英文:
Golang panic: interface conversion: interface {} is nil, not string
问题
我已经尝试创建CA配置文件、证书和私钥，我正在使用Go语言中的cfssl命令，并尝试从以下命令模拟相同的命令：
cfssl gencert -initca ca-csr.json | cfssljson -bare ca
以下是我的代码片段：
package mainimport ("bytes""fmt""io""os/exec""github.com/cloudflare/cfssl/log""encoding/json""io/ioutil""os""github.com/cloudflare/cfssl/cli""github.com/cloudflare/cfssl/cli/bundle""github.com/cloudflare/cfssl/cli/certinfo""github.com/cloudflare/cfssl/cli/gencert""github.com/cloudflare/cfssl/cli/gencrl""github.com/cloudflare/cfssl/cli/genkey""github.com/cloudflare/cfssl/cli/info""github.com/cloudflare/cfssl/cli/ocspdump""github.com/cloudflare/cfssl/cli/ocsprefresh""github.com/cloudflare/cfssl/cli/ocspserve""github.com/cloudflare/cfssl/cli/ocspsign"printdefaults "github.com/cloudflare/cfssl/cli/printdefault""github.com/cloudflare/cfssl/cli/revoke""github.com/cloudflare/cfssl/cli/scan""github.com/cloudflare/cfssl/cli/selfsign""github.com/cloudflare/cfssl/cli/serve""github.com/cloudflare/cfssl/cli/sign""github.com/cloudflare/cfssl/cli/version"// err "github.com/hyperledger/fabric/cop/errors""google.golang.org/grpc")func main() {var participantFile string = "key.pem"// file, err := os.Open("conf/ca-csr.json")// if err != nil {// log.Fatalf("missing config file: %v", err)// }// defer file.Close()// s, err := ioutil.ReadAll(file)// if err != nil {// log.Fatalf("could not read config file: %v", err)// }csr := `{"CN": "admin","key": {"algo": "rsa","size": 2048},"names": [{"C": "US","L": "Portland","O": "system:masters","OU": "Kubernetes The Hard Way","ST": "Oregon"}]}`//csr := string([]byte(s[:]))GenCert(csr, participantFile)}var cfsslCmds = map[string]*cli.Command{"bundle": bundle.Command,"certinfo": certinfo.Command,"sign": sign.Command,"serve": serve.Command,"version": version.Command,"genkey": genkey.Command,"gencert": gencert.Command,"gencrl": gencrl.Command,"ocspdump": ocspdump.Command,"ocsprefresh": ocsprefresh.Command,"ocspsign": ocspsign.Command,"ocspserve": ocspserve.Command,"selfsign": selfsign.Command,"scan": scan.Command,"info": info.Command,"print-defaults": printdefaults.Command,"revoke": revoke.Command,}// CertMgr is the default certificate managertype CertMgr struct {rootPath stringparticipantFilePath stringcert []bytegrpcServer *grpc.Server}type output struct {Cert string}type gencertOutput struct {cert []bytecsr []bytekey []byte}func GenCert(csr string, participantFile string) {var args []stringgencertCmd := cfsslCmds["gencert"]var c cli.Configc.IsCA = trueargs = append(args, csr)out := ExecuteCommand(args, gencertCmd, c)var gencertOut map[string]interface{}json.Unmarshal([]byte(out), &gencertOut)var writeJSON outputwriteJSON.Cert = gencertOut["cert"].(string)jsonOut, _ := json.Marshal(writeJSON)ioutil.WriteFile(participantFile, jsonOut, 0644)return}func ExecuteCommand(args []string, command *cli.Command, c cli.Config) string {cfsslJSONCmd := exec.Command("cfssljson", "-bare")old := os.Stdoutr, w, _ := os.Pipe()os.Stdout = werr := command.Main(args, c) // Execute commandif err != nil {log.Error(err)}outC := make(chan string)// copy the output in a separate goroutine so printing can't block indefinitelyvar buf bytes.Buffergo func() {io.Copy(&buf, r)cfsslJSONCmd.Stdin = &bufoutC <- buf.String()}()w.Close()out := <-outCoutByte := []byte(out)tmpFile, _ := ioutil.TempFile("", "tmp")defer os.Remove(tmpFile.Name())if _, err = tmpFile.Write(outByte); err != nil {fmt.Println("err: ", err)}os.Stdin = tmpFileos.Stdout = old // restoring the real stdouterr = cfsslJSONCmd.Run() // Execute cfssljson -bare <prefix>if err != nil {log.Error(err)}return out // To be used to store in participant file}
