[#30] Make contract address configurable

Signed-off-by: Angira Kekteeva <kira@nspcc.ru>

plugin/nns/README.md

@@ -6,14 +6,20 @@
 
 ## Description
 
-The nns plugin try to get value from TXT records in provided neo node 
+The nns plugin tries to get value from TXT records in provided neo node 
 (lookup in [NNS smart contract](https://docs.neo.org/docs/en-us/reference/nns.html)).
 You can specify NNS domain to map DNS domain from request (default no mapping).
 
 ## Syntax
 
 ``` txt
-nns NEO_N3_CHAIN_ENDPOINT [NNS_DOMAIN]
+nns NEO_N3_CHAIN_ENDPOINT CONTRACT_ADDRESS [NNS_DOMAIN]
+```
+
+`CONTRACT_ADDRESS` - hex-encoded contract script hash. The value is required, but if you are using the NNS contract 
+in side-chain, you can place `-` and the plugin will use contract with ID 1 as NNS.
+``` txt
+nns NEO_N3_CHAIN_ENDPOINT - [NNS_DOMAIN]
 ```
 
 ## Examples
@@ -23,7 +29,7 @@ requests to 8.8.8.8 if the neo request fails.
 
 ``` corefile
 . {
-  nns http://localhost:30333
+  nns http://localhost:30333 acf433b55b75907fd80e8c90c9c42140992c8240
   forward . 8.8.8.8
 }
 ```
@@ -34,7 +40,7 @@ It also enables zone transfer support:
 
 ``` corefile
 containers.testnet.fs.neo.org {
-  nns http://morph_chain.neofs.devenv:30333 containers
+  nns http://morph-chain.neofs.devenv:30333 - containers
   transfer {
       to *
   }
@@ -45,7 +51,7 @@ If there is no domain filter in config:
 
