Merge pull request #413 from prometheus/cleanup/do-some-todos

Cleanup/do some todos

rules/ast/ast.go

@@ -193,7 +193,6 @@ type (
 		iterators map[clientmodel.Fingerprint]local.SeriesIterator
 		metrics   map[clientmodel.Fingerprint]clientmodel.Metric
 		// Fingerprints are populated from label matchers at query analysis time.
-		// TODO: do we still need these?
 		fingerprints clientmodel.Fingerprints
 	}
 
@@ -234,7 +233,6 @@ type (
 		iterators map[clientmodel.Fingerprint]local.SeriesIterator
 		metrics   map[clientmodel.Fingerprint]clientmodel.Metric
 		// Fingerprints are populated from label matchers at query analysis time.
-		// TODO: do we still need these?
 		fingerprints clientmodel.Fingerprints
 		interval     time.Duration
 	}

rules/ast/view_adapter.go

@@ -1,16 +0,0 @@
-// Copyright 2013 Prometheus Team
-// 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 ast
-
-// TODO: remove file.

storage/local/chunk.go

@@ -45,9 +45,7 @@ type chunkDesc struct {
 func newChunkDesc(c chunk) *chunkDesc {
 	chunkOps.WithLabelValues(createAndPin).Inc()
 	atomic.AddInt64(&numMemChunks, 1)
-	// TODO: numMemChunkDescs is actually never read except during metrics
-	// collection. Turn it into a real metric.
-	atomic.AddInt64(&numMemChunkDescs, 1)
+	numMemChunkDescs.Inc()
 	return &chunkDesc{chunk: c, refCount: 1}
 }
 

storage/local/instrumentation.go

@@ -37,6 +37,12 @@ var (
 		},
 		[]string{opTypeLabel},
 	)
+	numMemChunkDescs = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: namespace,
+		Subsystem: subsystem,
+		Name:      "memory_chunkdescs",
+		Help:      "The current number of chunk descriptors in memory.",
+	})
 )
 
 const (
@@ -71,12 +77,13 @@ const (
 func init() {
 	prometheus.MustRegister(chunkOps)
 	prometheus.MustRegister(chunkDescOps)
+	prometheus.MustRegister(numMemChunkDescs)
 }
 
 var (
-	// Global counters, also used internally, so not implemented as
+	// Global counter, also used internally, so not implemented as
 	// metrics. Collected in memorySeriesStorage.Collect.
-	numMemChunks, numMemChunkDescs int64
+	numMemChunks int64
 
 	// Metric descriptors for the above.
 	numMemChunksDesc = prometheus.NewDesc(
@@ -84,9 +91,4 @@ var (
 		"The current number of chunks in memory, excluding cloned chunks (i.e. chunks without a descriptor).",
 		nil, nil,
 	)
-	numMemChunkDescsDesc = prometheus.NewDesc(
-		prometheus.BuildFQName(namespace, subsystem, "memory_chunkdescs"),
-		"The current number of chunk descriptors in memory.",
-		nil, nil,
-	)
 )

storage/local/persistence.go

@@ -349,7 +349,26 @@ func (p *persistence) recoverFromCrash(fingerprintToSeries map[clientmodel.Finge
 	return nil
 }
 
-// TODO: Document.
+// sanitizeSeries sanitizes a series based on its series file as defined by the provided directory and FileInfo.
+// The method returns the fingerprint as derived from the directory and file name, and whether the provided
+// file has been sanitized. A file that failed to be sanitized is deleted, if possible.
+//
+// The following steps are performed:
+//
+// - A file whose name doesn't comply with the naming scheme of a series file is simply deleted.
+//
+// - If the size of the series file isn't a multiple of the chunk size, extraneous bytes are truncated.
+//   If the truncation fails, the file is deleted instead.
+//
+// - A file that is empty (after truncation) is deleted.
+//
+// - A series that is not archived (i.e. it is in the fingerprintToSeries map) is checked for consistency of
+//   its various parameters (like head-chunk persistence state, offset of chunkDescs etc.). In particular,
+//   overlap between an in-memory head chunk with the most recent persisted chunk is checked. Inconsistencies
+//   are rectified.
+//
+// - A series this in archived (i.e. it is not in the fingerprintToSeries map) is checked for its presence
+//   in the index of archived series. If it cannot be found there, it is deleted.
 func (p *persistence) sanitizeSeries(dirname string, fi os.FileInfo, fingerprintToSeries map[clientmodel.Fingerprint]*memorySeries) (clientmodel.Fingerprint, bool) {
 	filename := path.Join(dirname, fi.Name())
 	purge := func() {
@@ -364,7 +383,11 @@ func (p *persistence) sanitizeSeries(dirname string, fi os.FileInfo, fingerprint
 		purge()
 		return fp, false
 	}
-	fp.LoadFromString(path.Base(dirname) + fi.Name()[:fpLen-seriesDirNameLen]) // TODO: Panics if that doesn't parse as hex.
+	if err := fp.LoadFromString(path.Base(dirname) + fi.Name()[:fpLen-seriesDirNameLen]); err != nil {
+		glog.Warningf("Error parsing file name %s: %s", filename, err)
+		purge()
+		return fp, false
+	}
 
