api: Support sys/leader endpoint

api/sys_leader.go

@@ -0,0 +1,20 @@
+package api
+
+func (c *Sys) Leader() (*LeaderResponse, error) {
+	r := c.c.NewRequest("GET", "/v1/sys/leader")
+	resp, err := c.c.RawRequest(r)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	var result LeaderResponse
+	err = resp.DecodeJSON(&result)
+	return &result, err
+}
+
+type LeaderResponse struct {
+	HAEnabled     bool   `json:"ha_enabled"`
+	IsSelf        bool   `json:"is_self"`
+	LeaderAddress string `json:"leader_address"`
+}