diff --git a/internal/interactor/config.go b/internal/interactor/config.go
deleted file mode 100644
index 68517b29..00000000
--- a/internal/interactor/config.go
+++ /dev/null
@@ -1,22 +0,0 @@
-package interactor
-
-import (
-	"context"
-
-	"github.com/gitploy-io/gitploy/ent"
-	"github.com/gitploy-io/gitploy/pkg/e"
-	"github.com/gitploy-io/gitploy/vo"
-)
-
-func (i *Interactor) GetEnv(ctx context.Context, u *ent.User, r *ent.Repo, env string) (*vo.Env, error) {
-	config, err := i.SCM.GetConfig(ctx, u, r)
-	if err != nil {
-		return nil, err
-	}
-
-	if !config.HasEnv(env) {
-		return nil, e.NewError(e.ErrorCodeConfigUndefinedEnv, nil)
-	}
-
-	return config.GetEnv(env), nil
-}
diff --git a/internal/interactor/config_test.go b/internal/interactor/config_test.go
deleted file mode 100644
index 47f63629..00000000
--- a/internal/interactor/config_test.go
+++ /dev/null
@@ -1,57 +0,0 @@
-package interactor
-
-import (
-	"context"
-	"testing"
-
-	"github.com/golang/mock/gomock"
-
-	"github.com/gitploy-io/gitploy/ent"
-	"github.com/gitploy-io/gitploy/internal/interactor/mock"
-	"github.com/gitploy-io/gitploy/pkg/e"
-	"github.com/gitploy-io/gitploy/vo"
-)
-
-func TestInteractor_GetEnv(t *testing.T) {
-	t.Run("Return an error when the environment is not defined.", func(t *testing.T) {
-		ctrl := gomock.NewController(t)
-		scm := mock.NewMockSCM(ctrl)
-
-		scm.
-			EXPECT().
-			GetConfig(gomock.Any(), gomock.AssignableToTypeOf(&ent.User{}), gomock.AssignableToTypeOf(&ent.Repo{})).
-			Return(&vo.Config{
-				Envs: []*vo.Env{},
-			}, nil)
-
-		i := &Interactor{SCM: scm}
-
-		_, err := i.GetEnv(context.Background(), &ent.User{}, &ent.Repo{}, "production")
-		if !e.HasErrorCode(err, e.ErrorCodeConfigUndefinedEnv) {
-			t.Fatalf("GetEnv error = %v, wanted ErrorCodeConfigUndefinedEnv", err)
-		}
-	})
-
-	t.Run("Return the environment.", func(t *testing.T) {
-		ctrl := gomock.NewController(t)
-		scm := mock.NewMockSCM(ctrl)
-
-		scm.
-			EXPECT().
-			GetConfig(gomock.Any(), gomock.AssignableToTypeOf(&ent.User{}), gomock.AssignableToTypeOf(&ent.Repo{})).
-			Return(&vo.Config{
-				Envs: []*vo.Env{
-					{
-						Name: "production",
-					},
-				},
-			}, nil)
-
-		i := &Interactor{SCM: scm}
-
-		_, err := i.GetEnv(context.Background(), &ent.User{}, &ent.Repo{}, "production")
-		if err != nil {
-			t.Fatalf("GetEnv returns an error: %v", err)
-		}
-	})
-}
diff --git a/internal/interactor/deployment.go b/internal/interactor/deployment.go
index 343f9efc..6515f9ed 100644
--- a/internal/interactor/deployment.go
+++ b/internal/interactor/deployment.go
@@ -37,10 +37,6 @@ func (i *Interactor) Deploy(ctx context.Context, u *ent.User, r *ent.Repo, d *en
 		return nil, err
 	}
 
-	if err := env.Eval(&vo.EvalValues{IsRollback: d.IsRollback}); err != nil {
-		return nil, err
-	}
-
 	number, err := i.Store.GetNextDeploymentNumberOfRepo(ctx, r)
 	if err != nil {
 		return nil, e.NewError(
@@ -139,10 +135,6 @@ func (i *Interactor) DeployToRemote(ctx context.Context, u *ent.User, r *ent.Rep
 		)
 	}
 