 ``` corefile
 . {
-  nns http://morph_chain.neofs.devenv:30333 containers
+  nns http://morph-chain.neofs.devenv:30333 - containers
 }
 ```
 

plugin/nns/nns.go

@@ -13,17 +13,17 @@ import (
 	"github.com/coredns/coredns/request"
 	"github.com/miekg/dns"
 	nns "github.com/nspcc-dev/neo-go/examples/nft-nd-nns"
-	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/rpc/client"
+	"github.com/nspcc-dev/neo-go/pkg/util"
 )
 
 type NNS struct {
-	Next      plugin.Handler
-	Client    *client.Client
-	CS        *state.Contract
-	Log       clog.P
-	nnsDomain string
-	dnsDomain string
+	Next         plugin.Handler
+	Client       *client.Client
+	ContractHash util.Uint160
+	Log          clog.P
+	nnsDomain    string
+	dnsDomain    string
 }
 
 const dot = "."
@@ -51,7 +51,7 @@ func (n NNS) Name() string { return pluginName }
 // Transfer implements the transfer.Transfer interface.
 func (n NNS) Transfer(zone string, serial uint32) (<-chan []dns.RR, error) {
 	trimmedZone := n.prepareName(zone)
-	records, err := getRecords(n.Client, n.CS.Hash, trimmedZone, nns.RecordType(dns.TypeSOA))
+	records, err := getRecords(n.Client, n.ContractHash, trimmedZone, nns.RecordType(dns.TypeSOA))
 	if err != nil {
 		n.Log.Warningf("couldn't transfer zone '%s' as '%s': %s", zone, trimmedZone, err.Error())
 		return nil, transfer.ErrNotAuthoritative
@@ -104,7 +104,7 @@ func (n NNS) resolveRecords(state request.Request) ([]dns.RR, error) {
 		return nil, fmt.Errorf("cannot resolve '%s' (type %d) as '%s': %w", state.QName(), state.QType(), name, err)
 	}
 
-	resolved, err := resolve(n.Client, n.CS.Hash, name, nnsType)
+	resolved, err := resolve(n.Client, n.ContractHash, name, nnsType)
 	if err != nil {
 		return nil, fmt.Errorf("cannot resolve '%s' (type %d) as '%s': %w", state.QName(), state.QType(), name, err)
 	}
@@ -118,7 +118,7 @@ func (n NNS) resolveRecords(state request.Request) ([]dns.RR, error) {
 }
 
 func (n NNS) zoneTransfer(name string) ([]dns.RR, error) {
-	records, err := getAllRecords(n.Client, n.CS.Hash, name)
+	records, err := getAllRecords(n.Client, n.ContractHash, name)
 	if err != nil {
 		return nil, err
 	}

plugin/nns/setup.go

@@ -10,10 +10,17 @@ import (
 	"github.com/coredns/coredns/plugin"
 	clog "github.com/coredns/coredns/plugin/pkg/log"
 	"github.com/nspcc-dev/neo-go/pkg/rpc/client"
+	"github.com/nspcc-dev/neo-go/pkg/util"
 )
 
 const pluginName = "nns"
 
+type Params struct {
+	Endpoint     string
+	ContractHash util.Uint160
+	Domain       string
+}
+
 func init() {
 	plugin.Register(pluginName, setup)
 }
@@ -24,33 +31,41 @@ func setup(c *caddy.Controller) error {
 		return plugin.Error(pluginName, c.Err(err.Error()))
 	}
 
-	endpoint, nnsDomain, err := parseArgs(c)
+	args, err := parseArgs(c)
 	if err != nil {
 		return err
 	}
 
-	cli, err := client.New(context.TODO(), endpoint, client.Options{})
+	cli, err := client.New(context.TODO(), args.Endpoint, client.Options{})
 	if err != nil {
 		return plugin.Error(pluginName, c.Err(err.Error()))
 	}
 	if err := cli.Init(); err != nil {
 		return plugin.Error(pluginName, c.Err(err.Error()))
 	}
 
-	cs, err := cli.GetContractStateByID(1)
-	if err != nil {
-		return plugin.Error(pluginName, c.Err(err.Error()))
+	if args.ContractHash.Equals(util.Uint160{}) {
+		cs, err := cli.GetContractStateByID(1)
+		if err != nil {
+			return plugin.Error(pluginName, c.Err(err.Error()))
+		}
+		args.ContractHash = cs.Hash
+	} else {
+		_, err := cli.GetContractStateByHash(args.ContractHash)
+		if err != nil {
+			return plugin.Error(pluginName, c.Err(err.Error()))
+		}
 	}
 
 	// Add the Plugin to CoreDNS, so Servers can use it in their plugin chain.
 	dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
 		nns := &NNS{
-			Next:   next,
-			Client: cli,
-			CS:     cs,
-			Log:    clog.NewWithPlugin(pluginName),
+			Next:         next,
+			Client:       cli,
+			ContractHash: args.ContractHash,
+			Log:          clog.NewWithPlugin(pluginName),
 		}
-		nns.setNNSDomain(nnsDomain)
+		nns.setNNSDomain(args.Domain)
 		nns.setDNSDomain(URL.Hostname())
 
 		return *nns
@@ -59,23 +74,36 @@ func setup(c *caddy.Controller) error {
 	return nil
 }
 
-func parseArgs(c *caddy.Controller) (string, string, error) {
+func parseArgs(c *caddy.Controller) (*Params, error) {
 	c.Next()
 	args := c.RemainingArgs()
-	if len(args) < 1 || len(args) > 2 {
-		return "", "", plugin.Error(pluginName, fmt.Errorf("support the following args template: 'NEO_CHAIN_ENDPOINT [NNS_DOMAIN]'"))
+	var (
+		err error
+		res Params
+	)
+
+	if len(args) < 2 || len(args) > 3 {
+		return nil, plugin.Error(pluginName, fmt.Errorf("support the following args template: 'NEO_CHAIN_ENDPOINT CONTRACT_ADDRESS [NNS_DOMAIN]'"))
 	}
-	endpoint := args[0]
-	if URL, err := url.Parse(endpoint); err != nil {
-		return "", "", plugin.Error(pluginName, fmt.Errorf("couldn't parse endpoint: %w", err))
+
+	res.Endpoint = args[0]
+	if URL, err := url.Parse(res.Endpoint); err != nil {
+		return nil, plugin.Error(pluginName, fmt.Errorf("couldn't parse endpoint: %w", err))
 	} else if URL.Scheme == "" || URL.Port() == "" {
-		return "", "", plugin.Error(pluginName, fmt.Errorf("invalid endpoint: %s", endpoint))
+		return nil, plugin.Error(pluginName, fmt.Errorf("invalid endpoint: %s", res.Endpoint))
+	}
+
+	hexStr := args[1]
+	if hexStr != "-" {
+		res.ContractHash, err = util.Uint160DecodeStringLE(hexStr)
+		if err != nil {
+			return nil, plugin.Error(pluginName, fmt.Errorf("invalid nns contract address"))
+		}
 	}
 
-	nnsDomain := ""
-	if len(args) == 2 {
-		nnsDomain = args[1]
+	if len(args) == 3 {
+		res.Domain = args[2]
 	}
 
-	return endpoint, nnsDomain, nil
+	return &res, nil
 }