*(dnsforward): finished new qlog_file implementation
This commit is contained in:
Andrey Meshkov
parent
67dc7d7d88
commit
712023112d
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@ -6,12 +6,14 @@ import (
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"sync"
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"time"
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"github.com/AdguardTeam/golibs/log"
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"github.com/pkg/errors"
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)
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var ErrSeekNotFound = errors.New("Seek not found the record")
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const bufferSize = 64 * 1024 // 64 KB is the buffer size
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const bufferSize = 256 * 1024 // 256 KB is the buffer size
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type QLogFile struct {
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file *os.File // the query log file
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@ -48,12 +50,16 @@ func NewQLogFile(path string) (*QLogFile, error) {
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// it shifts seek position to 3/4 of the file. Otherwise, to 1/4 of the file.
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// 5. It performs the search again, every time the search scope is narrowed twice.
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//
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// It returns the position of the line with the timestamp we were looking for.
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// It returns the position of the the line with the timestamp we were looking for
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// so that when we call "ReadNext" this line was returned.
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// If we could not find it, it returns 0 and ErrSeekNotFound
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func (q *QLogFile) Seek(timestamp uint64) (int64, error) {
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q.lock.Lock()
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defer q.lock.Unlock()
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// Empty the buffer
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q.buffer = nil
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// First of all, check the file size
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fileInfo, err := q.file.Stat()
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if err != nil {
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@ -61,38 +67,64 @@ func (q *QLogFile) Seek(timestamp uint64) (int64, error) {
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}
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// Define the search scope
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start := int64(0)
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end := fileInfo.Size()
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probe := (end - start) / 2
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start := int64(0) // start of the search interval (position in the file)
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end := fileInfo.Size() // end of the search interval (position in the file)
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probe := (end - start) / 2 // probe -- approximate index of the line we'll try to check
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var line string
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var lineIdx int64 // index of the probe line in the file
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var lastProbeLineIdx int64 // index of the last probe line
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// Get the line
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line, _, err := q.readProbeLine(probe)
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if err != nil {
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return 0, err
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// Count seek depth in order to detect mistakes
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// If depth is too large, we should stop the search
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depth := 0
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for {
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// Get the line at the specified position
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line, lineIdx, err = q.readProbeLine(probe)
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if err != nil {
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return 0, err
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}
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// Get the timestamp from the query log record
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ts := q.readTimestamp(line)
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if ts == 0 {
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return 0, ErrSeekNotFound
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}
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if ts == timestamp {
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// Hurray, returning the result
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break
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}
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if lastProbeLineIdx == lineIdx {
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// If we're testing the same line twice then most likely
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// the scope is too narrow and we won't find anything anymore
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return 0, ErrSeekNotFound
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}
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// Narrow the scope and repeat the search
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if ts > timestamp {
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// If the timestamp we're looking for is OLDER than what we found
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// Then the line is somewhere on the LEFT side from the current probe position
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end = probe
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probe = start + (end-start)/2
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} else {
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// If the timestamp we're looking for is NEWER than what we found
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// Then the line is somewhere on the RIGHT side from the current probe position
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start = probe
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probe = start + (end-start)/2
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}
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depth++
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if depth >= 100 {
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log.Error("Seek depth is too high, aborting. File %s, ts %v", q.file.Name(), timestamp)
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return 0, ErrSeekNotFound
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}
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}
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// Get the timestamp from the query log record
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ts := q.readTimestamp(line)
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if ts == timestamp {
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// Hurray, returning the result
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return probe, nil
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}
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// Narrow the scope and repeat the search
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if ts > timestamp {
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end := probe
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probe = (end - start) / 2
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} else {
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start := probe
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probe = (end - start) / 2
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}
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// TODO: temp
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q.position = probe
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// TODO: Check start/stop/probe values and loop this
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return 0, ErrSeekNotFound
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q.position = lineIdx + int64(len(line))
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return q.position, nil
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}
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// SeekStart changes the current position to the end of the file
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@ -102,6 +134,9 @@ func (q *QLogFile) SeekStart() (int64, error) {
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q.lock.Lock()
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defer q.lock.Unlock()
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// Empty the buffer
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q.buffer = nil
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// First of all, check the file size
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fileInfo, err := q.file.Stat()
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if err != nil {
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@ -111,7 +146,6 @@ func (q *QLogFile) SeekStart() (int64, error) {
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// Place the position to the very end of file
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q.position = fileInfo.Size() - 1
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if q.position < 0 {
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// TODO: test empty file
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q.position = 0
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}
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return q.position, nil
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@ -160,12 +194,13 @@ func (q *QLogFile) Close() error {
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// 4. read the line from the buffer
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func (q *QLogFile) readNextLine(position int64) (string, int64, error) {
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relativePos := position - q.bufferStart
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if q.buffer == nil || relativePos < maxEntrySize {
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if q.buffer == nil || (relativePos < maxEntrySize && q.bufferStart != 0) {
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// Time to re-init the buffer
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err := q.initBuffer(position)
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if err != nil {
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return "", 0, err
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}
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relativePos = position - q.bufferStart
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}
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// Look for the end of the prev line
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@ -201,7 +236,6 @@ func (q *QLogFile) initBuffer(position int64) error {
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q.buffer = make([]byte, bufferSize)
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}
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q.bufferLen, err = q.file.Read(q.buffer)
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// TODO: validate bufferLen
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if err != nil {
