Alerting: Enable interpolation for notification policies in file provisioning

pkg/services/provisioning/alerting/notification_policy_types.go

@@ -1,26 +1,54 @@
 package alerting
 
 import (
+	"encoding/json"
+
 	"github.com/grafana/grafana/pkg/services/ngalert/api/tooling/definitions"
 	"github.com/grafana/grafana/pkg/services/provisioning/values"
 )
 
 type NotificiationPolicyV1 struct {
-	OrgID  values.Int64Value `json:"orgId" yaml:"orgId"`
-	Policy definitions.Route `json:",inline" yaml:",inline"`
+	OrgID values.Int64Value `json:"orgId" yaml:"orgId"`
+	// We use JSONValue here, as we want to have interpolation the values.
+	Policy values.JSONValue `json:"-" yaml:"-"`
+}
+
+func (v1 *NotificiationPolicyV1) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	err := v1.Policy.UnmarshalYAML(unmarshal)
+	if err != nil {
+		return err
+	}
+	// As we also want to unmarshal the orgId and any other field that might be
+	// added in the future we create an alias type that prevents recursion
+	// and just uses the default marshler.
+	type plain NotificiationPolicyV1
+	return unmarshal((*plain)(v1))
 }
 
-func (v1 *NotificiationPolicyV1) mapToModel() NotificiationPolicy {
+func (v1 *NotificiationPolicyV1) mapToModel() (NotificiationPolicy, error) {
 	orgID := v1.OrgID.Value()
 	if orgID < 1 {
 		orgID = 1
 	}
-	// we don't need any further validation here as it's done by
-	// the notification policy service
+	var route definitions.Route
+	// We need the string json representation, so we marshal the policy back
+	// as a string and interpolate it at the same time.
+	data, err := json.Marshal(v1.Policy.Value())
+	if err != nil {
+		return NotificiationPolicy{}, err
+	}
+	// Now we can take the interpolated string json represtenation of the policy
+	// and unmarshal it in the concrete type.
+	err = json.Unmarshal(data, &route)
+	if err != nil {
+		return NotificiationPolicy{}, err
+	}
+	// We don't need any further validation here as it's done by
+	// the notification policy service.
 	return NotificiationPolicy{
 		OrgID:  orgID,
-		Policy: v1.Policy,
-	}
+		Policy: route,
+	}, nil
 }
 
 type NotificiationPolicy struct {

pkg/services/provisioning/alerting/notification_policy_types_test.go

@@ -0,0 +1,37 @@
+package alerting
+
+import (
+	"os"
+	"testing"
+
+	"gopkg.in/yaml.v2"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNotificationPolicy(t *testing.T) {
+	const (
+		envKey   = "NOTIFIER_EMAIL_REMINDER_FREQUENCY"
+		envValue = "4h"
+	)
+	err := os.Setenv(envKey, envValue)
+	require.NoError(t, err)
+	defer func() {
+		_ = os.Unsetenv(envKey)
+	}()
+	data := `orgId: 123
+receiver: test
+continue: true
+repeat_interval: ${NOTIFIER_EMAIL_REMINDER_FREQUENCY}
+`
+	var model NotificiationPolicyV1
+
+	err = yaml.Unmarshal([]byte(data), &model)
+	require.NoError(t, err)
+	np, err := model.mapToModel()
+	require.NoError(t, err)
+	require.Equal(t, int64(123), np.OrgID)
+	require.Equal(t, "test", np.Policy.Receiver)
+	require.True(t, np.Policy.Continue)
+	require.Equal(t, envValue, np.Policy.RepeatInterval.String())
+}

pkg/services/provisioning/alerting/types.go

@@ -51,7 +51,9 @@ func (fileV1 *AlertingFileV1) MapToModel() (AlertingFile, error) {
 	if err := fileV1.mapContactPoint(&alertingFile); err != nil {
 		return AlertingFile{}, fmt.Errorf("failure parsing contact points: %w", err)
 	}
-	fileV1.mapPolicies(&alertingFile)
+	if err := fileV1.mapPolicies(&alertingFile); err != nil {
+		return AlertingFile{}, fmt.Errorf("failure parsing policies: %w", err)
+	}
 	if err := fileV1.mapMuteTimes(&alertingFile); err != nil {
 		return AlertingFile{}, fmt.Errorf("failure parsing mute times: %w", err)
 	}
@@ -89,13 +91,18 @@ func (fileV1 *AlertingFileV1) mapMuteTimes(alertingFile *AlertingFile) error {
 	return nil
 }
 
-func (fileV1 *AlertingFileV1) mapPolicies(alertingFile *AlertingFile) {
+func (fileV1 *AlertingFileV1) mapPolicies(alertingFile *AlertingFile) error {
 	for _, npV1 := range fileV1.Policies {
-		alertingFile.Policies = append(alertingFile.Policies, npV1.mapToModel())
+		np, err := npV1.mapToModel()
+		if err != nil {
+			return err
+		}
+		alertingFile.Policies = append(alertingFile.Policies, np)
 	}
 	for _, orgIDV1 := range fileV1.ResetPolicies {
 		alertingFile.ResetPolicies = append(alertingFile.ResetPolicies, OrgID(orgIDV1.Value()))
 	}
+	return nil
 }
 
 func (fileV1 *AlertingFileV1) mapContactPoint(alertingFile *AlertingFile) error {