feat: add support for Vault AppRole auth (#2)

For more details, see : https://developer.hashicorp.com/vault/docs/auth/approle#approle-auth-method

Signed-off-by: thomasgouveia <[email protected]>

pkg/vaultauth/approle.go

@@ -0,0 +1,51 @@
+package vaultauth
+
+import (
+	"context"
+	"errors"
+
+	"github.com/hashicorp/vault-client-go"
+	"github.com/hashicorp/vault-client-go/schema"
+)
+
+var (
+	ErrRoleIdMustNotBeEmpty   = errors.New("vault/auth/approle: the role-id must not be empty")
+	ErrSecretIdMustNotBeEmpty = errors.New("vault/auth/approle: the secret-id must not be empty")
+)
+
+// approleStrategy defines the configuration that should be attached
+// to the command in order to configure the AppRole authentication.
+type approleStrategy struct {
+	MountPath string `flag.name:"approle.mount-path" flag.default:"approle" flag.desc:"The path to the AppRole authentication method in your Vault."`
+	RoleId    string `flag.name:"approle.role-id" flag.desc:"The identifier of the role to use to perform the login."`
+	SecretId  string `flag.name:"approle.secret-id" flag.desc:"The secret identifier of the role to use to perform the login."`
+}
+
+// Ensure the implementation satisfies the interface.
+var (
+	_ vaultLoginStrategy = &approleStrategy{}
+)
+
+// login performs the login using the AppRole authentication method on Vault.
+func (s *approleStrategy) login(ctx context.Context, client *vault.Client) (*vault.ResponseAuth, error) {
+	if s.RoleId == "" {
+		return nil, ErrRoleIdMustNotBeEmpty
+	}
+
+	if s.SecretId == "" {
+		return nil, ErrSecretIdMustNotBeEmpty
+	}
+
+	opts := []vault.RequestOption{vault.WithMountPath(s.MountPath)}
+	req := schema.AppRoleLoginRequest{
+		RoleId:   s.RoleId,
+		SecretId: s.SecretId,
+	}
+
+	resp, err := client.Auth.AppRoleLogin(ctx, req, opts...)
+	if err != nil {
+		return nil, err
+	}
+
+	return resp.Auth, nil
+}

pkg/vaultauth/auth.go

@@ -16,6 +16,7 @@ type AuthMethod string
 const (
 	Token    AuthMethod = "token"
 	Userpass AuthMethod = "userpass"
+	AppRole  AuthMethod = "approle"
 )
 
 // vaultLoginStrategy defines the common interface between all the authentication
@@ -31,6 +32,7 @@ type vaultLoginStrategy interface {
 var strategies = map[AuthMethod]vaultLoginStrategy{
 	Token:    &tokenStrategy{},
 	Userpass: &userpassStrategy{},
+	AppRole:  &approleStrategy{},
 }
 
 var (