statsclient: added symlinks

[govpp.git] / adapter / statsclient / statseg_v2.go

diff --git a/adapter/statsclient/statseg_v2.go b/adapter/statsclient/statseg_v2.go
index 10bc5f5..16f1729 100644 (file)
--- a/adapter/statsclient/statseg_v2.go
+++ b/adapter/statsclient/statseg_v2.go
@@ -15,6 +15,8 @@
 package statsclient
 
 import (
+       "bytes"
+       "encoding/binary"
        "sync/atomic"
        "unsafe"
 
@@ -38,6 +40,7 @@ type sharedHeaderV2 struct {
 type statSegDirectoryEntryV2 struct {
        directoryType dirType
        // unionData can represent:
+       // - symlink indexes
        // - index
        // - value
        // - pointer to data
@@ -87,7 +90,7 @@ func (ss *statSegmentV2) GetEpoch() (int64, bool) {
        return sh.epoch, sh.inProgress != 0
 }
 
-func (ss *statSegmentV2) CopyEntryData(segment dirSegment) adapter.Stat {
+func (ss *statSegmentV2) CopyEntryData(segment dirSegment, index uint32) adapter.Stat {
        dirEntry := (*statSegDirectoryEntryV2)(segment)
        if dirEntry.unionData == 0 {
                debugf("data value or pointer not defined for %s", dirEntry.name)
@@ -135,11 +138,21 @@ func (ss *statSegmentV2) CopyEntryData(segment dirSegment) adapter.Stat {
                                continue
                        }
                        counterVectorLength := *(*uint32)(vectorLen(counterVector))
-                       data[i] = make([]adapter.Counter, counterVectorLength)
-                       for j := uint32(0); j < counterVectorLength; j++ {
-                               offset := uintptr(j) * unsafe.Sizeof(adapter.Counter(0))
-                               val := *(*adapter.Counter)(statSegPointer(counterVector, offset))
-                               data[i][j] = val
+                       if index == ^uint32(0) {
+                               data[i] = make([]adapter.Counter, counterVectorLength)
+                               for j := uint32(0); j < counterVectorLength; j++ {
+                                       offset := uintptr(j) * unsafe.Sizeof(adapter.Counter(0))
+                                       data[i][j] = *(*adapter.Counter)(statSegPointer(counterVector, offset))
+                               }
+                       } else {
+                               data[i] = make([]adapter.Counter, 1) // expect single value
+                               for j := uint32(0); j < counterVectorLength; j++ {
+                                       offset := uintptr(j) * unsafe.Sizeof(adapter.Counter(0))
+                                       if index == j {
+                                               data[i][0] = *(*adapter.Counter)(statSegPointer(counterVector, offset))
+                                               break
+                                       }
+                               }
                        }
                }
                return adapter.SimpleCounterStat(data)
@@ -160,11 +173,21 @@ func (ss *statSegmentV2) CopyEntryData(segment dirSegment) adapter.Stat {
                                continue
                        }
                        counterVectorLength := *(*uint32)(vectorLen(counterVector))
-                       data[i] = make([]adapter.CombinedCounter, counterVectorLength)
-                       for j := uint32(0); j < counterVectorLength; j++ {
-                               offset := uintptr(j) * unsafe.Sizeof(adapter.CombinedCounter{})
-                               val := *(*adapter.CombinedCounter)(statSegPointer(counterVector, offset))
-                               data[i][j] = val
+                       if index == ^uint32(0) {
+                               data[i] = make([]adapter.CombinedCounter, counterVectorLength)
+                               for j := uint32(0); j < counterVectorLength; j++ {
+                                       offset := uintptr(j) * unsafe.Sizeof(adapter.CombinedCounter{})
+                                       data[i][j] = *(*adapter.CombinedCounter)(statSegPointer(counterVector, offset))
+                               }
+                       } else {
+                               data[i] = make([]adapter.CombinedCounter, 1) // expect single value pair
+                               for j := uint32(0); j < counterVectorLength; j++ {
+                                       offset := uintptr(j) * unsafe.Sizeof(adapter.CombinedCounter{})
+                                       if index == j {
+                                               data[i][0] = *(*adapter.CombinedCounter)(statSegPointer(counterVector, offset))
+                                               break
+                                       }
+                               }
                        }
                }
                return adapter.CombinedCounterStat(data)
@@ -205,6 +228,22 @@ func (ss *statSegmentV2) CopyEntryData(segment dirSegment) adapter.Stat {
                return adapter.EmptyStat("<none>")
                // no-op
 
+       case statDirSymlink:
+               // prevent recursion loops
+               if index != ^uint32(0) {
+                       debugf("received symlink with defined item index")
+                       return nil
+               }
+               i1, i2 := ss.getSymlinkIndexes(dirEntry)
+               // use first index to get the stats directory the symlink points to
+               header := ss.loadSharedHeader(ss.sharedHeader)
+               dirVector := ss.adjust(dirVector(&header.dirVector))
+               statSegDir2 := dirSegment(uintptr(dirVector) + uintptr(i1)*unsafe.Sizeof(statSegDirectoryEntryV2{}))
+
+               // retry with actual stats segment and use second index to get
+               // stats for the required item
+               return ss.CopyEntryData(statSegDir2, i2)
+
        default:
                // TODO: monitor occurrences with metrics
                debugf("Unknown type %d for stat entry: %q", dirEntry.directoryType, dirEntry.name)
@@ -349,3 +388,22 @@ func (ss *statSegmentV2) getErrorVector() dirVector {
        header := ss.loadSharedHeader(ss.sharedHeader)
        return ss.adjust(dirVector(&header.errorVector))
 }
+
+func (ss *statSegmentV2) getSymlinkIndexes(dirEntry *statSegDirectoryEntryV2) (index1, index2 uint32) {
+       var b bytes.Buffer
+       if err := binary.Write(&b, binary.LittleEndian, dirEntry.unionData); err != nil {
+               debugf("error getting symlink indexes for %s: %v", dirEntry.name, err)
+               return
+       }
+       if len(b.Bytes()) != 8 {
+               debugf("incorrect symlink union data length for %s: expected 8, got %d", dirEntry.name, len(b.Bytes()))
+               return
+       }
+       for i := range b.Bytes()[:4] {
+               index1 += uint32(b.Bytes()[i]) << (uint32(i) * 8)
+       }
+       for i := range b.Bytes()[4:] {
+               index2 += uint32(b.Bytes()[i+4]) << (uint32(i) * 8)
+       }
+       return
+}