Modbus Plugin: Panic due to bad configuration

[Jayclifford345]

Relevant telegraf.conf

# Telegraf Configuration
#
# Telegraf is entirely plugin driven. All metrics are gathered from the
# declared inputs, and sent to the declared outputs.
#
# Plugins must be declared in here to be active.
# To deactivate a plugin, comment out the name and any variables.
#
# Use 'telegraf -config telegraf.conf -test' to see what metrics a config
# file would generate.
#
# Environment variables can be used anywhere in this config file, simply surround
# them with ${}. For strings the variable must be within quotes (ie, "${STR_VAR}"),
# for numbers and booleans they should be plain (ie, ${INT_VAR}, ${BOOL_VAR})


# Global tags can be specified here in key="value" format.
[global_tags]
  # dc = "us-east-1" # will tag all metrics with dc=us-east-1
  # rack = "1a"
  ## Environment variables can be used as tags, and throughout the config file
  # user = "$USER"


# Configuration for telegraf agent
[agent]
  ## Default data collection interval for all inputs
  interval = "5s"
  ## Rounds collection interval to 'interval'
  ## ie, if interval="10s" then always collect on :00, :10, :20, etc.
  round_interval = true

  ## Telegraf will send metrics to outputs in batches of at most
  ## metric_batch_size metrics.
  ## This controls the size of writes that Telegraf sends to output plugins.
  metric_batch_size = 1000

  ## Maximum number of unwritten metrics per output.  Increasing this value
  ## allows for longer periods of output downtime without dropping metrics at the
  ## cost of higher maximum memory usage.
  metric_buffer_limit = 10000

  ## Collection jitter is used to jitter the collection by a random amount.
  ## Each plugin will sleep for a random time within jitter before collecting.
  ## This can be used to avoid many plugins querying things like sysfs at the
  ## same time, which can have a measurable effect on the system.
  collection_jitter = "5s"

  ## Default flushing interval for all outputs. Maximum flush_interval will be
  ## flush_interval + flush_jitter
  flush_interval = "10s"
  ## Jitter the flush interval by a random amount. This is primarily to avoid
  ## large write spikes for users running a large number of telegraf instances.
  ## ie, a jitter of 5s and interval 10s means flushes will happen every 10-15s
  flush_jitter = "5s"

  ## By default or when set to "0s", precision will be set to the same
  ## timestamp order as the collection interval, with the maximum being 1s.
  ##   ie, when interval = "10s", precision will be "1s"
  ##       when interval = "250ms", precision will be "1ms"
  ## Precision will NOT be used for service inputs. It is up to each individual
  ## service input to set the timestamp at the appropriate precision.
  ## Valid time units are "ns", "us" (or "µs"), "ms", "s".
  precision = ""


  ## Override default hostname, if empty use os.Hostname()
  hostname = ""
  ## If set to true, do no set the "host" tag in the telegraf agent.
  omit_hostname = false

  debug = true

  quiet = false


###############################################################################
#                            OUTPUT PLUGINS                                   #
###############################################################################

# Configuration for sending metrics to InfluxDB 2.0
[[outputs.influxdb_v2]]
alias = "opc-ua-db"
  ## The URLs of the InfluxDB cluster nodes.
  ##
  ## Multiple URLs can be specified for a single cluster, only ONE of the
  ## urls will be written to each interval.
  ##   ex: urls = ["https://us-west-2-1.aws.cloud2.influxdata.com"]
  urls = ["${INFLUX_HOST}"]

  ## Token for authentication.
  token = "${INFLUX_TOKEN}"

  ## Organization is the name of the organization you wish to write to.
  organization = "${INFLUX_ORG}"

  ## Destination bucket to write into.
  bucket = "${INFLUX_BUCKET}"



###############################################################################
#                            INPUT PLUGINS                                    #
###############################################################################
[[inputs.modbus]]
  ## Connection Configuration
  ##
  ## The plugin supports connections to PLCs via MODBUS/TCP, RTU over TCP, ASCII over TCP or
  ## via serial line communication in binary (RTU) or readable (ASCII) encoding
  ##
  ## Device name
  name = "Device"
   name_prefix = "egx150warehouse_"

  ## Slave ID - addresses a MODBUS device on the bus
  ## Range: 0 - 255 [0 = broadcast; 248 - 255 = reserved]
  slave_id = 1

  ## Timeout for each request
  timeout = "1s"

  ## Maximum number of retries and the time to wait between retries
  ## when a slave-device is busy.
  # busy_retries = 0
  # busy_retries_wait = "100ms"

  # TCP - connect via Modbus/TCP
  controller = "tcp://localhost:502"

  ## Serial (RS485; RS232)
  # controller = "file:///dev/ttyUSB0"
  # baud_rate = 9600
  # data_bits = 8
  # parity = "N"
  # stop_bits = 1

  ## For Modbus over TCP you can choose between "TCP", "RTUoverTCP" and "ASCIIoverTCP"
  ## default behaviour is "TCP" if the controller is TCP
  ## For Serial you can choose between "RTU" and "ASCII"
  # transmission_mode = "RTU"

  ## Trace the connection to the modbus device as debug messages
  ## Note: You have to enable telegraf's debug mode to see those messages!
   #debug_connection = true

  ## Measurements
  ##

  ## Digital Variables, Discrete Inputs and Coils
  ## measurement - the (optional) measurement name, defaults to "modbus"
  ## name        - the variable name
  ## address     - variable address

