Merge branch 'release/0.9.0'

1 files changed, 112 insertions, 0 deletions

diff --git a/logger/sys.go b/logger/sys.go
new file mode 100644
index 000000000..bd826b587
--- /dev/null
+++ b/logger/sys.go
@@ -0,0 +1,112 @@
+package logger
+
+import (
+	"sync"
+)
+
+type message struct {
+	level LogLevel
+	msg   string
+}
+
+var (
+	logMessageC = make(chan message)
+	addSystemC  = make(chan LogSystem)
+	flushC      = make(chan chan struct{})
+	resetC      = make(chan chan struct{})
+)
+
+func init() {
+	go dispatchLoop()
+}
+
+// each system can buffer this many messages before
+// blocking incoming log messages.
+const sysBufferSize = 500
+
+func dispatchLoop() {
+	var (
+		systems  []LogSystem
+		systemIn []chan message
+		systemWG sync.WaitGroup
+	)
+	bootSystem := func(sys LogSystem) {
+		in := make(chan message, sysBufferSize)
+		systemIn = append(systemIn, in)
+		systemWG.Add(1)
+		go sysLoop(sys, in, &systemWG)
+	}
+
+	for {
+		select {
+		case msg := <-logMessageC:
+			for _, c := range systemIn {
+				c <- msg
+			}
+
+		case sys := <-addSystemC:
+			systems = append(systems, sys)
+			bootSystem(sys)
+
+		case waiter := <-resetC:
+			// reset means terminate all systems
+			for _, c := range systemIn {
+				close(c)
+			}
+			systems = nil
+			systemIn = nil
+			systemWG.Wait()
+			close(waiter)
+
+		case waiter := <-flushC:
+			// flush means reboot all systems
+			for _, c := range systemIn {
+				close(c)
+			}
+			systemIn = nil
+			systemWG.Wait()
+			for _, sys := range systems {
+				bootSystem(sys)
+			}
+			close(waiter)
+		}
+	}
+}
+
+func sysLoop(sys LogSystem, in <-chan message, wg *sync.WaitGroup) {
+	for msg := range in {
+		switch sys.(type) {
+		case *rawLogSystem:
+			// This is a semantic hack since rawLogSystem has little to do with JsonLevel
+			if msg.level == JsonLevel {
+				sys.LogPrint(msg.level, msg.msg)
+			}
+		default:
+			if sys.GetLogLevel() >= msg.level {
+				sys.LogPrint(msg.level, msg.msg)
+			}
+		}
+	}
+	wg.Done()
+}
+
+// Reset removes all active log systems.
+// It blocks until all current messages have been delivered.
+func Reset() {
+	waiter := make(chan struct{})
+	resetC <- waiter
+	<-waiter
+}
+
+// Flush waits until all current log messages have been dispatched to
+// the active log systems.
+func Flush() {
+	waiter := make(chan struct{})
+	flushC <- waiter
+	<-waiter
+}
+
+// AddLogSystem starts printing messages to the given LogSystem.
+func AddLogSystem(sys LogSystem) {
+	addSystemC <- sys
+}