-	if err := env.Eval(&vo.EvalValues{IsRollback: d.IsRollback}); err != nil {
-		return nil, err
-	}
-
 	rd, err := i.createRemoteDeployment(ctx, u, r, d, env)
 	if err != nil {
 		return nil, err
diff --git a/internal/interactor/deployment_test.go b/internal/interactor/deployment_test.go
index fca2d386..2de6d565 100644
--- a/internal/interactor/deployment_test.go
+++ b/internal/interactor/deployment_test.go
@@ -289,7 +289,7 @@ func TestInteractor_DeployToRemote(t *testing.T) {
 		}
 	})
 
-	t.Run("create a new remote deployment and update the deployment.", func(t *testing.T) {
+	t.Run("Create a new remote deployment and update the deployment.", func(t *testing.T) {
 		input := struct {
 			d *ent.Deployment
 			e *vo.Env
diff --git a/internal/server/api/v1/repos/deployment.go b/internal/server/api/v1/repos/deployment.go
index 354aaf67..0aa854f0 100644
--- a/internal/server/api/v1/repos/deployment.go
+++ b/internal/server/api/v1/repos/deployment.go
@@ -85,15 +85,23 @@ func (r *Repo) CreateDeployment(c *gin.Context) {
 	vr, _ := c.Get(KeyRepo)
 	re := vr.(*ent.Repo)
 
-	env, err := r.i.GetEnv(ctx, u, re, p.Env)
+	config, err := r.i.GetConfig(ctx, u, re)
 	if e.HasErrorCode(err, e.ErrorCodeEntityNotFound) {
-		r.log.Check(gb.GetZapLogLevel(err), "The configuration file is not found.").Write(zap.Error(err))
-		// To override the HTTP status 422.
+		r.log.Check(gb.GetZapLogLevel(err), "Failed to get the configuration.").Write(zap.Error(err))
 		gb.ResponseWithStatusAndError(c, http.StatusUnprocessableEntity, err)
 		return
-	} else if err != nil {
-		r.log.Check(gb.GetZapLogLevel(err), "It has failed to get the configuration.").Write(zap.Error(err))
-		gb.ResponseWithError(c, err)
+	}
+
+	if err := config.Eval(&vo.EvalValues{}); err != nil {
+		r.log.Check(gb.GetZapLogLevel(err), "Failed to evaluate the configuration.").Write(zap.Error(err))
+		gb.ResponseWithStatusAndError(c, http.StatusUnprocessableEntity, err)
+		return
+	}
+
+	var env *vo.Env
+	if env = config.GetEnv(p.Env); env == nil {
+		r.log.Warn("The environment is not found.", zap.String("env", p.Env))
+		gb.ResponseWithStatusAndError(c, http.StatusUnprocessableEntity, e.NewError(e.ErrorCodeConfigUndefinedEnv, nil))
 		return
 	}
 
@@ -110,7 +118,6 @@ func (r *Repo) CreateDeployment(c *gin.Context) {
 		return
 	}
 
-	// TODO: Migrate the event logic into the interactor.
 	if _, err := r.i.CreateEvent(ctx, &ent.Event{
 		Kind:         event.KindDeployment,
 		Type:         event.TypeCreated,
@@ -124,6 +131,7 @@ func (r *Repo) CreateDeployment(c *gin.Context) {
 		d = de
 	}
 
+	r.log.Info("Start to deploy.", zap.String("repo", re.GetFullName()), zap.String("env", p.Env))
 	gb.Response(c, http.StatusCreated, d)
 }
 
@@ -149,15 +157,23 @@ func (r *Repo) UpdateDeployment(c *gin.Context) {
 		return
 	}
 
