added list buckets query

internal/dataloader.go

@@ -227,6 +227,40 @@ func handleLoaderError(k dataloader.Keys, err error) []*dataloader.Result {
 	return results
 }
 
+func listBucketsBatch(c context.Context, k dataloader.Keys) []*dataloader.Result {
+	log.Debug("listBucketsBatch")
+	var results []*dataloader.Result
+
+	s3Client, ok := c.Value("s3Client").(*minio.Client)
+
+	if !ok {
+		return handleLoaderError(k, fmt.Errorf("Failed to get s3Client from context"))
+	}
+
+	buckets, err := s3Client.ListBuckets(c)
+
+	if err != nil {
+		return handleLoaderError(k, err)
+	}
+
+	var bucketStrings []string
+
+	for _, v := range buckets {
+		bucketStrings = append(bucketStrings, v.Name)
+	}
+
+	result := &dataloader.Result{
+		Data:  bucketStrings,
+		Error: nil,
+	}
+
+	for range k {
+		results = append(results, result)
+	}
+
+	return results
+}
+
 // createDataloader create all dataloaders and return a map of them plus a cache for objects
 func createDataloader(config types.AppConfig) map[string]*dataloader.Loader {
 	loaderMap := make(map[string]*dataloader.Loader, 0)
@@ -256,5 +290,10 @@ func createDataloader(config types.AppConfig) map[string]*dataloader.Loader {
 		dataloader.WithCache(newCache(config.CacheTTL, config.CacheCleanup)),
 	)
 
+	loaderMap["listBuckets"] = dataloader.NewBatchedLoader(
+		listBucketsBatch,
+		dataloader.WithCache(newCache(config.CacheTTL, config.CacheCleanup)),
+	)
+
 	return loaderMap
 }

internal/gql/schema.go

@@ -100,6 +100,21 @@ func GraphqlSchema() (graphql.Schema, error) {
 				return auth, nil
 			},
 		},
+		"buckets": &graphql.Field{
+			Name:        "buckets",
+			Type:        graphql.NewNonNull(graphql.NewList(graphql.String)),
+			Description: "List available buckets",
+			Resolve: func(p graphql.ResolveParams) (interface{}, error) {
+				if !helper.IsAuthenticated(p.Context) {
+					return nil, s3errors.ErrNotAuthenticated
+				}
+
+				loader := p.Context.Value("loader").(map[string]*dataloader.Loader)
+				// The only reason we use a dataloader with a empty key is that we want to cache the result
+				thunk := loader["listBuckets"].Load(p.Context, dataloader.StringKey(""))
+				return thunk()
+			},
+		},
 	}
 
 	mutationFields := graphql.Fields{