FABG-936 Support minimal ccp for fabric samples (hyperledger#74)

The Fabcar sample in fabric-samples contains a minimal CCP definition with just a single gateway peer entry and no channel or orderer information.  It is also written to be run on a single dev system whereby hostnames need to be translated to localhost.  This commit adds support to the gateway package for:
- automatic creation of channel definition on invocation of `getNetwork(channelName)`
- support for translation of discovered peers/orderers to localhost via environment variable (DISCOVERY_AS_LOCALHOST)
Both of these align the behaviour with the Node and Java SDKs and are required to implement the Fabcar sample.

Signed-off-by: andrew-coleman <[email protected]>

pkg/gateway/gateway.go

@@ -7,28 +7,36 @@ SPDX-License-Identifier: Apache-2.0
 package gateway
 
 import (
-	"fmt"
+	"os"
+	"strings"
 	"time"
 
-	"github.com/hyperledger/fabric-sdk-go/pkg/client/msp"
+	fabricCaUtil "github.com/hyperledger/fabric-sdk-go/internal/github.com/hyperledger/fabric-ca/util"
 	"github.com/hyperledger/fabric-sdk-go/pkg/common/providers/context"
 	"github.com/hyperledger/fabric-sdk-go/pkg/common/providers/core"
+	"github.com/hyperledger/fabric-sdk-go/pkg/common/providers/fab"
 	mspProvider "github.com/hyperledger/fabric-sdk-go/pkg/common/providers/msp"
+	"github.com/hyperledger/fabric-sdk-go/pkg/core/cryptosuite"
 	"github.com/hyperledger/fabric-sdk-go/pkg/fabsdk"
+	"github.com/hyperledger/fabric-sdk-go/pkg/fabsdk/api"
 	"github.com/pkg/errors"
 )
 
 const (
-	defaultTimeout   = 5 * time.Minute
-	defaultDiscovery = true
+	defaultTimeout      = 5 * time.Minute
+	defaultDiscovery    = true
+	localhostEnvVarName = "DISCOVERY_AS_LOCALHOST"
 )
 
 // Gateway is the entry point to a Fabric network
 type Gateway struct {
-	sdk     *fabsdk.FabricSDK
-	options *gatewayOptions
-	cfg     core.ConfigBackend
-	org     string
+	sdk        *fabsdk.FabricSDK
+	options    *gatewayOptions
+	cfg        core.ConfigBackend
+	org        string
+	mspid      string
+	peers      []fab.PeerConfig
+	mspfactory api.MSPProviderFactory
 }
 
 type gatewayOptions struct {
@@ -58,14 +66,14 @@ func Connect(config ConfigOption, identity IdentityOption, options ...Option) (*
 		},
 	}
 
-	err := config(g)
+	err := identity(g)
 	if err != nil {
-		return nil, errors.Wrap(err, "Failed to apply config option")
+		return nil, errors.Wrap(err, "Failed to apply identity option")
 	}
 
-	err = identity(g)
+	err = config(g)
 	if err != nil {
-		return nil, errors.Wrap(err, "Failed to apply identity option")
+		return nil, errors.Wrap(err, "Failed to apply config option")
 	}
 
 	for _, option := range options {
@@ -81,14 +89,7 @@ func Connect(config ConfigOption, identity IdentityOption, options ...Option) (*
 // WithConfig configures the gateway from a network config, such as a ccp file.
 func WithConfig(config core.ConfigProvider) ConfigOption {
 	return func(gw *Gateway) error {
-		var err error
-		sdk, err := fabsdk.New(config)
-
-		if err != nil {
-			return err
-		}
-
-		gw.sdk = sdk
+		config = createGatewayConfigProvider(config, gw.getOrg)
 
 		configBackend, err := config()
 		if err != nil {
@@ -98,15 +99,38 @@ func WithConfig(config core.ConfigProvider) ConfigOption {
 			return errors.New("invalid config file")
 		}
 
-		cfg := configBackend[0]
-		gw.cfg = cfg
+		gw.cfg = configBackend[0]
 
