mirror of
https://github.com/42wim/matterbridge.git
synced 2024-12-24 01:22:00 -08:00
367 lines
9.0 KiB
Go
367 lines
9.0 KiB
Go
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package cfg
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import (
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"errors"
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"fmt"
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"strconv"
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"strings"
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"sync"
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"time"
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"github.com/wiggin77/cfg/timeconv"
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)
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// ErrNotFound returned when an operation is attempted on a
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// resource that doesn't exist, such as fetching a non-existing
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// property name.
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var ErrNotFound = errors.New("not found")
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type sourceEntry struct {
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src Source
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props map[string]string
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}
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// Config provides methods for retrieving property values from one or more
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// configuration sources.
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type Config struct {
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mutexSrc sync.RWMutex
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mutexListeners sync.RWMutex
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srcs []*sourceEntry
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chgListeners []ChangedListener
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shutdown chan interface{}
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wantPanicOnError bool
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}
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// PrependSource inserts one or more `Sources` at the beginning of
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// the list of sources such that the first source will be the
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// source checked first when resolving a property value.
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func (config *Config) PrependSource(srcs ...Source) {
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arr := config.wrapSources(srcs...)
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config.mutexSrc.Lock()
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if config.shutdown == nil {
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config.shutdown = make(chan interface{})
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}
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config.srcs = append(arr, config.srcs...)
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config.mutexSrc.Unlock()
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for _, se := range arr {
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if _, ok := se.src.(SourceMonitored); ok {
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config.monitor(se)
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}
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}
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}
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// AppendSource appends one or more `Sources` at the end of
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// the list of sources such that the last source will be the
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// source checked last when resolving a property value.
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func (config *Config) AppendSource(srcs ...Source) {
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arr := config.wrapSources(srcs...)
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config.mutexSrc.Lock()
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if config.shutdown == nil {
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config.shutdown = make(chan interface{})
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}
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config.srcs = append(config.srcs, arr...)
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config.mutexSrc.Unlock()
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for _, se := range arr {
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if _, ok := se.src.(SourceMonitored); ok {
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config.monitor(se)
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}
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}
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}
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// wrapSources wraps one or more Source's and returns
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// them as an array of `sourceEntry`.
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func (config *Config) wrapSources(srcs ...Source) []*sourceEntry {
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arr := make([]*sourceEntry, 0, len(srcs))
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for _, src := range srcs {
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se := &sourceEntry{src: src}
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config.reloadProps(se)
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arr = append(arr, se)
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}
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return arr
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}
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// SetWantPanicOnError sets the flag determining if Config
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// should panic when `GetProps` or `GetLastModified` errors
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// for a `Source`.
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func (config *Config) SetWantPanicOnError(b bool) {
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config.mutexSrc.Lock()
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config.wantPanicOnError = b
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config.mutexSrc.Unlock()
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}
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// ShouldPanicOnError gets the flag determining if Config
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// should panic when `GetProps` or `GetLastModified` errors
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// for a `Source`.
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func (config *Config) ShouldPanicOnError() (b bool) {
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config.mutexSrc.RLock()
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b = config.wantPanicOnError
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config.mutexSrc.RUnlock()
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return b
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}
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// getProp returns the value of a named property.
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// Each `Source` is checked, in the order created by adding via
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// `AppendSource` and `PrependSource`, until a value for the
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// property is found.
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func (config *Config) getProp(name string) (val string, ok bool) {
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config.mutexSrc.RLock()
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defer config.mutexSrc.RUnlock()
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var s string
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for _, se := range config.srcs {
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if se.props != nil {
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if s, ok = se.props[name]; ok {
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val = strings.TrimSpace(s)
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return
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}
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}
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}
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return
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}
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// String returns the value of the named prop as a string.
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// If the property is not found then the supplied default `def`
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// and `ErrNotFound` are returned.
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func (config *Config) String(name string, def string) (val string, err error) {
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if v, ok := config.getProp(name); ok {
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val = v
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err = nil
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return
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}
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err = ErrNotFound
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val = def
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return
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}
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// Int returns the value of the named prop as an `int`.
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// If the property is not found then the supplied default `def`
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// and `ErrNotFound` are returned.
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//
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// See config.String
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func (config *Config) Int(name string, def int) (val int, err error) {
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var s string
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if s, err = config.String(name, ""); err == nil {
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var i int64
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if i, err = strconv.ParseInt(s, 10, 32); err == nil {
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val = int(i)
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}
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}
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if err != nil {
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val = def
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}
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return
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}
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// Int64 returns the value of the named prop as an `int64`.
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// If the property is not found then the supplied default `def`
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// and `ErrNotFound` are returned.
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//
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// See config.String
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func (config *Config) Int64(name string, def int64) (val int64, err error) {
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var s string
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if s, err = config.String(name, ""); err == nil {
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val, err = strconv.ParseInt(s, 10, 64)
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}
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if err != nil {
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val = def
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}
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return
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}
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// Float64 returns the value of the named prop as a `float64`.
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// If the property is not found then the supplied default `def`
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// and `ErrNotFound` are returned.
