[cel] parse variables in context

cel/examples/celrun-with-context.yaml

@@ -0,0 +1,15 @@
+apiVersion: tekton.dev/v1alpha1
+kind: Run
+metadata:
+  generateName: celrun-with-context-
+spec:
+  ref:
+    apiVersion: cel.tekton.dev/v1alpha1
+    kind: CEL
+  params:
+    - name: name
+      value: "'hello'"
+    - name: types
+      value: "type(name)"
+    - name: expression-use-context
+      value: "name + ' is type of ' + types"

cel/pkg/reconciler/cel/celrun.go

@@ -19,7 +19,9 @@ package cel
 import (
 	"context"
 	"fmt"
+
 	"github.com/google/cel-go/cel"
+	"github.com/google/cel-go/checker/decls"
 	"github.com/google/cel-go/common/types"
 	"github.com/tektoncd/pipeline/pkg/client/injection/reconciler/pipeline/v1alpha1/run"
 	"knative.dev/pkg/apis"
@@ -94,6 +96,8 @@ func (r *Reconciler) ReconcileKind(ctx context.Context, run *v1alpha1.Run) recon
 	}
 
 	var runResults []v1alpha1.RunResult
+	contextExpressions := map[string]interface{}{}
+
 	for _, param := range run.Spec.Params {
 		// Combine the Parse and Check phases CEL program compilation to produce an Ast and associated issues
 		ast, iss := env.Compile(param.Value.StringVal)
@@ -114,7 +118,7 @@ func (r *Reconciler) ReconcileKind(ctx context.Context, run *v1alpha1.Run) recon
 		}
 
 		// Evaluate the CEL expression (Ast)
-		out, _, err := prg.Eval(map[string]interface{}{})
+		out, _, err := prg.Eval(contextExpressions)
 		if err != nil {
 			logger.Errorf("CEL expression %s could not be evaluated when reconciling Run %s/%s: %v", param.Name, run.Namespace, run.Name, err)
 			run.Status.MarkRunFailed(ReasonEvaluationError,
@@ -128,6 +132,14 @@ func (r *Reconciler) ReconcileKind(ctx context.Context, run *v1alpha1.Run) recon
 			Name:  param.Name,
 			Value: fmt.Sprintf("%s", out.ConvertToType(types.StringType).Value()),
 		})
+		contextExpressions[param.Name] = fmt.Sprintf("%s", out.ConvertToType(types.StringType).Value())
+		env, err = env.Extend(cel.Declarations(decls.NewVar(param.Name, decls.Any)))
+		if err != nil {
+			logger.Errorf("CEL expression %s could not be add to context env when reconciling Run %s/%s: %v", param.Name, run.Namespace, run.Name, err)
+			run.Status.MarkRunFailed(ReasonEvaluationError,
+				"CEL expression %s could not be add to context env", param.Name, err)
+			return nil
+		}
 	}
 
 	// All CEL expressions were evaluated successfully

cel/pkg/reconciler/cel/celrun_test.go

@@ -19,13 +19,18 @@ package cel
 import (
 	"context"
 	"fmt"
+
 	"github.com/google/go-cmp/cmp"
 	"github.com/tektoncd/experimental/cel/test"
 	"github.com/tektoncd/pipeline/pkg/apis/pipeline/v1alpha1"
 	"github.com/tektoncd/pipeline/pkg/apis/pipeline/v1beta1"
 	ttesting "github.com/tektoncd/pipeline/pkg/reconciler/testing"
 	"github.com/tektoncd/pipeline/test/diff"
 
+	"strings"
+	"testing"
+	"time"
+
 	"github.com/tektoncd/pipeline/test/names"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -36,9 +41,6 @@ import (
 	"knative.dev/pkg/controller"
 	"knative.dev/pkg/logging"
 	"knative.dev/pkg/reconciler"
-	"strings"
-	"testing"
-	"time"
 )
 
 func TestReconcileCelRun(t *testing.T) {
@@ -122,6 +124,45 @@ func TestReconcileCelRun(t *testing.T) {
 			Value: "true",
 		}},
 		expectedEvents: []string{"Normal RunReconciled Run reconciled: \"foo/cel-run\""},
+	}, {
+		name: "expressions with context variables successful",
+		run: &v1alpha1.Run{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "cel-run",
+				Namespace: "foo",
+				Labels: map[string]string{
+					"myTestLabel": "myTestLabelValue",
+				},
+				Annotations: map[string]string{
+					"myTestAnnotation": "myTestAnnotationValue",
+				},
+			},
+			Spec: v1alpha1.RunSpec{
+				Params: []v1beta1.Param{{
+					Name:  "expr1",
+					Value: v1beta1.ArrayOrString{Type: v1beta1.ParamTypeString, StringVal: "type(100)"},
+				}, {
+					Name:  "expr2",
+					Value: v1beta1.ArrayOrString{Type: v1beta1.ParamTypeString, StringVal: "expr1 == 'int'"},
+				}},
+				Ref: &v1alpha1.TaskRef{
+					APIVersion: apiVersion,
+					Kind:       kind,
+					Name:       "a-celrun",
+				},
+			},
+		},
+		expectedStatus:  corev1.ConditionTrue,
+		expectedReason:  ReasonEvaluationSuccess,
+		expectedMessage: "CEL expressions were evaluated successfully",
+		expectedResults: []v1alpha1.RunResult{{
+			Name:  "expr1",
+			Value: "int",
+		}, {
+			Name:  "expr2",
+			Value: "true",
+		}},
+		expectedEvents: []string{"Normal RunReconciled Run reconciled: \"foo/cel-run\""},
 	}, {
 		name: "CEL expressions with invalid type",
 		run: &v1alpha1.Run{