1 files changed, 299 insertions, 0 deletions
diff --git a/vendor/github.com/mattermost/logr/target.go b/vendor/github.com/mattermost/logr/target.go
new file mode 100644
index 00000000..f8e7bf75
--- /dev/null
+++ b/vendor/github.com/mattermost/logr/target.go
@@ -0,0 +1,299 @@
+package logr
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"sync"
+	"time"
+)
+
+// Target represents a destination for log records such as file,
+// database, TCP socket, etc.
+type Target interface {
+	// SetName provides an optional name for the target.
+	SetName(name string)
+
+	// IsLevelEnabled returns true if this target should emit
+	// logs for the specified level. Also determines if
+	// a stack trace is required.
+	IsLevelEnabled(Level) (enabled bool, stacktrace bool)
+
+	// Formatter returns the Formatter associated with this Target.
+	Formatter() Formatter
+
+	// Log outputs the log record to this target's destination.
+	Log(rec *LogRec)
+
+	// Shutdown makes best effort to flush target queue and
+	// frees/closes all resources.
+	Shutdown(ctx context.Context) error
+}
+
+// RecordWriter can convert a LogRecord to bytes and output to some data sink.
+type RecordWriter interface {
+	Write(rec *LogRec) error
+}
+
+// Basic provides the basic functionality of a Target that can be used
+// to more easily compose your own Targets. To use, just embed Basic
+// in your target type, implement `RecordWriter`, and call `(*Basic).Start`.
+type Basic struct {
+	target Target
+
+	filter    Filter
+	formatter Formatter
+
+	in   chan *LogRec
+	done chan struct{}
+	w    RecordWriter
+
+	mux  sync.RWMutex
+	name string
+
+	metrics        bool
+	queueSizeGauge Gauge
+	loggedCounter  Counter
+	errorCounter   Counter
+	droppedCounter Counter
+	blockedCounter Counter
+
+	metricsUpdateFreqMillis int64
+}
+
+// Start initializes this target helper and starts accepting log records for processing.
+func (b *Basic) Start(target Target, rw RecordWriter, filter Filter, formatter Formatter, maxQueued int) {
+	if filter == nil {
+		filter = &StdFilter{Lvl: Fatal}
+	}
+	if formatter == nil {
+		formatter = &DefaultFormatter{}
+	}
+
+	b.target = target
+	b.filter = filter
+	b.formatter = formatter
+	b.in = make(chan *LogRec, maxQueued)
+	b.done = make(chan struct{}, 1)
+	b.w = rw
+	go b.start()
+
+	if b.hasMetrics() {
+		go b.startMetricsUpdater()
+	}
+}
+
+func (b *Basic) SetName(name string) {
+	b.mux.Lock()
+	defer b.mux.Unlock()
+	b.name = name
+}
+
+// IsLevelEnabled returns true if this target should emit
+// logs for the specified level. Also determines if
+// a stack trace is required.
+func (b *Basic) IsLevelEnabled(lvl Level) (enabled bool, stacktrace bool) {
+	return b.filter.IsEnabled(lvl), b.filter.IsStacktraceEnabled(lvl)
+}
+
+// Formatter returns the Formatter associated with this Target.
+func (b *Basic) Formatter() Formatter {
+	return b.formatter
+}
+
+// Shutdown stops processing log records after making best
+// effort to flush queue.
+func (b *Basic) Shutdown(ctx context.Context) error {
+	// close the incoming channel and wait for read loop to exit.
+	close(b.in)
+	select {
+	case <-ctx.Done():
+	case <-b.done:
+	}
+
+	// b.in channel should now be drained.
+	return nil
+}
+
+// Log outputs the log record to this targets destination.
+func (b *Basic) Log(rec *LogRec) {
+	lgr := rec.Logger().Logr()
+	select {
+	case b.in <- rec:
+	default:
+		handler := lgr.OnTargetQueueFull
+		if handler != nil && handler(b.target, rec, cap(b.in)) {
+			b.incDroppedCounter()
+			return // drop the record
+		}
+		b.incBlockedCounter()
+
+		select {
+		case <-time.After(lgr.enqueueTimeout()):
+			lgr.ReportError(fmt.Errorf("target enqueue timeout for log rec [%v]", rec))
+		case b.in <- rec: // block until success or timeout
+		}
+	}
+}
+
+// Metrics enables metrics collection using the provided MetricsCollector.