-	env, err := r.i.GetEnv(ctx, u, re, d.Env)
+	config, err := r.i.GetConfig(ctx, u, re)
 	if e.HasErrorCode(err, e.ErrorCodeEntityNotFound) {
-		r.log.Check(gb.GetZapLogLevel(err), "The configuration file is not found.").Write(zap.Error(err))
-		// To override the HTTP status 422.
+		r.log.Check(gb.GetZapLogLevel(err), "Failed to get the configuration.").Write(zap.Error(err))
 		gb.ResponseWithStatusAndError(c, http.StatusUnprocessableEntity, err)
 		return
-	} else if err != nil {
-		r.log.Check(gb.GetZapLogLevel(err), "It has failed to get the configuration.").Write(zap.Error(err))
-		gb.ResponseWithError(c, err)
+	}
+
+	if err := config.Eval(&vo.EvalValues{IsRollback: d.IsRollback}); err != nil {
+		r.log.Check(gb.GetZapLogLevel(err), "Failed to evaludate the configuration.").Write(zap.Error(err))
+		gb.ResponseWithStatusAndError(c, http.StatusUnprocessableEntity, err)
+		return
+	}
+
+	var env *vo.Env
+	if env = config.GetEnv(d.Env); env == nil {
+		r.log.Warn("The environment is not found.", zap.String("env", d.Env))
+		gb.ResponseWithStatusAndError(c, http.StatusUnprocessableEntity, e.NewError(e.ErrorCodeConfigUndefinedEnv, nil))
 		return
 	}
 
@@ -180,6 +196,7 @@ func (r *Repo) UpdateDeployment(c *gin.Context) {
 		d = de
 	}
 
+	r.log.Info("Start to deploy.", zap.String("repo", re.GetFullName()), zap.Int("number", d.Number))
 	gb.Response(c, http.StatusOK, d)
 }
 
@@ -203,15 +220,23 @@ func (r *Repo) RollbackDeployment(c *gin.Context) {
 		return
 	}
 
-	env, err := r.i.GetEnv(ctx, u, re, d.Env)
+	config, err := r.i.GetConfig(ctx, u, re)
 	if e.HasErrorCode(err, e.ErrorCodeEntityNotFound) {
-		r.log.Check(gb.GetZapLogLevel(err), "The configuration file is not found.").Write(zap.Error(err))
-		// To override the HTTP status 422.
+		r.log.Check(gb.GetZapLogLevel(err), "Failed to get the configuration.").Write(zap.Error(err))
 		gb.ResponseWithStatusAndError(c, http.StatusUnprocessableEntity, err)
 		return
-	} else if err != nil {
-		r.log.Check(gb.GetZapLogLevel(err), "It has failed to get the configuration.").Write(zap.Error(err))
-		gb.ResponseWithError(c, err)
+	}
+
+	if err := config.Eval(&vo.EvalValues{IsRollback: true}); err != nil {
+		r.log.Check(gb.GetZapLogLevel(err), "Failed to evaludate the configuration.").Write(zap.Error(err))
+		gb.ResponseWithStatusAndError(c, http.StatusUnprocessableEntity, err)
+		return
+	}
+
+	var env *vo.Env
+	if env = config.GetEnv(d.Env); env == nil {
+		r.log.Warn("The environment is not found.", zap.String("env", d.Env))
+		gb.ResponseWithStatusAndError(c, http.StatusUnprocessableEntity, e.NewError(e.ErrorCodeConfigUndefinedEnv, nil))
 		return
 	}
 
@@ -242,6 +267,7 @@ func (r *Repo) RollbackDeployment(c *gin.Context) {
 		d = de
 	}
 
+	r.log.Info("Start to rollback.", zap.String("repo", re.GetFullName()), zap.Int("number", d.Number))
 	gb.Response(c, http.StatusCreated, d)
 }
 
diff --git a/internal/server/api/v1/repos/deployment_test.go b/internal/server/api/v1/repos/deployment_test.go
index 4ef33b70..8ccd7f4b 100644
--- a/internal/server/api/v1/repos/deployment_test.go
+++ b/internal/server/api/v1/repos/deployment_test.go
@@ -120,13 +120,15 @@ func TestRepo_CreateDeployment(t *testing.T) {
 		ctrl := gomock.NewController(t)
 		m := mock.NewMockInteractor(ctrl)
 
