fix: Stop policy eval when context is done

act/policy.go

@@ -37,12 +37,26 @@ func (p *Policy) MustCompile(extraOpts ...expr.Option) error {
 }
 
 func (p *Policy) Eval(ctx context.Context, input Input) (any, error) {
-	output, err := expr.Run(p.prg, input)
-	if err != nil {
-		return false, err
+	result := make(chan interface{})
+	errChan := make(chan error)
+
+	go func() {
+		output, err := expr.Run(p.prg, input)
+		if err != nil {
+			errChan <- err
+			return
+		}
+		result <- output
+	}()
+
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	case out := <-result:
+		return out, nil
+	case err := <-errChan:
+		return nil, err
 	}
-
-	return output, nil
 }
 
 func MustNewPolicy(

act/policy_test.go

@@ -0,0 +1,53 @@
+package act
+
+import (
+	"context"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"testing"
+)
+
+func TestPolicy_Eval(t *testing.T) {
+	t.Run("it should eval program correctly", func(t *testing.T) {
+		policy := MustNewPolicy("test", "1 + 1", map[string]any{})
+		resp, err := policy.Eval(context.Background(), Input{})
+		require.NoError(t, err)
+		assert.Equal(t, 2, resp)
+	})
+
+	t.Run("it should stop eval if context is timed out", func(t *testing.T) {
+		policy := MustNewPolicy("test", "repeat(\"Hi\", 100000)", map[string]any{})
+		ctx, cancel := context.WithTimeout(context.Background(), 10)
+		defer cancel()
+		_, err := policy.Eval(ctx, Input{})
+		require.Error(t, err)
+	})
+
+	t.Run("it should fail because of runtime error", func(t *testing.T) {
+		policy := MustNewPolicy("test", `nonExistantVariable`, map[string]any{})
+		_, err := policy.Eval(context.Background(), Input{
+			Policy: map[string]any{"key": "value"},
+		})
+		require.ErrorIs(t, err, context.DeadlineExceeded)
+	})
+}
+
+func TestPolicy_MustCompile(t *testing.T) {
+	t.Run("it should compile policy correctly", func(t *testing.T) {
+		policy := Policy{
+			Name:     "test",
+			Policy:   "1 + 1",
+			Metadata: map[string]any{"log": "enabled"},
+		}
+		require.NoError(t, policy.MustCompile())
+	})
+
+	t.Run("it should fail to compile policy if there is an error", func(t *testing.T) {
+		policy := Policy{
+			Name:     "test",
+			Policy:   "1 + \"Hi\"",
+			Metadata: map[string]any{"log": "enabled"},
+		}
+		require.Error(t, policy.MustCompile())
+	})
+}