spring-cloud-config-client v1.0.0
cloud-foundry-config-client
A simple client for pulling configuration from a PCF Spring Cloud Config Server
Installation
npm install cloud-foundry-config-client
or
yarn add cloud-foundry-config-client
Usage
cloud-foundry-config-client
exposes a method used to load the configuration on start of the application and a static property for reading the currently loaded configuration object.
The first step is to load
the configuration from a Cloud Foundry Config Server (or optionally from a local yaml file):
// index.js
import * as express from 'express';
import { Config } from 'cloud-foundry-config-client';
...
Config.load({
// defines the application name to used when querying the config server
appName: "myExpressApp",
// "remote" will query the config server, "local" will read from a local yaml file
configLocation: "remote",
// profile to use when querying the config server, e.g "dev", "uat", "prod"
profile: "dev",
// the name of the config server in PCF
configServerName: "myConfigServer"
})
.then(() => { // on successful load, start your application
const app = express()
app.get('/', function (req, res) {
res.send('Hello World')
})
app.listen(3000)
})
.catch(err => {
console.log(err);
});
Once the configuration has been loaded, it can be accessed in any other module buy referencing the current
property on the Config
object:
import * as jwt from 'express-jwt';
import { Config } from 'cloud-foundry-config-client';
...
// Get the JWT secret that was retrieved from config server
const { jwt_secret } = Config.current;
app.use(jwt({ secret: jwt_secret }));
app.use((err, req, res, next) => {
if (err.name === "UnauthorizedError") {
res.status(401).send("invalid token...");
}
});
}
Considerations
This is currently a very basic client and as such it enforces some limitations on the usage of the Spring Cloud Config Server.
- This client has only been tested with a git repo backing the config server
- The client expects configuration yaml files to be stored in the root of the git backing repo with the following file name convention:
{appName}-{profile}.yml //(e.g. myExpressApp-dev.yml)
Loading from a local file
If you haven't had a chance to configure a Cloud Foundry Cloud Config Server yet, you can fake it by loading configuration from a local yaml file:
Config.load({
appName: "myExpressApp",
configLocation: "local", // gets configuration from local yaml file
profile: "dev",
configServerName: "myConfigServer"
})
...
When loading from a local file, cloud-foundry-config-client expects the file to have a particular path and filename based on the { appName, profile, configServerName }
passed into the load function. These parameters are used to build the path and filename based on the following convention:
// relative to the current working directory
./{configServerName}/{appName}-{profile}.yml
Which, in our example above, translates to:
./myConfigServer/myExpressApp-dev.yml
Loading from a remote config server while running application locally
It is also possible to load configuration from a Cloud Foundry Config Server while running your application locally. cloud-foundry-config-client
looks in the VCAP_SERVICES environment variable to find the client credentials needed to connect to a Config Server (based on { configServerName }
passed into the load
function).
If you want to load your configuration from a remote Config Server while running locally, copy the relevent VCAP_SERVICES to your local machine and either set a VCAP_SERVICES envronment variable before running your app, or, more easily, copy the JSON into a vcap_services.json
file in the root of your application folder:
// vcap_services.js
// cloud-foundry-config-client checks here if no
// VCAP_SERVICES environment variable is found
{
"p-config-server": [
{
"credentials": {
"uri": "local.config",
"client_secret": "secret",
"client_id": "id",
"access_token_uri": "local.token"
},
"name": "test-config"
}
]
}
Then, just start your application locally, specifying { configLocation = "remote" }
in your load
function:
Config.load({
appName: "myExpressApp",
configLocation: "remote",
profile: "dev",
configServerName: "myConfigServer"
})
...
6 years ago