-		t.Log("Read the config file.")
 		m.
 			EXPECT().
-			GetEnv(gomock.Any(), gomock.AssignableToTypeOf(&ent.User{}), gomock.AssignableToTypeOf(&ent.Repo{}), gomock.Any()).
-			Return(&vo.Env{
-				Name: "prod",
-			}, nil)
+			GetConfig(gomock.Any(), gomock.AssignableToTypeOf(&ent.User{}), gomock.AssignableToTypeOf(&ent.Repo{})).
+			Return(&vo.Config{
+				Envs: []*vo.Env{
+					{
+						Name: "prod",
+					},
+				}}, nil)
 
 		t.Log("Deploy with the payload successfully.")
 		m.
diff --git a/internal/server/api/v1/repos/interface.go b/internal/server/api/v1/repos/interface.go
index d690ccff..c1d281a5 100644
--- a/internal/server/api/v1/repos/interface.go
+++ b/internal/server/api/v1/repos/interface.go
@@ -31,7 +31,6 @@ type (
 		Deploy(ctx context.Context, u *ent.User, re *ent.Repo, d *ent.Deployment, env *vo.Env) (*ent.Deployment, error)
 		DeployToRemote(ctx context.Context, u *ent.User, r *ent.Repo, d *ent.Deployment, env *vo.Env) (*ent.Deployment, error)
 		GetConfig(ctx context.Context, u *ent.User, r *ent.Repo) (*vo.Config, error)
-		GetEnv(ctx context.Context, u *ent.User, r *ent.Repo, env string) (*vo.Env, error)
 
 		ListReviews(ctx context.Context, d *ent.Deployment) ([]*ent.Review, error)
 		FindReviewOfUser(ctx context.Context, u *ent.User, d *ent.Deployment) (*ent.Review, error)
diff --git a/internal/server/api/v1/repos/lock.go b/internal/server/api/v1/repos/lock.go
index fb1002d1..755d1230 100644
--- a/internal/server/api/v1/repos/lock.go
+++ b/internal/server/api/v1/repos/lock.go
@@ -20,6 +20,7 @@ import (
 	"github.com/gitploy-io/gitploy/internal/server/global"
 	gb "github.com/gitploy-io/gitploy/internal/server/global"
 	"github.com/gitploy-io/gitploy/pkg/e"
+	"github.com/gitploy-io/gitploy/vo"
 )
 
 type (
@@ -84,15 +85,17 @@ func (r *Repo) CreateLock(c *gin.Context) {
 	vu, _ := c.Get(global.KeyUser)
 	u := vu.(*ent.User)
 
-	env, err := r.i.GetEnv(ctx, u, re, p.Env)
+	config, err := r.i.GetConfig(ctx, u, re)
 	if e.HasErrorCode(err, e.ErrorCodeEntityNotFound) {
-		r.log.Check(gb.GetZapLogLevel(err), "The configuration file is not found.").Write(zap.Error(err))
-		// To override the HTTP status 422.
+		r.log.Check(gb.GetZapLogLevel(err), "Failed to get the configuration.").Write(zap.Error(err))
 		gb.ResponseWithStatusAndError(c, http.StatusUnprocessableEntity, err)
 		return
-	} else if err != nil {
-		r.log.Check(gb.GetZapLogLevel(err), "It has failed to get the configuration.").Write(zap.Error(err))
-		gb.ResponseWithError(c, err)
+	}
+
+	var env *vo.Env
+	if env = config.GetEnv(p.Env); env == nil {
+		r.log.Warn("The environment is not found.", zap.String("env", p.Env))
+		gb.ResponseWithStatusAndError(c, http.StatusUnprocessableEntity, e.NewError(e.ErrorCodeConfigUndefinedEnv, nil))
 		return
 	}
 
diff --git a/internal/server/api/v1/repos/lock_test.go b/internal/server/api/v1/repos/lock_test.go
index 3ce07ca3..23a2547e 100644
--- a/internal/server/api/v1/repos/lock_test.go
+++ b/internal/server/api/v1/repos/lock_test.go
@@ -17,7 +17,6 @@ import (
 	"github.com/gitploy-io/gitploy/ent"
 	"github.com/gitploy-io/gitploy/internal/server/api/v1/repos/mock"
 	"github.com/gitploy-io/gitploy/internal/server/global"
-	"github.com/gitploy-io/gitploy/pkg/e"
 	"github.com/gitploy-io/gitploy/vo"
 )
 
