Update vendor (#1265)

vendor/github.com/wiggin77/cfg/source.go

@@ -0,0 +1,58 @@
+package cfg
+
+import (
+	"sync"
+	"time"
+)
+
+// Source is the interface required for any source of name/value pairs.
+type Source interface {
+
+	// GetProps fetches all the properties from a source and returns
+	// them as a map.
+	GetProps() (map[string]string, error)
+}
+
+// SourceMonitored is the interface required for any config source that is
+// monitored for changes.
+type SourceMonitored interface {
+	Source
+
+	// GetLastModified returns the time of the latest modification to any
+	// property value within the source. If a source does not support
+	// modifying properties at runtime then the zero value for `Time`
+	// should be returned to ensure reload events are not generated.
+	GetLastModified() (time.Time, error)
+
+	// GetMonitorFreq returns the frequency as a `time.Duration` between
+	// checks for changes to this config source.
+	//
+	// Returning zero (or less) will temporarily suspend calls to `GetLastModified`
+	// and `GetMonitorFreq` will be called every 10 seconds until resumed, after which
+	// `GetMontitorFreq` will be called at a frequency roughly equal to the `time.Duration`
+	// returned.
+	GetMonitorFreq() time.Duration
+}
+
+// AbstractSourceMonitor can be embedded in a custom `Source` to provide the
+// basic plumbing for monitor frequency.
+type AbstractSourceMonitor struct {
+	mutex sync.RWMutex
+	freq  time.Duration
+}
+
+// GetMonitorFreq returns the frequency as a `time.Duration` between
+// checks for changes to this config source.
+func (asm *AbstractSourceMonitor) GetMonitorFreq() (freq time.Duration) {
+	asm.mutex.RLock()
+	freq = asm.freq
+	asm.mutex.RUnlock()
+	return
+}
+
+// SetMonitorFreq sets the frequency between checks for changes to this config source.
+func (asm *AbstractSourceMonitor) SetMonitorFreq(freq time.Duration) {
+	asm.mutex.Lock()
+	asm.freq = freq
+	asm.mutex.Unlock()
+}