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Featureful configuration management library for Node.js (nested structure, schema validation, etc.)
Convict is a configuration management tool for Node.js applications. It allows you to define a schema for your configuration files, validate them, and load them from various sources such as JSON files, environment variables, or command-line arguments.
Define a Configuration Schema
This feature allows you to define a schema for your configuration. The schema can include various types of data such as strings, numbers, and arrays. You can also specify default values and environment variables.
const convict = require('convict');
const config = convict({
env: {
doc: 'The application environment.',
format: ['production', 'development', 'test'],
default: 'development',
env: 'NODE_ENV'
},
port: {
doc: 'The port to bind.',
format: 'port',
default: 8080,
env: 'PORT'
}
});
console.log(config.get('env'));
Load Configuration from Multiple Sources
Convict allows you to load configuration from multiple sources such as JSON files, environment variables, and command-line arguments. This makes it easy to manage configuration in different environments.
const convict = require('convict');
const config = convict({
env: {
doc: 'The application environment.',
format: ['production', 'development', 'test'],
default: 'development',
env: 'NODE_ENV'
},
port: {
doc: 'The port to bind.',
format: 'port',
default: 8080,
env: 'PORT'
}
});
config.loadFile('./config.json');
config.load({ port: 3000 });
console.log(config.get('port'));
Validate Configuration
Convict can validate your configuration against the schema you defined. This ensures that your configuration is correct and helps prevent runtime errors.
const convict = require('convict');
const config = convict({
env: {
doc: 'The application environment.',
format: ['production', 'development', 'test'],
default: 'development',
env: 'NODE_ENV'
},
port: {
doc: 'The port to bind.',
format: 'port',
default: 8080,
env: 'PORT'
}
});
config.validate({ allowed: 'strict' });
console.log('Configuration is valid');
The 'config' package is another popular configuration management tool for Node.js. It allows you to define configuration files for different environments and load them based on the current environment. Unlike Convict, it does not provide schema validation out of the box.
The 'dotenv' package is a simple module that loads environment variables from a .env file into process.env. It is more lightweight compared to Convict and does not provide schema validation or support for multiple configuration sources.
The 'nconf' package is a hierarchical configuration manager for Node.js. It allows you to load configuration from multiple sources and provides a flexible way to manage configuration. However, it does not provide schema validation like Convict.
Convict expands on the standard pattern of configuring node.js applications in a way that is more robust and accessible to collaborators, who may have less interest in digging through imperative code in order to inspect or modify settings. By introducing a configuration schema, convict gives project collaborators more context on each setting and enables validation and early failures for when configuration goes wrong.
npm install convict
An example config.js
file:
var convict = require('convict');
// Define a schema
var config = convict({
env: {
doc: "The application environment.",
format: ["production", "development", "test"],
default: "development",
env: "NODE_ENV"
},
ip: {
doc: "The IP address to bind.",
format: "ipaddress",
default: "127.0.0.1",
env: "IP_ADDRESS",
},
port: {
doc: "The port to bind.",
format: "port",
default: 8080,
env: "PORT",
arg: "port"
},
db: {
host: {
doc: "Database host name/IP",
format: '*',
default: 'server1.dev.test'
},
name: {
doc: "Database name",
format: String,
default: 'users'
}
}
});
// Load environment dependent configuration
var env = config.get('env');
config.loadFile('./config/' + env + '.json');
// Perform validation
config.validate({allowed: 'strict'});
module.exports = config;
An example server.js
file leveraging the config.js
file above:
var http = require('http');
var config = require('./config.js');
var server = http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
});
// Consume
server.listen(config.get('port'), config.get('ip'), function(x) {
var addy = server.address();
console.log('running on http://' + addy.address + ":" + addy.port);
});
To launch your example server, and set a port:
node ./server.js --port 8080
Note: arguments must be supplied with the double-hyphen --arg
. (Single hypen's are not supported at this time)
A configuration module, with its deep nested schema, could look like this:
config.js:
var config = convict({
db: {
name: {
format: String,
default: ''
},
synchro: {
active: {
format: 'Boolean',
default: false
},
remote_url: {
format: 'url',
default: 'http://localhost:8080/'
}
}
},
secret: {
doc: 'Secret used for session cookies and CSRF tokens',
format: '*',
default: '',
sensitive: true
}
});
config.loadFile(['./prod.json', './config.json']);
Each setting in the schema has the following possible properties, each aiding in convict's goal of being more robust and collaborator friendly.