@@ -34,11 +33,15 @@ func TestRepo_CreateLock(t *testing.T) {
 		ctrl := gomock.NewController(t)
 		m := mock.NewMockInteractor(ctrl)
 
-		t.Log("Read deploy.yml and check the env.")
 		m.
 			EXPECT().
-			GetEnv(gomock.Any(), gomock.AssignableToTypeOf(&ent.User{}), gomock.AssignableToTypeOf(&ent.Repo{}), gomock.Any()).
-			Return(nil, e.NewError(e.ErrorCodeConfigUndefinedEnv, nil))
+			GetConfig(gomock.Any(), gomock.AssignableToTypeOf(&ent.User{}), gomock.AssignableToTypeOf(&ent.Repo{})).
+			Return(&vo.Config{
+				Envs: []*vo.Env{
+					{
+						Name: "dev",
+					},
+				}}, nil)
 
 		r := NewRepo(RepoConfig{}, m)
 
@@ -72,13 +75,15 @@ func TestRepo_CreateLock(t *testing.T) {
 		ctrl := gomock.NewController(t)
 		m := mock.NewMockInteractor(ctrl)
 
-		t.Log("Read deploy.yml and check the env.")
 		m.
 			EXPECT().
-			GetEnv(gomock.Any(), gomock.AssignableToTypeOf(&ent.User{}), gomock.AssignableToTypeOf(&ent.Repo{}), gomock.Any()).
-			Return(&vo.Env{
-				Name: "production",
-			}, nil)
+			GetConfig(gomock.Any(), gomock.AssignableToTypeOf(&ent.User{}), gomock.AssignableToTypeOf(&ent.Repo{})).
+			Return(&vo.Config{
+				Envs: []*vo.Env{
+					{
+						Name: "production",
+					},
+				}}, nil)
 
 		t.Log("Lock the env.")
 		m.
diff --git a/internal/server/api/v1/repos/mock/interactor.go b/internal/server/api/v1/repos/mock/interactor.go
index c2696428..9bc3df33 100644
--- a/internal/server/api/v1/repos/mock/interactor.go
+++ b/internal/server/api/v1/repos/mock/interactor.go
@@ -336,21 +336,6 @@ func (mr *MockInteractorMockRecorder) GetConfig(ctx, u, r interface{}) *gomock.C
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "GetConfig", reflect.TypeOf((*MockInteractor)(nil).GetConfig), ctx, u, r)
 }
 
-// GetEnv mocks base method.
-func (m *MockInteractor) GetEnv(ctx context.Context, u *ent.User, r *ent.Repo, env string) (*vo.Env, error) {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "GetEnv", ctx, u, r, env)
-	ret0, _ := ret[0].(*vo.Env)
-	ret1, _ := ret[1].(error)
-	return ret0, ret1
-}
-
-// GetEnv indicates an expected call of GetEnv.
-func (mr *MockInteractorMockRecorder) GetEnv(ctx, u, r, env interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "GetEnv", reflect.TypeOf((*MockInteractor)(nil).GetEnv), ctx, u, r, env)
-}
-
 // GetTag mocks base method.
 func (m *MockInteractor) GetTag(ctx context.Context, u *ent.User, r *ent.Repo, tag string) (*vo.Tag, error) {
 	m.ctrl.T.Helper()
diff --git a/internal/server/slack/deploy.go b/internal/server/slack/deploy.go
index 685e2432..28509955 100644
--- a/internal/server/slack/deploy.go
+++ b/internal/server/slack/deploy.go
@@ -273,15 +273,21 @@ func (s *Slack) interactDeploy(c *gin.Context) {
 		return
 	}
 
-	cfg, err := s.i.GetConfig(ctx, cu.Edges.User, cb.Edges.Repo)
+	config, err := s.i.GetConfig(ctx, cu.Edges.User, cb.Edges.Repo)
 	if err != nil {
 		postMessageWithError(cu, err)
 		c.Status(http.StatusOK)
 		return
 	}
 
