lib/protoparser/prometheus: move streamparser to subpackage (#3814)

`lib/protoparser/prometheus` is used by various applications,
such as `app/vmalert`. The recent change to the
`lib/protoparser/prometheus` package introduced a new dependency
of `lib/writeconcurrencylimiter` which exposes some metrics.
Because of the dependency, now all applications which have this
dependency also expose these metrics.

Creating a new `lib/protoparser/prometheus/stream` package helps
to remove these metrics from apps which use `lib/protoparser/prometheus`
as dependency.

See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3761

Signed-off-by: hagen1778 <roman@victoriametrics.com>

app/vmagent/prometheusimport/request_handler.go

@@ -10,6 +10,7 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/prompbmarshal"
 	parserCommon "github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/common"
 	parser "github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus/stream"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/tenantmetrics"
 	"github.com/VictoriaMetrics/metrics"
 )
@@ -31,7 +32,7 @@ func InsertHandler(at *auth.Token, req *http.Request) error {
 		return err
 	}
 	isGzipped := req.Header.Get("Content-Encoding") == "gzip"
-	return parser.ParseStream(req.Body, defaultTimestamp, isGzipped, func(rows []parser.Row) error {
+	return stream.Parse(req.Body, defaultTimestamp, isGzipped, func(rows []parser.Row) error {
 		return insertRows(at, rows, extraLabels)
 	}, func(s string) {
 		httpserver.LogError(req, s)

app/vminsert/prometheusimport/request_handler.go

@@ -9,6 +9,7 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/prompbmarshal"
 	parserCommon "github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/common"
 	parser "github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus/stream"
 	"github.com/VictoriaMetrics/metrics"
 )
 
@@ -28,7 +29,7 @@ func InsertHandler(req *http.Request) error {
 		return err
 	}
 	isGzipped := req.Header.Get("Content-Encoding") == "gzip"
-	return parser.ParseStream(req.Body, defaultTimestamp, isGzipped, func(rows []parser.Row) error {
+	return stream.Parse(req.Body, defaultTimestamp, isGzipped, func(rows []parser.Row) error {
 		return insertRows(rows, extraLabels)
 	}, func(s string) {
 		httpserver.LogError(req, s)

lib/promscrape/scrapework.go

@@ -26,6 +26,7 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promrelabel"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promutils"
 	parser "github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus/stream"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/proxy"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/timerpool"
 	"github.com/VictoriaMetrics/metrics"
@@ -575,7 +576,7 @@ func (sw *scrapeWork) scrapeStream(scrapeTimestamp, realTimestamp int64) error {
 		if err == nil {
 			bodyString = bytesutil.ToUnsafeString(sbr.body)
 			areIdenticalSeries = sw.areIdenticalSeries(lastScrape, bodyString)
-			err = parser.ParseStream(&sbr, scrapeTimestamp, false, func(rows []parser.Row) error {
+			err = stream.Parse(&sbr, scrapeTimestamp, false, func(rows []parser.Row) error {
 				mu.Lock()
 				defer mu.Unlock()
 				samplesScraped += len(rows)
@@ -796,7 +797,7 @@ func (sw *scrapeWork) sendStaleSeries(lastScrape, currScrape string, timestamp i
 		// and https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3675
 		var mu sync.Mutex
 		br := bytes.NewBufferString(bodyString)
-		err := parser.ParseStream(br, timestamp, false, func(rows []parser.Row) error {
+		err := stream.Parse(br, timestamp, false, func(rows []parser.Row) error {
 			mu.Lock()
 			defer mu.Unlock()
 			for i := range rows {

lib/protoparser/prometheus/stream/streamparser.go

@@ -1,4 +1,4 @@
-package prometheus
+package stream
 
 import (
 	"bufio"
@@ -10,16 +10,17 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/cgroup"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/common"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/writeconcurrencylimiter"
 	"github.com/VictoriaMetrics/metrics"
 )
 
-// ParseStream parses lines with Prometheus exposition format from r and calls callback for the parsed rows.
+// Parse parses lines with Prometheus exposition format from r and calls callback for the parsed rows.
 //
 // The callback can be called concurrently multiple times for streamed data from r.
 //
 // callback shouldn't hold rows after returning.
-func ParseStream(r io.Reader, defaultTimestamp int64, isGzipped bool, callback func(rows []Row) error, errLogger func(string)) error {
+func Parse(r io.Reader, defaultTimestamp int64, isGzipped bool, callback func(rows []prometheus.Row) error, errLogger func(string)) error {
 	wcr := writeconcurrencylimiter.GetReader(r)
 	defer writeconcurrencylimiter.PutReader(wcr)
 	r = wcr
@@ -137,9 +138,9 @@ var streamContextPool sync.Pool
 var streamContextPoolCh = make(chan *streamContext, cgroup.AvailableCPUs())
 
 type unmarshalWork struct {
-	rows             Rows
+	rows             prometheus.Rows
 	ctx              *streamContext
-	callback         func(rows []Row) error
+	callback         func(rows []prometheus.Row) error
 	errLogger        func(string)
 	defaultTimestamp int64
 	reqBuf           []byte
@@ -154,7 +155,7 @@ func (uw *unmarshalWork) reset() {
 	uw.reqBuf = uw.reqBuf[:0]
 }
 
