fix: Statefull parser handling (#10575)

plugins/inputs/file/file.go

@@ -11,17 +11,16 @@ import (
 	"github.com/influxdata/telegraf/internal/globpath"
 	"github.com/influxdata/telegraf/plugins/common/encoding"
 	"github.com/influxdata/telegraf/plugins/inputs"
-	"github.com/influxdata/telegraf/plugins/parsers"
 )
 
 type File struct {
 	Files             []string `toml:"files"`
 	FileTag           string   `toml:"file_tag"`
 	CharacterEncoding string   `toml:"character_encoding"`
-	parser            parsers.Parser
 
-	filenames []string
+	parserFunc telegraf.ParserFunc
-	decoder   *encoding.Decoder
+	filenames  []string
+	decoder    *encoding.Decoder
 }
 
 const sampleConfig = `
@@ -89,8 +88,8 @@ func (f *File) Gather(acc telegraf.Accumulator) error {
 	return nil
 }
 
-func (f *File) SetParser(p parsers.Parser) {
+func (f *File) SetParserFunc(fn telegraf.ParserFunc) {
-	f.parser = p
+	f.parserFunc = fn
 }
 
 func (f *File) refreshFilePaths() error {
@@ -121,9 +120,13 @@ func (f *File) readMetric(filename string) ([]telegraf.Metric, error) {
 	r, _ := utfbom.Skip(f.decoder.Reader(file))
 	fileContents, err := io.ReadAll(r)
 	if err != nil {
-		return nil, fmt.Errorf("E! Error file: %v could not be read, %s", filename, err)
+		return nil, fmt.Errorf("could not read %q: %s", filename, err)
 	}
-	return f.parser.Parse(fileContents)
+	parser, err := f.parserFunc()
+	if err != nil {
+		return nil, fmt.Errorf("could not instantiate parser: %s", err)
+	}
+	return parser.Parse(fileContents)
 }
 
 func init() {

plugins/inputs/file/file_test.go

@@ -49,9 +49,7 @@ func TestFileTag(t *testing.T) {
 	parserConfig := parsers.Config{
 		DataFormat: "json",
 	}
-	nParser, err := parsers.NewParser(&parserConfig)
+	r.SetParserFunc(func() (telegraf.Parser, error) { return parsers.NewParser(&parserConfig) })
-	require.NoError(t, err)
-	r.parser = nParser
 
 	err = r.Gather(&acc)
 	require.NoError(t, err)
@@ -76,9 +74,7 @@ func TestJSONParserCompile(t *testing.T) {
 		DataFormat: "json",
 		TagKeys:    []string{"parent_ignored_child"},
 	}
-	nParser, err := parsers.NewParser(&parserConfig)
+	r.SetParserFunc(func() (telegraf.Parser, error) { return parsers.NewParser(&parserConfig) })
-	require.NoError(t, err)
-	r.parser = nParser
 
 	require.NoError(t, r.Gather(&acc))
 	require.Equal(t, map[string]string{"parent_ignored_child": "hi"}, acc.Metrics[0].Tags)
@@ -99,9 +95,7 @@ func TestGrokParser(t *testing.T) {
 		GrokPatterns: []string{"%{COMMON_LOG_FORMAT}"},
 	}
 
-	nParser, err := parsers.NewParser(&parserConfig)
+	r.SetParserFunc(func() (telegraf.Parser, error) { return parsers.NewParser(&parserConfig) })
-	r.parser = nParser
-	require.NoError(t, err)
 
 	err = r.Gather(&acc)
 	require.NoError(t, err)
@@ -183,7 +177,7 @@ func TestCharacterEncoding(t *testing.T) {
 	tests := []struct {
 		name   string
 		plugin *File
-		csv    *csv.Parser
+		csv    csv.Parser
 		file   string
 	}{
 		{
@@ -192,7 +186,7 @@ func TestCharacterEncoding(t *testing.T) {
 				Files:             []string{"testdata/mtr-utf-8.csv"},
 				CharacterEncoding: "",
 			},
-			csv: &csv.Parser{
+			csv: csv.Parser{
 				MetricName:  "file",
 				SkipRows:    1,
 				ColumnNames: []string{"", "", "status", "dest", "hop", "ip", "loss", "snt", "", "", "avg", "best", "worst", "stdev"},
@@ -205,7 +199,7 @@ func TestCharacterEncoding(t *testing.T) {
 				Files:             []string{"testdata/mtr-utf-8.csv"},
 				CharacterEncoding: "utf-8",
 			},
-			csv: &csv.Parser{
+			csv: csv.Parser{
 				MetricName:  "file",
 				SkipRows:    1,
 				ColumnNames: []string{"", "", "status", "dest", "hop", "ip", "loss", "snt", "", "", "avg", "best", "worst", "stdev"},
@@ -218,7 +212,7 @@ func TestCharacterEncoding(t *testing.T) {
 				Files:             []string{"testdata/mtr-utf-16le.csv"},
 				CharacterEncoding: "utf-16le",
 			},
-			csv: &csv.Parser{
+			csv: csv.Parser{
 				MetricName:  "file",
 				SkipRows:    1,
 				ColumnNames: []string{"", "", "status", "dest", "hop", "ip", "loss", "snt", "", "", "avg", "best", "worst", "stdev"},
@@ -231,7 +225,7 @@ func TestCharacterEncoding(t *testing.T) {
 				Files:             []string{"testdata/mtr-utf-16be.csv"},
 				CharacterEncoding: "utf-16be",
 			},
-			csv: &csv.Parser{
+			csv: csv.Parser{
 				MetricName:  "file",
 				SkipRows:    1,
 				ColumnNames: []string{"", "", "status", "dest", "hop", "ip", "loss", "snt", "", "", "avg", "best", "worst", "stdev"},
@@ -244,9 +238,11 @@ func TestCharacterEncoding(t *testing.T) {
 			err := tt.plugin.Init()
 			require.NoError(t, err)
 
-			parser := tt.csv
+			tt.plugin.SetParserFunc(func() (telegraf.Parser, error) {
-			require.NoError(t, parser.Init())
+				parser := tt.csv
-			tt.plugin.SetParser(parser)
+				err := parser.Init()
+				return &parser, err
+			})
 
 			var acc testutil.Accumulator
 			err = tt.plugin.Gather(&acc)
@@ -256,3 +252,120 @@ func TestCharacterEncoding(t *testing.T) {
 		})
 	}
 }
+
+func TestStatefulParsers(t *testing.T) {
+	expected := []telegraf.Metric{
+		testutil.MustMetric("file",
+			map[string]string{
+				"dest": "example.org",
+				"hop":  "1",
+				"ip":   "12.122.114.5",
+			},
+			map[string]interface{}{
+				"avg":    21.55,
+				"best":   19.34,
+				"loss":   0.0,
+				"snt":    10,
+				"status": "OK",
+				"stdev":  2.05,
+				"worst":  26.83,
+			},
+			time.Unix(0, 0),
+		),
+		testutil.MustMetric("file",
+			map[string]string{
+				"dest": "example.org",
+				"hop":  "2",
+				"ip":   "192.205.32.238",
+			},
+			map[string]interface{}{
+				"avg":    25.11,
+				"best":   20.8,
+				"loss":   0.0,
+				"snt":    10,
+				"status": "OK",
+				"stdev":  6.03,
+				"worst":  38.85,
+			},
+			time.Unix(0, 0),
+		),
+		testutil.MustMetric("file",
+			map[string]string{
+				"dest": "example.org",
+				"hop":  "3",
+				"ip":   "152.195.85.133",
+			},
+			map[string]interface{}{
+				"avg":    20.18,
+				"best":   19.75,
+				"loss":   0.0,
+				"snt":    10,
+				"status": "OK",
+				"stdev":  0.0,
+				"worst":  20.78,
+			},
+			time.Unix(0, 0),
+		),
+		testutil.MustMetric("file",
+			map[string]string{
+				"dest": "example.org",
+				"hop":  "4",
+				"ip":   "93.184.216.34",
+			},
+			map[string]interface{}{
+				"avg":    24.02,
+				"best":   19.75,
+				"loss":   0.0,
+				"snt":    10,
+				"status": "OK",
+				"stdev":  4.67,
+				"worst":  32.41,
+			},
+			time.Unix(0, 0),
+		),
+	}
+
+	tests := []struct {
+		name   string
+		plugin *File
+		csv    csv.Parser
+		file   string
+		count  int
+	}{
+		{
+			name: "read file twice",
+			plugin: &File{
+				Files:             []string{"testdata/mtr-utf-8.csv"},
+				CharacterEncoding: "",
+			},
+			csv: csv.Parser{
+				MetricName:  "file",
+				SkipRows:    1,
+				ColumnNames: []string{"", "", "status", "dest", "hop", "ip", "loss", "snt", "", "", "avg", "best", "worst", "stdev"},
+				TagColumns:  []string{"dest", "hop", "ip"},
+			},
+			count: 2,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := tt.plugin.Init()
+			require.NoError(t, err)
+
+			tt.plugin.SetParserFunc(func() (telegraf.Parser, error) {
+				parser := tt.csv
+				err := parser.Init()
+				return &parser, err
+			})
+
+			var acc testutil.Accumulator
+			for i := 0; i < tt.count; i++ {
+				require.NoError(t, tt.plugin.Gather(&acc))
+
+				testutil.RequireMetricsEqual(t, expected, acc.GetTelegrafMetrics(), testutil.IgnoreTime())
+				acc.ClearMetrics()
+			}
+		})
+	}
+}