+	if err := config.Eval(&vo.EvalValues{}); err != nil {
+		postMessageWithError(cu, err)
+		c.Status(http.StatusOK)
+		return
+	}
+
 	var env *vo.Env
-	if env = cfg.GetEnv(sm.Env); env == nil {
+	if env = config.GetEnv(sm.Env); env == nil {
 		postBotMessage(cu, "The env is not defined in the config.")
 		c.Status(http.StatusOK)
 		return
diff --git a/internal/server/slack/rollback.go b/internal/server/slack/rollback.go
index ef378823..7327e181 100644
--- a/internal/server/slack/rollback.go
+++ b/internal/server/slack/rollback.go
@@ -212,15 +212,21 @@ func (s *Slack) interactRollback(c *gin.Context) {
 		return
 	}
 
-	cfg, err := s.i.GetConfig(ctx, cu.Edges.User, cb.Edges.Repo)
+	config, err := s.i.GetConfig(ctx, cu.Edges.User, cb.Edges.Repo)
 	if err != nil {
 		postMessageWithError(cu, err)
 		c.Status(http.StatusOK)
 		return
 	}
 
+	if err := config.Eval(&vo.EvalValues{}); err != nil {
+		postMessageWithError(cu, err)
+		c.Status(http.StatusOK)
+		return
+	}
+
 	var env *vo.Env
-	if env = cfg.GetEnv(d.Env); env == nil {
+	if env = config.GetEnv(d.Env); env == nil {
 		postBotMessage(cu, "The env is not defined in the config.")
 		c.Status(http.StatusOK)
 		return
diff --git a/vo/config.go b/vo/config.go
index f2d0d055..ec1bd590 100644
--- a/vo/config.go
+++ b/vo/config.go
@@ -1,7 +1,6 @@
 package vo
 
 import (
-	"encoding/json"
 	"regexp"
 	"strconv"
 
@@ -14,6 +13,10 @@ import (
 type (
 	Config struct {
 		Envs []*Env `json:"envs" yaml:"envs"`
+
+		// save the content of the configuration file
+		// when it is unmarshalled.
+		source []byte
 	}
 
 	Env struct {
@@ -48,21 +51,61 @@ type (
 )
 
 const (
-	varnameDeployTask   = "GITPLOY_DEPLOY_TASK"
-	varnameRollbackTask = "GITPLOY_ROLLBACK_TASK"
-	varnameIsRollback   = "GITPLOY_IS_ROLLBACK"
+	VarnameDeployTask   = "GITPLOY_DEPLOY_TASK"
+	VarnameRollbackTask = "GITPLOY_ROLLBACK_TASK"
+	VarnameIsRollback   = "GITPLOY_IS_ROLLBACK"
 )
 
 const (
-	// defaultDeployTask is the value of the 'GITPLOY_DEPLOY_TASK' variable.
-	defaultDeployTask = "deploy"
-	// defaultRollbackTask is the value of the 'GITPLOY_ROLLBACK_TASK' variable.
-	defaultRollbackTask = "rollback"
+	// DefaultDeployTask is the value of the 'GITPLOY_DEPLOY_TASK' variable.
+	DefaultDeployTask = "deploy"
+	// DefaultRollbackTask is the value of the 'GITPLOY_ROLLBACK_TASK' variable.
+	DefaultRollbackTask = "rollback"
 )
 
 func UnmarshalYAML(content []byte, c *Config) error {
 	if err := yaml.Unmarshal([]byte(content), c); err != nil {
-		return err
+		return eutil.NewError(eutil.ErrorCodeConfigParseError, err)
+	}
+
+	c.source = content
+
+	return nil
+}
+
+func (c *Config) Eval(v *EvalValues) error {
+	// Evaluates variables
+	mapper := func(vn string) string {
+		if vn == VarnameDeployTask {
+			if !v.IsRollback {
+				return DefaultDeployTask
+			} else {
+				return ""
+			}
+		}
+
+		if vn == VarnameRollbackTask {
+			if v.IsRollback {
+				return DefaultRollbackTask
+			} else {
+				return ""
+			}
+		}
+
+		if vn == VarnameIsRollback {
+			return strconv.FormatBool(v.IsRollback)
+		}
+
+		return "ERR_NOT_IMPLEMENTED"
+	}
+
+	evalued, err := envsubst.Eval(string(c.source), mapper)
+	if err != nil {
+		return eutil.NewError(eutil.ErrorCodeConfigParseError, err)
+	}
+
+	if err := yaml.Unmarshal([]byte(evalued), c); err != nil {
+		return eutil.NewError(eutil.ErrorCodeConfigParseError, err)
 	}
 
