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lookup: makeEnv("TS_ALLOWED_SUGGESTED_EXIT_NODES", " \t "),
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want: []string{},
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},
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{
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name: "Configured/StringArray/Single",
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key: "AllowedSuggestedExitNodes",
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lookup: makeEnv("TS_ALLOWED_SUGGESTED_EXIT_NODES", "NodeA"),
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want: []string{"NodeA"},
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},
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{
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name: "Configured/StringArray/Multi",
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key: "AllowedSuggestedExitNodes",
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lookup: makeEnv("TS_ALLOWED_SUGGESTED_EXIT_NODES", "NodeA,NodeB,NodeC"),
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want: []string{"NodeA", "NodeB", "NodeC"},
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},
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{
|
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name: "Configured/StringArray/WithBlank",
|
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key: "AllowedSuggestedExitNodes",
|
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lookup: makeEnv("TS_ALLOWED_SUGGESTED_EXIT_NODES", "NodeA,\t,, ,NodeB"),
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want: []string{"NodeA", "NodeB"},
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},
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}
|
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for _, tt := range tests {
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t.Run(cmp.Or(tt.name, string(tt.key)), func(t *testing.T) {
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oldLookupEnv := lookupEnv
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t.Cleanup(func() { lookupEnv = oldLookupEnv })
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lookupEnv = tt.lookup
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var got any
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var err error
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var store EnvPolicyStore
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switch tt.want.(type) {
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case string:
|
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got, err = store.ReadString(tt.key)
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case uint64:
|
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got, err = store.ReadUInt64(tt.key)
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case bool:
|
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got, err = store.ReadBoolean(tt.key)
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case []string:
|
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got, err = store.ReadStringArray(tt.key)
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||||
}
|
||||
checkError(t, err, tt.wantErr, false)
|
||||
if !reflect.DeepEqual(got, tt.want) {
|
||||
t.Errorf("got %v; want %v", got, tt.want)
|
||||
}
|
||||
})
|
||||
}
|
||||
}
|
||||
|
||||
func checkError(tb testing.TB, got, want error, fatal bool) {
|
||||
tb.Helper()
|
||||
f := tb.Errorf
|
||||
if fatal {
|
||||
f = tb.Fatalf
|
||||
}
|
||||
if (want == nil && got != nil) ||
|
||||
(want != nil && got == nil) ||
|
||||
(want != nil && got != nil && !errors.Is(got, want) && want.Error() != got.Error()) {
|
||||
f("gotErr: %v; wantErr: %v", got, want)
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue