[FAB-6719] Allow system chaincode plugins

Change-Id: I2db25bdfd8ebffbcb22c3d7374364f6d2d8a6fd6
Signed-off-by: Divyank Katira <Divyank.Katira@securekey.com>

Author: d1vyank

core/scc/buildtags_experimental_test.go

@@ -0,0 +1,11 @@
+// +build experimental
+
+/*
+Copyright SecureKey Technologies Inc. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package scc
+
+var goBuildTags = "experimental"

core/scc/buildtags_test.go

@@ -0,0 +1,11 @@
+// +build !experimental
+
+/*
+Copyright SecureKey Technologies Inc. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package scc
+
+var goBuildTags = ""

core/scc/importsysccs.go

@@ -84,6 +84,8 @@ var systemChaincodes = []*SystemChaincode{
 //RegisterSysCCs is the hook for system chaincodes where system chaincodes are registered with the fabric
 //note the chaincode must still be deployed and launched like a user chaincode will be
 func RegisterSysCCs() {
+	systemChaincodes = append(systemChaincodes, loadSysCCs()...)
+
 	var aclProvider aclmgmt.ACLProvider
 	for _, sysCC := range systemChaincodes {
 		if reg, _ := registerSysCC(sysCC); reg {

core/scc/loadsysccs.go

@@ -0,0 +1,90 @@
+/*
+Copyright SecureKey Technologies Inc. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package scc
+
+import (
+	"fmt"
+	"os"
+	"plugin"
+	"sync"
+
+	"github.com/hyperledger/fabric/common/viperutil"
+	"github.com/hyperledger/fabric/core/chaincode/shim"
+	"github.com/pkg/errors"
+)
+
+const (
+	sccFactoryMethod = "New"
+)
+
+// PluginConfig SCC plugin configuration
+type PluginConfig struct {
+	Enabled           bool   `mapstructure:"enabled" yaml:"enabled"`
+	Name              string `mapstructure:"name" yaml:"name"`
+	Path              string `mapstructure:"path" yaml:"path"`
+	InvokableExternal bool   `mapstructure:"invokableExternal" yaml:"invokableExternal"`
+	InvokableCC2CC    bool   `mapstructure:"invokableCC2CC" yaml:"invokableCC2CC"`
+}
+
+var once sync.Once
+var sccPlugins []*SystemChaincode
+
+// loadSysCCs reads system chaincode plugin configuration and loads them
+func loadSysCCs() []*SystemChaincode {
+	once.Do(func() {
+		var config []*PluginConfig
+		err := viperutil.EnhancedExactUnmarshalKey("chaincode.systemPlugins", &config)
+		if err != nil {
+			panic(errors.WithMessage(err, "could not load YAML config"))
+		}
+		loadSysCCsWithConfig(config)
+	})
+	return sccPlugins
+}
+
+func loadSysCCsWithConfig(configs []*PluginConfig) {
+	for _, conf := range configs {
+		plugin := loadPlugin(conf.Path)
+		chaincode := &SystemChaincode{
+			Enabled:           conf.Enabled,
+			Name:              conf.Name,
+			Path:              conf.Path,
+			Chaincode:         *plugin,
+			InvokableExternal: conf.InvokableExternal,
+			InvokableCC2CC:    conf.InvokableCC2CC,
+		}
+		sccPlugins = append(sccPlugins, chaincode)
+		sysccLogger.Infof("Successfully loaded SCC %s from path %s", chaincode.Name, chaincode.Path)
+	}
+}
+
+func loadPlugin(path string) *shim.Chaincode {
+	if _, err := os.Stat(path); err != nil {
+		panic(fmt.Errorf("Could not find plugin at path %s: %s", path, err))
+	}
+
+	p, err := plugin.Open(path)
+	if err != nil {
+		panic(fmt.Errorf("Error opening plugin at path %s: %s", path, err))
+	}
+
+	sccFactorySymbol, err := p.Lookup(sccFactoryMethod)
+	if err != nil {
+		panic(fmt.Errorf(
+			"Could not find symbol %s. Plugin must export this method", sccFactoryMethod))
+	}
+
+	sccFactory, ok := sccFactorySymbol.(func() shim.Chaincode)
+	if !ok {
+		panic(fmt.Errorf("Function %s does not match expected definition func() shim.Chaincode",
+			sccFactoryMethod))
+	}
+
+	scc := sccFactory()
+
+	return &scc
+}