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//
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// See config.String
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func (config *Config) Float64(name string, def float64) (val float64, err error) {
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var s string
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if s, err = config.String(name, ""); err == nil {
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val, err = strconv.ParseFloat(s, 64)
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}
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if err != nil {
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val = def
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}
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return
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}
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// Bool returns the value of the named prop as a `bool`.
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// If the property is not found then the supplied default `def`
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// and `ErrNotFound` are returned.
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//
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// Supports (t, true, 1, y, yes) for true, and (f, false, 0, n, no) for false,
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// all case-insensitive.
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//
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// See config.String
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func (config *Config) Bool(name string, def bool) (val bool, err error) {
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var s string
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if s, err = config.String(name, ""); err == nil {
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switch strings.ToLower(s) {
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case "t", "true", "1", "y", "yes":
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val = true
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case "f", "false", "0", "n", "no":
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val = false
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default:
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err = errors.New("invalid syntax")
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}
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}
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if err != nil {
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val = def
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}
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return
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}
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// Duration returns the value of the named prop as a `time.Duration`, representing
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// a span of time.
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//
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// Units of measure are supported: ms, sec, min, hour, day, week, year.
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// See config.UnitsToMillis for a complete list of units supported.
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//
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// If the property is not found then the supplied default `def`
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// and `ErrNotFound` are returned.
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//
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// See config.String
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func (config *Config) Duration(name string, def time.Duration) (val time.Duration, err error) {
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var s string
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if s, err = config.String(name, ""); err == nil {
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var ms int64
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ms, err = timeconv.ParseMilliseconds(s)
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val = time.Duration(ms) * time.Millisecond
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}
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if err != nil {
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val = def
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}
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return
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}
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// AddChangedListener adds a listener that will receive notifications
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// whenever one or more property values change within the config.
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func (config *Config) AddChangedListener(l ChangedListener) {
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config.mutexListeners.Lock()
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defer config.mutexListeners.Unlock()
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config.chgListeners = append(config.chgListeners, l)
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}
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// RemoveChangedListener removes all instances of a ChangedListener.
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// Returns `ErrNotFound` if the listener was not present.
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func (config *Config) RemoveChangedListener(l ChangedListener) error {
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config.mutexListeners.Lock()
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defer config.mutexListeners.Unlock()
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dest := make([]ChangedListener, 0, len(config.chgListeners))
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err := ErrNotFound
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// Remove all instances of the listener by
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// copying list while filtering.
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for _, s := range config.chgListeners {
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if s != l {
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dest = append(dest, s)
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} else {
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err = nil
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}
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}
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config.chgListeners = dest
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return err
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}
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// Shutdown can be called to stop monitoring of all config sources.
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func (config *Config) Shutdown() {
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config.mutexSrc.RLock()
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defer config.mutexSrc.RUnlock()
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if config.shutdown != nil {
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close(config.shutdown)
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}
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}
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// onSourceChanged is called whenever one or more properties of a
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// config source has changed.
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func (config *Config) onSourceChanged(src SourceMonitored) {
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defer func() {
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if p := recover(); p != nil {
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fmt.Println(p)
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}
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}()
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config.mutexListeners.RLock()
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defer config.mutexListeners.RUnlock()
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for _, l := range config.chgListeners {
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l.ConfigChanged(config, src)
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}
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}
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// monitor periodically checks a config source for changes.
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func (config *Config) monitor(se *sourceEntry) {
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go func(se *sourceEntry, shutdown <-chan interface{}) {
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var src SourceMonitored
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var ok bool
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if src, ok = se.src.(SourceMonitored); !ok {
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return
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}
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paused := false
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last := time.Time{}
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freq := src.GetMonitorFreq()
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if freq <= 0 {
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paused = true
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freq = 10
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last, _ = src.GetLastModified()
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}
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timer := time.NewTimer(freq)
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for {
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select {
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case <-timer.C:
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if !paused {
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if latest, err := src.GetLastModified(); err != nil {
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if config.ShouldPanicOnError() {
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panic(fmt.Sprintf("error <%v> getting last modified for %v", err, src))
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}
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} else {
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if last.Before(latest) {
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last = latest
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config.reloadProps(se)
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// TODO: calc diff and provide detailed changes
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config.onSourceChanged(src)
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}
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}
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}
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freq = src.GetMonitorFreq()
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if freq <= 0 {
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paused = true
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freq = 10
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} else {
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paused = false
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}
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timer.Reset(freq)
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case <-shutdown:
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// stop the timer and exit
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if !timer.Stop() {
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<-timer.C
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}
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return
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}
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}
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}(se, config.shutdown)
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}
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// reloadProps causes a Source to reload its properties.
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func (config *Config) reloadProps(se *sourceEntry) {
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config.mutexSrc.Lock()
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defer config.mutexSrc.Unlock()
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m, err := se.src.GetProps()
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if err != nil {
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if config.wantPanicOnError {
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panic(fmt.Sprintf("GetProps error for %v", se.src))
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}
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return
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}
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se.props = make(map[string]string)
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for k, v := range m {
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se.props[k] = v
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}
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}
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