Fabric-samples开发模式下chaincode操作流程及错误锦集

首先简单介绍一下此次流程步骤，在go build阶段出现问题，然后说明一下如何解决的问题。
出现的问题的提示代码为：
问题1、go: github.com/hyperledger/[email protected]: Get "https://proxy.golang.org/github.com/hyperledger/fabric-chaincode-go/@v/v0.0.0-20190823162523-04390e015b85.mod": dial tcp 216.58.200.49:443: connect: connection refused

解决方案1：执行以下命令
$ go env -w GO111MODULE=on
$ go env -w GOPROXY=https://goproxy.io,direct
然后再执行go build，不再出现此类错误

问题2：go build github.com/hyperledger/fabric-samples/chaincode/sacc: copying /tmp/go-build462413933/b001/exe/a.out: open sacc: permission denied

解决方案2：
经分析，应该是权限问题，尝试很多办法，包括更改文件夹权限777等，最终发现更改文件夹权限无法作用到docker容器中，所以采用直接简单的一种方法，那就是以root身份进入容器执行各种操作。进入chaincode容器的指令如下：$ docker exec -it -u root chaincode sh

问题3：Error starting SimpleAsset chaincode: flag 'peer.address' must be set

解决方案3：尚未解决，各位大佬如果知道解决方案请留言

Fabric-samples开发模式下chaincode操作流程步骤：

1、在$GOPATH下的src文件夹下建立一个sacc文件，并创建一个sacc.go文件进行chaincode编码

$ mkdir -p $GOPATH/src/sacc && cd $GOPATH/src/sacc
$ touch sacc.go

2、在sacc.go中进行编码，编写Init、Invoke、set、get等函数，进行整合。具体的代码如下：

package main
import(
	"fmt"
	"github.com/hyperledger/fabric-chaincode-go/shim"
	"github.com/hyperledger/fabric-protos-go/peer"

)

// SimpleAsset implements a simple chaincode to manage an asset
type SimpleAsset struct {
	
}

// Init is called during chaincode Instantiation to initialize any data
// Note that chaincodeee upgrade also calls this function to reset or to migrate data,
// so be careful to avoid a scenario where you inadvertently clobber your ledger's data
func (t *SimpleAsset) Init(stub shim.ChaincodeStubInterface) peer.Response{
	// Get the args from the transaction proposal
	args := stub.GetStringArgs()
	if len(args) != 2 {
		return shim.Error("Incorrect arguments. Expection a key and a value...")
	}

	// Set up any variables or assets here by calling stub.PutStata()

	// We store the key and the value on the ledger
	err := stub.PutState(args[0], []byte(args[1]))
	if err != nil {
		return shim.Error(fmt.Sprintf("Failed to create asset: %s", args[0]))
	}
	return shim.Success(nil)
}


// Invoke is called per transaction on the chaincode. Each transaction is either a 'get'
// or a 'set' on the asset created by Init function. The 'set' method may create a new 
// asset by specifying a new key-value pair.
func (t *SimpleAsset) Invoke(stub shim.ChaincodeStubInterface) peer.Response{
	// Extract the function and args from the transaction proposal
	fn, args := stub.GetFunctionAndParameters()
	var result string
	var err error
	if fn == "set" {
		result, err = set(stub, args)
	}else{
		result, err = get(stub, args)
	}
	if err != nil {
		return shim.Error(err.Error())
	}
	
	// Return the result as success payload
	return shim.Success([]byte(result))
}



// Set stores the asset (both key and value) on the ledger. If the key exists,
// it will override the value with the new one
func set(stub shim.ChaincodeStubInterface, args []string) (string, error){
	if len(args) != 2 {
		return "", fmt.Errorf("Incorrect arguments. Expecting a key and a value")
	} 

	err := stub.PutState(args[0], []byte(args[1]))
	if err != nil {
		return "", fmt.Errorf("Failed to set asset: %s", args[0])
	}
	return args[1], nil
}


// Get returns the value of the specified asset key
func get(stub shim.ChaincodeStubInterface, args []string) (string, error){
	if len(args) != 1 {
		return "", fmt.Errorf("Incorrect arguments. Expecting a key and a value")
	} 

	value, err := stub.GetState(args[0])
	if err != nil {
		return "", fmt.Errorf("Failed to set asset: %s with error: %s", args[0], err)
	}
	if value == nil {
		return "", fmt.Errorf("Asset not found: %s", args[0])
	}
	return string(value), nil
}


// main function starts up the chaincode in the container during instantiate
func main() {
	err := shim.Start(new(SimpleAsset))
	if err != nil {
		fmt.Printf("Error starting SimpleAsset chaincode: %s", err)
	}
}

3、编译chaincode

$ go get -u --tags nopkcs11 github.com/hyperledger/fabric-chaincode-go/shim
$ go build --tags nopkcs11

4、在开发模式下进行测试（在/fabric-samples/chaincode-docker-devmode目录下启动3个终端）

（tip：需要先安装fabric-samples, 在我之前博客中有篇专门介绍如何安装）

$ cd hyerledger/fabric-samples/chaincode-docker-devmode

终端1：

$ docker-compose -f docker-compose-simple.yaml up

终端2：

$ docker exec -it chaincode sh
/opt/gopath/src/chaincode $ cd sacc
/opt/gopath/src/chaincode/sacc $ go build

当执行到这里出现错误：go: github.com/hyperledger/[email protected]: Get "https://proxy.golang.org/github.com/hyperledger/fabric-chaincode-go/@v/v0.0.0-20190823162523-04390e015b85.mod": dial tcp 216.58.200.49:443: connect: connection refused
解决方法参考上述解决方案1，截图 如下 ：
上面报的443错误已解决，但是go build后出现新的错误：go build github.com/hyperledger/fabric-samples/chaincode/sacc: copying /tmp/go-build462413933/b001/exe/a.out: open sacc: permission denied
经分析，应该是权限问题，尝试很多办法，包括更改文件夹权限777等，最终发现更改文件夹权限无法作用到docker容器中，所以采用直接简单的一种方法，那就是以root身份进入容器执行各种操作。

更改终端2指令（最终版）如下：

$ docker exec -it -u root chaincode sh
/opt/gopath/src/chaincode $ cd sacc
/opt/gopath/src/chaincode/sacc $ go env -w GO111MODULE=on
/opt/gopath/src/chaincode/sacc $ go env -w GOPROXY=https://goproxy.io,direct
/opt/gopath/src/chaincode/sacc $ go build
/opt/gopath/src/chaincode/sacc $ CORE_PEEER_ADDRESS=peer:7051 CORE_CHAINCODE_ID_NAME=mycc:0 ./sacc

又出现了错误：Error starting SimpleAsset chaincode: flag 'peer.address' must be set
尚未解决

终端3：

$ docker exec -it cli bash
$ peer chaincode install -p chaincodedev/chaincode/sacc -n mycc -v 0
$ peer chaincode instantiate -n mycc -v 0 -c '{"Args":["a","10"]}' -C myc
$ peer chaincode invoke -n mycc -v 0 -c '{"Args":["set","a","20"]}' -C myc
$ peer chaincode invoke -n mycc -v 0 -c '{"Args":["query","a"]}' -C myc