PesDa Cloud Config Client

PesDa Cloud Config Client provide client-side support to connect to a Spring Cloud Config Server to fetch the node js application's configurations.

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Install

# Using npm
npm install pesda-cloud-config-client

# Using yarn
yarn add pesda-cloud-config-client

Usage

In your application, use init method to start the load of variables in your process.env

//typescript
import {PropertySourcesContext} from 'pesda-cloud-config-client'

//javascript
const {PropertySourcesContext} = require('pesda-cloud-config-client')

...
...
// When in your nodejs application want to retry configuration from spring cloud config server
const propertySourcesContext = PropertySourcesContext.getInstance()
propertySourcesContext.loadProperties$()
.subscribe(() => ...);

// You can also await execution of load method
const propertySourcesContext = PropertySourcesContext.getInstance()
const result = await propertySourcesContext.loadProperties$().toPromise()

...

After loadProperties$ method, you can access environment variables from env with process.env:

const database_password = process.env['db.password']

Options

• PCCC_BASE_URI
• PCCC_APPLICATION_NAME
• PCCC_PROFILE
• PCCC_LABEL
• PCCC_FAIL_FAST
• PCCC_MAX_RETRY_ATTEMPTS
• PCCC_SCALING_DURATION
• PCCC_LOGGER_ENABLED
• PCCC_LOGGER_LEVEL

PCCC_BASE_URI

This property specify the entrypoint of target config server that node js need to call to get properties. ( Example target config server )

• Default: http://localhost:8888
• Type: string

PCCC_APPLICATION_NAME

This property specify the name of node js server that use this library. PCCC_APPLICATION_NAME will be use during get properties from the target config server. ( Example target config server )

• Default: application
• Type: string

PCCC_PROFILE

This property specify the profile that you decide to use for your node js server. In this way you can start in "develop" or "production" mode. ( Example target config server )

• Default: default
• Type: string

PCCC_LABEL

This property specify the label for your properties file on config server. ( Example target config server )

• Default: no default provided
• Type: string

PCCC_FAIL_FAST

This property speficy if you want the node js server immediatelly breackdown (or not) if get properties from config server fails.

In particular, if PCCC_FAIL_FAST set to "false", the node js server continue to is up and running despite the get properties from config server fails. Otherwhise if PCCC_FAIL_FAST set to "true" it will be applied the retry strategy provided in PCCC_MAX_RETRY_ATTEMPTS and PCCC_SCALING_DURATION_MS. If the fails continue, your server breack down. ( Config client retry )

• Default: false
• Type: true
• NB: Only accept true/false. Otherwise automatically set to default.

PCCC_MAX_RETRY_ATTEMPTS

This property specify how much times the node js server retry to get properties from config server after the first fail. ( Config client retry )

• Default: 6
• Type: number
• NB: This property is active only if PCCC_FAIL_FAST set to true.

PCCC_SCALING_DURATION_MS

This property specify how much delay beatween two retry.

The delay is expressed in milliseconds.

The duration is calculated by PCCC_SCALING_DURATION_MS multiplied by attempts number. ( Config client retry )

• Default: 1000
• Type: number
• NB: This property is active only if PCCC_FAIL_FAST set to true.

PCCC_LOGGER_ENABLED

You can turn on/off the log with property PCCC_LOGGER_ENABLED.

• Default: false
• Type: true
• NB: Only accept true/false. Otherwise automatically set to default.

PCCC_LOGGER_LEVEL

You can specify level log with property PCCC_LOGGER_LEVEL.

• Default: error
• Type: string
• NB:
  • Only accept error/info/debug. Otherwise automatically set to default;
  • This property is active only if PCCC_LOGGER_ENABLED set to true.

Example target config server

Based on properties PCCC_BASE_URI, PCCC_APPLICATION_NAME, PCCC_PROFILE and PCCC_LABEL will be create the rest call to get properties from config server based on the pattern <PCCC_BASE_URI>/<PCCC_APPLICATION_NAME>/<PCCC_PROFILE>/<PCCC_LABEL>

Example:

PCCC_BASE_URI	PCCC_APPLICATION_NAME	PCCC_PROFILE	PCCC_LABEL	Rest call
				http://localhost:8888/application/default
http://your.server/				http://your.server/application/default
	your-application-name			http://localhost:8888/your-application-name/default
		dev		http://localhost:8888/application/dev
			label	http://localhost:8888/application/default/label
http://your.server/	your-application-name	prod		http://your.server/your-application-name/prod
http://your.server/	your-application-name	prod	label	http://your.server/your-application-name/prod/label

Is also possible to ask for multiple profile, just set PCCC_PROFILE=profile1,profile2

Config client retry

You can specify what happen when get to config server fails.

If you want that when the call fails there are no error, set PCCC_FAIL_FAST=false.

Otherwise, specify PCCC_FAIL_FAST=true.

When PCCC_FAIL_FAST not set 'true' or 'false', is like set PCCC_FAIL_FAST to 'false'.

If PCCC_FAIL_FAST set to true, is applied a retry that follow the properties PCCC_MAX_RETRY_ATTEMPTS and PCCC_SCALING_DURATION

With PCCC_MAX_RETRY_ATTEMPTS specify how much times the retry will be performed.

With PCCC_SCALING_DURATION specify what is scaling duration beetwen two retry.

Example:

export PCCC_MAX_RETRY_ATTEMPTS=4
export PCCC_SCALING_DURATION=500

Suppose that your config server is down and does not respond.

After the first call to config server, pesda-cloud-config-client perform another call after 500 ms, after 1000 ms, after 1500 ms and after 2000 ms. After that pesda-cloud-config-client emit error.

More Documentation

For more documentation and information, visit this page.

Example usage

You can visit this repository for other example of pesda-cloud-config-client usage.

License

MIT License

Copyright (c) 2020 Effeppi

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.