Two functions, create-records-list takes tree structure such as custom-provider, and returns list of records that can be passed to ui/create, prepare-org-custom-provider takes this list and executes it and syncs the repos.

gistfile1.clj

(def custom-provider [{:name "fedorapeople"
                       :products [{:name "safari-1_0"
                                   :repos [{:name "safari-x86_64" 
                                            :url "http://inecas.fedorapeople.org/fakerepos/cds/content/safari/1.0/x86_64/rpms/"}]}]}])

(defn create-records-list [list org & parent]
  (into [] (flatten 
  (for [item list]
    (if (contains? item :products)
      (let [prov (kt/newProvider {:name (item :name) :org org})]
        (concat [prov]
                (create-records-list (item :products) org prov)))
       (if (contains? item :repos)
         (let [prod (kt/newProduct {:name (item :name) :provider parent :org org})]
           (concat [prod]
                (create-records-list (item :repos) org prod)))
         (kt/newRepository 
           {:name (item :name) 
           :url (item :url)
           :product parent})))))))

(defn prepare-org-custom-provider [org provider]
  (let [provider-list (create-records-list provider org)]
    (doseq [item provider-list]
      (ui/create item))
  (sync/perform-sync (filter  (partial instance? katello.Repository) provider-list))))