 	bytesToTrim := fi.Size() % int64(p.chunkLen+chunkHeaderLen)
 	chunksInFile := int(fi.Size()) / (p.chunkLen + chunkHeaderLen)
@@ -676,9 +699,6 @@ func (p *persistence) persistChunk(fp clientmodel.Fingerprint, c chunk) (int, er
 // each index in indexes. It is the caller's responsibility to not persist or
 // drop anything for the same fingerprint concurrently.
 func (p *persistence) loadChunks(fp clientmodel.Fingerprint, indexes []int, indexOffset int) ([]chunk, error) {
-	// TODO: we need to verify at some point that file length is a multiple of
-	// the chunk size. When is the best time to do this, and where to remember
-	// it? Right now, we only do it when loading chunkDescs.
 	f, err := p.openChunkFileForReading(fp)
 	if err != nil {
 		return nil, err
@@ -731,15 +751,11 @@ func (p *persistence) loadChunkDescs(fp clientmodel.Fingerprint, beforeTime clie
 	}
 	totalChunkLen := chunkHeaderLen + p.chunkLen
 	if fi.Size()%int64(totalChunkLen) != 0 {
-		// TODO: record number of encountered corrupt series files in a metric?
-
-		// Truncate the file size to the nearest multiple of chunkLen.
-		truncateTo := fi.Size() - fi.Size()%int64(totalChunkLen)
-		glog.Infof("Bad series file size for %s: %d bytes (no multiple of %d). Truncating to %d bytes.", fp, fi.Size(), totalChunkLen, truncateTo)
-		// TODO: this doesn't work, as this is a read-only file handle.
-		if err := f.Truncate(truncateTo); err != nil {
-			return nil, err
-		}
+		p.setDirty(true)
+		return nil, fmt.Errorf(
+			"size of series file for fingerprint %v is %d, which is not a multiple of the chunk length %d",
+			fp, fi.Size(), totalChunkLen,
+		)
 	}
 
 	numChunks := int(fi.Size()) / totalChunkLen
@@ -766,13 +782,49 @@ func (p *persistence) loadChunkDescs(fp clientmodel.Fingerprint, beforeTime clie
 		cds = append(cds, cd)
 	}
 	chunkDescOps.WithLabelValues(load).Add(float64(len(cds)))
-	atomic.AddInt64(&numMemChunkDescs, int64(len(cds)))
+	numMemChunkDescs.Add(float64(len(cds)))
 	return cds, nil
 }
 
 // checkpointSeriesMapAndHeads persists the fingerprint to memory-series mapping
 // and all open (non-full) head chunks. Do not call concurrently with
 // loadSeriesMapAndHeads.
+//
+// Description of the file format:
+//
+// (1) Magic string (const headsMagicString).
+//
+// (2) Varint-encoded format version (const headsFormatVersion).
+//
+// (3) Number of series in checkpoint as big-endian uint64.
+//
+// (4) Repeated once per series:
+//
+// (4.1) A flag byte, see flag constants above.
+//
+// (4.2) The fingerprint as big-endian uint64.
+//
+// (4.3) The metric as defined by codable.Metric.
+//
+// (4.4) The varint-encoded chunkDescsOffset.
+//
+// (4.5) The varint-encoded savedFirstTime.
+//
+// (4.6) The varint-encoded number of chunk descriptors.
+//
+// (4.7) Repeated once per chunk descriptor, oldest to most recent:
+//
+// (4.7.1) The varint-encoded first time.
+//
+// (4.7.2) The varint-encoded last time.
+//
+// (4.8) Exception to 4.7: If the most recent chunk is a non-persisted head chunk,
+// the following is persisted instead of the most recent chunk descriptor:
+//
+// (4.8.1) A byte defining the chunk type.
+//
+// (4.8.2) The head chunk itself, marshaled with the marshal() method.
+//
 func (p *persistence) checkpointSeriesMapAndHeads(fingerprintToSeries *seriesMap, fpLocker *fingerprintLocker) (err error) {
 	glog.Info("Checkpointing in-memory metrics and head chunks...")
 	begin := time.Now()
@@ -916,7 +968,7 @@ func (p *persistence) loadSeriesMapAndHeads() (sm *seriesMap, err error) {
 		}
 		if err == nil {
 			atomic.AddInt64(&numMemChunks, chunksTotal)
-			atomic.AddInt64(&numMemChunkDescs, chunkDescsTotal)
+			numMemChunkDescs.Add(float64(chunkDescsTotal))
 		}
 	}()
 
