Add HashiCorp Nomad provider (#483)

* provider: adding Nomad provider

* updating CONTRIBUTING.md with Nomad provider

* updated README.md by adding the Nomad provider

* fix typo

* adding nomad/api and nomad/testutil deps

* adding Nomad binary dependency for provider tests

* fixed the nomad binary download command step and added tolerations to the nomad provider.

* adding nomad provider demo gif

* adding my name to authors

* adding two missing go-rootcerts files after dep ensure

* delete pod comment

vendor/github.com/hashicorp/go-sockaddr/ipaddr.go

@@ -0,0 +1,169 @@
+package sockaddr
+
+import (
+	"fmt"
+	"math/big"
+	"net"
+	"strings"
+)
+
+// Constants for the sizes of IPv3, IPv4, and IPv6 address types.
+const (
+	IPv3len = 6
+	IPv4len = 4
+	IPv6len = 16
+)
+
+// IPAddr is a generic IP address interface for IPv4 and IPv6 addresses,
+// networks, and socket endpoints.
+type IPAddr interface {
+	SockAddr
+	AddressBinString() string
+	AddressHexString() string
+	Cmp(SockAddr) int
+	CmpAddress(SockAddr) int
+	CmpPort(SockAddr) int
+	FirstUsable() IPAddr
+	Host() IPAddr
+	IPPort() IPPort
+	LastUsable() IPAddr
+	Maskbits() int
+	NetIP() *net.IP
+	NetIPMask() *net.IPMask
+	NetIPNet() *net.IPNet
+	Network() IPAddr
+	Octets() []int
+}
+
+// IPPort is the type for an IP port number for the TCP and UDP IP transports.
+type IPPort uint16
+
+// IPPrefixLen is a typed integer representing the prefix length for a given
+// IPAddr.
+type IPPrefixLen byte
+
+// ipAddrAttrMap is a map of the IPAddr type-specific attributes.
+var ipAddrAttrMap map[AttrName]func(IPAddr) string
+var ipAddrAttrs []AttrName
+
+func init() {
+	ipAddrInit()
+}
+
+// NewIPAddr creates a new IPAddr from a string.  Returns nil if the string is
+// not an IPv4 or an IPv6 address.
+func NewIPAddr(addr string) (IPAddr, error) {
+	ipv4Addr, err := NewIPv4Addr(addr)
+	if err == nil {
+		return ipv4Addr, nil
+	}
+
+	ipv6Addr, err := NewIPv6Addr(addr)
+	if err == nil {
+		return ipv6Addr, nil
+	}
+
+	return nil, fmt.Errorf("invalid IPAddr %v", addr)
+}
+
+// IPAddrAttr returns a string representation of an attribute for the given
+// IPAddr.
+func IPAddrAttr(ip IPAddr, selector AttrName) string {
+	fn, found := ipAddrAttrMap[selector]
+	if !found {
+		return ""
+	}
+
+	return fn(ip)
+}
+
+// IPAttrs returns a list of attributes supported by the IPAddr type
+func IPAttrs() []AttrName {
+	return ipAddrAttrs
+}
+
+// MustIPAddr is a helper method that must return an IPAddr or panic on invalid
+// input.
+func MustIPAddr(addr string) IPAddr {
+	ip, err := NewIPAddr(addr)
+	if err != nil {
+		panic(fmt.Sprintf("Unable to create an IPAddr from %+q: %v", addr, err))
+	}
+	return ip
+}
+
+// ipAddrInit is called once at init()
+func ipAddrInit() {
+	// Sorted for human readability
+	ipAddrAttrs = []AttrName{
+		"host",
+		"address",
+		"port",
+		"netmask",
+		"network",
+		"mask_bits",
+		"binary",
+		"hex",
+		"first_usable",
+		"last_usable",
+		"octets",
+	}
+
+	ipAddrAttrMap = map[AttrName]func(ip IPAddr) string{
+		"address": func(ip IPAddr) string {
+			return ip.NetIP().String()
+		},
+		"binary": func(ip IPAddr) string {
+			return ip.AddressBinString()
+		},
+		"first_usable": func(ip IPAddr) string {
+			return ip.FirstUsable().String()
+		},
+		"hex": func(ip IPAddr) string {
+			return ip.AddressHexString()
+		},
+		"host": func(ip IPAddr) string {
+			return ip.Host().String()
+		},
+		"last_usable": func(ip IPAddr) string {
+			return ip.LastUsable().String()
+		},
+		"mask_bits": func(ip IPAddr) string {
+			return fmt.Sprintf("%d", ip.Maskbits())
+		},
+		"netmask": func(ip IPAddr) string {
+			switch v := ip.(type) {
+			case IPv4Addr:
+				ipv4Mask := IPv4Addr{
+					Address: IPv4Address(v.Mask),
+					Mask:    IPv4HostMask,
+				}
+				return ipv4Mask.String()
+			case IPv6Addr:
+				ipv6Mask := new(big.Int)
+				ipv6Mask.Set(v.Mask)
+				ipv6MaskAddr := IPv6Addr{
+					Address: IPv6Address(ipv6Mask),
+					Mask:    ipv6HostMask,
+				}
+				return ipv6MaskAddr.String()
+			default:
+				return fmt.Sprintf("<unsupported type: %T>", ip)
+			}
+		},
+		"network": func(ip IPAddr) string {
+			return ip.Network().NetIP().String()
+		},
+		"octets": func(ip IPAddr) string {
+			octets := ip.Octets()
+			octetStrs := make([]string, 0, len(octets))
+			for _, octet := range octets {
+				octetStrs = append(octetStrs, fmt.Sprintf("%d", octet))
+			}
+			return strings.Join(octetStrs, " ")
+		},
+		"port": func(ip IPAddr) string {
+			return fmt.Sprintf("%d", ip.IPPort())
+		},
+	}
+}