statsclient: allow index as pattern

* ListStats() returns stats identifiers containing the stat name and index
* New method PrepareDirOnIndex(indexes...). Instead of the name filter
  it does not browse through all available indexes
* Stats example shows how to get the last epoch value (added "e" or "epoch" command)

Change-Id: Ibb15090fb0dfdb7f9b0ecf8ac07a5eb9a9ace8f8
Signed-off-by: Vladimir Lavor <vlavor@cisco.com>

2 files changed, 19 insertions, 5 deletions

diff --git a/adapter/vppapiclient/stat_client.go b/adapter/vppapiclient/stat_client.go
index a124f59..734c158 100644
--- a/adapter/vppapiclient/stat_client.go
+++ b/adapter/vppapiclient/stat_client.go
@@ -83,7 +83,7 @@ func (c *statClient) Disconnect() error {
 	return nil
 }
 
-func (c *statClient) ListStats(patterns ...string) (stats []string, err error) {
+func (c *statClient) ListStats(patterns ...string) (indexes []adapter.StatIdentifier, err error) {
 	dir := C.govpp_stat_segment_ls(convertStringSlice(patterns))
 	if dir == nil {
 		return nil, adapter.ErrStatsDataBusy
@@ -93,11 +93,14 @@ func (c *statClient) ListStats(patterns ...string) (stats []string, err error) {
 	l := C.govpp_stat_segment_vec_len(unsafe.Pointer(dir))
 	for i := 0; i < int(l); i++ {
 		nameChar := C.govpp_stat_segment_dir_index_to_name(dir, C.uint32_t(i))
-		stats = append(stats, C.GoString(nameChar))
+		indexes = append(indexes, adapter.StatIdentifier{
+			Name:  []byte(C.GoString(nameChar)),
+			Index: uint32(i),
+		})
 		C.free(unsafe.Pointer(nameChar))
 	}
 
-	return stats, nil
+	return indexes, nil
 }
 
 func (c *statClient) DumpStats(patterns ...string) (stats []adapter.StatEntry, err error) {
@@ -121,7 +124,10 @@ func (c *statClient) DumpStats(patterns ...string) (stats []adapter.StatEntry, e
 		typ := adapter.StatType(C.govpp_stat_segment_data_type(&v))
 
 		stat := adapter.StatEntry{
-			Name: []byte(name),
+			StatIdentifier: adapter.StatIdentifier{
+				Name:  []byte(name),
+				Index: uint32(i),
+			},
 			Type: typ,
 		}
 
@@ -184,6 +190,10 @@ func (c *statClient) PrepareDir(prefixes ...string) (*adapter.StatDir, error) {
 	return nil, adapter.ErrNotImplemented
 }
 
+func (c *statClient) PrepareDirOnIndex(indexes ...uint32) (*adapter.StatDir, error) {
+	return nil, adapter.ErrNotImplemented
+}
+
 func (c *statClient) UpdateDir(dir *adapter.StatDir) error {
 	return adapter.ErrNotImplemented
 }
diff --git a/adapter/vppapiclient/stat_client_stub.go b/adapter/vppapiclient/stat_client_stub.go
index c764391..856a1e3 100644
--- a/adapter/vppapiclient/stat_client_stub.go
+++ b/adapter/vppapiclient/stat_client_stub.go
@@ -36,7 +36,7 @@ func (*stubStatClient) Disconnect() error {
 	return nil
 }
 
-func (*stubStatClient) ListStats(patterns ...string) (statNames []string, err error) {
+func (*stubStatClient) ListStats(patterns ...string) (indexes []adapter.StatIdentifier, err error) {
 	return nil, adapter.ErrNotImplemented
 }
 
@@ -48,6 +48,10 @@ func (*stubStatClient) PrepareDir(prefixes ...string) (*adapter.StatDir, error)
 	return nil, adapter.ErrNotImplemented
 }
 
+func (*stubStatClient) PrepareDirOnIndex(indexes ...uint32) (*adapter.StatDir, error) {
+	return nil, adapter.ErrNotImplemented
+}
+
 func (*stubStatClient) UpdateDir(dir *adapter.StatDir) error {
 	return adapter.ErrNotImplemented
 }