Adding upstream version 2.5.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

index/upsidedown/store/metrics/batch.go

@@ -0,0 +1,46 @@
+//  Copyright (c) 2015 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metrics
+
+import store "github.com/blevesearch/upsidedown_store_api"
+
+type Batch struct {
+	s *Store
+	o store.KVBatch
+}
+
+func (b *Batch) Set(key, val []byte) {
+	b.o.Set(key, val)
+}
+
+func (b *Batch) Delete(key []byte) {
+	b.o.Delete(key)
+}
+
+func (b *Batch) Merge(key, val []byte) {
+	b.s.timerBatchMerge.Time(func() {
+		b.o.Merge(key, val)
+	})
+}
+
+func (b *Batch) Reset() {
+	b.o.Reset()
+}
+
+func (b *Batch) Close() error {
+	err := b.o.Close()
+	b.o = nil
+	return err
+}

index/upsidedown/store/metrics/iterator.go

@@ -0,0 +1,58 @@
+//  Copyright (c) 2015 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metrics
+
+import store "github.com/blevesearch/upsidedown_store_api"
+
+type Iterator struct {
+	s *Store
+	o store.KVIterator
+}
+
+func (i *Iterator) Seek(x []byte) {
+	i.s.timerIteratorSeek.Time(func() {
+		i.o.Seek(x)
+	})
+}
+
+func (i *Iterator) Next() {
+	i.s.timerIteratorNext.Time(func() {
+		i.o.Next()
+	})
+}
+
+func (i *Iterator) Current() ([]byte, []byte, bool) {
+	return i.o.Current()
+}
+
+func (i *Iterator) Key() []byte {
+	return i.o.Key()
+}
+
+func (i *Iterator) Value() []byte {
+	return i.o.Value()
+}
+
+func (i *Iterator) Valid() bool {
+	return i.o.Valid()
+}
+
+func (i *Iterator) Close() error {
+	err := i.o.Close()
+	if err != nil {
+		i.s.AddError("Iterator.Close", err, nil)
+	}
+	return err
+}