我得到了以下错误：
[ERROR] open {"CN": "admin","key": {"algo": "rsa","size": 2048},"names": [{"C": "US","L": "Portland","O": "system:masters","OU": "Kubernetes The Hard Way","ST": "Oregon"}]}: no such file or directory2022/03/25 19:23:39 [ERROR] exit status 1panic: interface conversion: interface {} is nil, not stringgoroutine 1 [running]:main.GenCert({0xb9179c, 0xda}, {0xb3a3f3, 0x7})/home/Documents/git-repo/kunets-vpc-test/main.go:126 +0x229main.main()/home/Documents/git-repo/kunets-vpc-test/main.go:70 +0x31任何帮助和建议将不胜感激，非常感谢！<details><summary>英文:</summary>I have tried to create CA configuration file, certificate and private key, I am using `cfssl` command in go and try to simulate same command fromcfssl gencert -initca ca-csr.json | cfssljson -bare caHere is my code snippedpackage mainimport ("bytes""fmt""io""os/exec""github.com/cloudflare/cfssl/log""encoding/json""io/ioutil""os""github.com/cloudflare/cfssl/cli""github.com/cloudflare/cfssl/cli/bundle""github.com/cloudflare/cfssl/cli/certinfo""github.com/cloudflare/cfssl/cli/gencert""github.com/cloudflare/cfssl/cli/gencrl""github.com/cloudflare/cfssl/cli/genkey""github.com/cloudflare/cfssl/cli/info""github.com/cloudflare/cfssl/cli/ocspdump""github.com/cloudflare/cfssl/cli/ocsprefresh""github.com/cloudflare/cfssl/cli/ocspserve""github.com/cloudflare/cfssl/cli/ocspsign"printdefaults "github.com/cloudflare/cfssl/cli/printdefault""github.com/cloudflare/cfssl/cli/revoke""github.com/cloudflare/cfssl/cli/scan""github.com/cloudflare/cfssl/cli/selfsign""github.com/cloudflare/cfssl/cli/serve""github.com/cloudflare/cfssl/cli/sign""github.com/cloudflare/cfssl/cli/version"// err "github.com/hyperledger/fabric/cop/errors""google.golang.org/grpc")func main() {var participantFile string = "key.pem"// file, err := os.Open("conf/ca-csr.json")// if err != nil {// log.Fatalf("missing config file: %v", err)// }// defer file.Close()// s, err := ioutil.ReadAll(file)// if err != nil {// log.Fatalf("could not read config file: %v", err)// }csr := `{"CN": "admin","key": {"algo": "rsa","size": 2048},"names": [{"C": "US","L": "Portland","O": "system:masters","OU": "Kubernetes The Hard Way","ST": "Oregon"}]}`//csr := string([]byte(s[:]))GenCert(csr, participantFile)}var cfsslCmds = map[string]*cli.Command{"bundle": bundle.Command,"certinfo": certinfo.Command,"sign": sign.Command,"serve": serve.Command,"version": version.Command,"genkey": genkey.Command,"gencert": gencert.Command,"gencrl": gencrl.Command,"ocspdump": ocspdump.Command,"ocsprefresh": ocsprefresh.Command,"ocspsign": ocspsign.Command,"ocspserve": ocspserve.Command,"selfsign": selfsign.Command,"scan": scan.Command,"info": info.Command,"print-defaults": printdefaults.Command,"revoke": revoke.Command,}// CertMgr is the default certificate managertype CertMgr struct {rootPath stringparticipantFilePath stringcert []bytegrpcServer *grpc.Server}type output struct {Cert string}type gencertOutput struct {cert []bytecsr []bytekey []byte}func GenCert(csr string, participantFile string) {var args []stringgencertCmd := cfsslCmds["gencert"]var c cli.Configc.IsCA = trueargs = append(args, csr)out := ExecuteCommand(args, gencertCmd, c)var gencertOut map[string]interface{}json.Unmarshal([]byte(out), &gencertOut)var writeJSON outputwriteJSON.Cert = gencertOut["cert"].