Add test for bug when removing and re-creating log file

plugins/inputs/logparser/logparser_test.go

@@ -6,6 +6,7 @@ import (
 	"runtime"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/influxdata/telegraf/testutil"
 
@@ -118,6 +119,134 @@ func TestGrokParseLogFilesAppearLater(t *testing.T) {
 		map[string]string{"response_code": "200"})
 }
 
+// TestGrokParseLogFilesOneFileRemovedandRecreated tests that after removing and re-creating an observed log file new
+// log lines from that file are still monitored
+func TestGrokParseLogFilesOneFileRemovedandRecreated(t *testing.T) {
+	logdir, err := ioutil.TempDir("", "TestGrokParseLogFilesRemoveOneFile")
+	defer os.RemoveAll(logdir)
+	assert.NoError(t, err)
+
+	file1, fileErr1 := os.Create(logdir + "/test_1.log")
+	assert.NoError(t, fileErr1)
+
+	file2, fileErr2 := os.Create(logdir + "/test_2.log")
+	assert.NoError(t, fileErr2)
+
+	thisdir := getCurrentDir()
+	p := &grok.Parser{
+		Patterns:           []string{"%{TEST_LOG_A}", "%{TEST_LOG_B}"},
+		CustomPatternFiles: []string{thisdir + "grok/testdata/test-patterns"},
+	}
+
+	logparser := &LogParserPlugin{
+		FromBeginning: true,
+		Files:         []string{logdir + "/*.log"},
+		GrokParser:    p,
+	}
+
+	acc := testutil.Accumulator{}
+	assert.NoError(t, logparser.Start(&acc))
+
+	acc.SetDebug(true)
+
+	assert.Equal(t, acc.NFields(), 0)
+
+	// write log into file1 and check accumulator
+	_, fwErr1 := file1.WriteString("[04/Jun/2016:12:41:45 +0100] 1.25 200 192.168.1.1 5.432µs 101\n")
+	assert.NoError(t, fwErr1)
+
+	file1.Sync()
+
+	assert.NoError(t, acc.GatherError(logparser.Gather))
+	time.Sleep(100 * time.Millisecond)
+
+	acc.AssertContainsTaggedFields(t, "logparser_grok",
+		map[string]interface{}{
+			"clientip":      "192.168.1.1",
+			"myfloat":       float64(1.25),
+			"response_time": int64(5432),
+			"myint":         int64(101),
+		},
+		map[string]string{"response_code": "200"})
+
+	acc.ClearMetrics()
+
+	// write log into file2 and check accumulator
+	_, fwErr3 := file2.WriteString("[04/Jun/2016:12:41:45 +0100] 1.25 200 192.168.1.3 5.432µs 101\n")
+	assert.NoError(t, fwErr3)
+
+	file2.Sync()
+
+	assert.NoError(t, acc.GatherError(logparser.Gather))
+	time.Sleep(100 * time.Millisecond)
+
+	acc.AssertContainsTaggedFields(t, "logparser_grok",
+		map[string]interface{}{
+			"clientip":      "192.168.1.3",
+			"myfloat":       float64(1.25),
+			"response_time": int64(5432),
+			"myint":         int64(101),
+		},
+		map[string]string{"response_code": "200"})
+
+	acc.ClearMetrics()
+
+	// close file1 and re-create it at the same place
+	closeErr := file1.Close()
+	assert.NoError(t, closeErr)
+
+	var removeErr = os.Remove(logdir + "/test_1.log")
+	assert.NoError(t, removeErr)
+
+	fileNew1, fileNewErr1 := os.Create(logdir + "/test_1.log")
+	assert.NoError(t, fileNewErr1)
+
+	// write log into file2 again and check accumulator
+	_, fwErr4 := file2.WriteString("[04/Jun/2016:12:41:45 +0100] 1.25 200 192.168.1.4 5.432µs 101\n")
+	assert.NoError(t, fwErr4)
+
+	file2.Sync()
+
+	assert.NoError(t, acc.GatherError(logparser.Gather))
+	time.Sleep(100 * time.Millisecond)
+
+	acc.AssertContainsTaggedFields(t, "logparser_grok",
+		map[string]interface{}{
+			"clientip":      "192.168.1.4",
+			"myfloat":       float64(1.25),
+			"response_time": int64(5432),
+			"myint":         int64(101),
+		},
+		map[string]string{"response_code": "200"})
+
+	acc.ClearMetrics()
+
+	// write log into re-created file1 again check accumulator
+	_, fwErr5 := fileNew1.WriteString("[04/Jun/2016:12:41:45 +0100] 1.25 200 192.168.1.5 5.432µs 101\n")
+	assert.NoError(t, fwErr5)
+
+	fileNew1.Sync()
+
+	assert.NoError(t, acc.GatherError(logparser.Gather))
+	time.Sleep(100 * time.Millisecond)
+
+	acc.AssertContainsTaggedFields(t, "logparser_grok",
+		map[string]interface{}{
+			"clientip":      "192.168.1.5",
+			"myfloat":       float64(1.25),
+			"response_time": int64(5432),
+			"myint":         int64(101),
+		},
+		map[string]string{"response_code": "200"})
+
+	acc.ClearMetrics()
+
+	logparser.Stop()
+
+	file2.Close()
+	fileNew1.Close()
+}
+
 // Test that test_a.log line gets parsed even though we don't have the correct
 // pattern available for test_b.log
 func TestGrokParseLogFilesOneBad(t *testing.T) {