Local Filesystem Context Store

New in 0.19

The Local Filesystem Context store holds context data in local files. By default it caches context data in memory, allowing both synchronous and asynchronous access.

If the caching mode is disabled, the store only supports asynchronous access.

Configuration

To create a file store, the following configuration can be used.

contextStorage: {
   default: {
       module:"localfilesystem",
       config: {
           // see below
       }
   }
}

Options

The file store can take the following configuration options:

The default configuration for a file context store is to use the directory ~/.node-red/context, with caching enabled and writes to storage happening every 30 seconds.

The flushInterval is provided to minimise wear on the underlying storage, such as on a Raspberry Pi’s SD card. Note that if Node-RED is unexpectedly killed, any data that has not yet been flushed will be lost.

Implementation details

This context store uses a separate file for each context scope. At the top level is a directory for each flow scope and one for the global scope. Within each flow scope directory is a file containing the flow scope, flow.json and a file for each node context.

   $HOME/.node-red/context
     ├── global
     │     └── global.json
     ├── <id of Flow 1>
     │     ├── flow.json
     │     ├── <id of Node a>.json
     │     └── <id of Node b>.json
     └── <id of Flow 2>
           ├── flow.json
           ├── <id of Node x>.json
           └── <id of Node y>.json