149 lines
3.5 KiB
Go
149 lines
3.5 KiB
Go
// Copyright 2018 Prometheus Team
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package config
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import (
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"context"
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"crypto/tls"
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"fmt"
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"io"
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"log/slog"
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"net/http"
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"os"
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"strings"
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"github.com/alecthomas/kingpin/v2"
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"gopkg.in/yaml.v3"
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)
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type getFlagger interface {
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GetFlag(name string) *kingpin.FlagClause
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}
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// Resolver represents a configuration file resolver for kingpin.
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type Resolver struct {
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flags map[string]string
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}
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// NewResolver returns a Resolver structure.
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func NewResolver(file string, logger *slog.Logger, insecureSkipVerify bool) (*Resolver, error) {
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flags := map[string]string{}
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var fileBytes []byte
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var err error
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if strings.HasPrefix(file, "http://") || strings.HasPrefix(file, "https://") {
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fileBytes, err = readFromURL(file, logger, insecureSkipVerify)
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if err != nil {
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return nil, err
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}
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} else {
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fileBytes, err = readFromFile(file, logger)
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if err != nil {
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return nil, err
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}
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}
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var rawValues map[string]interface{}
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err = yaml.Unmarshal(fileBytes, &rawValues)
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if err != nil {
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return nil, fmt.Errorf("failed to unmarshal configuration file: %w", err)
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}
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// Flatten nested YAML values
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flattenedValues := flatten(rawValues)
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for k, v := range flattenedValues {
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if _, ok := flags[k]; !ok {
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flags[k] = v
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}
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}
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return &Resolver{flags: flags}, nil
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}
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func readFromFile(file string, logger *slog.Logger) ([]byte, error) {
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logger.Info("Loading configuration file: " + file)
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if _, err := os.Stat(file); err != nil {
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return nil, fmt.Errorf("failed to read configuration file: %w", err)
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}
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fileBytes, err := os.ReadFile(file)
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if err != nil {
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return nil, fmt.Errorf("failed to read configuration file: %w", err)
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}
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return fileBytes, nil
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}
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func readFromURL(file string, logger *slog.Logger, insecureSkipVerify bool) ([]byte, error) {
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logger.Info("Loading configuration file from URL: " + file)
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tr := &http.Transport{
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TLSClientConfig: &tls.Config{InsecureSkipVerify: insecureSkipVerify}, //nolint:gosec
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}
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if insecureSkipVerify {
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logger.Warn("Loading configuration file with TLS verification disabled")
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}
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client := &http.Client{Transport: tr}
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req, err := http.NewRequestWithContext(context.Background(), http.MethodGet, file, nil)
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if err != nil {
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return nil, fmt.Errorf("failed to create HTTP request: %w", err)
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}
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resp, err := client.Do(req)
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if err != nil {
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return nil, fmt.Errorf("failed to read configuration file from URL: %w", err)
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}
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defer resp.Body.Close()
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fileBytes, err := io.ReadAll(resp.Body)
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if err != nil {
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return nil, err
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}
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return fileBytes, nil
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}
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func (c *Resolver) setDefault(v getFlagger) {
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for name, value := range c.flags {
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f := v.GetFlag(name)
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if f != nil {
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f.Default(value)
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}
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}
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}
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// Bind sets active flags with their default values from the configuration file(s).
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func (c *Resolver) Bind(app *kingpin.Application, args []string) error {
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// Parse the command line arguments to get the selected command.
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pc, err := app.ParseContext(args)
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if err != nil {
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return err
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}
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c.setDefault(app)
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if pc.SelectedCommand != nil {
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c.setDefault(pc.SelectedCommand)
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}
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return nil
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}
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