Introduce close_eof harvster option

CHANGELOG.asciidoc

@@ -53,7 +53,8 @@ https://github.com/elastic/beats/compare/v5.0.0-alpha3...master[Check the HEAD d
 *Topbeat*
 
 *Filebeat*
-- Introdce close_removed and close_renamed harvester options {issue}1600[1600]
+- Introduce close_removed and close_renamed harvester options {issue}1600[1600]
+- Introduce close_eof harvester options {issue}1600[1600]
 
 
 *Winlogbeat*

filebeat/etc/beat.full.yml

@@ -176,6 +176,11 @@ filebeat.prospectors:
   # Note: Potential data loss if file reading was not finished when file was removed.
   #close_removed: false
 
+  # Closes the file handler as soon as the harvesters reaches then end of the file.
+  # The file will be picked up again by the harvester at previous known state
+  # after scan_frequency in case the file can still be discovered by the prospector.
+  #close_eof: false
+
 #----------------------------- Stdin prospector -------------------------------
 # Configuration to use stdin input
 #- input_type: stdin

filebeat/filebeat.full.yml

@@ -176,6 +176,11 @@ filebeat.prospectors:
   # Note: Potential data loss if file reading was not finished when file was removed.
   #close_removed: false
 
+  # Closes the file handler as soon as the harvesters reaches then end of the file.
+  # The file will be picked up again by the harvester at previous known state
+  # after scan_frequency in case the file can still be discovered by the prospector.
+  #close_eof: false
+
 #----------------------------- Stdin prospector -------------------------------
 # Configuration to use stdin input
 #- input_type: stdin

filebeat/harvester/config.go

@@ -26,6 +26,7 @@ var (
 		MaxBytes:        10 * (1 << 20), // 10MB
 		CloseRemoved:    false,
 		CloseRenamed:    false,
+		CloseEOF:        false,
 		ForceCloseFiles: false,
 	}
 )
@@ -43,6 +44,7 @@ type harvesterConfig struct {
 	CloseOlder           time.Duration              `config:"close_older"`
 	CloseRemoved         bool                       `config:"close_removed"`
 	CloseRenamed         bool                       `config:"close_renamed"`
+	CloseEOF             bool                       `config:"close_eof"`
 	ForceCloseFiles      bool                       `config:"force_close_files"`
 	ExcludeLines         []*regexp.Regexp           `config:"exclude_lines"`
 	IncludeLines         []*regexp.Regexp           `config:"include_lines"`
@@ -53,7 +55,7 @@ type harvesterConfig struct {
 
 func (config *harvesterConfig) Validate() error {
 
-	// TODO: remove in 7.0
+	// DEPRECATED: remove in 6.0
 	if config.ForceCloseFiles {
 		config.CloseRemoved = true
 		config.CloseRenamed = true

filebeat/harvester/log.go

@@ -6,6 +6,8 @@ import (
 
 	"golang.org/x/text/transform"
 
+	"io"
+
 	"github.com/elastic/beats/filebeat/config"
 	"github.com/elastic/beats/filebeat/harvester/encoding"
 	"github.com/elastic/beats/filebeat/harvester/processor"
@@ -40,6 +42,7 @@ func (h *Harvester) Harvest() {
 		CloseRemoved:       cfg.CloseRemoved,
 		CloseRenamed:       cfg.CloseRenamed,
 		CloseOlder:         cfg.CloseOlder,
+		CloseEOF:           cfg.CloseEOF,
 		BackoffDuration:    cfg.Backoff,
 		MaxBackoffDuration: cfg.MaxBackoff,
 		BackoffFactor:      cfg.BackoffFactor,
@@ -69,24 +72,19 @@ func (h *Harvester) Harvest() {
 		// Partial lines return error and are only read on completion
 		ts, text, bytesRead, jsonFields, err := readLine(processor)
 		if err != nil {
-
-			if err == reader.ErrFileTruncate {
+			switch err {
+			case reader.ErrFileTruncate:
 				logp.Info("File was truncated. Begin reading file from offset 0: %s", h.Path)
 				h.SetOffset(0)
-				return
-			}
-
-			if err == reader.ErrRemoved {
+			case reader.ErrRemoved:
 				logp.Info("File was removed: %s. Closing because close_removed is enabled.", h.Path)
-				return
+			case reader.ErrRenamed:
+				logp.Info("File was renamed: %s. Closing because close_renamed is enabled.", h.Path)
+			case io.EOF:
+				logp.Info("End of file reached: %s. Closing because close_eof is enabled.", h.Path)
+			default:
+				logp.Info("Read line error: %s", err)
 			}
-
-			if err == reader.ErrRenamed {
-				logp.Info("File was renamed: %s Closing because close_renamed is enabled.", h.Path)
-				return
-			}
-
-			logp.Info("Read line error: %s", err)
 			return
 		}
 

filebeat/harvester/reader/log.go

@@ -34,6 +34,7 @@ type LogFileReaderConfig struct {
 	BackoffFactor      int
 	CloseRenamed       bool
 	CloseRemoved       bool
+	CloseEOF           bool
 }
 
 func NewLogFileReader(
@@ -81,13 +82,12 @@ func (r *logFileReader) Read(buf []byte) (int, error) {
 			return n, nil
 		}
 
-		continuable := r.fs.Continuable()
-		if err == io.EOF && !continuable {
-			logp.Info("Reached end of file: %s", r.fs.Name())
+		if err == io.EOF && r.config.CloseEOF {
 			return n, err
 		}
 
-		if err != io.EOF || !continuable {
+		// Stdin is not continuable
+		if err != io.EOF || !r.fs.Continuable() {
 			logp.Err("Unexpected state reading from %s; error: %s", r.fs.Name(), err)
 			return n, err
 		}

filebeat/tests/system/config/filebeat.yml.j2

@@ -21,6 +21,7 @@ filebeat.prospectors:
   max_backoff: 0.1s
   close_removed: {{close_removed}}
   close_renamed: {{close_renamed}}
+  close_eof: {{close_eof}}
 
   {% if fields %}
   fields:

filebeat/tests/system/test_harvester.py

@@ -104,3 +104,45 @@ def test_close_removed(self):
 
         # Make sure the state for the file was persisted
         assert len(data) == 1
+
+
+    def test_close_eof(self):
+        """
+        Checks that a file is closed if eof is reached
+        """
+        self.render_config_template(
+            path=os.path.abspath(self.working_dir) + "/log/test.log",
+            close_eof="true",
+            scan_frequency="0.1s"
+        )
+        os.mkdir(self.working_dir + "/log/")
+
+        testfile1 = self.working_dir + "/log/test.log"
+        file = open(testfile1, 'w')
+
+        iterations1 = 5
+        for n in range(0, iterations1):
+            file.write("rotation file")
+            file.write("\n")
+
+        file.close()
+
+        filebeat = self.start_beat()
+
+        # Let it read the file
+        self.wait_until(
+            lambda: self.output_has(lines=iterations1), max_timeout=10)
+
+
+        # Wait until error shows up on windows
+        self.wait_until(
+            lambda: self.log_contains(
+                "Closing because close_eof is enabled"),
+            max_timeout=15)
+
+        filebeat.check_kill_and_wait()
+
+        data = self.get_registry()
+
+        # Make sure the state for the file was persisted
+        assert len(data) == 1