-func (uw *unmarshalWork) runCallback(rows []Row) {
+func (uw *unmarshalWork) runCallback(rows []prometheus.Row) {
 	ctx := uw.ctx
 	if err := uw.callback(rows); err != nil {
 		ctx.callbackErrLock.Lock()

lib/protoparser/prometheus/stream/streamparser_test.go

@@ -1,4 +1,4 @@
-package prometheus
+package stream
 
 import (
 	"bytes"
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/common"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus"
 )
 
 func TestParseStream(t *testing.T) {
@@ -17,13 +18,13 @@ func TestParseStream(t *testing.T) {
 	defer common.StopUnmarshalWorkers()
 
 	const defaultTimestamp = 123
-	f := func(s string, rowsExpected []Row) {
+	f := func(s string, rowsExpected []prometheus.Row) {
 		t.Helper()
 		bb := bytes.NewBufferString(s)
-		var result []Row
+		var result []prometheus.Row
 		var lock sync.Mutex
 		doneCh := make(chan struct{})
-		err := ParseStream(bb, defaultTimestamp, false, func(rows []Row) error {
+		err := Parse(bb, defaultTimestamp, false, func(rows []prometheus.Row) error {
 			lock.Lock()
 			result = appendRowCopies(result, rows)
 			if len(result) == len(rowsExpected) {
@@ -56,7 +57,7 @@ func TestParseStream(t *testing.T) {
 		}
 		result = nil
 		doneCh = make(chan struct{})
-		err = ParseStream(bb, defaultTimestamp, true, func(rows []Row) error {
+		err = Parse(bb, defaultTimestamp, true, func(rows []prometheus.Row) error {
 			lock.Lock()
 			result = appendRowCopies(result, rows)
 			if len(result) == len(rowsExpected) {
@@ -79,12 +80,12 @@ func TestParseStream(t *testing.T) {
 		}
 	}
 
-	f("foo 123 456", []Row{{
+	f("foo 123 456", []prometheus.Row{{
 		Metric:    "foo",
 		Value:     123,
 		Timestamp: 456000,
 	}})
-	f(`foo{bar="baz"} 1 2`+"\n"+`aaa{} 3 4`, []Row{
+	f(`foo{bar="baz"} 1 2`+"\n"+`aaa{} 3 4`, []prometheus.Row{
 		{
 			Metric:    "aaa",
 			Value:     3,
@@ -92,7 +93,7 @@ func TestParseStream(t *testing.T) {
 		},
 		{
 			Metric: "foo",
-			Tags: []Tag{{
+			Tags: []prometheus.Tag{{
 				Key:   "bar",
 				Value: "baz",
 			}},
@@ -100,29 +101,29 @@ func TestParseStream(t *testing.T) {
 			Timestamp: 2000,
 		},
 	})
-	f("foo 23", []Row{{
+	f("foo 23", []prometheus.Row{{
 		Metric:    "foo",
 		Value:     23,
 		Timestamp: defaultTimestamp,
 	}})
 }
 
-func sortRows(rows []Row) {
+func sortRows(rows []prometheus.Row) {
 	sort.Slice(rows, func(i, j int) bool {
 		a, b := rows[i], rows[j]
 		return a.Metric < b.Metric
 	})
 }
 
-func appendRowCopies(dst, src []Row) []Row {
+func appendRowCopies(dst, src []prometheus.Row) []prometheus.Row {
 	for _, r := range src {
-		// Make a copy of r, since r may contain garbage after returning from the callback to ParseStream.
-		var rCopy Row
+		// Make a copy of r, since r may contain garbage after returning from the callback to Parse.
+		var rCopy prometheus.Row
 		rCopy.Metric = copyString(r.Metric)
 		rCopy.Value = r.Value
 		rCopy.Timestamp = r.Timestamp
 		for _, tag := range r.Tags {
-			rCopy.Tags = append(rCopy.Tags, Tag{
+			rCopy.Tags = append(rCopy.Tags, prometheus.Tag{
 				Key:   copyString(tag.Key),
 				Value: copyString(tag.Value),
 			})