index/upsidedown/store/metrics/metrics_test.go

@@ -0,0 +1,141 @@
+//  Copyright (c) 2015 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metrics
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"testing"
+
+	"github.com/blevesearch/bleve/v2/index/upsidedown/store/gtreap"
+)
+
+func TestMetricsStore(t *testing.T) {
+	_, err := New(nil, map[string]interface{}{})
+	if err == nil {
+		t.Errorf("expected err when bad config")
+	}
+
+	_, err = New(nil, map[string]interface{}{
+		"kvStoreName_actual": "some-invalid-kvstore-name",
+	})
+	if err == nil {
+		t.Errorf("expected err when unknown kvStoreName_actual")
+	}
+
+	s, err := New(nil, map[string]interface{}{
+		"kvStoreName_actual": gtreap.Name,
+		"path":               "",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	b := bytes.NewBuffer(nil)
+	err = s.(*Store).WriteJSON(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if b.Len() <= 0 {
+		t.Errorf("expected some output from WriteJSON")
+	}
+	var m map[string]interface{}
+	err = json.Unmarshal(b.Bytes(), &m)
+	if err != nil {
+		t.Errorf("expected WriteJSON to be unmarshallable")
+	}
+	if len(m) == 0 {
+		t.Errorf("expected some entries")
+	}
+
+	b = bytes.NewBuffer(nil)
+	s.(*Store).WriteCSVHeader(b)
+	if b.Len() <= 0 {
+		t.Errorf("expected some output from WriteCSVHeader")
+	}
+
+	b = bytes.NewBuffer(nil)
+	s.(*Store).WriteCSV(b)
+	if b.Len() <= 0 {
+		t.Errorf("expected some output from WriteCSV")
+	}
+}
+
+func TestErrors(t *testing.T) {
+	s, err := New(nil, map[string]interface{}{
+		"kvStoreName_actual": gtreap.Name,
+		"path":               "",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	x, ok := s.(*Store)
+	if !ok {
+		t.Errorf("expecting a Store")
+	}
+
+	x.AddError("foo", fmt.Errorf("Foo"), []byte("fooKey"))
+	x.AddError("bar", fmt.Errorf("Bar"), nil)
+	x.AddError("baz", fmt.Errorf("Baz"), []byte("bazKey"))
+
+	b := bytes.NewBuffer(nil)
+	err = x.WriteJSON(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var m map[string]interface{}
+	err = json.Unmarshal(b.Bytes(), &m)
+	if err != nil {
+		t.Errorf("expected unmarshallable writeJSON, err: %v, b: %s",
+			err, b.Bytes())
+	}
+
+	errorsi, ok := m["Errors"]
+	if !ok || errorsi == nil {
+		t.Errorf("expected errorsi")
+	}
+	errors, ok := errorsi.([]interface{})
+	if !ok || errors == nil {
+		t.Errorf("expected errorsi is array")
+	}
+	if len(errors) != 3 {
+		t.Errorf("expected errors len 3")
+	}
+
+	e := errors[0].(map[string]interface{})
+	if e["Op"].(string) != "foo" ||
+		e["Err"].(string) != "Foo" ||
+		len(e["Time"].(string)) < 10 ||
+		e["Key"].(string) != "fooKey" {
+		t.Errorf("expected foo, %#v", e)
+	}
+	e = errors[1].(map[string]interface{})
+	if e["Op"].(string) != "bar" ||
+		e["Err"].(string) != "Bar" ||
+		len(e["Time"].(string)) < 10 ||
+		e["Key"].(string) != "" {
+		t.Errorf("expected bar, %#v", e)
+	}
+	e = errors[2].(map[string]interface{})
+	if e["Op"].(string) != "baz" ||
+		e["Err"].(string) != "Baz" ||
+		len(e["Time"].(string)) < 10 ||
+		e["Key"].(string) != "bazKey" {
+		t.Errorf("expected baz, %#v", e)
+	}
+}

index/upsidedown/store/metrics/reader.go

@@ -0,0 +1,64 @@
+//  Copyright (c) 2015 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metrics
+
+import store "github.com/blevesearch/upsidedown_store_api"
+
+type Reader struct {
+	s *Store
+	o store.KVReader
+}
+
+func (r *Reader) Get(key []byte) (v []byte, err error) {
+	r.s.timerReaderGet.Time(func() {
+		v, err = r.o.Get(key)
+		if err != nil {
+			r.s.AddError("Reader.Get", err, key)
+		}
+	})
+	return
+}
+
+func (r *Reader) MultiGet(keys [][]byte) (vals [][]byte, err error) {
+	r.s.timerReaderMultiGet.Time(func() {
+		vals, err = r.o.MultiGet(keys)
+		if err != nil {
+			r.s.AddError("Reader.MultiGet", err, nil)
+		}
+	})
+	return
+}
+
+func (r *Reader) PrefixIterator(prefix []byte) (i store.KVIterator) {
+	r.s.timerReaderPrefixIterator.Time(func() {
+		i = &Iterator{s: r.s, o: r.o.PrefixIterator(prefix)}
+	})
+	return
+}
+
+func (r *Reader) RangeIterator(start, end []byte) (i store.KVIterator) {
+	r.s.timerReaderRangeIterator.Time(func() {
+		i = &Iterator{s: r.s, o: r.o.RangeIterator(start, end)}
+	})
+	return
+}
+
+func (r *Reader) Close() error {
+	err := r.o.Close()
+	if err != nil {
+		r.s.AddError("Reader.Close", err, nil)
+	}
+	return err
+}

