Different configs for meteor dev/staging/production environments.

client_config.js

getS3Bucket = function() {
  var host = document.location.host;
  if (host === 'localhost:3000') {
    return 'myapp-dev';
  } else if (host === 'myapp.meteor.com') {
    return 'myapp-staging';
  } else if (host === 'myapp.com') {
    return 'myapp-production';
  }
}

server_config.js

function getS3Bucket() {
  if (Meteor.absoluteUrl() === 'http://localhost:3000/') {
    return 'myapp-dev';
  } else if (Meteor.absoluteUrl() === 'http://myapp.meteor.com/') {
    return 'myapp-staging';
  } else if (Meteor.absoluteUrl() === 'http://myapp.com/') {
    return 'myapp-production';
  }
}