(string)jsonOut, _ := json.Marshal(writeJSON)ioutil.WriteFile(participantFile, jsonOut, 0644)return}func ExecuteCommand(args []string, command *cli.Command, c cli.Config) string {cfsslJSONCmd := exec.Command("cfssljson", "-bare")old := os.Stdoutr, w, _ := os.Pipe()os.Stdout = werr := command.Main(args, c) // Execute commandif err != nil {log.Error(err)}outC := make(chan string)// copy the output in a separate goroutine so printing can't block indefinitelyvar buf bytes.Buffergo func() {io.Copy(&buf, r)cfsslJSONCmd.Stdin = &bufoutC <- buf.String()}()w.Close()out := <-outCoutByte := []byte(out)tmpFile, _ := ioutil.TempFile("", "tmp")defer os.Remove(tmpFile.Name())if _, err = tmpFile.Write(outByte); err != nil {fmt.Println("err: ", err)}os.Stdin = tmpFileos.Stdout = old // restoring the real stdouterr = cfsslJSONCmd.Run() // Execute cfssljson -bare <prefix>if err != nil {log.Error(err)}return out // To be used to store in participant file}and I am getting that error[ERROR] open {"CN": "admin","key": {"algo": "rsa","size": 2048},"names": [{"C": "US","L": "Portland","O": "system:masters","OU": "Kubernetes The Hard Way","ST": "Oregon"}]}: no such file or directory2022/03/25 19:23:39 [ERROR] exit status 1panic: interface conversion: interface {} is nil, not stringgoroutine 1 [running]:main.GenCert({0xb9179c, 0xda}, {0xb3a3f3, 0x7})/home/Documents/git-repo/kunets-vpc-test/main.go:126 +0x229main.main()/home/Documents/git-repo/kunets-vpc-test/main.go:70 +0x31Any help advice would be appreciated, thank you very much!</details># 答案1**得分**: 4我认为你在 goroutine 运行时关闭了 w，并且以某种方式突然结束了进程或读取命令输出。尝试通过打印 "out" 来确认，如果是这个问题，可以使用 defer 关闭 w。使用安全转换来避免 panic，并使用 spew.Dump（需要外部库）来检查数据。或者使用调试器。```govariable, ok := something.(string)if !ok {// 无法转换为字符串，现在该怎么办???}
英文:
I think you are closing the w while the goroutine is running and somehow it ends abruptly the process or reading the command output. Try confirm by print the “out” and if it is the issue, close w with defer
Use a safe convertion to avoid panic and use spew.Dump (need external library) to inspect the data.
Or use a debugger
variable, ok := something.(string)if !ok {// cant convert to string, now what???}</details># 答案2**得分**: 0我在模拟时遇到了类似的问题。```gotype MockSomethingRepository struct {mock.Mock}func (msr *MockSomethingRepository) FindById(id string) (*entity.Session, error) {args := msr.Called(id)return args.Get(0).(*entity.Session), args.Error(1)}
然后我尝试像这样使用模拟对象：
mockSomethignRepository.On("FindById", "1").Return(nil, fmt.Errorf("something went wrong"))
我得到了类似的错误interface conversion: interface {} is *[]entity.Session, not []entity.Session。
我在https://go.dev/play/p/CLyY2y9-2VF找到了解决方案，所以我通过以下方式解决了问题：
type MockSomethingRepository struct {mock.Mock}func (msr *MockSomethingRepository) FindById(id string) (*entity.Session, error) {args := msr.Called(id)if args.Error(1) != nil {return nil, args.Error(1)}return args.Get(0).(*entity.Session), args.Error(1)}
我没有解释，但它有效！
英文:
I was struggling with a similar problem when I was mocking.
type MockSomethingRepository struct {mock.Mock}func (msr *MockSomethingRepository) FindById(id string) (*entity.Session, error) {args := msr.Called(id)return args.Get(0).(*entity.Session), args.Error(1)}
and Then I tried to use the mock like this
mockSomethignRepository.On("FindById", "1").Return(nil, fmt.Errorf("something went wrong"))
I got similar error nterface conversion: interface {} is *[]entity.Session, not []entity.Session
I have found solution in https://go.dev/play/p/CLyY2y9-2VF
so I have solved it by
type MockSomethingRepository struct {mock.Mock}func (msr *MockSomethingRepository) FindById(id string) (*entity.Session, error) {args := msr.Called(id)if args.Error(1) != nil {return nil, args.Error(1)}return args.Get(0).(*entity.Session), args.Error(1)}
I don't have an explanation but It works!
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论