index/upsidedown/store/metrics/stats.go

@@ -0,0 +1,50 @@
+//  Copyright (c) 2014 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metrics
+
+import (
+	"github.com/blevesearch/bleve/v2/util"
+	store "github.com/blevesearch/upsidedown_store_api"
+)
+
+type stats struct {
+	s *Store
+}
+
+func (s *stats) statsMap() map[string]interface{} {
+	ms := map[string]interface{}{}
+
+	ms["metrics"] = map[string]interface{}{
+		"reader_get":             TimerMap(s.s.timerReaderGet),
+		"reader_multi_get":       TimerMap(s.s.timerReaderMultiGet),
+		"reader_prefix_iterator": TimerMap(s.s.timerReaderPrefixIterator),
+		"reader_range_iterator":  TimerMap(s.s.timerReaderRangeIterator),
+		"writer_execute_batch":   TimerMap(s.s.timerWriterExecuteBatch),
+		"iterator_seek":          TimerMap(s.s.timerIteratorSeek),
+		"iterator_next":          TimerMap(s.s.timerIteratorNext),
+		"batch_merge":            TimerMap(s.s.timerBatchMerge),
+	}
+
+	if o, ok := s.s.o.(store.KVStoreStats); ok {
+		ms["kv"] = o.StatsMap()
+	}
+
+	return ms
+}
+
+func (s *stats) MarshalJSON() ([]byte, error) {
+	m := s.statsMap()
+	return util.MarshalJSON(m)
+}

