Adding to "Don't run bower/npm install/update on production" - a lot of package managers have a local mirror available and you can point your build server to it

Adding to "Don't run bower/npm install/update on production" - a lot of package managers have a local mirror available and you can point your build server to it. This gives you some redundancy if the public mirror goes down, and also faster downloads within the network. Bandersnatch mirrors all of pypi, there are some others that will just mirror the parts of pypi you need and fetch new packages as you try to pip install things that don't exist in its local cache.