fix(inputs/directory_monitor): Add support for multiline file parsing

plugins/inputs/directory_monitor/README.md

@@ -1,7 +1,7 @@
 # Directory Monitor Input Plugin
 
 This plugin monitors a single directory (without looking at sub-directories), and takes in each file placed in the directory.
-The plugin will gather all files in the directory at a configurable interval (`monitor_interval`), and parse the ones that haven't been picked up yet.
+The plugin will gather all files in the directory at the configured interval, and parse the ones that haven't been picked up yet.
 
 This plugin is intended to read files that are moved or copied to the monitored directory, and thus files should also not be used by another process or else they may fail to be gathered. Please be advised that this plugin pulls files directly after they've been in the directory for the length of the configurable `directory_duration_threshold`, and thus files should not be written 'live' to the monitored directory. If you absolutely must write files directly, they must be guaranteed to finish writing before the `directory_duration_threshold`.
 
@@ -46,10 +46,13 @@ This plugin is intended to read files that are moved or copied to the monitored
   ## https://docs.influxdata.com/influxdb/cloud/reference/glossary/#series-cardinality
   # file_tag = ""
   #
+  ## Specify if the file can be read completely at once or if it needs to be read line by line (default).
+  ## Possible values: line-by-line, complete-file
+  # parse_method = "line-by-line" 
+  #
   ## The dataformat to be read from the files.
   ## Each data format has its own unique set of configuration options, read
   ## more about them here:
   ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md
-  ## NOTE: We currently only support parsing newline-delimited JSON. See the format here: https://github.com/ndjson/ndjson-spec
   data_format = "influx"
 ```

plugins/inputs/directory_monitor/directory_monitor.go

@@ -20,6 +20,7 @@ import (
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/config"
+	"github.com/influxdata/telegraf/internal/choice"
 	"github.com/influxdata/telegraf/plugins/inputs"
 	"github.com/influxdata/telegraf/plugins/parsers"
 	"github.com/influxdata/telegraf/plugins/parsers/csv"
@@ -36,6 +37,7 @@ var (
 	defaultMaxBufferedMetrics         = 10000
 	defaultDirectoryDurationThreshold = config.Duration(0 * time.Millisecond)
 	defaultFileQueueSize              = 100000
+	defaultParseMethod                = "line-by-line"
 )
 
 type DirectoryMonitor struct {
@@ -50,6 +52,7 @@ type DirectoryMonitor struct {
 	DirectoryDurationThreshold config.Duration `toml:"directory_duration_threshold"`
 	Log                        telegraf.Logger `toml:"-"`
 	FileQueueSize              int             `toml:"file_queue_size"`
+	ParseMethod                string          `toml:"parse_method"`
 
 	filesInUse          sync.Map
 	cancel              context.CancelFunc
@@ -200,7 +203,7 @@ func (monitor *DirectoryMonitor) ingestFile(filePath string) error {
 
 	parser, err := monitor.parserFunc()
 	if err != nil {
-		return fmt.Errorf("E! Creating parser: %s", err.Error())
+		return fmt.Errorf("creating parser: %w", err)
 	}
 
 	// Handle gzipped files.
@@ -218,41 +221,66 @@ func (monitor *DirectoryMonitor) ingestFile(filePath string) error {
 }
 
 func (monitor *DirectoryMonitor) parseFile(parser parsers.Parser, reader io.Reader, fileName string) error {
-	scanner := bufio.NewScanner(reader)
-	for scanner.Scan() {
-		metrics, err := monitor.parseLine(parser, scanner.Bytes())
