flow-eng

update serial port permission when dev on local PC

sudo chmod 666 /dev/ttyUSB0

node payload

using this api you can write a value to a node without having to download/deploy a new flow

method HTTP-POST

url

http://0.0.0.0:1665/api/nodes/payload/NODE-ID

body a float value

{
  "float": 2
}

body a bool value

{
  "boolean": true
}

body a string value

{
  "string": "abc"
}

body as an interface

{
  "any": [1,2,3,4]
}

null values

func (inst *Not) Process() {
in, null := inst.ReadPinBoolOk(node.Inp)
if null { // if input is null then set output to nil
inst.WritePinNull(node.Outp)
return
}
if in {
inst.WritePinFalse(node.Outp)
} else {
inst.WritePinTrue(node.Outp)
}
}

reading inputs

inst.ReadPinFloat(name InputName) (value float46, null bool) // will return the value as a float and if its `null/nil` the `boolean` `null` flag will be `true` 
inst.ReadPinBool(name InputName) (value bool, null bool) // same as above but value is a boolean

writing outputs

inst.WritePinFloat(node.Outp, f, inst.precision) // you can add number of decimal places 
inst.WritePinFloat(name OutputName, value float64) // set output to number value (float64)
inst.WritePinNull(node.Outp) // set output to nil
inst.WritePinTrue(node.Outp) // set output to true
inst.WritePinFalse(node.Outp) // set output to false

interface

check if input value has been updated and boolCOV will let you know if an input went from false to true

InputUpdated(name InputName) (updated bool, boolCOV bool)

get the flow loop count and if its the first loop

count, firstLoop := Loop()

check if an input has a connection

if InputHasConnection(node.InBoolean) {
log.Infof("log: comment: %s boolean: %t", comment, inBool)
}

blocking go-routine

when a blocking function is need to be executed eg:(do a database call) a go-routine can be used, see example below

example