MB-19040 - cbdatasource logVBucketStates() for more diagnosis info

Change-Id: Ia664671645f1d35fb96e8d022d14261ca61624e2
Reviewed-on: http://review.couchbase.org/62783
Reviewed-by: Marty Schoch <marty.schoch@gmail.com>
Tested-by: Steve Yen <steve.yen@gmail.com>

cbdatasource/cbdatasource.go

@@ -1092,6 +1092,11 @@ func (d *bucketDataSource) worker(server string, workerCh chan []uint16) int {
 	d.Kick("new-worker")
 
 	for {
+		currVBucketsMutex.Lock()
+		d.logVBucketStates(server, uprOpenName, "worker, looping beg",
+			currVBuckets, nil)
+		currVBucketsMutex.Unlock()
+
 		select {
 		case <-sendEndCh:
 			atomic.AddUint64(&d.stats.TotWorkerSendEndCh, 1)
@@ -1114,7 +1119,11 @@ func (d *bucketDataSource) worker(server string, workerCh chan []uint16) int {
 			}
 
 			currVBucketsMutex.Lock()
+			d.logVBucketStates(server, uprOpenName, "refreshWorker-prior",
+				currVBuckets, nil)
 			err := d.refreshWorker(sendCh, currVBuckets, wantVBucketIDs)
+			d.logVBucketStates(server, uprOpenName, "refreshWorker-after",
+				currVBuckets, err)
 			currVBucketsMutex.Unlock()
 			if err != nil {
 				return cleanup(0, err)
@@ -1535,6 +1544,67 @@ func (d *bucketDataSource) Kick(reason string) error {
 
 // --------------------------------------------------------------
 
+func (d *bucketDataSource) logVBucketStates(server, uprOpenName, prefix string,
+	vbucketStates map[uint16]*VBucketState, errToLog error) {
+	if d.options.Logf == nil {
+		return
+	}
+
+	if len(vbucketStates) <= 0 {
+		d.options.Logf("cbdatasource: server: %s, uprOpenName: %s, %s,"+
+			" vbucketStates empty", server, uprOpenName, prefix)
+	}
+
+	// Key is VBucketState.State (ex: "", "running", "closing"),
+	// and value is array of vbid's.
+	byState := map[string]sort.IntSlice{}
+	for vbid, vbucketState := range vbucketStates {
+		byState[vbucketState.State] =
+			append(byState[vbucketState.State], int(vbid))
+	}
+
+	for state, vbids := range byState {
+		var buf bytes.Buffer
+
+		if len(vbids) > 0 {
+			first := true
+			emitRange := func(beg, end int) {
+				if !first {
+					fmt.Fprint(&buf, ", ")
+				}
+				if beg < end {
+					fmt.Fprintf(&buf, "%d-%d", beg, end)
+				} else {
+					fmt.Fprintf(&buf, "%d", beg)
+				}
+				first = false
+			}
+
+			sort.Sort(vbids)
+
+			vbidRangeBeg := vbids[0]
+			vbidRangeEnd := vbids[0]
+
+			for i := 1; i < len(vbids); i++ {
+				vbid := vbids[i]
+				if vbid > vbidRangeEnd+1 {
+					emitRange(vbidRangeBeg, vbidRangeEnd)
+					vbidRangeBeg = vbid
+				}
+				vbidRangeEnd = vbid
+			}
+
+			emitRange(vbidRangeBeg, vbidRangeEnd)
+		}
+
+		d.options.Logf("cbdatasource: server: %s, uprOpenName: %s, %s,"+
+			" vbucketState: %q (has %d vbuckets), %s",
+			server, uprOpenName, prefix, state, len(vbids), buf.String())
+	}
+}
+
+// --------------------------------------------------------------
+
 type bucketWrapper struct {
 	b *couchbase.Bucket
 }