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338
config.go
Normal file
338
config.go
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@ -0,0 +1,338 @@
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package nebula
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import (
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"fmt"
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"github.com/imdario/mergo"
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"github.com/sirupsen/logrus"
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"gopkg.in/yaml.v2"
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"io/ioutil"
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"os"
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"os/signal"
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"path/filepath"
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"sort"
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"strconv"
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"strings"
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"syscall"
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"time"
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)
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type Config struct {
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path string
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files []string
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Settings map[interface{}]interface{}
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oldSettings map[interface{}]interface{}
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callbacks []func(*Config)
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}
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func NewConfig() *Config {
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return &Config{
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Settings: make(map[interface{}]interface{}),
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}
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}
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// Load will find all yaml files within path and load them in lexical order
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func (c *Config) Load(path string) error {
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c.path = path
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c.files = make([]string, 0)
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err := c.resolve(path)
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if err != nil {
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return err
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}
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sort.Strings(c.files)
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err = c.parse()
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if err != nil {
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return err
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}
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return nil
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}
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// RegisterReloadCallback stores a function to be called when a config reload is triggered. The functions registered
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// here should decide if they need to make a change to the current process before making the change. HasChanged can be
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// used to help decide if a change is necessary.
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// These functions should return quickly or spawn their own go routine if they will take a while
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func (c *Config) RegisterReloadCallback(f func(*Config)) {
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c.callbacks = append(c.callbacks, f)
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}
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// HasChanged checks if the underlying structure of the provided key has changed after a config reload. The value of
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// k in both the old and new settings will be serialized, the result of the string comparison is returned.
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// If k is an empty string the entire config is tested.
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// It's important to note that this is very rudimentary and susceptible to configuration ordering issues indicating
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// there is change when there actually wasn't any.
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func (c *Config) HasChanged(k string) bool {
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if c.oldSettings == nil {
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return false
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}
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var (
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nv interface{}
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ov interface{}
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)
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if k == "" {
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nv = c.Settings
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ov = c.oldSettings
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k = "all settings"
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} else {
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nv = c.get(k, c.Settings)
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ov = c.get(k, c.oldSettings)
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}
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newVals, err := yaml.Marshal(nv)
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if err != nil {
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l.WithField("config_path", k).WithError(err).Error("Error while marshaling new config")
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}
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oldVals, err := yaml.Marshal(ov)
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if err != nil {
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l.WithField("config_path", k).WithError(err).Error("Error while marshaling old config")
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}
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return string(newVals) != string(oldVals)
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}
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// CatchHUP will listen for the HUP signal in a go routine and reload all configs found in the
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// original path provided to Load. The old settings are shallow copied for change detection after the reload.
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func (c *Config) CatchHUP() {
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ch := make(chan os.Signal, 1)
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signal.Notify(ch, syscall.SIGHUP)
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go func() {
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for range ch {
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l.Info("Caught HUP, reloading config")
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c.ReloadConfig()
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}
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}()
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}
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func (c *Config) ReloadConfig() {
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c.oldSettings = make(map[interface{}]interface{})
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for k, v := range c.Settings {
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c.oldSettings[k] = v
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}
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err := c.Load(c.path)
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if err != nil {
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l.WithField("config_path", c.path).WithError(err).Error("Error occurred while reloading config")
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return
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}
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for _, v := range c.callbacks {
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v(c)
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}
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}
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// GetString will get the string for k or return the default d if not found or invalid
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func (c *Config) GetString(k, d string) string {
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r := c.Get(k)
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if r == nil {
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return d
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}
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return fmt.Sprintf("%v", r)
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}
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// GetStringSlice will get the slice of strings for k or return the default d if not found or invalid
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func (c *Config) GetStringSlice(k string, d []string) []string {
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r := c.Get(k)
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if r == nil {
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return d
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}
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rv, ok := r.([]interface{})
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if !ok {
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return d
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}
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v := make([]string, len(rv))
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for i := 0; i < len(v); i++ {
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v[i] = fmt.Sprintf("%v", rv[i])
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}
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return v
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}
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// GetMap will get the map for k or return the default d if not found or invalid
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func (c *Config) GetMap(k string, d map[interface{}]interface{}) map[interface{}]interface{} {