format
property specifies either a built-in convict format (ipaddress
, port
, int
, etc.), or it can be a function to check a custom format. During validation, if a format check fails it will be added to the error report.env
has a value, it will overwrite the setting's default value. An environment variable may not be mapped to more than one setting.arg
is supplied, it will overwrite the setting's default value or the value derived from env
.doc
property is pretty self-explanatory. The nice part about having it in the schema rather than as a comment is that we can call config.getSchemaString()
and have it displayed in the output.sensitive
is set to true
, this value will be masked to "[Sensitive]"
when config.toString()
is called. This helps avoid disclosing secret keys when printing configuration at application start for debugging purposes.In order to help detect misconfigurations, convict allows you to define a format for each setting. By default, convict checks if the value of the property has the same type (according to Object.prototype.toString.call
) as the default value specified in the schema. You can define a custom format checking function in the schema by setting the format
property.
convict provides several predefined formats for validation that you can use (using node-validator and moment.js). Most of them are self-explanatory:
*
- any value is validint
port
windows_named_pipe
port_or_windows_named_pipe
url
email
ipaddress
- IPv4 and IPv6 addressesduration
- milliseconds or a human readable string (e.g. 3000, "5 days")timestamp
- Unix timestamps or date strings recognized by moment.jsnat
- positive integer (natural number)If format
is set to one of the built-in JavaScript constructors, Object
, Array
, String
, Number
, RegExp
, or Boolean
, validation will use Object.prototype.toString.call to check that the setting is the proper type.
You can specify a custom format checking method on a property basis.
For example:
var config = convict({
key: {
doc: "API key",
format: function check (val) {
if (!/^[a-fA-F0-9]{64}$/.test(val)) {
throw new Error('must be a 64 character hex key')
}
},
default: '3cec609c9bc601c047af917a544645c50caf8cd606806b4e0a23312441014deb'
},
name: {
doc: "user name",
format: function check (val) {
if (typeof val.first_name !== 'string') {
throw new TypeError(`first name '${val.first_name}' is not a string`);
}
if (typeof val.last_name !== 'string') {
throw new TypeError(`last name '${val.last_name}' is not a string`);
}
},
default: {
first_name: 'John',
last_name: 'Doe'
}
}
});
Or, you can use convict.addFormat()
to register a custom format checking
method that can be reused for many different properties:
convict.addFormat({
name: 'float-percent',
validate: function(val) {
if (val !== 0 && (!val || val > 1 || val < 0)) {
throw new Error('must be a float between 0 and 1, inclusive');
}
},
coerce: function(val) {
return parseFloat(val, 10);
}
});
var config = convict({
space_used: {
format: 'float-percent',
default: 0.5
},
success_rate: {
format: 'float-percent',
default: 60.0
}
});
The coerce
function is optional.
Convict will automatically coerce environmental variables from strings to their proper types when importing them. For instance, values with the format int
, nat
, port
, or Number
will become numbers after a straight forward parseInt
or parseFloat
. duration
and timestamp
are also parse and converted into numbers, though they utilize moment.js for date parsing.
When merging configuration values from different sources, Convict follows precedence rules. The order, from lowest to highest, is:
config.loadFile()
)env
property is set in schema; can be overridden using the env
option of the convict function)arg
property is set in schema; can be overridden using the args
option of the convict function)config.set()
and config.load()
)Convict is able to parse files with custom file types during loadFile
.
For this specify the corresponding parsers with the associated file extensions.
convict.addParser({ extension: 'toml', parse: toml.parse });
convict.addParser({ extension: ['yml', 'yaml'], parse: yaml.safeLoad });
convict.addParser([
{ extension: 'json', parse: JSON.parse },
{ extension: 'json5', parse: json5.parse },
{ extension: ['yml', 'yaml'], parse: yaml.safeLoad },
{ extension: 'toml', parse: toml.parse }
]);
const config = convict({ ... });
config.loadFile('config.toml');
If no supported extension is detected, loadFile
will fallback to using the
default json5 parser for backward compatibility.
convict()
takes a schema object or a path to a schema JSON file and returns a
convict configuration object.
JSON files are loaded using JSON5
, so they can contain comments.
