One suggestion to condiser: now, it's all or nothing: one failed request for listing file cuases all repos being skipped. Sometimes however, there was only temporary inconsistence in cdn, with other repos being accessible normally. Therefore, what could be done is catching the exception on CdnVarSubstitutor and returning the failure messages in array as second output argument. Just a suggestion: what @ares @thomasmckay @bbuckingham think?