feat: add readme

README.md

@@ -0,0 +1,44 @@
+# go-grpc-certificate
+
+## Problem's context
+I've got some trouble while I want to use gRPC through TLS certificates. I've created a certificated from a .pem key file which had
+a password and I couldn't use it through `go` standard library. I found a solution based on this **[SO answer](https://stackoverflow.com/a/56131169/6329540)** to this **[question](https://stackoverflow.com/questions/56129533/tls-with-certificate-private-key-and-pass-phrase/56131169#comment132834574_56131169)**
+
+## Solution
+I've decided to use **[openssl](https://www.openssl.org/docs/manmaster/man1/)** to achieve this task as far as I was not able to found a solution in go standard library.
+
+## Installation requirements
+I've used this version on development. So we should check if it backwards compatible.
+```shell
+$ openssl version
+OpenSSL 3.0.8 7 Feb 2023 (Library: OpenSSL 3.0.8 7 Feb 2023)
+```
+
+
+## How to use
+In your `go` project you just have to type in your terminal:
+```shell
+$ go get gitea.urkob.com/urko/go-grpc-certificate
+```
+
+Then place in your code like this
+```go
+package main
+
+// here should be defined your imports
+certcreds "gitea.urkob.com/urko/go-grpc-certificate/pkg/credentials"
+
+
+func main() {
+    certPath := "place your certificate path"
+    certKeyPath := "place your key file path"
+    keyPassword := "place your key password here"
+
+    creds, err = certcreds.CredentialsFromKeyWithPasswd(
+        certPah, certKeyPath, keyPassword,
+    )
+    if err != nil {
+        log.Fatalf("Failed loading certificates: %v\n", err)
+    }
+}
+```

pkg/credentials/credentials.go

@@ -12,7 +12,10 @@ import (
 	"google.golang.org/grpc/credentials"
 )
 
-func CredentialsFromKeyWithPasswd(certFile, certKey, passwd string) (credentials.TransportCredentials, error) {
+// FromRSAKeyWithPassword receives a certificate .pem file which was
+// requested with .pem key file secured by password. By default go doesn't provide a
+// standard packag that is not deprecated:
+func FromRSAKeyWithPassword(certFile, certKey, passwd string) (credentials.TransportCredentials, error) {
 	if certFile == "" {
 		return nil, errors.New("certFile cannot be empty")
 	}

pkg/credentials/credentials_test.go

@@ -83,10 +83,10 @@ func TestCredentialsFromKeyWithPasswd(t *testing.T) {
 		require.NoError(t, deleteTestDir())
 	}()
 
-	_, err := CredentialsFromKeyWithPasswd(testCert, testCertKey, testKeyPass)
+	_, err := FromRSAKeyWithPassword(testCert, testCertKey, testKeyPass)
 	assert.NoError(t, err, "key with password should not fail")
 
-	_, err = CredentialsFromKeyWithPasswd(testCert, testCertKey, "wrong-pass")
+	_, err = FromRSAKeyWithPassword(testCert, testCertKey, "wrong-pass")
 	assert.Error(t, err, "key with wrong pass password should not fail")
 }
 
@@ -98,30 +98,30 @@ func TestCredentialsFromKeyWithPasswdError(t *testing.T) {
 		require.NoError(t, deleteTestDir())
 	}()
 
-	_, err := CredentialsFromKeyWithPasswd("", "", "")
+	_, err := FromRSAKeyWithPassword("", "", "")
 	assert.Error(t, err)
 
-	_, err = CredentialsFromKeyWithPasswd(testCert, "", "")
+	_, err = FromRSAKeyWithPassword(testCert, "", "")
 	assert.Error(t, err)
 
-	_, err = CredentialsFromKeyWithPasswd(testCert, "not-exists.txt", "")
+	_, err = FromRSAKeyWithPassword(testCert, "not-exists.txt", "")
 	assert.Error(t, err)
 
 	require.NoError(t, os.WriteFile(testKeyError, []byte(""), os.ModeAppend))
 
-	_, err = CredentialsFromKeyWithPasswd(testCert, testKeyError, testKeyPass)
+	_, err = FromRSAKeyWithPassword(testCert, testKeyError, testKeyPass)
 	require.Error(t, err)
 
 	require.NoError(t, os.WriteFile(testCertKeyError, []byte(certKeyError), os.ModeAppend))
-	_, err = CredentialsFromKeyWithPasswd(testCert, testCertKeyError, testKeyPass)
+	_, err = FromRSAKeyWithPassword(testCert, testCertKeyError, testKeyPass)
 	assert.Error(t, err)
 
 	require.NoError(t, os.Remove(testCertKeyError))
 	assert.NoError(t, os.WriteFile(testCertKeyError, []byte(certKeyOk), os.ModeAppend))
-	_, err = CredentialsFromKeyWithPasswd(testCert, testCertKeyError, testKeyPass)
+	_, err = FromRSAKeyWithPassword(testCert, testCertKeyError, testKeyPass)
 	assert.Error(t, err, "key without password should fail")
 
 	require.NoError(t, createEncryptedKeyFile())
-	_, err = CredentialsFromKeyWithPasswd(testCert, testCertKey, testKeyPass)
+	_, err = FromRSAKeyWithPassword(testCert, testCertKey, testKeyPass)
 	assert.Error(t, err, "key without password should fail")
 }