Use SPF Viper for configuration

Closes #68 (closed)

forks/goarista/gnmi/arbitration.go

+// Copyright (c) 2019 Arista Networks, Inc.
+// Use of this source code is governed by the Apache License 2.0
+// that can be found in the COPYING file.
+
+package gnmi
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/openconfig/gnmi/proto/gnmi_ext"
+)
+
+// ArbitrationExt takes a string representation of a master arbitration value
+// (e.g. "23", "role:42") and return a *gnmi_ext.Extension.
+func ArbitrationExt(s string) (*gnmi_ext.Extension, error) {
+	if s == "" {
+		return nil, nil
+	}
+	roleID, electionID, err := parseArbitrationString(s)
+	if err != nil {
+		return nil, err
+	}
+	arb := &gnmi_ext.MasterArbitration{
+		Role:       &gnmi_ext.Role{Id: roleID},
+		ElectionId: &gnmi_ext.Uint128{High: 0, Low: electionID},
+	}
+	ext := gnmi_ext.Extension_MasterArbitration{MasterArbitration: arb}
+	return &gnmi_ext.Extension{Ext: &ext}, nil
+}
+
+// parseArbitrationString parses the supplied string and returns the role and election id
+// values. Input is of the form [<role>:]<election_id>, where election_id is a uint64.
+//
+// Examples:
+//  "1"
+//  "admin:42"
+func parseArbitrationString(s string) (string, uint64, error) {
+	tokens := strings.Split(s, ":")
+	switch len(tokens) {
+	case 1: // just election id
+		id, err := parseElectionID(tokens[0])
+		return "", id, err
+	case 2: // role and election id
+		id, err := parseElectionID(tokens[1])
+		return tokens[0], id, err
+	}
+	return "", 0, fmt.Errorf("badly formed arbitration id (%s)", s)
+}
+
+func parseElectionID(s string) (uint64, error) {
+	id, err := strconv.ParseUint(s, 0, 64)
+	if err != nil {
+		return 0, fmt.Errorf("badly formed arbitration id (%s)", s)
+	}
+	return id, nil
+}