@@ -1328,7 +1380,18 @@ func (p *persistence) openChunkFileForWriting(fp clientmodel.Fingerprint) (*os.F
 	if err := os.MkdirAll(p.dirNameForFingerprint(fp), 0700); err != nil {
 		return nil, err
 	}
-	return os.OpenFile(p.fileNameForFingerprint(fp), os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0640)
+	f, err := os.OpenFile(p.fileNameForFingerprint(fp), os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0640)
+	if err != nil {
+		return f, err
+	}
+	offset, err := f.Seek(0, os.SEEK_CUR)
+	if offset%int64(chunkHeaderLen+p.chunkLen) != 0 {
+		return f, fmt.Errorf(
+			"size of series file for fingerprint %v is %d, which is not a multiple of the chunk length %d",
+			fp, offset, chunkHeaderLen+p.chunkLen,
+		)
+	}
+	return f, err
 }
 
 func (p *persistence) openChunkFileForReading(fp clientmodel.Fingerprint) (*os.File, error) {

storage/local/preload.go

@@ -99,10 +99,6 @@ func (p *memorySeriesPreloader) GetMetricRangeAtInterval(fp clientmodel.Fingerpr
 
 // Close implements Preloader.
 func (p *memorySeriesPreloader) Close() {
-	// TODO: Idea about a primitive but almost free heuristic to not evict
-	// "recently used" chunks: Do not unpin the chunks right here, but hand
-	// over the pinnedChunkDescs to a manager that will delay the unpinning
-	// based on time and memory pressure.
 	for _, cd := range p.pinnedChunkDescs {
 		cd.unpin(p.storage.evictRequests)
 	}

storage/local/series.go

@@ -235,7 +235,7 @@ func (s *memorySeries) evictChunkDescs(iOldestNotEvicted int) {
 		lenEvicted := len(s.chunkDescs) - lenToKeep
 		s.chunkDescsOffset += lenEvicted
 		chunkDescOps.WithLabelValues(evict).Add(float64(lenEvicted))
-		atomic.AddInt64(&numMemChunkDescs, -int64(lenEvicted))
+		numMemChunkDescs.Sub(float64(lenEvicted))
 		s.chunkDescs = append(
 			make([]*chunkDesc, 0, lenToKeep),
 			s.chunkDescs[lenEvicted:]...,
@@ -257,7 +257,7 @@ func (s *memorySeries) purgeOlderThan(t clientmodel.Timestamp) (int, bool) {
 	}
 	if keepIdx > 0 {
 		s.chunkDescs = append(make([]*chunkDesc, 0, len(s.chunkDescs)-keepIdx), s.chunkDescs[keepIdx:]...)
-		atomic.AddInt64(&numMemChunkDescs, -int64(keepIdx))
+		numMemChunkDescs.Sub(float64(keepIdx))
 	}
 	return keepIdx, len(s.chunkDescs) == 0
 }
@@ -281,8 +281,7 @@ func (s *memorySeries) preloadChunks(indexes []int, mss *memorySeriesStorage) ([
 			panic("requested loading chunks from persistence in a situation where we must not have persisted data for chunk descriptors in memory")
 		}
 		fp := s.metric.Fingerprint()
-		// TODO: Remove law-of-Demeter violation?
-		chunks, err := mss.persistence.loadChunks(fp, loadIndexes, s.chunkDescsOffset)
+		chunks, err := mss.loadChunks(fp, loadIndexes, s.chunkDescsOffset)
 		if err != nil {
 			// Unpin the chunks since we won't return them as pinned chunks now.
 			for _, cd := range pinnedChunkDescs {
@@ -343,8 +342,7 @@ func (s *memorySeries) preloadChunksForRange(
 		firstChunkDescTime = s.chunkDescs[0].firstTime()
 	}
 	if s.chunkDescsOffset != 0 && from.Before(firstChunkDescTime) {
-		// TODO: Remove law-of-demeter violation?
-		cds, err := mss.persistence.loadChunkDescs(fp, firstChunkDescTime)
+		cds, err := mss.loadChunkDescs(fp, firstChunkDescTime)
 		if err != nil {
 			return nil, err
 		}

