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/sockaddrs.go

@@ -0,0 +1,193 @@
+package sockaddr
+
+import (
+	"bytes"
+	"sort"
+)
+
+// SockAddrs is a slice of SockAddrs
+type SockAddrs []SockAddr
+
+func (s SockAddrs) Len() int      { return len(s) }
+func (s SockAddrs) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+
+// CmpAddrFunc is the function signature that must be met to be used in the
+// OrderedAddrBy multiAddrSorter
+type CmpAddrFunc func(p1, p2 *SockAddr) int
+
+// multiAddrSorter implements the Sort interface, sorting the SockAddrs within.
+type multiAddrSorter struct {
+	addrs SockAddrs
+	cmp   []CmpAddrFunc
+}
+
+// Sort sorts the argument slice according to the Cmp functions passed to
+// OrderedAddrBy.
+func (ms *multiAddrSorter) Sort(sockAddrs SockAddrs) {
+	ms.addrs = sockAddrs
+	sort.Sort(ms)
+}
+
+// OrderedAddrBy sorts SockAddr by the list of sort function pointers.
+func OrderedAddrBy(cmpFuncs ...CmpAddrFunc) *multiAddrSorter {
+	return &multiAddrSorter{
+		cmp: cmpFuncs,
+	}
+}
+
+// Len is part of sort.Interface.
+func (ms *multiAddrSorter) Len() int {
+	return len(ms.addrs)
+}
+
+// Less is part of sort.Interface. It is implemented by looping along the
+// Cmp() functions until it finds a comparison that is either less than,
+// equal to, or greater than.
+func (ms *multiAddrSorter) Less(i, j int) bool {
+	p, q := &ms.addrs[i], &ms.addrs[j]
+	// Try all but the last comparison.
+	var k int
+	for k = 0; k < len(ms.cmp)-1; k++ {
+		cmp := ms.cmp[k]
+		x := cmp(p, q)
+		switch x {
+		case -1:
+			// p < q, so we have a decision.
+			return true
+		case 1:
+			// p > q, so we have a decision.
+			return false
+		}
+		// p == q; try the next comparison.
+	}
+	// All comparisons to here said "equal", so just return whatever the
+	// final comparison reports.
+	switch ms.cmp[k](p, q) {
+	case -1:
+		return true
+	case 1:
+		return false
+	default:
+		// Still a tie! Now what?
+		return false
+	}
+}
+
+// Swap is part of sort.Interface.
+func (ms *multiAddrSorter) Swap(i, j int) {
+	ms.addrs[i], ms.addrs[j] = ms.addrs[j], ms.addrs[i]
+}
+
+const (
+	// NOTE (sean@): These constants are here for code readability only and
+	// are sprucing up the code for readability purposes.  Some of the
+	// Cmp*() variants have confusing logic (especially when dealing with
+	// mixed-type comparisons) and this, I think, has made it easier to grok
+	// the code faster.
+	sortReceiverBeforeArg = -1
+	sortDeferDecision     = 0
+	sortArgBeforeReceiver = 1
+)
+
+// AscAddress is a sorting function to sort SockAddrs by their respective
+// address type.  Non-equal types are deferred in the sort.
+func AscAddress(p1Ptr, p2Ptr *SockAddr) int {
+	p1 := *p1Ptr
+	p2 := *p2Ptr
+
+	switch v := p1.(type) {
+	case IPv4Addr:
+		return v.CmpAddress(p2)
+	case IPv6Addr:
+		return v.CmpAddress(p2)
+	case UnixSock:
+		return v.CmpAddress(p2)
+	default:
+		return sortDeferDecision
+	}
+}
+
+// AscPort is a sorting function to sort SockAddrs by their respective address
+// type.  Non-equal types are deferred in the sort.
+func AscPort(p1Ptr, p2Ptr *SockAddr) int {
+	p1 := *p1Ptr
+	p2 := *p2Ptr
+
+	switch v := p1.(type) {
+	case IPv4Addr:
+		return v.CmpPort(p2)
+	case IPv6Addr:
+		return v.CmpPort(p2)
+	default:
+		return sortDeferDecision
+	}
+}
+
+// AscPrivate is a sorting function to sort "more secure" private values before
+// "more public" values.  Both IPv4 and IPv6 are compared against RFC6890
+// (RFC6890 includes, and is not limited to, RFC1918 and RFC6598 for IPv4, and
+// IPv6 includes RFC4193).
+func AscPrivate(p1Ptr, p2Ptr *SockAddr) int {
+	p1 := *p1Ptr
+	p2 := *p2Ptr
+
+	switch v := p1.(type) {
+	case IPv4Addr, IPv6Addr:
+		return v.CmpRFC(6890, p2)
+	default:
+		return sortDeferDecision
+	}
+}
+
+// AscNetworkSize is a sorting function to sort SockAddrs based on their network
+// size.  Non-equal types are deferred in the sort.
+func AscNetworkSize(p1Ptr, p2Ptr *SockAddr) int {
+	p1 := *p1Ptr
+	p2 := *p2Ptr
+	p1Type := p1.Type()
+	p2Type := p2.Type()
+
+	// Network size operations on non-IP types make no sense
+	if p1Type != p2Type && p1Type != TypeIP {
+		return sortDeferDecision
+	}
+
+	ipA := p1.(IPAddr)
+	ipB := p2.(IPAddr)
+
+	return bytes.Compare([]byte(*ipA.NetIPMask()), []byte(*ipB.NetIPMask()))
+}
+
+// AscType is a sorting function to sort "more secure" types before
+// "less-secure" types.
+func AscType(p1Ptr, p2Ptr *SockAddr) int {
+	p1 := *p1Ptr
+	p2 := *p2Ptr
+	p1Type := p1.Type()
+	p2Type := p2.Type()
+	switch {
+	case p1Type < p2Type:
+		return sortReceiverBeforeArg
+	case p1Type == p2Type:
+		return sortDeferDecision
+	case p1Type > p2Type:
+		return sortArgBeforeReceiver
+	default:
+		return sortDeferDecision
+	}
+}
+
+// FilterByType returns two lists: a list of matched and unmatched SockAddrs
+func (sas SockAddrs) FilterByType(type_ SockAddrType) (matched, excluded SockAddrs) {
+	matched = make(SockAddrs, 0, len(sas))
+	excluded = make(SockAddrs, 0, len(sas))
+
+	for _, sa := range sas {
+		if sa.Type()&type_ != 0 {
+			matched = append(matched, sa)
+		} else {
+			excluded = append(excluded, sa)
+		}
+	}
+	return matched, excluded
+}