hrpc: enable ScanMetrics

Enable tracking scan metrics in the ScanResponse. Clients can access
the metrics via calls to scanner.GetScanMetrics()
Support for  HBase versions < 2.6.0 where ScanMetrics provides
ROWS_SCANNED and ROWS_FILTERED metrics.

hrpc/call.go

@@ -259,12 +259,12 @@ type Result struct {
 	Cells   []*Cell
 	Stale   bool
 	Partial bool
-	// Exists is only set if existance_only was set in the request query.
+	// Exists is only set if existence_only was set in the request query.
 	Exists *bool
 }
 
 func (c *Result) String() string {
-	return fmt.Sprintf("cells:%v stale:%v partial:%v exists:%v ",
+	return fmt.Sprintf("cells:%v stale:%v partial:%v exists:%v",
 		c.Cells, c.Stale, c.Partial, c.Exists)
 }
 

hrpc/hrpc_test.go

@@ -285,6 +285,7 @@ func TestScanToProto(t *testing.T) {
 					Column:        []*pb.Column{},
 					TimeRange:     &pb.TimeRange{},
 				},
+				TrackScanMetrics: proto.Bool(false),
 			},
 		},
 		{ // explicitly set configurable attributes to default values
@@ -317,6 +318,7 @@ func TestScanToProto(t *testing.T) {
 					MaxVersions:   nil,
 					CacheBlocks:   nil,
 				},
+				TrackScanMetrics: proto.Bool(false),
 			},
 		},
 		{ // set configurable attributes to non-default values
@@ -350,6 +352,7 @@ func TestScanToProto(t *testing.T) {
 					MaxVersions: proto.Uint32(89),
 					CacheBlocks: proto.Bool(!DefaultCacheBlocks),
 				},
+				TrackScanMetrics: proto.Bool(false),
 			},
 		},
 		{ // test that pb.ScanRequest.Scan is nil when scanner id is specificed
@@ -374,6 +377,7 @@ func TestScanToProto(t *testing.T) {
 				ClientHandlesPartials:   proto.Bool(true),
 				ClientHandlesHeartbeats: proto.Bool(true),
 				Scan:                    nil,
+				TrackScanMetrics:        proto.Bool(false),
 			},
 		},
 		{ // set reversed attribute
@@ -393,6 +397,7 @@ func TestScanToProto(t *testing.T) {
 					TimeRange:     &pb.TimeRange{},
 					Reversed:      proto.Bool(true),
 				},
+				TrackScanMetrics: proto.Bool(false),
 			},
 		},
 		{ // set scan attribute
@@ -418,6 +423,7 @@ func TestScanToProto(t *testing.T) {
 						{Name: proto.String("key2"), Value: []byte("value2")},
 					},
 				},
+				TrackScanMetrics: proto.Bool(false),
 			},
 		},
 		{ // scan key range
@@ -438,6 +444,7 @@ func TestScanToProto(t *testing.T) {
 					StartRow:      startRow,
 					StopRow:       stopRow,
 				},
+				TrackScanMetrics: proto.Bool(false),
 			},
 		},
 		{ // set filters and families
@@ -459,6 +466,7 @@ func TestScanToProto(t *testing.T) {
 						TimeRange:     &pb.TimeRange{},
 						Filter:        pbFilter,
 					},
+					TrackScanMetrics: proto.Bool(false),
 				}
 			}(),
 		},
@@ -478,8 +486,30 @@ func TestScanToProto(t *testing.T) {
 					Column:        []*pb.Column{},
 					TimeRange:     &pb.TimeRange{},
 				},
+				TrackScanMetrics: proto.Bool(false),
 			},
 		},
+		// set TrackScanMetrics
+		{
+			s: func() *Scan {
+				s, _ := NewScanStr(ctx, "", TrackScanMetrics())
+				return s
+			}(),
+			expProto: func() *pb.ScanRequest {
+				return &pb.ScanRequest{
+					Region:                  rs,
+					NumberOfRows:            proto.Uint32(DefaultNumberOfRows),
+					CloseScanner:            proto.Bool(false),
+					ClientHandlesPartials:   proto.Bool(true),
+					ClientHandlesHeartbeats: proto.Bool(true),
+					Scan: &pb.Scan{
+						MaxResultSize: proto.Uint64(DefaultMaxResultSize),
+						TimeRange:     &pb.TimeRange{},
+					},
+					TrackScanMetrics: proto.Bool(true),
+				}
+			}(),
+		},
 	}
 