index/upsidedown/store/metrics/store.go

@@ -0,0 +1,277 @@
+//  Copyright (c) 2015 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package metrics provides a bleve.store.KVStore implementation that
+// wraps another, real KVStore implementation, and uses go-metrics to
+// track runtime performance metrics.
+package metrics
+
+import (
+	"container/list"
+	"encoding/json"
+	"fmt"
+	"io"
+	"sync"
+	"time"
+
+	"github.com/blevesearch/bleve/v2/registry"
+	"github.com/blevesearch/bleve/v2/util"
+	"github.com/blevesearch/go-metrics"
+	store "github.com/blevesearch/upsidedown_store_api"
+)
+
+const Name = "metrics"
+
+type Store struct {
+	o store.KVStore
+
+	timerReaderGet            metrics.Timer
+	timerReaderMultiGet       metrics.Timer
+	timerReaderPrefixIterator metrics.Timer
+	timerReaderRangeIterator  metrics.Timer
+	timerWriterExecuteBatch   metrics.Timer
+	timerIteratorSeek         metrics.Timer
+	timerIteratorNext         metrics.Timer
+	timerBatchMerge           metrics.Timer
+
+	m      sync.Mutex // Protects the fields that follow.
+	errors *list.List // Capped list of StoreError's.
+
+	s *stats
+}
+
+func New(mo store.MergeOperator, config map[string]interface{}) (store.KVStore, error) {
+
+	name, ok := config["kvStoreName_actual"].(string)
+	if !ok || name == "" {
+		return nil, fmt.Errorf("metrics: missing kvStoreName_actual,"+
+			" config: %#v", config)
+	}
+
+	if name == Name {
+		return nil, fmt.Errorf("metrics: circular kvStoreName_actual")
+	}
+
+	ctr := registry.KVStoreConstructorByName(name)
+	if ctr == nil {
+		return nil, fmt.Errorf("metrics: no kv store constructor,"+
+			" kvStoreName_actual: %s", name)
+	}
+
+	kvs, err := ctr(mo, config)
+	if err != nil {
+		return nil, err
+	}
+
+	rv := &Store{
+		o: kvs,
+
+		timerReaderGet:            metrics.NewTimer(),
+		timerReaderMultiGet:       metrics.NewTimer(),
+		timerReaderPrefixIterator: metrics.NewTimer(),
+		timerReaderRangeIterator:  metrics.NewTimer(),
+		timerWriterExecuteBatch:   metrics.NewTimer(),
+		timerIteratorSeek:         metrics.NewTimer(),
+		timerIteratorNext:         metrics.NewTimer(),
+		timerBatchMerge:           metrics.NewTimer(),
+
+		errors: list.New(),
+	}
+
+	rv.s = &stats{s: rv}
+
+	return rv, nil
+}
+
+func init() {
+	err := registry.RegisterKVStore(Name, New)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func (s *Store) Close() error {
+	return s.o.Close()
+}
+
+func (s *Store) Reader() (store.KVReader, error) {
+	o, err := s.o.Reader()
+	if err != nil {
+		s.AddError("Reader", err, nil)
+		return nil, err
+	}
+	return &Reader{s: s, o: o}, nil
+}
+
+func (s *Store) Writer() (store.KVWriter, error) {
+	o, err := s.o.Writer()
+	if err != nil {
+		s.AddError("Writer", err, nil)
+		return nil, err
+	}
+	return &Writer{s: s, o: o}, nil
+}
+
+// Metric specific code below:
+
+const MaxErrors = 100
+
+type StoreError struct {
+	Time string
+	Op   string
+	Err  string
+	Key  string
+}
+
+func (s *Store) AddError(op string, err error, key []byte) {
+	e := &StoreError{
+		Time: time.Now().Format(time.RFC3339Nano),
+		Op:   op,
+		Err:  fmt.Sprintf("%v", err),
+		Key:  string(key),
+	}
+
+	s.m.Lock()
+	for s.errors.Len() >= MaxErrors {
+		s.errors.Remove(s.errors.Front())
+	}
+	s.errors.PushBack(e)
+	s.m.Unlock()
+}
+
+func (s *Store) WriteJSON(w io.Writer) (err error) {
+	_, err = w.Write([]byte(`{"TimerReaderGet":`))
+	if err != nil {
+		return
+	}
+	WriteTimerJSON(w, s.timerReaderGet)
+	_, err = w.Write([]byte(`,"TimerReaderMultiGet":`))
+	if err != nil {
+		return
+	}
+	WriteTimerJSON(w, s.timerReaderMultiGet)
+	_, err = w.Write([]byte(`,"TimerReaderPrefixIterator":`))
+	if err != nil {
+		return
+	}
+	WriteTimerJSON(w, s.timerReaderPrefixIterator)
+	_, err = w.Write([]byte(`,"TimerReaderRangeIterator":`))
+	if err != nil {
+		return
+	}
+	WriteTimerJSON(w, s.timerReaderRangeIterator)
+	_, err = w.Write([]byte(`,"TimerWriterExecuteBatch":`))
+	if err != nil {
+		return
+	}
+	WriteTimerJSON(w, s.timerWriterExecuteBatch)
+	_, err = w.Write([]byte(`,"TimerIteratorSeek":`))
+	if err != nil {
+		return
+	}
+	WriteTimerJSON(w, s.timerIteratorSeek)
+	_, err = w.Write([]byte(`,"TimerIteratorNext":`))
+	if err != nil {
+		return
+	}
+	WriteTimerJSON(w, s.timerIteratorNext)
+	_, err = w.Write([]byte(`,"TimerBatchMerge":`))
+	if err != nil {
+		return
+	}
+	WriteTimerJSON(w, s.timerBatchMerge)
+
+	_, err = w.Write([]byte(`,"Errors":[`))
+	if err != nil {
+		return
+	}
+	s.m.Lock()
+	defer s.m.Unlock()
+	e := s.errors.Front()
+	i := 0
+	for e != nil {
+		se, ok := e.Value.(*StoreError)
+		if ok && se != nil {
+			if i > 0 {
+				_, err = w.Write([]byte(","))
+				if err != nil {
+					return
+				}
+			}
+			var buf []byte
+			buf, err = util.MarshalJSON(se)
+			if err == nil {
+				_, err = w.Write(buf)
+				if err != nil {
+					return
+				}
+			}
+		}
+		e = e.Next()
+		i = i + 1
+	}
+	_, err = w.Write([]byte(`]`))
+	if err != nil {
+		return
+	}
+
+	// see if the underlying implementation has its own stats
+	if o, ok := s.o.(store.KVStoreStats); ok {
+		storeStats := o.Stats()
+		var storeBytes []byte
+		storeBytes, err = util.MarshalJSON(storeStats)
+		if err != nil {
+			return
+		}
+		_, err = fmt.Fprintf(w, `, "store": %s`, string(storeBytes))
+		if err != nil {
+			return
+		}
+	}
+
+	_, err = w.Write([]byte(`}`))
+	if err != nil {
+		return
+	}
+
+	return
+}
+
+func (s *Store) WriteCSVHeader(w io.Writer) {
+	WriteTimerCSVHeader(w, "TimerReaderGet")
+	WriteTimerCSVHeader(w, "TimerReaderPrefixIterator")
+	WriteTimerCSVHeader(w, "TimerReaderRangeIterator")
+	WriteTimerCSVHeader(w, "TimerWtierExecuteBatch")
+	WriteTimerCSVHeader(w, "TimerIteratorSeek")
+	WriteTimerCSVHeader(w, "TimerIteratorNext")
+	WriteTimerCSVHeader(w, "TimerBatchMerge")
+}
+
+func (s *Store) WriteCSV(w io.Writer) {
+	WriteTimerCSV(w, s.timerReaderGet)
+	WriteTimerCSV(w, s.timerReaderPrefixIterator)
+	WriteTimerCSV(w, s.timerReaderRangeIterator)
+	WriteTimerCSV(w, s.timerWriterExecuteBatch)
+	WriteTimerCSV(w, s.timerIteratorSeek)
+	WriteTimerCSV(w, s.timerIteratorNext)
+	WriteTimerCSV(w, s.timerBatchMerge)
+}
+
+func (s *Store) Stats() json.Marshaler {
+	return s.s
+}
+
+func (s *Store) StatsMap() map[string]interface{} {
+	return s.s.statsMap()
+}

