If one of the developers on one of my teams had done this, I would have (a) told him to get some sleep and (b) mocked him for at least a week afterwards.

Saturday night I spent four hours trying to figure out why something that worked perfectly in my local Azure emulator failed with a cryptic "One of the request inputs is out of range" message in the Cloud. I even posted to StackOverflow for help.

This morning, I spent about 90 minutes building a sample Cloud application up from scratch, adding one component at a time until I got to the same failure. And, eventually, I got to the same failure. Then I stepped through the code to figure out

And I immediately saw why.

The problem turned out to be this: I have two settings:

    <?xml version="1.0" encoding="utf-8"?>
    <ServiceDefinition name="Cloud" ...>
      <WebRole name="WebRole" vmsize="Small">
        <ConfigurationSettings>
          <Setting name="MessagesConfigurationBlobName" />
          <Setting name="MessagesConfigurationBlobContainerName" />
        </ConfigurationSettings>
      </WebRole>
    </ServiceDefinition>

Here's the local (emulator) configuration file:

    <?xml version="1.0" encoding="utf-8"?>
    <ServiceConfiguration ...>
      <Role name="WebRole">
        <ConfigurationSettings>
          <Setting name="MessagesConfigurationBlobName" value="LocalMessageConfig.xml"/>
          <Setting name="MessagesConfigurationBlobContainerName" value="containername"/>
        </ConfigurationSettings>
      </Role >
    </ServiceConfiguration>

Here's the Cloud file:

    <?xml version="1.0" encoding="utf-8"?>
    <ServiceConfiguration ...>
      <Role name="WebRole">
        <ConfigurationSettings>
          <Setting name="MessagesConfigurationBlobName" value="containername" />
          <Setting name="MessagesConfigurationBlobContainerName" value="CloudMessageConfig.xml"/>
        </ConfigurationSettings>
      </Role >
    </ServiceConfiguration>

I will now have a good cry and adjust my time tracking (at 3am Saturday) from "Emergency client work" to "Developer PEBCAK".

The moral of the story is, when identical code fails in one environment and succeeds in another, don't just compare the environments, compare *everything that could be different in your own code* between the environments.

Oh, and don't try to deploy software at 3am. Ever.