 	return nil
@@ -125,46 +168,3 @@ func (e *Env) IsAutoDeployOn(ref string) (bool, error) {
 func (e *Env) HasReview() bool {
 	return e.Review != nil && e.Review.Enabled
 }
-
-func (e *Env) Eval(v *EvalValues) error {
-	byts, err := json.Marshal(e)
-	if err != nil {
-		return eutil.NewError(eutil.ErrorCodeConfigParseError, err)
-	}
-
-	// Evaluates variables
-	mapper := func(vn string) string {
-		if vn == varnameDeployTask {
-			if !v.IsRollback {
-				return defaultDeployTask
-			} else {
-				return ""
-			}
-		}
-
-		if vn == varnameRollbackTask {
-			if v.IsRollback {
-				return defaultRollbackTask
-			} else {
-				return ""
-			}
-		}
-
-		if vn == varnameIsRollback {
-			return strconv.FormatBool(v.IsRollback)
-		}
-
-		return "ERR_NOT_IMPLEMENTED"
-	}
-
-	evalued, err := envsubst.Eval(string(byts), mapper)
-	if err != nil {
-		return eutil.NewError(eutil.ErrorCodeConfigParseError, err)
-	}
-
-	if err := json.Unmarshal([]byte(evalued), e); err != nil {
-		return eutil.NewError(eutil.ErrorCodeConfigParseError, err)
-	}
-
-	return nil
-}
diff --git a/vo/config_test.go b/vo/config_test.go
index cd8a6cf6..5ec69884 100644
--- a/vo/config_test.go
+++ b/vo/config_test.go
@@ -1,7 +1,6 @@
 package vo
 
 import (
-	"fmt"
 	"reflect"
 	"testing"
 
@@ -31,6 +30,7 @@ envs:
 					RequiredContexts: &[]string{"github-action"},
 				},
 			},
+			source: []byte(s),
 		}
 		if !reflect.DeepEqual(c, e) {
 			tt.Errorf("Config = %s, expected %s", spew.Sdump(c), spew.Sdump(e))
@@ -57,6 +57,7 @@ envs:
 					AutoMerge: pointer.ToBool(false),
 				},
 			},
+			source: []byte(s),
 		}
 		if !reflect.DeepEqual(c, e) {
 			tt.Errorf("Config = %s, expected %s", spew.Sdump(c), spew.Sdump(e))
@@ -72,8 +73,7 @@ envs:
 
 		err := UnmarshalYAML([]byte(s), c)
 		if err != nil {
-			tt.Errorf("failed to parse: %s", err)
-			tt.FailNow()
+			tt.Fatalf("failed to parse: %s", err)
 		}
 
 		e := &Config{
@@ -83,6 +83,7 @@ envs:
 					AutoMerge: pointer.ToBool(true),
 				},
 			},
+			source: []byte(s),
 		}
 		if !reflect.DeepEqual(c, e) {
 			tt.Errorf("Config = %s, expected %s", spew.Sdump(c), spew.Sdump(e))
@@ -90,6 +91,70 @@ envs:
 	})
 }
 
