Access to metadata in policy

Vault
1

Hello,

I would like some help. I try to create this architecture:
token => alias => entity => policies => kv

The first step seeams be ok (token => alias => entity). But I have e problème with policies. I want template policies like this:

path "client_kv/data/{{ identity.entity.metadata.service_name }}/*" {
  capabilities = ["read", "list"]
}

service_name is a metadata in entity but that not work. Do you have e suggestion ?

Here, a part of my code:

func (v *VClient) createEntity(service string) (canonI string) {
	// Create or Get entity ID
	log.Println("Created or get info entitie for =>", service)
	entitieName := "entitie_customer_" + service
	var canonId string
	if _, ok := v.EntitiesList[entitieName]; ok {
		entitie, _ := v.vaultClient.Identity.EntityReadByName(v.ctx, entitieName)
		canonId = entitie.Data["id"].(string)
	} else {
		result, err := v.vaultClient.Identity.EntityCreate(v.ctx, schema.EntityCreateRequest{
			Name:     entitieName,
			Metadata: map[string]interface{}{"service_name": service, "type": "entitie"},
			Policies: []string{"customer_default", "default"},
		})
		if err != nil {
			panic(err)
		}
		v.EntitiesList[entitieName] = true
		canonId = result.Data["id"].(string)
	}
	return canonId
}

func (v *VClient) createAlias(service, canonId string) {
	log.Println("Created alias for =>", service)
	_, err := v.vaultClient.Identity.EntityCreateAlias(v.ctx, schema.EntityCreateAliasRequest{
		Name:           "alias_" + service,
		CanonicalId:    canonId,
		MountAccessor:  santeclair_kv_accessor,
		CustomMetadata: map[string]interface{}{"service_name": service, "type": "alias"},
	})

	if err != nil {
		panic(err)
	}
}

Best regards,
Nicolas