propman
v0.1.3
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Property and config loader and manager, allowing you to load hierarchical property values based on environment variables
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propman
Simple property and config manager that allows you to load up your properties files and hierarchical variations of those properties files specific to individual environments. Can be used when you want to keep the management of your properties simple and local to the code instead of using external tools.
Can also be used for loading up text for internalization.
Example 1
You have two servers that you deploy your code to; PROD1 and PROD2. Both servers might need to point to different database instances. Both servers also share common properties like labels for form buttons.
appConfig.properties
db.url=dev.db.foo.com
appConfig.properties_en_UK
button1=submit button2=signin
appConfig.properties_en_UK_PROD1
db.url=prod1.db.foo.com
appConfig.properties_en_UK_PROD2
db.url=prod2.db.foo.com
In your node code, you do
var propMan = require('./propman').getInstance();
propMan.loadProperty('./directory/to/properties','appConfig.properties');
var dbServer = propMan.getProperty('appConfig.properties','db.url');
You can then use the following environment variable
PROPMANENV
to load the properties file specific to the environment your code is running on. So for PROD1 we can start the node instance as
PROPMANENV=en_UK_PROD1 node server.js
And this will load up the following properties files
appConfig.properties appConfig.properties_en_UK appConfig.properties_en_UK_PROD1
And the following properties value
db.url=prod1.db.foo.com button1=submit button2=signin
On PROD2 we would pass in PROPMANENV=en_UK_PROD2 which would then load
appConfig.properties appConfig.properties_en_UK appConfig.properties_en_UK_PROD2
with the following properties being loaded
db.url=prod2.db.foo.com button1=submit button2=signin
Example 2
You want to test the code locally on your development laptop but want to test it against a TEST database and a UAT database, maybe for troubleshooting or debugging
appConfig.properties
db.url=dev.db.foo.com
appConfig.properties_en_UK_TEST
db.url=test.db.foo.com
appConfig.properties_en_UK_UAT
db.url=uat.db.foo.com
You can then use
PROPMANENV=en_UK_TEST to load up the TEST db.url which will give you test.db.foo.com PROPMANENV=en_UK_UAT to load up the UAT db.url which will give you uat.db.foo.com
If you don't pass in any environment variable you will get the default which will be dev.db.foo.com
Example 3
You have a piece of text with word/s that need to be substituted by runtime value. You can specify runtime value substitution using {{}}
e.g.
frontpage.blurb=The quick {{colour}} {{animal}} jumped over the lazy {{animal2}}
Then in your code you can pass in a map that contains the actual value to put in.
var text = propMan.getProperty('propertyfile.properties','frontpage.blurb', {colour : 'brown', animal: 'fox', animal2: 'dog'});
You will end up with the text
The quick brown fox jumped over the lazy dog
Example 4
You can make sure a property must be set a value by using {{{required}}}. If the property hasn't been set after loading all the hierarchical properties files, an error will be thrown.
appConfig.properties
property.that.has.to.be.set={{{required}}} label1={{{required}}}
appConfig.properties_en_UK
property.that.has.to.be.set=UK specific value label1=press for lift
appConfig.properties_en_US
property.that.has.to.be.set=US specific value label1=press for elevator
If you just load appConfig.properties (i.e. without any PROPMANENV) it will throw an error as both properties has a value of {{{required}}}.
e.g.
var propMan = require('./propman').getInstance();
try {
propMan.loadProperty('./directory/to/properties','appConfig.properties');
} catch (err) {
// deal with err
// you can get access to an object that has a map of all the properties that has been set {{{required}}} by using err.extra
// e.g.
console.dir(err.extra);
}
Extra
You can also pass in the PROPMANENV environment programmatically
var propMan = require('./propman').getInstance('en_UK_PROD1');