influxdata/telegraf

[inputs.modbus] Modbus UDP Feature Resquest

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#10,664 opened on Feb 16, 2022

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Description

Feature Request

Add the ability to use Modbus/TCP over a UDP transport.

Proposal:

Add the ability to poll Modbus/TCP slaves over UDP controller = "udp://localhost:502"

Current behavior:

controller = "tcp://localhost:502" modbus plugin establishes a TCP connection to the modbus slaves and polls registers

Desired behavior:

controller = "udp://localhost:502" modbus plugin send modbus request over UDP to poll registers

Use case:

Modbus slaves that support UDP would benefit from the reduced overhead especially when telegraf isn't the only master polling the device for data. The same RTUoverTCP and ASCIIoverTCP options could remain.

Contributor guide

Tech stack
go
Domain
backenddata
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Gomodbus protocolTelegraf plugin development
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35
Research direction
The request is to add UDP transport support to the Modbus input plugin in Telegraf. Start by examining the existing modbus input plugin code at plugins/inputs/modbus/. Understand how TCP transport is implemented and create a similar implementation for UDP using Go's net package. Check the configuration parsing for the 'controller' field and extend it to accept 'udp://' schemes. Consider adding tests for the new transport. Look at the discussion in the issue for any additional details or constraints.