[GitHub] [pulsar] jianyun8023 opened a new issue #7884: Correctly handle the asynchronous programming suggestions of api and base in the admin api of pulsar-broker.

[GitBox <gi...@apache.org>]

jianyun8023 opened a new issue #7884:
URL: https://github.com/apache/pulsar/issues/7884


   **Is your feature request related to a problem? Please describe.**
   I recently did topic level configuration. In the admin web module `org.apache.pulsar.broker.admin`, the asynchronous call between the api and the base made me feel very frustrated. The `asyncResponse` of the api layer was passed to the base layer, which made the handling of exceptions very complicated. . And this operation couples the api layer and the base layer together.
   
   I understand that base is equivalent to the service layer, and api is the interface layer, and their responsibilities should be separated.
   
   **Describe the solution you'd like**
   For base layer methods that support asynchronous, it is recommended to use `CompletableFuture` return instead of passing in `asyncResponse`
   
   For exceptions, normal throw is fine, no other operations are required.
   
   **Describe alternatives you've considered**
   no
   
   **Additional context**
   
   [`org.apache.pulsar.broker.admin.v2.Namespaces#deleteNamespace`](https://github.com/apache/pulsar/blob/master/pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/v2/Namespaces.java#L1154)
   ```java
   @DELETE
       @Path("/{tenant}/{namespace}")
       @ApiOperation(value = "Delete a namespace and all the topics under it.")
       @ApiResponses(value = {
               @ApiResponse(code = 307, message = "Current broker doesn't serve the namespace"),
               @ApiResponse(code = 403, message = "Don't have admin permission"),
               @ApiResponse(code = 404, message = "Tenant or cluster or namespace doesn't exist"),
               @ApiResponse(code = 409, message = "Namespace is not empty") })
       public void deleteNamespace(@Suspended final AsyncResponse asyncResponse, @PathParam("tenant") String tenant,
               @PathParam("namespace") String namespace,
               @QueryParam("authoritative") @DefaultValue("false") boolean authoritative) {
           try {
               validateNamespaceName(tenant, namespace);
               internalDeleteNamespace(asyncResponse, authoritative); 
           } catch (WebApplicationException wae) {
               asyncResponse.resume(wae);
           } catch (Exception e) {
               asyncResponse.resume(new RestException(e));
           }
       }
   ```
   
   [`org.apache.pulsar.broker.admin.impl.NamespacesBase#internalDeleteNamespace`](https://github.com/apache/pulsar/blob/master/pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/impl/NamespacesBase.java#L149)
   In `NamespacesBase#internalDeleteNamespace`, you can see that the exception handling becomes cumbersome
   
   ![image](https://user-images.githubusercontent.com/18240360/90979862-615db480-e58a-11ea-8204-62cbf24d5021.png)
   
   


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