 	for i, tcase := range tests {

hrpc/scan.go

@@ -49,9 +49,14 @@ type Scanner interface {
 
 	// Close should be called if it is desired to stop scanning before getting all of results.
 	// If you call Next() after calling Close() you might still get buffered results.
-	// Othwerwise, in case all results have been delivered or in case of an error, the Scanner
+	// Otherwise, in case all results have been delivered or in case of an error, the Scanner
 	// will be closed automatically. It's okay to close an already closed scanner.
 	Close() error
+	// GetScanMetrics returns the scan metrics for the scanner at the time of call.
+	// The scan metrics are non-nil only if the Scan has TrackScanMetrics() enabled
+	// The scan metrics for a Scan are only accurate and complete if the scanner has
+	// been closed with an io.EOF.
+	GetScanMetrics() map[string]int64
 }
 
 // Scan represents a scanner on an HBase table.
@@ -64,10 +69,11 @@ type Scan struct {
 
 	scannerID uint64
 
-	maxResultSize uint64
-	numberOfRows  uint32
-	reversed      bool
-	attribute     []*pb.NameBytesPair
+	maxResultSize    uint64
+	numberOfRows     uint32
+	reversed         bool
+	attribute        []*pb.NameBytesPair
+	trackScanMetrics bool
 
 	closeScanner        bool
 	allowPartialResults bool
@@ -178,6 +184,11 @@ func (s *Scan) NumberOfRows() uint32 {
 	return s.numberOfRows
 }
 
+// TrackScanMetrics returns true if the client is requesting to track scan metrics.
+func (s *Scan) TrackScanMetrics() bool {
+	return s.trackScanMetrics
+}
+
 // ToProto converts this Scan into a protobuf message
 func (s *Scan) ToProto() proto.Message {
 	scan := &pb.ScanRequest{
@@ -189,6 +200,7 @@ func (s *Scan) ToProto() proto.Message {
 		// tell server that we "handle" heartbeats by ignoring them
 		// since we don't really time out our scans (unless context was cancelled)
 		ClientHandlesHeartbeats: proto.Bool(true),
+		TrackScanMetrics:        &s.trackScanMetrics,
 	}
 	if s.scannerID != math.MaxUint64 {
 		scan.ScannerId = &s.scannerID
@@ -334,6 +346,19 @@ func AllowPartialResults() func(Call) error {
 	}
 }
 
+// TrackScanMetrics is an option for scan requests.
+// Enables tracking scan metrics from HBase, which will be returned in the scan response.
+func TrackScanMetrics() func(Call) error {
+	return func(g Call) error {
+		scan, ok := g.(*Scan)
+		if !ok {
+			return errors.New("'TrackScanMetrics' option can only be used with Scan queries")
+		}
+		scan.trackScanMetrics = true
+		return nil
+	}
+}
+
 // Reversed is a Scan-only option which allows you to scan in reverse key order
 // To use it the startKey would be greater than the end key
 func Reversed() func(Call) error {

integration_test.go

@@ -16,6 +16,7 @@ import (
 	"flag"
 	"fmt"
 	"io"
+	"math"
 	"os"
 	"os/exec"
 	"reflect"
@@ -25,8 +26,6 @@ import (
 	"testing"
 	"time"
 
-	"math"
-
 	log "github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
 	"github.com/tsuna/gohbase"
@@ -1022,6 +1021,110 @@ func TestScanTimeRangeVersions(t *testing.T) {
 	}
 }
 