storage/local/storage.go

@@ -774,6 +774,16 @@ func (s *memorySeriesStorage) purgeSeries(fp clientmodel.Fingerprint, beforeTime
 	s.persistence.updateArchivedTimeRange(fp, newFirstTime, lastTime)
 }
 
+// See persistence.loadChunks for detailed explanation.
+func (s *memorySeriesStorage) loadChunks(fp clientmodel.Fingerprint, indexes []int, indexOffset int) ([]chunk, error) {
+	return s.persistence.loadChunks(fp, indexes, indexOffset)
+}
+
+// See persistence.loadChunkDescs for detailed explanation.
+func (s *memorySeriesStorage) loadChunkDescs(fp clientmodel.Fingerprint, beforeTime clientmodel.Timestamp) ([]*chunkDesc, error) {
+	return s.persistence.loadChunkDescs(fp, beforeTime)
+}
+
 // To expose persistQueueCap as metric:
 var (
 	persistQueueCapDesc = prometheus.NewDesc(
@@ -801,7 +811,6 @@ func (s *memorySeriesStorage) Describe(ch chan<- *prometheus.Desc) {
 	ch <- persistQueueCapDesc
 
 	ch <- numMemChunksDesc
-	ch <- numMemChunkDescsDesc
 }
 
 // Collect implements prometheus.Collector.
@@ -820,6 +829,4 @@ func (s *memorySeriesStorage) Collect(ch chan<- prometheus.Metric) {
 
 	count := atomic.LoadInt64(&numMemChunks)
 	ch <- prometheus.MustNewConstMetric(numMemChunksDesc, prometheus.GaugeValue, float64(count))
-	count = atomic.LoadInt64(&numMemChunkDescs)
-	ch <- prometheus.MustNewConstMetric(numMemChunkDescsDesc, prometheus.GaugeValue, float64(count))
 }

storage/local/test_helpers.go

@@ -11,10 +11,14 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// NOTE ON FILENAME: Do not rename this file helpers_test.go (which might appear
+// an obvious choice). We need NewTestStorage in tests outside of the local
+// package, too. On the other hand, moving NewTestStorage in its own package
+// would cause circular dependencies in the tests in packages local.
+
 package local
 
 import (
-	"testing"
 	"time"
 
 	"github.com/prometheus/prometheus/utility/test"
@@ -33,7 +37,7 @@ func (t *testStorageCloser) Close() {
 // NewTestStorage creates a storage instance backed by files in a temporary
 // directory. The returned storage is already in serving state. Upon closing the
 // returned test.Closer, the temporary directory is cleaned up.
-func NewTestStorage(t testing.TB) (Storage, test.Closer) {
+func NewTestStorage(t test.T) (Storage, test.Closer) {
 	directory := test.NewTemporaryDirectory("test_storage", t)
 	o := &MemorySeriesStorageOptions{
 		MemoryChunks:               1000000,

utility/test/directory.go

@@ -16,7 +16,6 @@ package test
 import (
 	"io/ioutil"
 	"os"
-	"testing"
 )
 
 const (
@@ -51,12 +50,21 @@ type (
 	// their interactions.
 	temporaryDirectory struct {
 		path   string
-		tester testing.TB
+		tester T
 	}
 
 	callbackCloser struct {
 		fn func()
 	}
+
+	// T implements the needed methods of testing.TB so that we do not need
+	// to actually import testing (which has the side affect of adding all
+	// the test flags, which we do not want in non-test binaries even if
+	// they make use of these utilities for some reason).
+	T interface {
+		Fatal(args ...interface{})
+		Fatalf(format string, args ...interface{})
+	}
 )
 
 func (c nilCloser) Close() {
@@ -90,7 +98,7 @@ func (t temporaryDirectory) Path() string {
 
 // NewTemporaryDirectory creates a new temporary directory for transient POSIX
 // activities.
-func NewTemporaryDirectory(name string, t testing.TB) (handler TemporaryDirectory) {
+func NewTemporaryDirectory(name string, t T) (handler TemporaryDirectory) {
 	var (
 		directory string
 		err       error