-		value, ok := cfg.Lookup("client.organization")
+		value, ok := gw.cfg.Lookup("client.organization")
 		if !ok {
 			return errors.New("No client organization defined in the config")
 		}
 		gw.org = value.(string)
 
+		value, ok = gw.cfg.Lookup("organizations." + gw.org + ".mspid")
+		if !ok {
+			return errors.New("No client organization defined in the config")
+		}
+		gw.mspid = value.(string)
+
+		opts := []fabsdk.Option{}
+		if gw.mspfactory != nil {
+			opts = append(opts, fabsdk.WithMSPPkg(gw.mspfactory))
+		}
+
+		sdk, err := fabsdk.New(config, opts...)
+
+		if err != nil {
+			return err
+		}
+
+		gw.sdk = sdk
+
+		//  find the 'gateway' peers
+		ctx := sdk.Context()
+		client, _ := ctx()
+		gw.peers, _ = client.EndpointConfig().PeersConfig(gw.org)
+
 		return nil
 	}
 }
@@ -137,26 +161,22 @@ func WithSDK(sdk *fabsdk.FabricSDK) ConfigOption {
 // All operations under this gateway connection will be performed using this identity.
 func WithIdentity(wallet wallet, label string) IdentityOption {
 	return func(gw *Gateway) error {
-		mspClient, err := msp.New(gw.getSDK().Context(), msp.WithOrg(gw.getOrg()))
-		if err != nil {
-			return err
-		}
-
 		creds, err := wallet.Get(label)
 		if err != nil {
 			return err
 		}
 
-		var identity mspProvider.SigningIdentity
-		switch v := creds.(type) {
-		case *X509Identity:
-			identity, err = mspClient.CreateSigningIdentity(mspProvider.WithCert([]byte(v.Certificate())), mspProvider.WithPrivateKey([]byte(v.Key())))
-			if err != nil {
-				return err
-			}
+		privateKey, _ := fabricCaUtil.ImportBCCSPKeyFromPEMBytes([]byte(creds.(*X509Identity).Key()), cryptosuite.GetDefault(), true)
+		wid := &walletIdentity{
+			id:                    label,
+			mspID:                 creds.mspID(),
+			enrollmentCertificate: []byte(creds.(*X509Identity).Certificate()),
+			privateKey:            privateKey,
 		}
 
-		gw.options.Identity = identity
+		gw.options.Identity = wid
+		gw.mspfactory = &walletmsp{}
+
 		return nil
 	}
 }
@@ -189,29 +209,6 @@ func WithTimeout(timeout time.Duration) Option {
 	}
 }
 