+func TestScanWithScanMetrics(t *testing.T) {
+	var (
+		key          = "TestScanWithScanMetrics"
+		now          = time.Now()
+		r1           = fmt.Sprintf("%s_%d", key, 1)
+		r2           = fmt.Sprintf("%s_%d", key, 2)
+		r3           = fmt.Sprintf("%s_%d", key, 3)
+		val          = []byte("1")
+		family       = "cf"
+		ctx          = context.Background()
+		rowsScanned  = "ROWS_SCANNED"
+		rowsFiltered = "ROWS_FILTERED"
+	)
+
+	c := gohbase.NewClient(*host)
+	defer c.Close()
+
+	for _, r := range []string{r1, r2, r3} {
+		err := insertKeyValue(c, r, family, val, hrpc.Timestamp(now))
+		if err != nil {
+			t.Fatalf("Put failed: %s", err)
+		}
+	}
+
+	tcases := []struct {
+		description          string
+		filters              func(call hrpc.Call) error
+		expectedRowsScanned  int64
+		expectedRowsFiltered int64
+		noScanMetrics        bool
+	}{
+		{
+			description:          "scan metrics not enabled",
+			expectedRowsScanned:  0,
+			expectedRowsFiltered: 0,
+			noScanMetrics:        true,
+		},
+		{
+			description:          "2 rows scanned",
+			expectedRowsScanned:  2,
+			expectedRowsFiltered: 0,
+		},
+		{
+			description:          "1 row scanned 1 row filtered",
+			filters:              hrpc.Filters(filter.NewPrefixFilter([]byte(r1))),
+			expectedRowsScanned:  1,
+			expectedRowsFiltered: 1,
+		},
+	}
+
+	for _, tc := range tcases {
+		t.Run(tc.description, func(t *testing.T) {
+			var (
+				scan *hrpc.Scan
+				err  error
+			)
+			if tc.noScanMetrics {
+				scan, err = hrpc.NewScanRangeStr(ctx, table, r1, r3)
+			} else if tc.filters == nil {
+				scan, err = hrpc.NewScanRangeStr(ctx, table, r1, r3, hrpc.TrackScanMetrics())
+			} else {
+				scan, err = hrpc.NewScanRangeStr(ctx, table, r1, r3, hrpc.TrackScanMetrics(),
+					tc.filters)
+			}
+			if err != nil {
+				t.Fatalf("Scan req failed: %s", err)
+			}
+
+			var results []*hrpc.Result
+			scanner := c.Scan(scan)
+			for {
+				var r *hrpc.Result
+				r, err = scanner.Next()
+				if err == io.EOF {
+					break
+				}
+				if err != nil {
+					t.Fatal(err)
+				}
+				results = append(results, r)
+			}
+
+			actualMetrics := scanner.GetScanMetrics()
+
+			if tc.noScanMetrics && actualMetrics != nil {
+				t.Fatalf("Expected nil scan metrics, got %v", actualMetrics)
+			}
+
+			scanned := actualMetrics[rowsScanned]
+			if tc.expectedRowsScanned != scanned {
+				t.Errorf("Did not get expected rows scanned - expected: %d, actual %d",
+					tc.expectedRowsScanned, scanned)
+			}
+
+			filtered := actualMetrics[rowsFiltered]
+			if tc.expectedRowsFiltered != filtered {
+				t.Errorf("Did not get expected rows filtered - expected: %d, actual %d",
+					tc.expectedRowsFiltered, filtered)
+			}
+		})
+	}
+
+}
+
 func TestPutTTL(t *testing.T) {
 	key := "TestPutTTL"
 	c := gohbase.NewClient(*host)
@@ -1034,13 +1137,13 @@ func TestPutTTL(t *testing.T) {
 		t.Fatalf("Put failed: %s", err)
 	}
 
-	//Wait ttl duration and try to get the value
+	// Wait ttl duration and try to get the value
 	time.Sleep(ttl)
 
 	get, err := hrpc.NewGetStr(context.Background(), table, key,
 		hrpc.Families(map[string][]string{"cf": nil}))
 
-	//Make sure we dont get a result back
+	// Make sure we don't get a result back
 	res, err := c.Get(get)
 	if err != nil {
 		t.Fatalf("Get failed: %s", err)