Add support for log tags in newest CRI spec (elastic#8265)

* Add support for log tags in newest CRI spec

CRI spec has changed to include tags (to tell if the line is full or
partial):

```
2016-10-06T00:17:09.669794202Z stdout F The content of the log entry 1
2016-10-06T00:17:09.669794202Z stdout P First line of log entry 2
2016-10-06T00:17:09.669794202Z stdout P Second line of the log entry 2
2016-10-06T00:17:10.113242941Z stderr F Last line of the log entry 2
```

I still have to determine how this affects the older format, obviously
this change is breaking it, but to be seen if CRI is still supporting
it.

For more details you can check:
https://github.com/kubernetes/community/blob/master/contributors/design-proposals/node/kubelet-cri-logging.md

(cherry picked from commit 0a20f58)

CHANGELOG.asciidoc

@@ -55,6 +55,7 @@ https://github.com/elastic/beats/compare/v6.4.0...6.4[Check the HEAD diff]
 
 - Fixed a memory leak when harvesters are closed. {pull}7820[7820]
 - Fixed a docker input error due to the offset update bug in partial log join.{pull}8177[8177]
+- Update CRI format to support partial/full tags. {pull}8265[8265]
 
 *Heartbeat*
 

filebeat/docs/inputs/input-docker.asciidoc

@@ -55,6 +55,12 @@ Enable partial messages joining. Docker `json-file` driver splits log lines larg
 end of line (`\n`) is present for common lines in the resulting file, while it's not the for the lines
 that have been split. `combine_partial` joins them back together when enabled. It is enabled by default.
 
+===== `cri.parse_flags`
+
+Enable CRI flags parsing from the log file. CRI uses flags to signal a partial line, enabling this will
+ensure partial lines are rejoined. It is disabled by default.
+
+
 The following input configures {beatname_uc} to read the `stdout` stream from
 all containers under the default Docker containers path:
 

filebeat/input/docker/config.go

@@ -31,12 +31,15 @@ type config struct {
 
 	// Partial configures the prospector to join partial lines
 	Partial bool `config:"combine_partials"`
+
+	// Enable CRI flags parsing (to be switched to default in 7.0)
+	CRIFlags bool `config:"cri.parse_flags"`
 }
 
 type containers struct {
 	IDs  []string `config:"ids"`
 	Path string   `config:"path"`
 
-	// Stream can be all,stdout or stderr
+	// Stream can be all, stdout or stderr
 	Stream string `config:"stream"`
 }

filebeat/input/docker/input.go

@@ -71,6 +71,10 @@ func NewInput(
 		return nil, errors.Wrap(err, "update input config")
 	}
 
+	if err := cfg.SetBool("docker-json.cri_flags", -1, config.Partial); err != nil {
+		return nil, errors.Wrap(err, "update input config")
+	}
+
 	// Add stream to meta to ensure different state per stream
 	if config.Containers.Stream != "all" {
 		if context.Meta == nil {

filebeat/input/log/config.go

@@ -104,10 +104,9 @@ type config struct {
 
 	// Hidden on purpose, used by the docker input:
 	DockerJSON *struct {
-		Stream string `config:"stream"`
-
-		// TODO move this to true by default
-		Partial bool `config:"partial"`
+		Stream   string `config:"stream"`
+		Partial  bool   `config:"partial"`
+		CRIFlags bool   `config:"cri_flags"`
 	} `config:"docker-json"`
 }
 

filebeat/input/log/harvester.go

@@ -559,7 +559,7 @@ func (h *Harvester) newLogFileReader() (reader.Reader, error) {
 
 	if h.config.DockerJSON != nil {
 		// Docker json-file format, add custom parsing to the pipeline
-		r = docker_json.New(r, h.config.DockerJSON.Stream, h.config.DockerJSON.Partial)
+		r = docker_json.New(r, h.config.DockerJSON.Stream, h.config.DockerJSON.Partial, h.config.DockerJSON.CRIFlags)
 	}
 
 	if h.config.JSON != nil {

filebeat/reader/docker_json/docker_json.go

@@ -37,76 +37,118 @@ type Reader struct {
 
 	// join partial lines
 	partial bool
-}
 
-type dockerLog struct {
-	Timestamp string `json:"time"`
-	Log       string `json:"log"`
-	Stream    string `json:"stream"`
+	// parse CRI flags
+	criflags bool
 }
 
-type crioLog struct {
-	Timestamp time.Time
-	Stream    string
-	Log       []byte
+type logLine struct {
+	Partial   bool      `json:"-"`
+	Timestamp time.Time `json:"-"`
+	Time      string    `json:"time"`
+	Stream    string    `json:"stream"`
+	Log       string    `json:"log"`
 }
 
 // New creates a new reader renaming a field
-func New(r reader.Reader, stream string, partial bool) *Reader {
+func New(r reader.Reader, stream string, partial bool, CRIFlags bool) *Reader {
 	return &Reader{
-		stream:  stream,
-		partial: partial,
-		reader:  r,
+		stream:   stream,
+		partial:  partial,
+		reader:   r,
+		criflags: CRIFlags,
 	}
 }
 