core/scc/loadsysccs_test.go

@@ -0,0 +1,65 @@
+// +build go1.9,linux,cgo
+// +build !ppc64le
+
+/*
+Copyright SecureKey Technologies Inc. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package scc
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"os/exec"
+	"testing"
+
+	"github.com/hyperledger/fabric/core/chaincode/shim"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/assert"
+)
+
+const (
+	examplePluginPackage = "github.com/hyperledger/fabric/examples/plugins/scc"
+	pluginName           = "testscc"
+)
+
+var pluginPath = os.TempDir() + "/scc-plugin.so"
+
+func TestLoadSCCPlugin(t *testing.T) {
+	buildExamplePlugin(pluginPath, examplePluginPackage)
+	defer os.Remove(pluginPath)
+
+	testConfig := fmt.Sprintf(`
+  chaincode:
+    systemPlugins:
+      - enabled: true
+        name: %s
+        path: %s
+        invokableExternal: true
+        invokableCC2CC: true
+  `, pluginName, pluginPath)
+	viper.SetConfigType("yaml")
+	viper.ReadConfig(bytes.NewBuffer([]byte(testConfig)))
+
+	sccs := loadSysCCs()
+	assert.Len(t, sccs, 1, "expected one SCC to be loaded")
+	resp := sccs[0].Chaincode.Invoke(nil)
+	assert.Equal(t, int32(shim.OK), resp.Status, "expected success response from scc")
+}
+
+func TestLoadSCCPluginInvalid(t *testing.T) {
+	assert.Panics(t, func() { loadPlugin("/invalid/path.so") },
+		"expected panic with invalid path")
+}
+
+func buildExamplePlugin(path, pluginPackage string) {
+	cmd := exec.Command("go", "build", "-tags", goBuildTags, "-o", path, "-buildmode=plugin",
+		pluginPackage)
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		panic(fmt.Errorf("Error: %s, Could not build plugin: %s", err, string(output)))
+	}
+}

core/scc/scc_test.go

@@ -33,7 +33,6 @@ func init() {
 	viper.Set("chaincode.system", map[string]string{"lscc": "enable", "a": "enable"})
 	viper.Set("peer.fileSystemPath", os.TempDir())
 	ccprovider.RegisterChaincodeProviderFactory(&ccprovider2.MockCcProviderFactory{})
-	RegisterSysCCs()
 }
 
 func TestDeploy(t *testing.T) {
@@ -103,6 +102,8 @@ func TestMockRegisterAndResetSysCCs(t *testing.T) {
 }
 
 func TestRegisterSysCC(t *testing.T) {
+	assert.NotPanics(t, func() { RegisterSysCCs() }, "expected successful init")
+
 	_, err := registerSysCC(&SystemChaincode{
 		Name:    "lscc",
 		Path:    "path",

examples/plugins/scc/plugin.go

@@ -0,0 +1,31 @@
+/*
+Copyright SecureKey Technologies Inc. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package main
+
+import (
+	"github.com/hyperledger/fabric/core/chaincode/shim"
+	pb "github.com/hyperledger/fabric/protos/peer"
+)
+
+// New returns an implementation of the chaincode interface
+func New() shim.Chaincode {
+	return &scc{}
+}
+
+type scc struct{}
+
+// Init implements the chaincode shim interface
+func (s *scc) Init(stub shim.ChaincodeStubInterface) pb.Response {
+	return shim.Success(nil)
+}
+
+// Invoke implements the chaincode shim interface
+func (s *scc) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
+	return shim.Success(nil)
+}
+
+func main() {}

sampleconfig/core.yaml

@@ -446,6 +446,20 @@ chaincode:
         qscc: enable
         rscc: disable
 
+    # System chaincode plugins: in addition to being imported and compiled
+    # into fabric through core/chaincode/importsysccs.go, system chaincodes
+    # can also be loaded as shared objects compiled as Go plugins.
+    # See examples/plugins/scc for an example.
+    # Like regular system chaincodes, plugins must also be white listed in the
+    # chaincode.system section above.
+    systemPlugins:
+      # example configuration:
+      # - enabled: true
+      #   name: myscc
+      #   path: /opt/lib/myscc.so
+      #   invokableExternal: true
+      #   invokableCC2CC: true
+
     # Logging section for the chaincode container
     logging:
       # Default level for all loggers within the chaincode container
@@ -534,4 +548,4 @@ metrics:
         promReporter:
 
               # prometheus http server listen address for pull metrics
-              listenAddress: 0.0.0.0:8080
+              listenAddress: 0.0.0.0:8080