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return err
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}
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@ -218,7 +252,6 @@ func (q *QLogFile) readProbeLine(position int64) (string, int64, error) {
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seekPosition := int64(0)
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relativePos := position // position relative to the buffer we're going to read
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if (position - maxEntrySize) > 0 {
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// TODO: cover this case in tests
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seekPosition = position - maxEntrySize
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relativePos = maxEntrySize
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}
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@ -267,12 +300,12 @@ func (q *QLogFile) readTimestamp(str string) uint64 {
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}
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if len(val) == 0 {
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// TODO: log
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log.Error("Couldn't find timestamp in %s: %s", q.file.Name(), str)
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return 0
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}
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tm, err := time.Parse(time.RFC3339, val)
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if err != nil {
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// TODO: log
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log.Error("Couldn't parse timestamp in %s: %s", q.file.Name(), val)
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return 0
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}
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return uint64(tm.UnixNano())
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@ -14,15 +14,157 @@ import (
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)
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func TestQLogFileEmpty(t *testing.T) {
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// TODO: test empty file
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testDir := prepareTestDir()
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defer func() { _ = os.RemoveAll(testDir) }()
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testFile := prepareTestFile(testDir, 0)
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// create the new QLogFile instance
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q, err := NewQLogFile(testFile)
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assert.Nil(t, err)
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assert.NotNil(t, q)
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// seek to the start
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pos, err := q.SeekStart()
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assert.Nil(t, err)
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assert.Equal(t, int64(0), pos)
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// try reading anyway
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line, err := q.ReadNext()
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assert.Equal(t, io.EOF, err)
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assert.Equal(t, "", line)
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}
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func TestQLogFileLarge(t *testing.T) {
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// TODO: test reading large file
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// should be large enough
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count := 50000
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testDir := prepareTestDir()
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defer func() { _ = os.RemoveAll(testDir) }()
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testFile := prepareTestFile(testDir, count)
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// create the new QLogFile instance
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q, err := NewQLogFile(testFile)
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assert.Nil(t, err)
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assert.NotNil(t, q)
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// seek to the start
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pos, err := q.SeekStart()
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assert.Nil(t, err)
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assert.NotEqual(t, int64(0), pos)
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read := 0
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var line string
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for err == nil {
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line, err = q.ReadNext()
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if err == nil {
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assert.True(t, len(line) > 0)
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read += 1
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}
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}
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assert.Equal(t, count, read)
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assert.Equal(t, io.EOF, err)
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}
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func TestQLogFileSeek(t *testing.T) {
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// TODO: test seek method on a small file
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func TestQLogFileSeekLargeFile(t *testing.T) {
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// more or less big file
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count := 10000
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testDir := prepareTestDir()
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defer func() { _ = os.RemoveAll(testDir) }()
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testFile := prepareTestFile(testDir, count)
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// create the new QLogFile instance
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q, err := NewQLogFile(testFile)
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assert.Nil(t, err)
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assert.NotNil(t, q)
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// CASE 1: NOT TOO OLD LINE
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testSeekLine(t, q, 300)
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// CASE 2: OLD LINE
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testSeekLine(t, q, count-300)
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// CASE 3: FIRST LINE
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testSeekLine(t, q, 0)
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// CASE 4: LAST LINE
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testSeekLine(t, q, count)
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// CASE 5: Seek non-existent (too low)
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_, err = q.Seek(123)
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assert.NotNil(t, err)
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// CASE 6: Seek non-existent (too high)
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ts, _ := time.Parse(time.RFC3339, "2100-01-02T15:04:05Z07:00")
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_, err = q.Seek(uint64(ts.UnixNano()))
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assert.NotNil(t, err)
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}
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func TestQLogFileSeekSmallFile(t *testing.T) {
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// more or less big file
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count := 10
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testDir := prepareTestDir()
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defer func() { _ = os.RemoveAll(testDir) }()
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testFile := prepareTestFile(testDir, count)
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// create the new QLogFile instance
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q, err := NewQLogFile(testFile)
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assert.Nil(t, err)
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assert.NotNil(t, q)
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// CASE 1: NOT TOO OLD LINE
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testSeekLine(t, q, 2)
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// CASE 2: OLD LINE
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testSeekLine(t, q, count-2)
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// CASE 3: FIRST LINE
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testSeekLine(t, q, 0)
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// CASE 4: LAST LINE
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testSeekLine(t, q, count)
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// CASE 5: Seek non-existent (too low)
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_, err = q.Seek(123)
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assert.NotNil(t, err)
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// CASE 6: Seek non-existent (too high)
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ts, _ := time.Parse(time.RFC3339, "2100-01-02T15:04:05Z07:00")
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_, err = q.Seek(uint64(ts.UnixNano()))
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assert.NotNil(t, err)
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}
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func testSeekLine(t *testing.T, q *QLogFile, lineNumber int) {
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line, err := getQLogLine(q, lineNumber)
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assert.Nil(t, err)
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ts := q.readTimestamp(line)
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assert.NotEqual(t, uint64(0), ts)
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// try seeking to that line now
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pos, err := q.Seek(ts)
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assert.Nil(t, err)
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assert.NotEqual(t, int64(0), pos)
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testLine, err := q.ReadNext()
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assert.Nil(t, err)
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assert.Equal(t, line, testLine)
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}
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func getQLogLine(q *QLogFile, lineNumber int) (string, error) {
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_, err := q.SeekStart()
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if err != nil {
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return "", err
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}
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for i := 1; i < lineNumber; i++ {
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_, err := q.ReadNext()
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if err != nil {
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return "", err
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}
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}
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return q.ReadNext()
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}
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// Check adding and loading (with filtering) entries from disk and memory
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