 // parseCRILog parses logs in CRI log format.
 // CRI log format example :
 // 2017-09-12T22:32:21.212861448Z stdout 2017-09-12 22:32:21.212 [INFO][88] table.go 710: Invalidating dataplane cache
-func parseCRILog(message reader.Message, msg *crioLog) (reader.Message, error) {
-	log := strings.SplitN(string(message.Content), " ", 3)
-	if len(log) < 3 {
-		return message, errors.New("invalid CRI log")
+func (p *Reader) parseCRILog(message *reader.Message, msg *logLine) error {
+	split := 3
+	// read line tags if split is enabled:
+	if p.criflags {
+		split = 4
 	}
-	ts, err := time.Parse(time.RFC3339, log[0])
+
+	// current field
+	i := 0
+
+	// timestamp
+	log := strings.SplitN(string(message.Content), " ", split)
+	if len(log) < split {
+		return errors.New("invalid CRI log format")
+	}
+	ts, err := time.Parse(time.RFC3339, log[i])
 	if err != nil {
-		return message, errors.Wrap(err, "parsing CRI timestamp")
+		return errors.Wrap(err, "parsing CRI timestamp")
+	}
+	message.Ts = ts
+	i++
+
+	// stream
+	msg.Stream = log[i]
+	i++
+
+	// tags
+	partial := false
+	if p.criflags {
+		// currently only P(artial) or F(ull) are available
+		tags := strings.Split(log[i], ":")
+		for _, tag := range tags {
+			if tag == "P" {
+				partial = true
+			}
+		}
+		i++
 	}
 
-	msg.Timestamp = ts
-	msg.Stream = log[1]
-	msg.Log = []byte(log[2])
+	msg.Partial = partial
 	message.AddFields(common.MapStr{
 		"stream": msg.Stream,
 	})
-	message.Content = msg.Log
-	message.Ts = ts
+	// Remove ending \n for partial messages
+	message.Content = []byte(log[i])
+	if partial {
+		message.Content = bytes.TrimRightFunc(message.Content, func(r rune) bool {
+			return r == '\n' || r == '\r'
+		})
+	}
 
-	return message, nil
+	return nil
 }
 
 // parseReaderLog parses logs in Docker JSON log format.
 // Docker JSON log format example:
 // {"log":"1:M 09 Nov 13:27:36.276 # User requested shutdown...\n","stream":"stdout"}
-func parseDockerJSONLog(message reader.Message, msg *dockerLog) (reader.Message, error) {
+func (p *Reader) parseDockerJSONLog(message *reader.Message, msg *logLine) error {
 	dec := json.NewDecoder(bytes.NewReader(message.Content))
+
 	if err := dec.Decode(&msg); err != nil {
-		return message, errors.Wrap(err, "decoding docker JSON")
+		return errors.Wrap(err, "decoding docker JSON")
 	}
 
 	// Parse timestamp
-	ts, err := time.Parse(time.RFC3339, msg.Timestamp)
+	ts, err := time.Parse(time.RFC3339, msg.Time)
 	if err != nil {
-		return message, errors.Wrap(err, "parsing docker timestamp")
+		return errors.Wrap(err, "parsing docker timestamp")
 	}
 
 	message.AddFields(common.MapStr{
 		"stream": msg.Stream,
 	})
 	message.Content = []byte(msg.Log)
 	message.Ts = ts
+	msg.Partial = message.Content[len(message.Content)-1] != byte('\n')
+
+	return nil
+}
+
+func (p *Reader) parseLine(message *reader.Message, msg *logLine) error {
+	if strings.HasPrefix(string(message.Content), "{") {
+		return p.parseDockerJSONLog(message, msg)
+	}
 
-	return message, nil
+	return p.parseCRILog(message, msg)
 }
 
 // Next returns the next line.
@@ -117,32 +159,27 @@ func (p *Reader) Next() (reader.Message, error) {
 			return message, err
 		}
 
-		var dockerLine dockerLog
-		var crioLine crioLog
+		var logLine logLine
+		err = p.parseLine(&message, &logLine)
+		if err != nil {
+			return message, err
+		}
 
-		if strings.HasPrefix(string(message.Content), "{") {
-			message, err = parseDockerJSONLog(message, &dockerLine)
+		// Handle multiline messages, join partial lines
+		for p.partial && logLine.Partial {
+			next, err := p.reader.Next()
 			if err != nil {
 				return message, err
 			}
-			// Handle multiline messages, join lines that don't end with \n
-			for p.partial && message.Content[len(message.Content)-1] != byte('\n') {
-				next, err := p.reader.Next()
-				if err != nil {
-					return message, err
-				}
-				next, err = parseDockerJSONLog(next, &dockerLine)
-				if err != nil {
-					return message, err
-				}
-				message.Content = append(message.Content, next.Content...)
-				message.Bytes += next.Bytes
+			err = p.parseLine(&next, &logLine)
+			if err != nil {
+				return message, err
 			}
-		} else {
-			message, err = parseCRILog(message, &crioLine)
+			message.Content = append(message.Content, next.Content...)
+			message.Bytes += next.Bytes
 		}
 
-		if p.stream != "all" && p.stream != dockerLine.Stream && p.stream != crioLine.Stream {
+		if p.stream != "all" && p.stream != logLine.Stream {
 			continue
 		}