checkenv
- Check Your EnvironmentA modern best-practice is to store your application's configuration in environmental variables. This allows you to keep all config data outside of your repository, and store it in a standard, system-agnostic location. Modern build/deploy/development tools make it easier to manage these variables per-host, but they're still often undocumented, and can lead to bugs when missing.
This module lets you define all the environmental variables your application relies on in an env.json
file. It then provides a method to check for these variables at application launch, and print a help screen if any are missing.
$ npm i -S checkenv
First, define a JSON file called env.json
in your project root (see below). Then, add the following line to the top of your project's entry file:
require('checkenv').check();
By default, checkenv
will print a pretty error message and call process.exit(1)
if any required variables are missing. It will also print an error message if optional variables are missing, but will not exit the process.
If you would like to handle errors yourself, check
takes an optional pretty
argument which causes it to throw errors instead of printing an error message. This will only result in an error being thrown on missing required variables.
try {
require('checkenv').check(false);
} catch (e) {
// Do something with this error
}
Your JSON file should define the environmental variables as keys, and either a boolean (required) as the value, or a configuration object with any of the options below.
{
"NODE_ENV": {
"description": "This defines the current environment",
"validators": [{
"name": "in",
"options": ["development", "testing", "staging", "production"]
}]
},
"PORT": {
"description": "This is the port the API server will run on",
"default": 3000
},
"NODE_PATH": true,
"DEBUG": {
"required": false,
"description": "If set, enables additional debug messages"
}
}
required
Defines whether or not this variable is required. By default, all variables are required, so you must explicitly set them to optional by setting this to false
description
Describes the variable and how it should be used. Useful for new developers setting up the project, and is printed in the error output if present.
default
Defines the default value to use if variable is unset. Implicitly sets required
to false
.
validators
An array of validators that the variable must pass. See validator.js for details about all validators. Format for each validator is:
{
/* ... */
"validators": [
"validator name", // Option-less validators can be passed as strings
{ // Validators w/ options must be passed as objects
"name": "validator name",
"options": options // Option format varies, see below
}
]
/* ... */
}
Possible validators (see validator.js for details):
contains
— options
should be a string with what the value should containequals
— options
should be a string of the exact valuebefore
— options
should be a dateafter
— options
should be a datealpha
alphanumeric
ascii
base64
boolean
date
decimal
fqdn
float
— options
MAY be an object with min
or max
propertieshex-color
hexadecimal
ip4
— same as ip
with "options": 4
ip6
— same as ip
with "options": 6
ip
— options
MAY be number (4
or 6
)iso8601
enum
— alias for in
in
— options
MUST be an array of possible valuesint
— options
MAY be an object with min
or max
propertiesjson
length
— options
MUST be an object with min
, max
or bothlowercase
mac-address
numeric
url
uuid3
— same as uuid
with "options": 3
uuid4
— same as uuid
with "options": 4
uuid5
— same as uuid
with "options": 5
uuid
— options
MAY be a number (3
, 4
or 5
)uppercase
regex
— alias for matches
regexp
— alias for matches
matches
— options
MUST be either a string representing a regex, or an array in the format ["regex", "modifiers"]
If you like this module, you may also want to check out:
dotenv
Load missing environmental variables from .env
app-root-path
Automatically determine
the root path for the current applicationenforce-node-path
Enforce the usage of
the NODE_PATH
environmental variableenv.json
(thanks yalcindo!)setFilename()