The configuration object has an API for getting and setting values, described below.
var config = convict({
env: {
doc: "The applicaton environment.",
format: ["production", "development", "test"],
default: "development",
env: "NODE_ENV"
},
log_file_path: {
"doc": "Log file path",
"format": String,
"default": "/tmp/app.log"
}
});
// or
config = convict('/some/path/to/a/config-schema.json');
Adds new parsers for custom file extensions
Adds a new custom format, format
being an object, see example below.
convict.addFormat({
name: 'float-percent',
validate: function(val) {
if (val !== 0 && (!val || val > 1 || val < 0)) {
throw new Error('must be a float between 0 and 1, inclusive');
}
},
coerce: function(val) {
return parseFloat(val, 10);
}
});
Adds new custom formats, formats
being an object whose keys are the new custom
format names, see example below.
convict.addFormats({
prime: {
validate: function(val) {
function isPrime(n) {
if (n <= 1) return false; // zero and one are not prime
for (let i=2; i*i <= n; i++) {
if (n % i === 0) return false;
}
return true;
}
if (!isPrime(val)) throw new Error('must be a prime number');
},
coerce: function(val) {
return parseInt(val, 10);
}
},
'hex-string': {
validate: function(val) {
if (/^[0-9a-fA-F]+$/.test(val)) {
throw new Error('must be a hexidecimal string');
}
}
}
});
Returns the current value of the name
property. name
can use dot notation to reference nested values. E.g.:
config.get('db.host');
// or
config.get('db').host;
Returns the default value of the name
property. name
can use dot notation to reference nested values. E.g.:
config.default('server.port');
Resets a property to its default value as defined in the schema. E.g.:
config.reset('server.port');
Returns true
if the property name
is defined, or false
otherwise. E.g.:
if (config.has('some.property')) {
// Do something
}
Sets the value of name
to value. name
can use dot notation to reference
nested values, e.g. "db.port"
. If objects in the chain don't yet exist,
they will be initialized to empty objects.
E.g.:
config.set('property.that.may.not.exist.yet', 'some value');
config.get('property.that.may.not.exist.yet');
// Returns "some value"
Loads and merges a JavaScript object into config
. E.g.:
config.load({
"env": "test",
"ip": "127.0.0.1",
"port": 80
});
Loads and merges one or multiple JSON configuration files into config
.
JSON files are loaded using JSON5
, so they can contain comments.
E.g.:
config.loadFile('./config/' + conf.get('env') + '.json');
Or, loading multiple files at once:
// CONFIG_FILES=/path/to/production.json,/path/to/secrets.json,/path/to/sitespecific.json
config.loadFile(process.env.CONFIG_FILES.split(','));
Validates config
against the schema used to initialize it. All errors are
collected and thrown or displayed at once.
warn
: If set to warn
(that is {allowed: 'warn'}
is passed), any
properties specified in config files that are not declared in the schema will
print a warning. This is the default behavior.
strict
: If set to strict
(that is {allowed: 'strict'}
is passed), any
properties specified in config files that are not declared in the schema will
throw errors. This is to ensure that the schema and the config files are in
sync.
Exports all the properties (that is the keys and their current values) as JSON.
Exports all the properties (that is the keys and their current values) as a JSON string, with sensitive values masked. Sensitive values are masked even if they aren't set, to avoid revealing any information.
Exports the schema as JSON.
Exports the schema as a JSON string.
The array of process arguments (not including the launcher and application file arguments). Defaults to process.argv unless an override is specified using the args key of the second (options) argument of the convict function.
The map of environment variables. Defaults to process.env unless an override is specified using the env key of the second argument (options) argument of the convict function.
The philosophy was to have production values be the default values. Usually you only want to change defaults for deploy or instance (in aws speak) specific tweaks. However, you can set a default value to null
and if your format doesn't accept null
it will throw an error.
Thanks to browserify, convict
can be used for web applications too. To do so,
brfs
to ensure the fs.loadFileSync
schema-loading calls are inlined at build time rather than resolved at runtime (in Gulp, add .transform(brfs)
to your browserify pipe).http://foo.bar/some.json
URL", build a thin wrapper around convict using your favorite http package (e.g. superagent
). Typically, in the success callback, call convict's load()
on the body of the response.Read the Contributing doc.
FAQs
Featureful configuration management library for Node.js (nested structure, schema validation, etc.)
We found that convict demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 5 open source maintainers collaborating on the project.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
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