+	if monitor.ParseMethod == "complete-file" {
+		bytes, err := io.ReadAll(reader)
 		if err != nil {
 			return err
 		}
 
-		if monitor.FileTag != "" {
-			for _, m := range metrics {
-				m.AddTag(monitor.FileTag, filepath.Base(fileName))
-			}
+		metrics, err := monitor.parseMetrics(parser, bytes, fileName)
+		if err != nil {
+			return err
 		}
 
 		if err := monitor.sendMetrics(metrics); err != nil {
 			return err
 		}
 	}
 
-	return nil
+	scanner := bufio.NewScanner(reader)
+	/* To be used when we add a new scanner based parse method
+	switch monitor.ParseMethod {
+	case "line-by-line":
+		scanner.Split(bufio.ScanLines)
+	case "future-split-type":
+		scanner.Split(func(data []byte, atEOF bool) (advance int, token []byte, err error) { return })
+	} */
+
+	for scanner.Scan() {
+		metrics, err := monitor.parseMetrics(parser, scanner.Bytes(), fileName)
+		if err != nil {
+			return err
+		}
+
+		if err := monitor.sendMetrics(metrics); err != nil {
+			return err
+		}
+	}
+
+	return scanner.Err()
 }
 
-func (monitor *DirectoryMonitor) parseLine(parser parsers.Parser, line []byte) ([]telegraf.Metric, error) {
+func (monitor *DirectoryMonitor) parseMetrics(parser parsers.Parser, line []byte, fileName string) (metrics []telegraf.Metric, err error) {
 	switch parser.(type) {
 	case *csv.Parser:
-		m, err := parser.Parse(line)
+		metrics, err = parser.Parse(line)
 		if err != nil {
 			if errors.Is(err, io.EOF) {
 				return nil, nil
 			}
 			return nil, err
 		}
-		return m, err
 	default:
-		return parser.Parse(line)
+		metrics, err = parser.Parse(line)
 	}
+
+	if monitor.FileTag != "" {
+		for _, m := range metrics {
+			m.AddTag(monitor.FileTag, filepath.Base(fileName))
+		}
+	}
+
+	return metrics, err
 }
 
 func (monitor *DirectoryMonitor) sendMetrics(metrics []telegraf.Metric) error {
@@ -357,6 +385,10 @@ func (monitor *DirectoryMonitor) Init() error {
 		monitor.fileRegexesToIgnore = append(monitor.fileRegexesToIgnore, regex)
 	}
 
+	if err := choice.Check(monitor.ParseMethod, []string{"line-by-line", "complete-file"}); err != nil {
+		return fmt.Errorf("config option parse_method: %w", err)
+	}
+
 	return nil
 }
 
@@ -368,6 +400,7 @@ func init() {
 			MaxBufferedMetrics:         defaultMaxBufferedMetrics,
 			DirectoryDurationThreshold: defaultDirectoryDurationThreshold,
 			FileQueueSize:              defaultFileQueueSize,
+			ParseMethod:                defaultParseMethod,
 		}
 	})
 }

plugins/inputs/directory_monitor/directory_monitor_test.go

@@ -27,8 +27,9 @@ func TestCSVGZImport(t *testing.T) {
 	r := DirectoryMonitor{
 		Directory:          processDirectory,
 		FinishedDirectory:  finishedDirectory,
-		MaxBufferedMetrics: 1000,
-		FileQueueSize:      100000,
+		MaxBufferedMetrics: defaultMaxBufferedMetrics,
+		FileQueueSize:      defaultFileQueueSize,
+		ParseMethod:        defaultParseMethod,
 	}
 	err := r.Init()
 	require.NoError(t, err)
@@ -91,8 +92,9 @@ func TestMultipleJSONFileImports(t *testing.T) {
 	r := DirectoryMonitor{
 		Directory:          processDirectory,
 		FinishedDirectory:  finishedDirectory,
-		MaxBufferedMetrics: 1000,
-		FileQueueSize:      1000,
+		MaxBufferedMetrics: defaultMaxBufferedMetrics,
+		FileQueueSize:      defaultFileQueueSize,
+		ParseMethod:        defaultParseMethod,
 	}
 	err := r.Init()
 	require.NoError(t, err)
@@ -140,8 +142,9 @@ func TestFileTag(t *testing.T) {
 		Directory:          processDirectory,
 		FinishedDirectory:  finishedDirectory,
 		FileTag:            "filename",
-		MaxBufferedMetrics: 1000,
-		FileQueueSize:      1000,