+func TestConfig_Eval(t *testing.T) {
+	t.Run("Evaluate the configuration.", func(t *testing.T) {
+		s := `
+envs:
+  - name: dev
+    task: ${GITPLOY_DEPLOY_TASK}:kubernetes`
+
+		c := &Config{}
+		if err := UnmarshalYAML([]byte(s), c); err != nil {
+			t.Fatalf("Failed to parse the configuration file: %v", err)
+		}
+
+		err := c.Eval(&EvalValues{})
+		if err != nil {
+			t.Fatalf("Eval returns an error: %v", err)
+		}
+
+		e := &Config{
+			Envs: []*Env{
+				{
+					Name: "dev",
+					Task: pointer.ToString("deploy:kubernetes"),
+				},
+			},
+			source: []byte(s),
+		}
+		if !reflect.DeepEqual(c, e) {
+			t.Errorf("Config = %v expected %v", spew.Sdump(c), spew.Sdump(e))
+		}
+	})
+
+	t.Run("Evaluate the configuration with the regexp.", func(t *testing.T) {
+		s := `
+envs:
+  - name: dev
+    task: ${GITPLOY_DEPLOY_TASK}:kubernetes
+    deployable_ref: 'v.*\..*\..*'`
+
+		c := &Config{}
+		if err := UnmarshalYAML([]byte(s), c); err != nil {
+			t.Fatalf("Failed to parse the configuration file: %v", err)
+		}
+
+		err := c.Eval(&EvalValues{})
+		if err != nil {
+			t.Fatalf("Eval returns an error: %v", err)
+		}
+
+		e := &Config{
+			Envs: []*Env{
+				{
+					Name:          "dev",
+					Task:          pointer.ToString("deploy:kubernetes"),
+					DeployableRef: pointer.ToString(`v.*\..*\..*`),
+				},
+			},
+			source: []byte(s),
+		}
+		if !reflect.DeepEqual(c, e) {
+			t.Errorf("Config = %v expected %v", spew.Sdump(c), spew.Sdump(e))
+		}
+	})
+}
+
 func TestEnv_IsProductionEnvironment(t *testing.T) {
 	t.Run("Reutrn false when the production environment is nil", func(t *testing.T) {
 		e := &Env{}
@@ -159,79 +224,3 @@ func TestEnv_IsDeployableRef(t *testing.T) {
 		}
 	})
 }
-
-func TestEnv_Eval(t *testing.T) {
-	t.Run("eval the task.", func(t *testing.T) {
-		cs := []struct {
-			env  *Env
-			want *Env
-		}{
-			{
-				env: &Env{
-					Task: pointer.ToString("${GITPLOY_DEPLOY_TASK}"),
-				},
-				want: &Env{
-					Task: pointer.ToString(defaultDeployTask),
-				},
-			},
-			{
-				env: &Env{
-					Task: pointer.ToString("${GITPLOY_DEPLOY_TASK}:kubernetes"),
-				},
-				want: &Env{
-					Task: pointer.ToString(fmt.Sprintf("%s:kubernetes", defaultDeployTask)),
-				},
-			},
-			{
-				env: &Env{
-					Task: pointer.ToString("${GITPLOY_DEPLOY_TASK}${GITPLOY_ROLLBACK_TASK}"),
-				},
-				want: &Env{
-					Task: pointer.ToString(defaultDeployTask),
-				},
-			},
-		}
-
-		for _, c := range cs {
-			err := c.env.Eval(&EvalValues{})
-			if err != nil {
-				t.Fatalf("Eval returns an error: %s", err)
-			}
-			if !reflect.DeepEqual(c.env, c.want) {
-				t.Fatalf("Eval = %v, wanted %v", *c.env.Task, *c.want.Task)
-			}
-		}
-	})
-
-	t.Run("eval the is_rollback.", func(t *testing.T) {
-		const (
-			isRollback = true
-		)
-
-		cs := []struct {
-			env  *Env
-			want *Env
-		}{
-			{
-				env: &Env{
-					Payload: pointer.ToString("{\"is_rollback\": ${GITPLOY_IS_ROLLBACK}}"),
-				},
-				want: &Env{
-					Payload: pointer.ToString("{\"is_rollback\": true}"),
-				},
-			},
-		}
-
-		for _, c := range cs {
-			err := c.env.Eval(&EvalValues{
-				IsRollback: isRollback,
-			})
-			if err != nil {
-				t.Fatalf("Eval returns an error: %s", err)
-			}
-			if !reflect.DeepEqual(c.env, c.want) {
-				t.Fatalf("Eval = %v, wanted %v", c.env, c.want)
-			}
-		}
-	})
-}