hardwired configuration loader
npm install run-conjavascript
var conf = require('run-con')(appname, {
//defaults go here.
port: 2468,
//defaults which are objects will be merged, not replaced
views: {
engine: 'jade'
}
});
`
run-con will return your configuration options merged with the defaults you specify.
If you pass in a predefined defaults object, it will be mutated:
`javascript
var conf = {};
require('run-con')(appname, conf);
`
If run-con finds any config files for your app, the returned config object will have
a configs array containing their paths:
`javascript
var appCfg = require('run-con')(appname, conf);
appCfg.configs[0] // /etc/appnamerc
appCfg.configs[1] // /home/dominictarr/.config/appname
appCfg.config // same as appCfg.configs[appCfg.configs.length - 1]
`
Standards
Given your application name (appname), run-con will look in all the obvious places for configuration.
* command line arguments, parsed by minimist _(e.g. --foo baz, also nested: --foo.bar=baz)_
* environment variables prefixed with ${appname}_
* or use "\_\_" to indicate nested properties
_(e.g. appname_foo__bar__baz => foo.bar.baz)_
* if you passed an option --config file then from that file
* a local .${appname}rc or the first found looking in ./ ../ ../../ ../../../ etc.
* $HOME/.${appname}rc
* $HOME/.${appname}/config
* $HOME/.config/${appname}
* $HOME/.config/${appname}/config
* /etc/${appname}rc
* /etc/${appname}/config
* the defaults object you passed in.
All configuration sources that were found will be flattened into one object,
so that sources earlier in this list override later ones.
Configuration File Formats
Configuration files (e.g. .appnamerc) may be in either json or ini format. No file extension (.json or .ini) should be used. The example configurations below are equivalent:
#### Formatted as ini
`
; You can include comments in ini format if you want.
dependsOn=0.10.0
; run-con has built-in support for ini sections, see?
[commands]
www = ./commands/www
console = ./commands/repl
; You can even do nested sections
[generators.options]
engine = ejs
[generators.modules]
new = generate-new
engine = generate-backend
`
#### Formatted as json
`javascript
{
// You can even comment your JSON, if you want
"dependsOn": "0.10.0",
"commands": {
"www": "./commands/www",
"console": "./commands/repl"
},
"generators": {
"options": {
"engine": "ejs"
},
"modules": {
"new": "generate-new",
"backend": "generate-backend"
}
}
}
`
Comments are stripped from JSON config via strip-json-comments.
> Since ini, and env variables do not have a standard for types, your application needs be prepared for strings.
To ensure that string representations of booleans and numbers are always converted into their proper types (especially useful if you intend to do strict === comparisons), consider using a module such as parse-strings-in-object to wrap the config object returned from run-con.
Simple example demonstrating precedence
Assume you have an application like this (notice the hard-coded defaults passed to run-con):
`
const conf = require('run-con')('myapp', {
port: 12345,
mode: 'test'
});
console.log(JSON.stringify(conf, null, 2));
`
You also have a file config.json, with these contents:
`
{
"port": 9000,
"foo": "from config json",
"something": "else"
}
`
And a file .myapprc in the same folder, with these contents:
`
{
"port": "3001",
"foo": "bar"
}
`
Here is the expected output from various commands:
node .
`
{
"port": "3001",
"mode": "test",
"foo": "bar",
"_": [],
"configs": [
"/Users/stephen/repos/conftest/.myapprc"
],
"config": "/Users/stephen/repos/conftest/.myapprc"
}
`
Default mode from hard-coded object is retained, but port is overridden by .myapprc file (automatically found based on appname match), and foo is added.
node . --foo baz
`
{
"port": "3001",
"mode": "test",
"foo": "baz",
"_": [],
"configs": [
"/Users/stephen/repos/conftest/.myapprc"
],
"config": "/Users/stephen/repos/conftest/.myapprc"
}
`
Same result as above but foo is overridden because command-line arguments take precedence over .myapprc file.
node . --foo barbar --config config.json
`
{
"port": 9000,
"mode": "test",
"foo": "barbar",
"something": "else",
"_": [],
"config": "config.json",
"configs": [
"/Users/stephen/repos/conftest/.myapprc",
"config.json"
]
}
`
Now the port comes from the config.json file specified (overriding the value from .myapprc), and foo value is overridden by command-line despite also being specified in the config.json file.
Advanced Usage
#### Pass in your own argv
You may pass in your own argv as the third argument to run-con. This is in case you want to use your own command-line opts parser.
`javascript
require('run-con')(appname, defaults, customArgvParser);
`
Pass in your own parser
If you have a special need to use a non-standard parser,
you can do so by passing in the parser as the 4th argument.
(leave the 3rd as null to get the default args parser)
`javascript
require('run-con')(appname, defaults, null, parser);
`
This may also be used to force a more strict format,
such as strict, valid JSON only.
Note on Performance
run-con is running fs.statSync`-- so make sure you don't use it in a hot code path (e.g. a request handler)