index/upsidedown/store/metrics/store_test.go

@@ -0,0 +1,95 @@
+//  Copyright (c) 2015 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metrics
+
+import (
+	"testing"
+
+	"github.com/blevesearch/bleve/v2/index/upsidedown/store/gtreap"
+	store "github.com/blevesearch/upsidedown_store_api"
+	"github.com/blevesearch/upsidedown_store_api/test"
+)
+
+func open(t *testing.T, mo store.MergeOperator) store.KVStore {
+	rv, err := New(mo, map[string]interface{}{
+		"kvStoreName_actual": gtreap.Name,
+		"path":               "",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	return rv
+}
+
+func cleanup(t *testing.T, s store.KVStore) {
+	err := s.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestMetricsKVCrud(t *testing.T) {
+	s := open(t, nil)
+	defer cleanup(t, s)
+	test.CommonTestKVCrud(t, s)
+}
+
+func TestMetricsReaderIsolation(t *testing.T) {
+	s := open(t, nil)
+	defer cleanup(t, s)
+	test.CommonTestReaderIsolation(t, s)
+}
+
+func TestMetricsReaderOwnsGetBytes(t *testing.T) {
+	s := open(t, nil)
+	defer cleanup(t, s)
+	test.CommonTestReaderOwnsGetBytes(t, s)
+}
+
+func TestMetricsWriterOwnsBytes(t *testing.T) {
+	s := open(t, nil)
+	defer cleanup(t, s)
+	test.CommonTestWriterOwnsBytes(t, s)
+}
+
+func TestMetricsPrefixIterator(t *testing.T) {
+	s := open(t, nil)
+	defer cleanup(t, s)
+	test.CommonTestPrefixIterator(t, s)
+}
+
+func TestMetricsPrefixIteratorSeek(t *testing.T) {
+	s := open(t, nil)
+	defer cleanup(t, s)
+	test.CommonTestPrefixIteratorSeek(t, s)
+}
+
+func TestMetricsRangeIterator(t *testing.T) {
+	s := open(t, nil)
+	defer cleanup(t, s)
+	test.CommonTestRangeIterator(t, s)
+}
+
+func TestMetricsRangeIteratorSeek(t *testing.T) {
+	s := open(t, nil)
+	defer cleanup(t, s)
+	test.CommonTestRangeIteratorSeek(t, s)
+}
+
+func TestMetricsMerge(t *testing.T) {
+	s := open(t, &test.TestMergeCounter{})
+	defer cleanup(t, s)
+	test.CommonTestMerge(t, s)
+}

