Retain environment variable when loading key from config (#78)

accounts/keys.go

@@ -71,9 +71,14 @@ var _ Key = &KMSKey{}
 
 var _ Key = &BIP44Key{}
 
+var _ Key = &EnvKey{}
+
 func keyFromConfig(accountKeyConf config.AccountKey) (Key, error) {
 	switch accountKeyConf.Type {
 	case config.KeyTypeHex:
+		if accountKeyConf.Env != "" {
+			return envKeyFromConfig(accountKeyConf)
+		}
 		return hexKeyFromConfig(accountKeyConf)
 	case config.KeyTypeBip44:
 		return bip44KeyFromConfig(accountKeyConf)
@@ -315,6 +320,44 @@ func NewFileKey(
 	}
 }
 
+// EnvKey represents a key that is saved in an environment variable.
+type EnvKey struct {
+	*baseKey
+	privateKey crypto.PrivateKey
+	env        string
+}
+
+func envKeyFromConfig(accountKey config.AccountKey) (*EnvKey, error) {
+	return &EnvKey{
+		baseKey:    baseKeyFromConfig(accountKey),
+		privateKey: accountKey.PrivateKey,
+		env:        accountKey.Env,
+	}, nil
+}
+
+func (f *EnvKey) Signer(ctx context.Context) (crypto.Signer, error) {
+	key, err := f.PrivateKey()
+	if err != nil {
+		return nil, err
+	}
+
+	return crypto.NewInMemorySigner(*key, f.HashAlgo())
+}
+
+func (f *EnvKey) PrivateKey() (*crypto.PrivateKey, error) {
+	return &f.privateKey, nil
+}
+
+func (f *EnvKey) ToConfig() config.AccountKey {
+	return config.AccountKey{
+		Type:       config.KeyTypeHex,
+		SigAlgo:    f.sigAlgo,
+		HashAlgo:   f.hashAlgo,
+		PrivateKey: f.privateKey,
+		Env:        f.env,
+	}
+}
+
 // FileKey represents a key that is saved in a seperate file and will be lazy-loaded.
 //
 // The FileKey stores location of the file where private key is stored in hex-encoded format.

accounts/keys_test.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 
+	"github.com/onflow/flow-go-sdk/crypto"
 	"github.com/onflow/flowkit/v2/tests"
 
 	"github.com/onflow/flowkit/v2/config"
@@ -89,3 +90,30 @@ func Test_BIP44(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, pubKey, sig.PublicKey().String())
 }
+
+func Test_EnvKey(t *testing.T) {
+	pk, err := crypto.DecodePrivateKeyHex(config.DefaultSigAlgo, "64cfa38591cf755e84379d78884e5322af0fd2a94cff48569d6578cdd733d455") // TEST KEY DO NOT USE
+	assert.NoError(t, err)
+
+	confKey := config.AccountKey{
+		Type:       config.KeyTypeHex,
+		Index:      0,
+		SigAlgo:    config.DefaultSigAlgo,
+		HashAlgo:   config.DefaultHashAlgo,
+		PrivateKey: pk,
+		Env:        "TEST",
+	}
+
+	key, err := envKeyFromConfig(confKey)
+	assert.NoError(t, err)
+
+	const pubKey = "0x1e585ddefde564eb9d86c606a2cf33996c9434a4f658d7338a7b811e337adf6e38e2ae4a5c7a79751b5bf8b08a90428d0a29aa27e6ddc195099ac1b2deb9519a"
+	assert.Equal(t, confKey, key.ToConfig())
+	pkey, err := key.PrivateKey()
+	assert.NoError(t, err)
+	assert.Equal(t, pubKey, (*pkey).PublicKey().String())
+
+	sig, err := key.Signer(context.Background())
+	assert.NoError(t, err)
+	assert.Equal(t, pubKey, sig.PublicKey().String())
+}