ftrm-basic

Footurama Package: Basic

This package includes basic building blocks for Footurama.

ftrm-basic/inject

Inject values into the realm.

Configuration:

• input: 0.
• output: 1. Target pipe for injected values.
• inject: Function generating values: () => value. Can be deferred using Promises.
• interval: Interval between two injections in milliseconds.

Example:

// Inject random numbers every second
module.exports = [require('ftrm-basic/inject'), {
    output: 'output-pipe-with-numbers',
    inject: () => Math.random(),
    interval: 1000
}];

ftrm-basic/map

Map values from one pipe to another.

Configuration:

• input: 1. Values to be mapped
• output: 1. Mapped values
• map: Function to map the input to the output: (input) => output. Can be deferred using Promises.

Example:

// Check whether input is greater or equal to zero
module.exports = [require('ftrm-basic/map'), {
    input: 'input-pipe-with-numbers',
    output: 'output-pipe-with-booleans',
    map: (input) => input >= 0
}];

ftrm-basic/to-writable

Write values from a pipe into a writable stream. Useful for debug logging to stdout!

Configuration:

• input: 1. Values to be written to the stream.
• output: 0.
• stream: Instance of stream.Writable.
• dontCloseStream: Don't close the stream on exit. This is required when writing to process.stdout. This stream cannot be closed.
• format: Function to format incoming values to chunks for the stream: (value, timestamp, src) => chunk. timestamp is the time when value was created. src is the tubemail event locally raised when the value has been received. srv.event contains the actual event. Useful when working with wild characters in the input pipe.

Example:

// Debug log all pipes to stdout
module.exports = [require('ftrm-basic/to-writable'), {
    input: '#', // Wild character for all pipes
    stream: process.stdout,
    dontCloseStream: true,
    format: (value, ts, src) => `${new Date(ts)}\t${src.event}\t${value.toString()}\n`
}];

ftrm-basic/from-event

Grab values from arbitrary event busses and output them into pipes.

Configuration:

• input: 0.
• output: 1..n. Outputs to write values to. The output's name will be used to select the event accordingly.
• bus: Instance of EventEmitter.

Example:

// Eventbus emitting 'random' and 'time' event
const EventEmitter = require('events');
const myEventBus = new EventEmitter();
setInterval(() => myEventBus.emit('time', new Date()), 1000);
setInterval(() => myEventBus.emit('random', Math.random()), 3000);
 
module.exports = [require('ftrm-basic/from-event'), {
    output: {
        'time': 'some-pipe-for-time',
        'random': 'some-pipe-for-random-numbers'
    },
    bus: myEventBus
}];

ftrm-basic/select

Select one input pipe out of many to forward it to the output pipe.

Configuration:

• input: 1..n. Input pipes to select from.
• output: 1.
• weight: Can be either a string or a function.
  • Function: (input, index) => score. Is called for every input. input holds the input's instance and has the properties input.value, input.timestamp and input.expired. index is the respective index in the input array. The input that returned the highest score will be picked for the output. If the function returns undefined it won't be taken into account.
  • String:
    • 'prio': Takes the first input that has a value that is not undefined and is not expired.
    • 'max': Takes the input with the highest value that is not expired.
    • 'min': Takes the input with the lowest value that is not expired.

Example:

// Select 'setpoint' from several inputs
module.exports = [require('ftrm-basic/select'), {
    input: [
        // Possible inputs. First has highest priority.
        // 1. Manual override. One recieved value stays valid for one hour.
        {pipe: 'setpoint.override', expire: 60 * 60 * 1000},
        // 2. From schedule. Will be valid for 10 minutes.
        {pipe: 'setpoint.schedule', expire: 10 * 60 * 1000},
        // 3. No pipe attached, but a constant value is given: Default set point.
        {value: 10}
    ],
    output: 'setpoint',
    weight: 'prio'
}];