Introduce StatsAPI and it's initial implementation

- this implementation is basically Go wrapper around VPP's vppapiclient C library

Change-Id: I6f53dc3e228868834bf3a8a00c686ad05e22f3dd
Signed-off-by: Ondrej Fabry <ofabry@cisco.com>

1 files changed, 86 insertions, 0 deletions

diff --git a/adapter/stats_api.go b/adapter/stats_api.go
new file mode 100644
index 0000000..8815aae
--- /dev/null
+++ b/adapter/stats_api.go
@@ -0,0 +1,86 @@
+package adapter
+
+// StatsAPI provides connection to VPP stats API.
+type StatsAPI interface {
+	// Connect establishes client connection to the stats API.
+	Connect() error
+
+	// Disconnect terminates client connection.
+	Disconnect() error
+
+	// ListStats lists names for all stats.
+	ListStats(patterns ...string) (statNames []string, err error)
+
+	// DumpStats dumps all stat entries.
+	DumpStats(patterns ...string) ([]*StatEntry, error)
+}
+
+// StatType represents type of stat directory and simply
+// defines what type of stat data is stored in the stat entry.
+type StatType int
+
+const (
+	_ StatType = iota
+	ScalarIndex
+	SimpleCounterVector
+	CombinedCounterVector
+	ErrorIndex
+)
+
+func (d StatType) String() string {
+	switch d {
+	case ScalarIndex:
+		return "ScalarIndex"
+	case SimpleCounterVector:
+		return "SimpleCounterVector"
+	case CombinedCounterVector:
+		return "CombinedCounterVector"
+	case ErrorIndex:
+		return "ErrorIndex"
+	}
+	return "UnknownStatType"
+}
+
+// StatEntry represents single stat entry. The type of stat stored in Data
+// is defined by Type.
+type StatEntry struct {
+	Name string
+	Type StatType
+	Data Stat
+}
+
+// Counter represents simple counter with single value.
+type Counter uint64
+
+// CombinedCounter represents counter with two values, for packet count and bytes count.
+type CombinedCounter struct {
+	Packets Counter
+	Bytes   Counter
+}
+
+// ScalarStat represents stat for ScalarIndex.
+type ScalarStat float64
+
+// ErrorStat represents stat for ErrorIndex.
+type ErrorStat uint64
+
+// SimpleCounterStat represents stat for SimpleCounterVector.
+// The outer array represents workers and the inner array represents sw_if_index.
+// Values should be aggregated per interface for every worker.
+type SimpleCounterStat [][]Counter
+
+// CombinedCounterStat represents stat for CombinedCounterVector.
+// The outer array represents workers and the inner array represents sw_if_index.
+// Values should be aggregated per interface for every worker.
+type CombinedCounterStat [][]CombinedCounter
+
+// Data represents some type of stat which is usually defined by StatType.
+type Stat interface {
+	// isStat is unexported to limit implementations of Data interface to this package,
+	isStat()
+}
+
+func (ScalarStat) isStat()          {}
+func (ErrorStat) isStat()           {}
+func (SimpleCounterStat) isStat()   {}
+func (CombinedCounterStat) isStat() {}