index/upsidedown/store/metrics/util.go

@@ -0,0 +1,135 @@
+//  Copyright (c) 2015 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metrics
+
+import (
+	"fmt"
+	"io"
+	"math"
+
+	"github.com/blevesearch/go-metrics"
+)
+
+// NOTE: This is copy & pasted from cbft as otherwise there
+// would be an import cycle.
+
+var timerPercentiles = []float64{0.5, 0.75, 0.95, 0.99, 0.999}
+
+func TimerMap(timer metrics.Timer) map[string]interface{} {
+
+	rv := make(map[string]interface{})
+	t := timer.Snapshot()
+	p := t.Percentiles(timerPercentiles)
+
+	percentileKeys := []string{"median", "75%", "95%", "99%", "99.9%"}
+	percentiles := make(map[string]interface{})
+	for i, pi := range p {
+		if !isNanOrInf(pi) {
+			percentileKey := percentileKeys[i]
+			percentiles[percentileKey] = pi
+		}
+	}
+
+	rateKeys := []string{"1-min", "5-min", "15-min", "mean"}
+	rates := make(map[string]interface{})
+	for i, ri := range []float64{t.Rate1(), t.Rate5(), t.Rate15(), t.RateMean()} {
+		if !isNanOrInf(ri) {
+			rateKey := rateKeys[i]
+			rates[rateKey] = ri
+		}
+	}
+
+	rv["count"] = t.Count()
+	rv["min"] = t.Min()
+	rv["max"] = t.Max()
+	mean := t.Mean()
+	if !isNanOrInf(mean) {
+		rv["mean"] = mean
+	}
+	stddev := t.StdDev()
+	if !isNanOrInf(stddev) {
+		rv["stddev"] = stddev
+	}
+	rv["percentiles"] = percentiles
+	rv["rates"] = rates
+
+	return rv
+}
+
+func isNanOrInf(v float64) bool {
+	if math.IsNaN(v) || math.IsInf(v, 0) {
+		return true
+	}
+	return false
+}
+
+func WriteTimerJSON(w io.Writer, timer metrics.Timer) {
+	t := timer.Snapshot()
+	p := t.Percentiles(timerPercentiles)
+
+	fmt.Fprintf(w, `{"count":%9d,`, t.Count())
+	fmt.Fprintf(w, `"min":%9d,`, t.Min())
+	fmt.Fprintf(w, `"max":%9d,`, t.Max())
+	fmt.Fprintf(w, `"mean":%12.2f,`, t.Mean())
+	fmt.Fprintf(w, `"stddev":%12.2f,`, t.StdDev())
+	fmt.Fprintf(w, `"percentiles":{`)
+	fmt.Fprintf(w, `"median":%12.2f,`, p[0])
+	fmt.Fprintf(w, `"75%%":%12.2f,`, p[1])
+	fmt.Fprintf(w, `"95%%":%12.2f,`, p[2])
+	fmt.Fprintf(w, `"99%%":%12.2f,`, p[3])
+	fmt.Fprintf(w, `"99.9%%":%12.2f},`, p[4])
+	fmt.Fprintf(w, `"rates":{`)
+	fmt.Fprintf(w, `"1-min":%12.2f,`, t.Rate1())
+	fmt.Fprintf(w, `"5-min":%12.2f,`, t.Rate5())
+	fmt.Fprintf(w, `"15-min":%12.2f,`, t.Rate15())
+	fmt.Fprintf(w, `"mean":%12.2f}}`, t.RateMean())
+}
+
+func WriteTimerCSVHeader(w io.Writer, prefix string) {
+	fmt.Fprintf(w, "%s-count,", prefix)
+	fmt.Fprintf(w, "%s-min,", prefix)
+	fmt.Fprintf(w, "%s-max,", prefix)
+	fmt.Fprintf(w, "%s-mean,", prefix)
+	fmt.Fprintf(w, "%s-stddev,", prefix)
+	fmt.Fprintf(w, "%s-percentile-50%%,", prefix)
+	fmt.Fprintf(w, "%s-percentile-75%%,", prefix)
+	fmt.Fprintf(w, "%s-percentile-95%%,", prefix)
+	fmt.Fprintf(w, "%s-percentile-99%%,", prefix)
+	fmt.Fprintf(w, "%s-percentile-99.9%%,", prefix)
+	fmt.Fprintf(w, "%s-rate-1-min,", prefix)
+	fmt.Fprintf(w, "%s-rate-5-min,", prefix)
+	fmt.Fprintf(w, "%s-rate-15-min,", prefix)
+	fmt.Fprintf(w, "%s-rate-mean", prefix)
+}
+
+func WriteTimerCSV(w io.Writer, timer metrics.Timer) {
+	t := timer.Snapshot()
+	p := t.Percentiles(timerPercentiles)
+
+	fmt.Fprintf(w, `%d,`, t.Count())
+	fmt.Fprintf(w, `%d,`, t.Min())
+	fmt.Fprintf(w, `%d,`, t.Max())
+	fmt.Fprintf(w, `%f,`, t.Mean())
+	fmt.Fprintf(w, `%f,`, t.StdDev())
+	fmt.Fprintf(w, `%f,`, p[0])
+	fmt.Fprintf(w, `%f,`, p[1])
+	fmt.Fprintf(w, `%f,`, p[2])
+	fmt.Fprintf(w, `%f,`, p[3])
+	fmt.Fprintf(w, `%f,`, p[4])
+	fmt.Fprintf(w, `%f,`, t.Rate1())
+	fmt.Fprintf(w, `%f,`, t.Rate5())
+	fmt.Fprintf(w, `%f,`, t.Rate15())
+	fmt.Fprintf(w, `%f`, t.RateMean())
+}

