chore: import upstream snapshot with attribution

debug/log/memory/memory.go

@@ -0,0 +1,119 @@
+// Package memory provides an in memory log buffer
+package memory
+
+import (
+	"fmt"
+
+	"go-micro.dev/v6/debug/log"
+	"go-micro.dev/v6/internal/util/ring"
+)
+
+var (
+	// DefaultSize of the logger buffer.
+	DefaultSize = 1024
+)
+
+// memoryLog is default micro log.
+type memoryLog struct {
+	*ring.Buffer
+}
+
+// NewLog returns default Logger with.
+func NewLog(opts ...log.Option) log.Log {
+	// get default options
+	options := log.DefaultOptions()
+
+	// apply requested options
+	for _, o := range opts {
+		o(&options)
+	}
+
+	return &memoryLog{
+		Buffer: ring.New(options.Size),
+	}
+}
+
+// Write writes logs into logger.
+func (l *memoryLog) Write(r log.Record) error {
+	l.Put(fmt.Sprint(r.Message))
+	return nil
+}
+
+// Read reads logs and returns them.
+func (l *memoryLog) Read(opts ...log.ReadOption) ([]log.Record, error) {
+	options := log.ReadOptions{}
+	// initialize the read options
+	for _, o := range opts {
+		o(&options)
+	}
+
+	var entries []*ring.Entry
+	// if Since options ha sbeen specified we honor it
+	if !options.Since.IsZero() {
+		entries = l.Since(options.Since)
+	}
+
+	// only if we specified valid count constraint
+	// do we end up doing some serious if-else kung-fu
+	// if since constraint has been provided
+	// we return *count* number of logs since the given timestamp;
+	// otherwise we return last count number of logs
+	if options.Count > 0 {
+		switch len(entries) > 0 {
+		case true:
+			// if we request fewer logs than what since constraint gives us
+			if options.Count < len(entries) {
+				entries = entries[0:options.Count]
+			}
+		default:
+			entries = l.Get(options.Count)
+		}
+	}
+
+	records := make([]log.Record, 0, len(entries))
+	for _, entry := range entries {
+		record := log.Record{
+			Timestamp: entry.Timestamp,
+			Message:   entry.Value,
+		}
+		records = append(records, record)
+	}
+
+	return records, nil
+}
+
+// Stream returns channel for reading log records
+// along with a stop channel, close it when done.
+func (l *memoryLog) Stream() (log.Stream, error) {
+	// get stream channel from ring buffer
+	stream, stop := l.Buffer.Stream()
+	// make a buffered channel
+	records := make(chan log.Record, 128)
+	// get last 10 records
+	last10 := l.Get(10)
+
+	// stream the log records
+	go func() {
+		// first send last 10 records
+		for _, entry := range last10 {
+			records <- log.Record{
+				Timestamp: entry.Timestamp,
+				Message:   entry.Value,
+				Metadata:  make(map[string]string),
+			}
+		}
+		// now stream continuously
+		for entry := range stream {
+			records <- log.Record{
+				Timestamp: entry.Timestamp,
+				Message:   entry.Value,
+				Metadata:  make(map[string]string),
+			}
+		}
+	}()
+
+	return &logStream{
+		stream: records,
+		stop:   stop,
+	}, nil
+}