configrr: configrr

In jmarca/configr: configr: reads usernames and passwords from config.json.

Description

A function that returns a function that will read in one or more config files, return each as an object, and on subsequent reads skip the whole part about hitting the file system

Usage

configrr(storedconfig = list())

Arguments

storedconfig

optional list to store config file results

Details

This is a closure generator.

It will return a function.

That function does the real work.

The returned function takes either a file as an argument, or will look up the environment variable R_CONFIGR_FILE. And it presumes the file is JSON. If it isn't use another library. Or better, use Perl and one of those anyconfig libraries that are so handy.

If no file is passed in and the environment variable is not set, it will return NULL.

An example config file:

"couchdb": "host": "192.168.0.1", "port":5984, "trackingdb":"a_test_state_db", "auth":"username":"blabbity", "password":"correct horse battery staple" , "postgresql": "host":"192.168.0.1", "port":5432, "auth":"username":"sqlrulez", "grid_merge_sqlquery_db":"spatialspaces"

Note that if you want to use any of the convenience functions then you should follow the above patter for "auth", but really it doesn't matter. Just get the config file as an R object and do what you want with in on your end.

One approach is to follow namespacing. So above CouchDB entry has "trackingdb" that might be used by some program called tracking, while the PostgreSQL entry has an entry called grid_merge_sqlquery_db that would be used by a package or script called grid_merge_sqlquery. This way if you have multiple programs that all need access to a database or other, you can share the auth stuff.

On the other hand, if program A needs access to postgresql on two machines, say Q and R, then you'd have to use a different approach, say namespace by machine. So for example, you might have:

"postgresql": "a": "host":"192.168.0.1", "port":5432, "auth":"username":"sqlrulez", "grid_merge_sqlquery_db":"spatialspaces" "b": "host":"192.168.0.7", "port":5432, "auth":"username":"spredsheetsdroolz", "grid_merge_sqlquery_db":"spatialspaces" "open_street_map_db":"spatialspaces"

Value

a function that in turn will return a fucntion that will return: the configuration specified in the file, as an R object. On the second and subsequent invocations, if you don't pass in a file parameter, then it will return the *first* configuration file read.

You can actually run this multiple times, and store different files each time. In that case, you have to specify the file name if you want something different than the first file stored.

Author(s)

James E. Marca

jmarca/configr documentation built on May 19, 2019, 1:50 p.m.