node-red-contrib-context-consul

Consul context store for Node-RED. This allows nodes to maintain a persistent state using a Consul key value store. It's also possible to set locks for synchronization needs or setting limits etc. More on - node-red context.

Usage

Node-red contextStorage configuration needs to be added. The host, port, secure, ca, token, timeout, datacenter and consistent settings are just passed through to Consul lib

contextStorage: {
	consul: {
		module: require("node-red-contrib-context-consul"),
		config: { //see https://www.npmjs.com/package/consul#init for more info
			//CONFIG HERE
		}
	}
}

//CONFIG
prefix: "mytest",	//all KV stored in path _nrcontext/[prefix]/
host: "consul",		//IP or hostname of consul,
port: 8500,		//listening consul port
secure: false,		//TLS (https) secured?
ca: {},	//TLS info -- ca (String[]): array of strings or Buffers in PEM format
token: "something",	//(optional) Consul token to be included in all API calls
timeout: 3000,		//API timeout in ms
datacenter: "mydc",	//populates the dc option in all API calls
consistent: true,	//consistency normal (false) or strong (true, default)
lock: false,		//EXPERIMENTAL - bool, default is no locking
lockttl: 30s,		//(string: "") - lock time to live (between 10s and 86400s).
locknode: "server2",	//Specifies the name of the consul node,
			// this must refer to a node that is already registered.
lockdelay: "10s",	//(string:"15s") Delay before allowing locks 
			// after a session has been invalidated. (> 0).
debug: false		//Flag to enable console debug messages

When you fire up node-red up a series of checks will execute to ensure Consul is available and working as expected. If any of them fail an error is thrown and node-red will not start. The "prefix" is basically the node-red instance ID, all KV pairs will prefixed with _nrcontext/[prefix string] so multiple instances can make use of the same Consul cluster.

note - if you do not lock (still experimental) and run multiple instances using the same prefix you are asking for trouble and KV pairs may clash.

Testing

If you have docker available, run a then docker-compose up to bring up node-red with a basic consul cluster available to store context data.

More info

Check out these links for more info, Node-red Context Docs, Node-red Context API, Consul lib on NPM