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r := c.Get(k)
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if r == nil {
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return d
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}
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v, ok := r.(map[interface{}]interface{})
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if !ok {
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return d
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}
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return v
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}
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// GetInt will get the int for k or return the default d if not found or invalid
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func (c *Config) GetInt(k string, d int) int {
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r := c.GetString(k, strconv.Itoa(d))
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v, err := strconv.Atoi(r)
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if err != nil {
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return d
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}
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return v
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}
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// GetBool will get the bool for k or return the default d if not found or invalid
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func (c *Config) GetBool(k string, d bool) bool {
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r := strings.ToLower(c.GetString(k, fmt.Sprintf("%v", d)))
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v, err := strconv.ParseBool(r)
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if err != nil {
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switch r {
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case "y", "yes":
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return true
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case "n", "no":
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return false
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}
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return d
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}
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return v
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}
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// GetDuration will get the duration for k or return the default d if not found or invalid
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func (c *Config) GetDuration(k string, d time.Duration) time.Duration {
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r := c.GetString(k, "")
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v, err := time.ParseDuration(r)
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if err != nil {
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return d
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}
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return v
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}
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func (c *Config) Get(k string) interface{} {
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return c.get(k, c.Settings)
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}
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func (c *Config) get(k string, v interface{}) interface{} {
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parts := strings.Split(k, ".")
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for _, p := range parts {
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m, ok := v.(map[interface{}]interface{})
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if !ok {
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return nil
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}
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v, ok = m[p]
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if !ok {
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return nil
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}
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}
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return v
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}
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func (c *Config) resolve(path string) error {
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i, err := os.Stat(path)
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if err != nil {
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return nil
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}
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if !i.IsDir() {
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c.addFile(path)
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return nil
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}
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paths, err := readDirNames(path)
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if err != nil {
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return fmt.Errorf("problem while reading directory %s: %s", path, err)
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}
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for _, p := range paths {
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err := c.resolve(filepath.Join(path, p))
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if err != nil {
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return err
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}
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}
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return nil
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}
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func (c *Config) addFile(path string) error {
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ext := filepath.Ext(path)
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if ext != ".yaml" && ext != ".yml" {
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return nil
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}
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ap, err := filepath.Abs(path)
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if err != nil {
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return err
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}
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c.files = append(c.files, ap)
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return nil
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}
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func (c *Config) parse() error {
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var m map[interface{}]interface{}
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for _, path := range c.files {
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b, err := ioutil.ReadFile(path)
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if err != nil {
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return err
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}
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var nm map[interface{}]interface{}
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err = yaml.Unmarshal(b, &nm)
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if err != nil {
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return err
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}
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// We need to use WithAppendSlice so that firewall rules in separate
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// files are appended together
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err = mergo.Merge(&nm, m, mergo.WithAppendSlice)
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m = nm
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if err != nil {
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return err
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}
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}
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c.Settings = m
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return nil
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}
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func readDirNames(path string) ([]string, error) {
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f, err := os.Open(path)
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if err != nil {
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return nil, err
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}
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paths, err := f.Readdirnames(-1)
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f.Close()
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if err != nil {
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return nil, err
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}
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sort.Strings(paths)
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return paths, nil
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}
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func configLogger(c *Config) error {
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// set up our logging level
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logLevel, err := logrus.ParseLevel(strings.ToLower(c.GetString("logging.level", "info")))
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if err != nil {
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return fmt.Errorf("%s; possible levels: %s", err, logrus.AllLevels)
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}
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l.SetLevel(logLevel)
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logFormat := strings.ToLower(c.GetString("logging.format", "text"))
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switch logFormat {
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case "text":
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l.Formatter = &logrus.TextFormatter{}
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case "json":
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l.Formatter = &logrus.JSONFormatter{}
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default:
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return fmt.Errorf("unknown log format `%s`. possible formats: %s", logFormat, []string{"text", "json"})
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}
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return nil
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}
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