-func (gw *Gateway) getSDK() *fabsdk.FabricSDK {
-	return gw.sdk
-}
-
-func (gw *Gateway) getOrg() string {
-	return gw.org
-}
-
-func (gw *Gateway) getPeersForOrg(org string) ([]string, error) {
-	value, ok := gw.cfg.Lookup("organizations." + org + ".peers")
-	if !ok {
-		return nil, errors.New("No client organization defined in the config")
-	}
-
-	val := value.([]interface{})
-	s := make([]string, len(val))
-	for i, v := range val {
-		s[i] = fmt.Sprint(v)
-	}
-
-	return s, nil
-}
-
 // GetNetwork returns an object representing a network channel.
 func (gw *Gateway) GetNetwork(name string) (*Network, error) {
 	var channelProvider context.ChannelProvider
@@ -228,3 +225,137 @@ func (gw *Gateway) GetNetwork(name string) (*Network, error) {
 func (gw *Gateway) Close() {
 	// future use
 }
+
+func (gw *Gateway) getOrg() string {
+	return gw.org
+}
+
+func createGatewayConfigProvider(config core.ConfigProvider, org func() string) func() ([]core.ConfigBackend, error) {
+	return func() ([]core.ConfigBackend, error) {
+		configBackend, err := config()
+		if err != nil {
+			return nil, err
+		}
+		if len(configBackend) != 1 {
+			return nil, errors.New("invalid config file")
+		}
+
+		cfg := configBackend[0]
+
+		lhConfig := make([]core.ConfigBackend, 0)
+		lhConfig = append(lhConfig, createGatewayConfig(cfg, org()))
+
+		return lhConfig, nil
+	}
+}
+
+func createGatewayConfig(backend core.ConfigBackend, org string) *gatewayConfig {
+	var matchers map[string][]map[string]string
+	if strings.ToUpper(os.Getenv(localhostEnvVarName)) == "TRUE" {
+		matchers = createLocalhostMappings()
+	}
+
+	var channelConfig map[string]map[string]map[string]map[string]bool
+	_, exists := backend.Lookup("channels")
+	if !exists {
+		channelConfig = createDefaultChannelConfig(backend, org)
+	}
+
+	return &gatewayConfig{
+		backend:    backend,
+		matchers:   matchers,
+		channelDef: channelConfig,
+	}
+}
+
+/* dynamically add the following to CCP:
+
+entityMatchers:
+  peer:
+    - pattern: ([^:]+):(\\d+)
+      urlSubstitutionExp: localhost:${2}
+      sslTargetOverrideUrlSubstitutionExp: ${1}
+      mappedHost: ${1}
+  peer:
+    - pattern: ([^:]+):(\\d+)
+      urlSubstitutionExp: localhost:${2}
+      sslTargetOverrideUrlSubstitutionExp: localhost
+      mappedHost: ${1}
+*/
+func createLocalhostMappings() map[string][]map[string]string {
+	matchers := make(map[string][]map[string]string)
+	peerMappings := make([]map[string]string, 0)
+	ordererMappings := make([]map[string]string, 0)
+	mappedHost := "${1}"
+
+	peerMapping := make(map[string]string)
+	peerMapping["pattern"] = "([^:]+):(\\d+)"
+	peerMapping["urlSubstitutionExp"] = "localhost:${2}"
+	peerMapping["sslTargetOverrideUrlSubstitutionExp"] = mappedHost
+	peerMapping["mappedHost"] = mappedHost
+	peerMappings = append(peerMappings, peerMapping)
+
+	matchers["peer"] = peerMappings
+
+	ordererMapping := make(map[string]string)
+	ordererMapping["pattern"] = "([^:]+):(\\d+)"
+	ordererMapping["urlSubstitutionExp"] = "localhost:${2}"
+	ordererMapping["sslTargetOverrideUrlSubstitutionExp"] = "localhost"
+	ordererMapping["mappedHost"] = mappedHost
+	ordererMappings = append(ordererMappings, ordererMapping)
+
+	matchers["orderer"] = ordererMappings
+	return matchers
+}
+
+/* dynamically add the following to CCP:
+
+channels:
+  _default:
+    peers:
+      <gateway_peer_name>:
+        endorsingPeer: true
+        chaincodeQuery: true
+        ledgerQuery: true
+        eventSource: true
+*/
+func createDefaultChannelConfig(backend core.ConfigBackend, org string) map[string]map[string]map[string]map[string]bool {
+	channels := make(map[string]map[string]map[string]map[string]bool)
+	_default := make(map[string]map[string]map[string]bool)
+	gateways := make(map[string]map[string]bool)
+	roles := make(map[string]bool)
+	roles["endorsingPeer"] = true
+	roles["chaincodeQuery"] = true
+	roles["ledgerQuery"] = true
+	roles["eventSource"] = true
+
+	value, ok := backend.Lookup("organizations." + org + ".peers")
+	if !ok {
+		return nil
+	}
+	arr := value.([]interface{})
+	for _, gatewayPeer := range arr {
+		gateways[gatewayPeer.(string)] = roles
+	}
+
+	_default["peers"] = gateways
+	channels["_default"] = _default
+	return channels
+}
+
+type gatewayConfig struct {
+	backend    core.ConfigBackend
+	matchers   map[string][]map[string]string
+	channelDef map[string]map[string]map[string]map[string]bool
+}
+
+func (gc *gatewayConfig) Lookup(key string) (interface{}, bool) {
+	if key == "entityMatchers" && gc.matchers != nil {
+		return gc.matchers, true
+	}
+	conf, exists := gc.backend.Lookup(key)
+	if key == "channels" && gc.channelDef != nil {
+		return gc.channelDef, true
+	}
+	return conf, exists
+}