plugins/inputs/http/http.go

@@ -13,7 +13,6 @@ import (
 	"github.com/influxdata/telegraf/internal"
 	httpconfig "github.com/influxdata/telegraf/plugins/common/http"
 	"github.com/influxdata/telegraf/plugins/inputs"
-	"github.com/influxdata/telegraf/plugins/parsers"
 )
 
 type HTTP struct {
@@ -33,13 +32,12 @@ type HTTP struct {
 
 	SuccessStatusCodes []int `toml:"success_status_codes"`
 
-	client *http.Client
-	httpconfig.HTTPClientConfig
 	Log telegraf.Logger `toml:"-"`
 
-	// The parser will automatically be set by Telegraf core code because
+	httpconfig.HTTPClientConfig
-	// this plugin implements the ParserInput interface (i.e. the SetParser method)
+
-	parser parsers.Parser
+	client     *http.Client
+	parserFunc telegraf.ParserFunc
 }
 
 var sampleConfig = `
@@ -153,9 +151,9 @@ func (h *HTTP) Gather(acc telegraf.Accumulator) error {
 	return nil
 }
 
-// SetParser takes the data_format from the config and finds the right parser for that format
+// SetParserFunc takes the data_format from the config and finds the right parser for that format
-func (h *HTTP) SetParser(parser parsers.Parser) {
+func (h *HTTP) SetParserFunc(fn telegraf.ParserFunc) {
-	h.parser = parser
+	h.parserFunc = fn
 }
 
 // Gathers data from a particular URL
@@ -230,12 +228,17 @@ func (h *HTTP) gatherURL(
 
 	b, err := io.ReadAll(resp.Body)
 	if err != nil {
-		return err
+		return fmt.Errorf("reading body failed: %v", err)
 	}
 
-	metrics, err := h.parser.Parse(b)
+	// Instantiate a new parser for the new data to avoid trouble with stateful parsers
+	parser, err := h.parserFunc()
 	if err != nil {
-		return err
+		return fmt.Errorf("instantiating parser failed: %v", err)
+	}
+	metrics, err := parser.Parse(b)
+	if err != nil {
+		return fmt.Errorf("parsing metrics failed: %v", err)
 	}
 
 	for _, metric := range metrics {

plugins/inputs/http/http_test.go

@@ -8,13 +8,16 @@ import (
 	"net/http/httptest"
 	"net/url"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/require"
 
+	"github.com/influxdata/telegraf"
 	httpconfig "github.com/influxdata/telegraf/plugins/common/http"
 	"github.com/influxdata/telegraf/plugins/common/oauth"
 	httpplugin "github.com/influxdata/telegraf/plugins/inputs/http"
 	"github.com/influxdata/telegraf/plugins/parsers"
+	"github.com/influxdata/telegraf/plugins/parsers/csv"
 	"github.com/influxdata/telegraf/testutil"
 )
 
@@ -35,11 +38,12 @@ func TestHTTPWithJSONFormat(t *testing.T) {
 	}
 	metricName := "metricName"
 
-	p, _ := parsers.NewParser(&parsers.Config{
+	plugin.SetParserFunc(func() (telegraf.Parser, error) {
-		DataFormat: "json",
+		return parsers.NewParser(&parsers.Config{
-		MetricName: "metricName",
+			DataFormat: "json",
+			MetricName: "metricName",
+		})
 	})
-	plugin.SetParser(p)
 
 	var acc testutil.Accumulator
 	require.NoError(t, plugin.Init())
@@ -78,11 +82,12 @@ func TestHTTPHeaders(t *testing.T) {
 		Log:     testutil.Logger{},
 	}
 
-	p, _ := parsers.NewParser(&parsers.Config{
+	plugin.SetParserFunc(func() (telegraf.Parser, error) {
-		DataFormat: "json",
+		return parsers.NewParser(&parsers.Config{
-		MetricName: "metricName",
+			DataFormat: "json",
+			MetricName: "metricName",
+		})
 	})
-	plugin.SetParser(p)
 
 	var acc testutil.Accumulator
 	require.NoError(t, plugin.Init())
@@ -101,12 +106,12 @@ func TestInvalidStatusCode(t *testing.T) {
 		Log:  testutil.Logger{},
 	}
 
-	metricName := "metricName"
+	plugin.SetParserFunc(func() (telegraf.Parser, error) {
-	p, _ := parsers.NewParser(&parsers.Config{
+		return parsers.NewParser(&parsers.Config{
-		DataFormat: "json",
+			DataFormat: "json",
-		MetricName: metricName,
+			MetricName: "metricName",
+		})
 	})
-	plugin.SetParser(p)
 
 	var acc testutil.Accumulator
 	require.NoError(t, plugin.Init())
@@ -126,12 +131,12 @@ func TestSuccessStatusCodes(t *testing.T) {
 		Log:                testutil.Logger{},
 	}
 