+func (b *Basic) EnableMetrics(collector MetricsCollector, updateFreqMillis int64) error {
+	name := fmt.Sprintf("%v", b)
+
+	b.mux.Lock()
+	defer b.mux.Unlock()
+
+	b.metrics = true
+	b.metricsUpdateFreqMillis = updateFreqMillis
+
+	var err error
+
+	if b.queueSizeGauge, err = collector.QueueSizeGauge(name); err != nil {
+		return err
+	}
+	if b.loggedCounter, err = collector.LoggedCounter(name); err != nil {
+		return err
+	}
+	if b.errorCounter, err = collector.ErrorCounter(name); err != nil {
+		return err
+	}
+	if b.droppedCounter, err = collector.DroppedCounter(name); err != nil {
+		return err
+	}
+	if b.blockedCounter, err = collector.BlockedCounter(name); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (b *Basic) hasMetrics() bool {
+	b.mux.RLock()
+	defer b.mux.RUnlock()
+	return b.metrics
+}
+
+func (b *Basic) setQueueSizeGauge(val float64) {
+	b.mux.RLock()
+	defer b.mux.RUnlock()
+	if b.queueSizeGauge != nil {
+		b.queueSizeGauge.Set(val)
+	}
+}
+
+func (b *Basic) incLoggedCounter() {
+	b.mux.RLock()
+	defer b.mux.RUnlock()
+	if b.loggedCounter != nil {
+		b.loggedCounter.Inc()
+	}
+}
+
+func (b *Basic) incErrorCounter() {
+	b.mux.RLock()
+	defer b.mux.RUnlock()
+	if b.errorCounter != nil {
+		b.errorCounter.Inc()
+	}
+}
+
+func (b *Basic) incDroppedCounter() {
+	b.mux.RLock()
+	defer b.mux.RUnlock()
+	if b.droppedCounter != nil {
+		b.droppedCounter.Inc()
+	}
+}
+
+func (b *Basic) incBlockedCounter() {
+	b.mux.RLock()
+	defer b.mux.RUnlock()
+	if b.blockedCounter != nil {
+		b.blockedCounter.Inc()
+	}
+}
+
+// String returns a name for this target. Use `SetName` to specify a name.
+func (b *Basic) String() string {
+	b.mux.RLock()
+	defer b.mux.RUnlock()
+
+	if b.name != "" {
+		return b.name
+	}
+	return fmt.Sprintf("%T", b.target)
+}
+
+// Start accepts log records via In channel and writes to the
+// supplied writer, until Done channel signaled.
+func (b *Basic) start() {
+	defer func() {
+		if r := recover(); r != nil {
+			fmt.Fprintln(os.Stderr, "Basic.start -- ", r)
+			go b.start()
+		}
+	}()
+
+	for rec := range b.in {
+		if rec.flush != nil {
+			b.flush(rec.flush)
+		} else {
+			err := b.w.Write(rec)
+			if err != nil {
+				b.incErrorCounter()
+				rec.Logger().Logr().ReportError(err)
+			} else {
+				b.incLoggedCounter()
+			}
+		}
+	}
+	close(b.done)
+}
+
+// startMetricsUpdater updates the metrics for any polled values every `MetricsUpdateFreqSecs` seconds until
+// target is closed.
+func (b *Basic) startMetricsUpdater() {
+	for {
+		updateFreq := b.getMetricsUpdateFreqMillis()
+		if updateFreq == 0 {
+			updateFreq = DefMetricsUpdateFreqMillis
+		}
+		if updateFreq < 250 {
+			updateFreq = 250 // don't peg the CPU
+		}
+
+		select {
+		case <-b.done:
+			return
+		case <-time.After(time.Duration(updateFreq) * time.Millisecond):
+			b.setQueueSizeGauge(float64(len(b.in)))
+		}
+	}
+}
+
+func (b *Basic) getMetricsUpdateFreqMillis() int64 {
+	b.mux.RLock()
+	defer b.mux.RUnlock()
+	return b.metricsUpdateFreqMillis
+}
+
+// flush drains the queue and notifies when done.
+func (b *Basic) flush(done chan<- struct{}) {
+	for {
+		var rec *LogRec
+		var err error
+		select {
+		case rec = <-b.in:
+			// ignore any redundant flush records.
+			if rec.flush == nil {
+				err = b.w.Write(rec)
+				if err != nil {
+					b.incErrorCounter()
+					rec.Logger().Logr().ReportError(err)
+				}
+			}
+		default:
+			done <- struct{}{}
+			return
+		}
+	}
+}