// Find the children of a given span id.
func (store *dataStore) FindChildren(sid common.SpanId, lim int32) []common.SpanId {
childIds := make([]common.SpanId, 0)
var err error
startIdx := store.getShardIndex(sid)
idx := startIdx
numShards := len(store.shards)
for {
if lim == 0 {
break
}
shd := store.shards[idx]
childIds, lim, err = shd.FindChildren(sid, childIds, lim)
if err != nil {
store.lg.Errorf("Shard(%s): FindChildren(%s) error: %s\n",
shd.path, sid.String(), err.Error())
}
idx++
if idx >= numShards {
idx = 0
}
if idx == startIdx {
break
}
}
return childIds
}
// Find the child IDs of a given span ID.
func (hcl *Client) FindChildren(sid common.SpanId, lim int) ([]common.SpanId, error) {
buf, _, err := hcl.makeGetRequest(fmt.Sprintf("span/%s/children?lim=%d",
sid.String(), lim))
if err != nil {
return nil, err
}
var spanIds []common.SpanId
err = json.Unmarshal(buf, &spanIds)
if err != nil {
return nil, errors.New(fmt.Sprintf("Error: error unmarshalling response "+
"body %s: %s", string(buf), err.Error()))
}
return spanIds, nil
}
// Get information about a trace span. Returns nil, nil if the span was not found.
func (hcl *Client) FindSpan(sid common.SpanId) (*common.Span, error) {
buf, rc, err := hcl.makeGetRequest(fmt.Sprintf("span/%s", sid.String()))
if err != nil {
if rc == http.StatusNoContent {
return nil, nil
}
return nil, err
}
var span common.Span
err = json.Unmarshal(buf, &span)
if err != nil {
return nil, errors.New(fmt.Sprintf("Error unmarshalling response "+
"body %s: %s", string(buf), err.Error()))
}
return &span, nil
}
func (shd *shard) FindSpan(sid common.SpanId) *common.Span {
lg := shd.store.lg
primaryKey := append([]byte{SPAN_ID_INDEX_PREFIX}, sid.Val()...)
buf, err := shd.ldb.Get(shd.store.readOpts, primaryKey)
if err != nil {
if strings.Index(err.Error(), "NotFound:") != -1 {
return nil
}
lg.Warnf("Shard(%s): FindSpan(%s) error: %s\n",
shd.path, sid.String(), err.Error())
return nil
}
var span *common.Span
span, err = shd.decodeSpan(sid, buf)
if err != nil {
lg.Errorf("Shard(%s): FindSpan(%s) decode error: %s\n",
shd.path, sid.String(), err.Error())
return nil
}
return span
}
// Fill in the entry in the 'next' array for a specific shard.
func (src *source) populateNextFromShard(shardIdx int) {
lg := src.store.lg
var err error
iter := src.iters[shardIdx]
if iter == nil {
lg.Debugf("Can't populate: No more entries in shard %d\n", shardIdx)
return // There are no more entries in this shard.
}
if src.nexts[shardIdx] != nil {
lg.Debugf("No need to populate shard %d\n", shardIdx)
return // We already have a valid entry for this shard.
}
for {
if !iter.Valid() {
lg.Debugf("Can't populate: Iterator for shard %d is no longer valid.\n", shardIdx)
break // Can't read past end of DB
}
src.numRead[shardIdx]++
key := iter.Key()
if !bytes.HasPrefix(key, []byte{src.keyPrefix}) {
lg.Debugf("Can't populate: Iterator for shard %d does not have prefix %s\n",
shardIdx, string(src.keyPrefix))
break // Can't read past end of indexed section
}
var span *common.Span
var sid common.SpanId
if src.keyPrefix == SPAN_ID_INDEX_PREFIX {
// The span id maps to the span itself.
sid = common.SpanId(key[1:17])
span, err = src.store.shards[shardIdx].decodeSpan(sid, iter.Value())
if err != nil {
lg.Debugf("Internal error decoding span %s in shard %d: %s\n",
sid.String(), shardIdx, err.Error())
break
}
} else {
// With a secondary index, we have to look up the span by id.
sid = common.SpanId(key[9:25])
span = src.store.shards[shardIdx].FindSpan(sid)
if span == nil {
lg.Debugf("Internal error rehydrating span %s in shard %d\n",
sid.String(), shardIdx)
break
}
}
if src.pred.Op.IsDescending() {
iter.Prev()
} else {
iter.Next()
}
if src.pred.satisfiedBy(span) {
lg.Debugf("Populated valid span %v from shard %d.\n", sid, shardIdx)
src.nexts[shardIdx] = span // Found valid entry
return
} else {
lg.Debugf("Span %s from shard %d does not satisfy the predicate.\n",
sid.String(), shardIdx)
if src.numRead[shardIdx] <= 1 && mayRequireOneSkip(src.pred.Op) {
continue
}
// This and subsequent entries don't satisfy predicate
break
}
}
lg.Debugf("Closing iterator for shard %d.\n", shardIdx)
iter.Close()
src.iters[shardIdx] = nil
}
// Fill in the entry in the 'next' array for a specific shard.
func (src *source) populateNextFromShard(shardIdx int) {
lg := src.store.lg
var err error
iter := src.iters[shardIdx]
shdPath := src.shards[shardIdx].path
if iter == nil {
lg.Debugf("Can't populate: No more entries in shard %s\n", shdPath)
return // There are no more entries in this shard.
}
if src.nexts[shardIdx] != nil {
lg.Debugf("No need to populate shard %s\n", shdPath)
return // We already have a valid entry for this shard.
}
for {
if !iter.Valid() {
lg.Debugf("Can't populate: Iterator for shard %s is no longer valid.\n", shdPath)
break // Can't read past end of DB
}
src.numRead[shardIdx]++
key := iter.Key()
if len(key) < 1 {
lg.Warnf("Encountered invalid zero-byte key in shard %s.\n", shdPath)
break
}
ret := src.checkKeyPrefix(key[0], iter)
if ret == NOT_SATISFIED {
break // Can't read past end of indexed section
} else if ret == NOT_YET_SATISFIED {
if src.pred.Op.IsDescending() {
iter.Prev()
} else {
iter.Next()
}
continue // Try again because we are not yet at the indexed section.
}
var span *common.Span
var sid common.SpanId
if src.keyPrefix == SPAN_ID_INDEX_PREFIX {
// The span id maps to the span itself.
sid = common.SpanId(key[1:17])
span, err = src.shards[shardIdx].decodeSpan(sid, iter.Value())
if err != nil {
if lg.DebugEnabled() {
lg.Debugf("Internal error decoding span %s in shard %s: %s\n",
sid.String(), shdPath, err.Error())
}
break
}
} else {
// With a secondary index, we have to look up the span by id.
sid = common.SpanId(key[9:25])
span = src.shards[shardIdx].FindSpan(sid)
if span == nil {
if lg.DebugEnabled() {
lg.Debugf("Internal error rehydrating span %s in shard %s\n",
sid.String(), shdPath)
}
break
}
}
if src.pred.Op.IsDescending() {
iter.Prev()
} else {
iter.Next()
}
ret = src.pred.satisfiedBy(span)
if ret == SATISFIED {
if lg.DebugEnabled() {
lg.Debugf("Populated valid span %v from shard %s.\n", sid, shdPath)
}
src.nexts[shardIdx] = span // Found valid entry
return
}
if ret == NOT_SATISFIED {
// This and subsequent entries don't satisfy predicate
break
}
}
lg.Debugf("Closing iterator for shard %s.\n", shdPath)
iter.Close()
src.iters[shardIdx] = nil
}