index/upsidedown/store/metrics/writer.go

@@ -0,0 +1,60 @@
+//  Copyright (c) 2015 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metrics
+
+import (
+	"fmt"
+
+	store "github.com/blevesearch/upsidedown_store_api"
+)
+
+type Writer struct {
+	s *Store
+	o store.KVWriter
+}
+
+func (w *Writer) Close() error {
+	err := w.o.Close()
+	if err != nil {
+		w.s.AddError("Writer.Close", err, nil)
+	}
+	return err
+}
+
+func (w *Writer) NewBatch() store.KVBatch {
+	return &Batch{s: w.s, o: w.o.NewBatch()}
+}
+
+func (w *Writer) NewBatchEx(options store.KVBatchOptions) ([]byte, store.KVBatch, error) {
+	buf, b, err := w.o.NewBatchEx(options)
+	if err != nil {
+		return nil, nil, err
+	}
+	return buf, &Batch{s: w.s, o: b}, nil
+}
+
+func (w *Writer) ExecuteBatch(b store.KVBatch) (err error) {
+	batch, ok := b.(*Batch)
+	if !ok {
+		return fmt.Errorf("wrong type of batch")
+	}
+	w.s.timerWriterExecuteBatch.Time(func() {
+		err = w.o.ExecuteBatch(batch.o)
+		if err != nil {
+			w.s.AddError("Writer.ExecuteBatch", err, nil)
+		}
+	})
+	return
+}