I'm having some annoyances with gflags which I'd like to air out here. Maybe we can come to a consensus about how to move forward with them. I find gflags annoying in the following ways:
a) flags are irritating for global settings. Settings that apply to the project as a whole have to be set in multiple places so that the binaries all get them properly. This can be fixed somewhat by a shared flagfile. For example: /etc/nova/nova-manage.conf: --flagfile=/etc/nova/nova-common.conf # shared settings --otherflag=true #manage specific settings The problem here is that the shared settings can only include settings that are imported by EVERY binary, or one of the binaries will choke. So if you have a flag that 4 of 5 binaries use, you either have to set it in four flagfiles or put it in common with an ugly undefok= line. This all seems nasty to me. Other possibilities include moving truly common/settings related flags into the common flags.py so that they are available to all binaries. It all seems a bit hackish. b) including files for flags only There are places where we need access to a flag, but we aren't actually making calls in the file. Pyflakes and pylint complain about unused imports. Perhaps we fix this by moving these flags into common flagfile? c) dependency injection This is related to the issue above. If we are dynamically loading specific drivers (for example the auth driver or a datastore backend) as specified by a flag, the import is often done later than the parent file is imported. Therefore using flags to configure settings for the driver will fail, because the binary recognizing the flags is dependent on the file that contains the flags being imported. Workarounds here include finding a different method for dependency injection, hacking flags to search for flags in injected dependencies somehow, or configuring drivers differently than the rest of the system. So I see 3 options for moving forward 1) ditch gflags completely and use a different method for specifying settings 2) use a combination of some kind of settings file for general configuration, and flags for specific runtime settings/hacks 3) find good standard practices/workarounds for the above issues Thoughts? Vish
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