Merge pull request #187 from tsegismont/jira/HWKMETRICS-44

HWKMETRICS-44 Tenant list endpoint does not report internal server error correctly
hawkular · Mar 24, 2015 · 4cbf4cb · 4cbf4cb
2 parents 5d7f0d1 + cc11b19
commit 4cbf4cb
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Showing 2 changed files with 31 additions and 34 deletions.
diff --git a/api/metrics-api-jaxrs/src/main/java/org/hawkular/metrics/api/jaxrs/TenantsHandler.java b/api/metrics-api-jaxrs/src/main/java/org/hawkular/metrics/api/jaxrs/TenantsHandler.java
@@ -19,7 +19,6 @@
 import static javax.ws.rs.core.MediaType.APPLICATION_JSON;
 
 import java.net.URI;
-import java.util.Collection;
 import java.util.List;
 
 import javax.inject.Inject;
@@ -35,12 +34,11 @@
 import javax.ws.rs.core.Response.Status;
 import javax.ws.rs.core.UriInfo;
 
+import org.hawkular.metrics.api.jaxrs.callback.SimpleDataCallback;
 import org.hawkular.metrics.api.jaxrs.callback.TenantCreatedCallback;
 import org.hawkular.metrics.core.api.MetricsService;
 import org.hawkular.metrics.core.api.Tenant;
 
-import com.google.common.base.Throwables;
-import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.wordnik.swagger.annotations.Api;
@@ -91,34 +89,16 @@ public void createTenant(
         Futures.addCallback(insertFuture, tenantCreatedCallback);
     }
 
-
-
     @GET
     @ApiOperation(value = "Returns a list of tenants.")
-    @ApiResponses(value = { @ApiResponse(code = 200, message = "Returned a list of tenants successfully."),
+    @ApiResponses(value = {
+            @ApiResponse(code = 200, message = "Returned a list of tenants successfully."),
             @ApiResponse(code = 204, message = "No tenants were found."),
             @ApiResponse(code = 500, message = "Unexpected error occurred while fetching tenants.",
                          response = ApiError.class)
     })
-    public void findTenants(@Suspended AsyncResponse response) {
+    public void findTenants(@Suspended AsyncResponse asyncResponse) {
         ListenableFuture<List<Tenant>> tenantsFuture = metricsService.getTenants();
-        Futures.addCallback(tenantsFuture, new FutureCallback<Collection<Tenant>>() {
-            @Override
-            public void onSuccess(Collection<Tenant> tenants) {
-                if (tenants.isEmpty()) {
-                    response.resume(Response.ok().status(Status.NO_CONTENT).build());
-                    return;
-                }
-                response.resume(Response.status(Status.OK).entity(tenants).build());
-            }
-
-            @Override
-            public void onFailure(Throwable t) {
-                ApiError errors = new ApiError(
-                        "Failed to fetch tenants due to an "
-                    + "unexpected error: " + Throwables.getRootCause(t).getMessage());
-                response.resume(Response.status(Status.INTERNAL_SERVER_ERROR).entity(errors).build());
-            }
-        });
+        Futures.addCallback(tenantsFuture, new SimpleDataCallback<>(asyncResponse));
     }
 }
diff --git a/...-impl/src/main/java/org/hawkular/metrics/core/impl/cassandra/MetricsServiceCassandra.java b/...-impl/src/main/java/org/hawkular/metrics/core/impl/cassandra/MetricsServiceCassandra.java
@@ -101,6 +101,8 @@ public class MetricsServiceCassandra implements MetricsService {
 
     private static final AvailabilityMetricMapper AVAILABILITY_METRIC_MAPPER = new AvailabilityMetricMapper();
 
+    private static final TenantMapper TENANT_MAPPER = new TenantMapper();
+
     private static class DataRetentionKey {
         private final String tenantId;
         private final MetricId metricId;
@@ -408,15 +410,30 @@ public ListenableFuture<Void> apply(ResultSet resultSet) {
 
     @Override
     public ListenableFuture<List<Tenant>> getTenants() {
-        TenantMapper mapper = new TenantMapper();
-        List<String> ids = loadTenantIds();
-        List<ListenableFuture<Tenant>> tenantFutures = new ArrayList<>(ids.size());
-        for (String id : ids) {
-            ResultSetFuture queryFuture = dataAccess.findTenant(id);
-            ListenableFuture<Tenant> tenantFuture = Futures.transform(queryFuture, mapper, metricsTasks);
-            tenantFutures.add(tenantFuture);
-        }
-        return Futures.allAsList(tenantFutures);
+        ListenableFuture<List<String>> tenantIdsFuture = Futures.transform(
+                dataAccess.findAllTenantIds(), (ResultSet input) -> {
+                    if (input.isExhausted()) {
+                        return null;
+                    }
+                    List<String> tenantIds = new ArrayList<>();
+                    for (Row row : input) {
+                        tenantIds.add(row.getString(0));
+                    }
+                    return tenantIds;
+                }, metricsTasks
+        );
+        return Futures.transform(
+                tenantIdsFuture, (List<String> input) -> {
+                    if (input == null) {
+                        return Futures.immediateFuture(null);
+                    }
+                    List<ListenableFuture<Tenant>> tenantFutures = new ArrayList<>();
+                    for (String tenantId : input) {
+                        tenantFutures.add(Futures.transform(dataAccess.findTenant(tenantId), TENANT_MAPPER));
+                    }
+                    return Futures.allAsList(tenantFutures);
+                }
+        );
     }
 
     private List<String> loadTenantIds() {