I added a clojars mirror to ~/.lein/profiles.clj as in

{:user {:plugins [[lein-license "0.1.3"]
                  [cider/cider-nrepl "0.10.0"]]
        :dependencies [[org.clojure/tools.nrepl "0.2.12"]]
        :mirrors {#"clojars"
                  {:name "clojars mirror"
                   :url ""}}}}

lein clean still hangs with a mirror.

DoS attacks on linode are neutralizing leiningen users.

cljsbuild reports that lein-cjlsbuild 1.1.1 is not available in the local repository, but it's in ~/.m2/repository/lein-cljsbuild/1.1.1.

$ lein cljsbuild once prod
The repository system is offline but the artifact lein-cljsbuild:lein-cljsbuild:jar:1.1.1 is not available in the local repository.
The repository system is offline but the artifact lein-figwheel:lein-figwheel:jar:0.5.0-2 is not available in the local repository.
The repository system is offline but the artifact lein-license:lein-license:jar:0.1.3 is not available in the local repository.
The repository system is offline but the artifact cider:cider-nrepl:jar:0.10.0 is not available in the local repository.
This could be due to a typo in :dependencies or network issues.
If you are behind a proxy, try setting the 'http_proxy' environment variable.

Actually, lein clean also reports that those packages are not in the local repository.

It seems the issue affectin me is https://github.com/technomancy/leiningen/issues/2055

When clojars is down, it strikes users.