Currently that CouchDB handles configuration stuff is to reads in it's
configuration setting at startup time the couch.ini file, and then
feeds those settings as startup arguments to the various child servers
processes. This requires that to change a setting you must restart to
take effect.
This is fine for now, but we can do better. I'd like to enhance this
by providing a configuration module that allows for configuration
settings to be changed at runtime, and automatically have those
changes take effect without requiring a server restart.
The way I was thinking it would work, at startup the server
configuration module sucks up the settings from the couch.ini, then
the child processes are started normally, but without startup
arguments. The child processes then query the runtime module at
startup, or whenever, to get their configuration data.
It should be possible for the core modules to subscribe notifications
of configuration updates. In Erlang, this is typically done by the
modules registering a callback function. So when a configuration
setting is updated, it would get invoked with the changed settings as
arguments.
And when a configuration setting is changed at runtime, the module
should write the new setting back to the couch.ini file. And it should
be able to handle updates to settings, etc, and ideally still preserve
all previous formatting and comments.
So, some questions. What do people think of this in general? Or should
we be using the apache conf format instead of ini? Maybe we should use
json?
One things I'd like to see is that configuration stuff be editable in
a text editor. However, I might be dissuaded to start using a CouchDB
database to store everything but the most critical startup information.
Thoughts please.
- server configuration stuff Damien Katz
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