+		MaxBufferedMetrics: defaultMaxBufferedMetrics,
+		FileQueueSize:      defaultFileQueueSize,
+		ParseMethod:        defaultParseMethod,
 	}
 	err := r.Init()
 	require.NoError(t, err)
@@ -194,8 +197,9 @@ func TestCSVNoSkipRows(t *testing.T) {
 	r := DirectoryMonitor{
 		Directory:          processDirectory,
 		FinishedDirectory:  finishedDirectory,
-		MaxBufferedMetrics: 1000,
-		FileQueueSize:      100000,
+		MaxBufferedMetrics: defaultMaxBufferedMetrics,
+		FileQueueSize:      defaultFileQueueSize,
+		ParseMethod:        defaultParseMethod,
 	}
 	err := r.Init()
 	require.NoError(t, err)
@@ -262,8 +266,9 @@ func TestCSVSkipRows(t *testing.T) {
 	r := DirectoryMonitor{
 		Directory:          processDirectory,
 		FinishedDirectory:  finishedDirectory,
-		MaxBufferedMetrics: 1000,
-		FileQueueSize:      100000,
+		MaxBufferedMetrics: defaultMaxBufferedMetrics,
+		FileQueueSize:      defaultFileQueueSize,
+		ParseMethod:        defaultParseMethod,
 	}
 	err := r.Init()
 	require.NoError(t, err)
@@ -332,8 +337,9 @@ func TestCSVMultiHeader(t *testing.T) {
 	r := DirectoryMonitor{
 		Directory:          processDirectory,
 		FinishedDirectory:  finishedDirectory,
-		MaxBufferedMetrics: 1000,
-		FileQueueSize:      100000,
+		MaxBufferedMetrics: defaultMaxBufferedMetrics,
+		FileQueueSize:      defaultFileQueueSize,
+		ParseMethod:        defaultParseMethod,
 	}
 	err := r.Init()
 	require.NoError(t, err)
@@ -387,3 +393,55 @@ hello,80,test_name2`
 		require.Equal(t, expectedFields, m.Fields)
 	}
 }
+
+func TestParseCompleteFile(t *testing.T) {
+	acc := testutil.Accumulator{}
+
+	// Establish process directory and finished directory.
+	finishedDirectory := t.TempDir()
+	processDirectory := t.TempDir()
+
+	// Init plugin.
+	r := DirectoryMonitor{
+		Directory:          processDirectory,
+		FinishedDirectory:  finishedDirectory,
+		MaxBufferedMetrics: defaultMaxBufferedMetrics,
+		FileQueueSize:      defaultFileQueueSize,
+		ParseMethod:        "complete-file",
+	}
+	err := r.Init()
+	require.NoError(t, err)
+	r.Log = testutil.Logger{}
+
+	parserConfig := parsers.Config{
+		DataFormat:  "json",
+		JSONNameKey: "name",
+		TagKeys:     []string{"tag1"},
+	}
+
+	r.SetParserFunc(func() (parsers.Parser, error) {
+		return parsers.NewParser(&parserConfig)
+	})
+
+	testJSON := `{
+		"name": "test1",
+		"value": 100.1,
+		"tag1": "value1"
+	}`
+
+	// Write json file to process into the 'process' directory.
+	f, _ := os.CreateTemp(processDirectory, "test.json")
+	_, _ = f.WriteString(testJSON)
+	_ = f.Close()
+
+	err = r.Start(&acc)
+	require.NoError(t, err)
+	err = r.Gather(&acc)
+	require.NoError(t, err)
+	acc.Wait(1)
+	r.Stop()
+
+	require.NoError(t, acc.FirstError())
+	require.Len(t, acc.Metrics, 1)
+	testutil.RequireMetricEqual(t, testutil.TestMetric(100.1), acc.GetTelegrafMetrics()[0], testutil.IgnoreTime())
+}

plugins/inputs/directory_monitor/sample.conf

@@ -36,9 +36,12 @@
   ## https://docs.influxdata.com/influxdb/cloud/reference/glossary/#series-cardinality
   # file_tag = ""
   #
+  ## Specify if the file can be read completely at once or if it needs to be read line by line (default).
+  ## Possible values: line-by-line, complete-file
+  # parse_method = "line-by-line" 
+  #
   ## The dataformat to be read from the files.
   ## Each data format has its own unique set of configuration options, read
   ## more about them here:
   ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md
-  ## NOTE: We currently only support parsing newline-delimited JSON. See the format here: https://github.com/ndjson/ndjson-spec
   data_format = "influx"