mirror of https://github.com/grafana/grafana.git
155 lines
3.2 KiB
Go
155 lines
3.2 KiB
Go
package setting
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import (
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"fmt"
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"io/ioutil"
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"os"
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"regexp"
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"sort"
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"strings"
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"gopkg.in/ini.v1"
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)
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type Expander interface {
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SetupExpander(file *ini.File) error
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Expand(string) (string, error)
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}
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type registeredExpander struct {
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name string
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priority int64
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expander Expander
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}
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var expanders = []registeredExpander{
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{
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name: "env",
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priority: -10,
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expander: envExpander{},
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},
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{
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name: "file",
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priority: -5,
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expander: fileExpander{},
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},
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}
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func AddExpander(name string, priority int64, e Expander) {
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expanders = append(expanders, registeredExpander{
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name: name,
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priority: priority,
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expander: e,
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})
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}
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var regex = regexp.MustCompile(`\$(|__\w+){([^}]+)}`)
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// Slightly hacky function to avoid code duplication. If this is eventually called in multiple places, consider refactoring or potentially adding more general helper functions to this package
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func GetExpanderRegex() *regexp.Regexp {
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return regex
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}
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func expandConfig(file *ini.File) error {
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sort.Slice(expanders, func(i, j int) bool {
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return expanders[i].priority < expanders[j].priority
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})
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for _, expander := range expanders {
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err := expander.expander.SetupExpander(file)
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if err != nil {
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return fmt.Errorf("got error during initilazation of expander '%s': %w", expander.name, err)
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}
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for _, section := range file.Sections() {
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for _, key := range section.Keys() {
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updated, err := applyExpander(key.Value(), expander)
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if err != nil {
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return fmt.Errorf("got error while expanding %s.%s with expander '%s': %w",
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section.Name(),
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key.Name(),
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expander.name,
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err)
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}
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key.SetValue(updated)
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}
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}
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}
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return nil
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}
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func ExpandVar(s string) (string, error) {
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for _, expander := range expanders {
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var err error
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s, err = applyExpander(s, expander)
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if err != nil {
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return "", fmt.Errorf("got error while expanding expander %s: %w", expander.name, err)
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}
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}
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return s, nil
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}
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func applyExpander(s string, e registeredExpander) (string, error) {
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matches := regex.FindAllStringSubmatch(s, -1)
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for _, match := range matches {
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if len(match) < 3 {
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return "", fmt.Errorf("regex error, got %d results back for match, expected 3", len(match))
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}
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_, isEnv := e.expander.(envExpander)
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if match[1] == "__"+e.name || (match[1] == "" && isEnv) {
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updated, err := e.expander.Expand(match[2])
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if err != nil {
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return "", err
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}
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s = strings.Replace(s, match[0], updated, 1)
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}
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}
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return s, nil
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}
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type envExpander struct {
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}
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func (e envExpander) SetupExpander(file *ini.File) error {
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return nil
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}
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func (e envExpander) Expand(s string) (string, error) {
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envValue := os.Getenv(s)
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// if env variable is hostname and it is empty use os.Hostname as default
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if s == "HOSTNAME" && envValue == "" {
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return os.Hostname()
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}
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return os.Getenv(s), nil
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}
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type fileExpander struct {
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}
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func (e fileExpander) SetupExpander(file *ini.File) error {
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return nil
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}
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func (e fileExpander) Expand(s string) (string, error) {
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_, err := os.Stat(s)
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if err != nil {
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return "", err
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}
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// nolint:gosec
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// We can ignore the gosec G304 warning on this one because `s` comes from configuration section keys
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f, err := ioutil.ReadFile(s)
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if err != nil {
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return "", err
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}
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return strings.TrimSpace(string(f)), nil
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}
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