-	metricName := "metricName"
+	plugin.SetParserFunc(func() (telegraf.Parser, error) {
-	p, _ := parsers.NewParser(&parsers.Config{
+		return parsers.NewParser(&parsers.Config{
-		DataFormat: "json",
+			DataFormat: "json",
-		MetricName: metricName,
+			MetricName: "metricName",
+		})
 	})
-	plugin.SetParser(p)
 
 	var acc testutil.Accumulator
 	require.NoError(t, plugin.Init())
@@ -154,11 +159,12 @@ func TestMethod(t *testing.T) {
 		Log:    testutil.Logger{},
 	}
 
-	p, _ := parsers.NewParser(&parsers.Config{
+	plugin.SetParserFunc(func() (telegraf.Parser, error) {
-		DataFormat: "json",
+		return parsers.NewParser(&parsers.Config{
-		MetricName: "metricName",
+			DataFormat: "json",
+			MetricName: "metricName",
+		})
 	})
-	plugin.SetParser(p)
 
 	var acc testutil.Accumulator
 	require.NoError(t, plugin.Init())
@@ -170,6 +176,11 @@ const simpleJSON = `
     "a": 1.2
 }
 `
+const simpleCSVWithHeader = `
+# Simple CSV with header(s)
+a,b,c
+1.2,3.1415,ok
+`
 
 func TestBodyAndContentEncoding(t *testing.T) {
 	ts := httptest.NewServer(http.NotFoundHandler())
@@ -253,15 +264,13 @@ func TestBodyAndContentEncoding(t *testing.T) {
 				tt.queryHandlerFunc(t, w, r)
 			})
 
-			parser, err := parsers.NewParser(&parsers.Config{DataFormat: "influx"})
+			tt.plugin.SetParserFunc(func() (telegraf.Parser, error) {
-			require.NoError(t, err)
+				return parsers.NewParser(&parsers.Config{DataFormat: "influx"})
-
+			})
-			tt.plugin.SetParser(parser)
 
 			var acc testutil.Accumulator
 			require.NoError(t, tt.plugin.Init())
-			err = tt.plugin.Gather(&acc)
+			require.NoError(t, tt.plugin.Gather(&acc))
-			require.NoError(t, err)
 		})
 	}
 }
@@ -335,8 +344,10 @@ func TestOAuthClientCredentialsGrant(t *testing.T) {
 				}
 			})
 
-			parser, _ := parsers.NewValueParser("metric", "string", "", nil)
+			tt.plugin.SetParserFunc(func() (telegraf.Parser, error) {
-			tt.plugin.SetParser(parser)
+				return parsers.NewValueParser("metric", "string", "", nil)
+			})
+
 			err = tt.plugin.Init()
 			require.NoError(t, err)
 
@@ -346,3 +357,55 @@ func TestOAuthClientCredentialsGrant(t *testing.T) {
 		})
 	}
 }
+
+func TestHTTPWithCSVFormat(t *testing.T) {
+	fakeServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/endpoint" {
+			_, _ = w.Write([]byte(simpleCSVWithHeader))
+		} else {
+			w.WriteHeader(http.StatusNotFound)
+		}
+	}))
+	defer fakeServer.Close()
+
+	address := fakeServer.URL + "/endpoint"
+	plugin := &httpplugin.HTTP{
+		URLs: []string{address},
+		Log:  testutil.Logger{},
+	}
+
+	plugin.SetParserFunc(func() (telegraf.Parser, error) {
+		parser := &csv.Parser{
+			MetricName:  "metricName",
+			SkipRows:    2,
+			ColumnNames: []string{"a", "b", "c"},
+			TagColumns:  []string{"c"},
+		}
+		err := parser.Init()
+		return parser, err
+	})
+
+	expected := []telegraf.Metric{
+		testutil.MustMetric("metricName",
+			map[string]string{
+				"url": address,
+				"c":   "ok",
+			},
+			map[string]interface{}{
+				"a": 1.2,
+				"b": 3.1415,
+			},
+			time.Unix(0, 0),
+		),
+	}
+
+	var acc testutil.Accumulator
+	require.NoError(t, plugin.Init())
+	require.NoError(t, acc.GatherError(plugin.Gather))
+	testutil.RequireMetricsEqual(t, expected, acc.GetTelegrafMetrics(), testutil.IgnoreTime())
+
+	// Run the parser a second time to test for correct stateful handling
+	acc.ClearMetrics()
+	require.NoError(t, acc.GatherError(plugin.Gather))
+	testutil.RequireMetricsEqual(t, expected, acc.GetTelegrafMetrics(), testutil.IgnoreTime())
+}