  #discrete_inputs = [
   # { name = "start",          address = [4]}

  #]
 # coils = [
   # { name = "motor1_run",     address = [4]}
  #]

  ## Analog Variables, Input Registers and Holding Registers
  ## measurement - the (optional) measurement name, defaults to "modbus"
  ## name        - the variable name
  ## byte_order  - the ordering of bytes
  ##  |---AB, ABCD   - Big Endian
  ##  |---BA, DCBA   - Little Endian
  ##  |---BADC       - Mid-Big Endian
  ##  |---CDAB       - Mid-Little Endian
  ## data_type  - INT16, UINT16, INT32, UINT32, INT64, UINT64, FLOAT32-IEEE, FLOAT64-IEEE (the IEEE 754 binary representation)
  ##              FLOAT32 (deprecated), FIXED, UFIXED (fixed-point representation on input)
  ## scale      - the final numeric variable representation
  ## address    - variable address

  holding_registers = [
    { name = "power_factor", byte_order = "DCBA",   data_type = "UINT64", scale=0.01,  address = [0, 1]}
  ]
  #input_registers = [
    #{ name = "tank_level",   byte_order = "BA",   data_type = "FIXED",   scale=0.01,     address = [1]},
  #]

  ## Enable workarounds required by some devices to work correctly
  # [inputs.modbus.workarounds]
    ## Pause between read requests sent to the device. This might be necessary for (slow) serial devices.
    # pause_between_requests = "0ms"
    ## Close the connection after every gather cycle. Usually the plugin closes the connection after a certain
    ## idle-timeout, however, if you query a device with limited simultaneous connectivity (e.g. serial devices)
    ## from multiple instances you might want to only stay connected during gather and disconnect afterwards.
    # close_connection_after_gather = false

Logs from Telegraf

jayclifford@Jays-MBP Telegraf-Community-Configs % telegraf --debug --test --config ./modbus/telegraf-modbus.conf
2023-06-23T09:55:24Z I! Loading config: ./modbus/telegraf-modbus.conf
2023-06-23T09:55:24Z I! Starting Telegraf 1.27.1
2023-06-23T09:55:24Z I! Available plugins: 237 inputs, 9 aggregators, 28 processors, 23 parsers, 59 outputs, 4 secret-stores
2023-06-23T09:55:24Z I! Loaded inputs: modbus
2023-06-23T09:55:24Z I! Loaded aggregators:
2023-06-23T09:55:24Z I! Loaded processors:
2023-06-23T09:55:24Z I! Loaded secretstores:
2023-06-23T09:55:24Z W! Outputs are not used in testing mode!
2023-06-23T09:55:24Z I! Tags enabled: host=Jays-MBP
2023-06-23T09:55:24Z D! [agent] Initializing plugins
2023-06-23T09:55:24Z I! [inputs.modbus] Got 1 request(s) touching 2 holding registers for 1 fields (slave 1)
2023-06-23T09:55:24Z I! [inputs.modbus] Got 0 request(s) touching 0 inputs registers for 0 fields (slave 1)
2023-06-23T09:55:24Z I! [inputs.modbus] Got 0 request(s) touching 0 discrete registers for 0 fields (slave 1)
2023-06-23T09:55:24Z I! [inputs.modbus] Got 0 request(s) touching 0 coil registers for 0 fields (slave 1)
2023-06-23T09:55:24Z D! [agent] Starting service inputs
2023-06-23T09:55:24Z D! [inputs.modbus] Reading slave 1 for tcp://localhost:502...
2023-06-23T09:55:24Z D! [inputs.modbus] trying to read holding@0[2]...
2023-06-23T09:55:24Z D! [inputs.modbus] got holding@0[2]: [0 20 0 30]
panic: runtime error: index out of range [7] with length 4

goroutine 69 [running]:
encoding/binary.littleEndian.Uint64(...)
	encoding/binary/binary.go:102
github.com/influxdata/telegraf/plugins/inputs/modbus.determineConverterU64Scale.func1({0xc000aa8009?, 0x106884fc8?, 0xfb?})
	github.com/influxdata/telegraf/plugins/inputs/modbus/type_conversions64.go:146 +0x31
github.com/influxdata/telegraf/plugins/inputs/modbus.(*Modbus).gatherRequestsHolding(0xc000882d00, {0xc000e58d50?, 0x1, 0xc000e89ba8?})
	github.com/influxdata/telegraf/plugins/inputs/modbus/modbus.go:464 +0x49c
github.com/influxdata/telegraf/plugins/inputs/modbus.(*Modbus).gatherFields(0x1068a8948?, {{0x0, 0x0, 0x0}, {0x0, 0x0, 0x0}, {0xc000e58d50, 0x1, 0x1}, ...})
	github.com/influxdata/telegraf/plugins/inputs/modbus/modbus.go:387 +0x6d
github.com/influxdata/telegraf/plugins/inputs/modbus.(*Modbus).readSlaveData(0xc000882d00, 0x0?, {{0x0, 0x0, 0x0}, {0x0, 0x0, 0x0}, {0xc000e58d50, 0x1, ...}, ...})
	github.com/influxdata/telegraf/plugins/inputs/modbus/modbus.go:377 +0x1fb
github.com/influxdata/telegraf/plugins/inputs/modbus.(*Modbus).Gather(0xc000882d00, {0x10749c600, 0xc000819b60})
	github.com/influxdata/telegraf/plugins/inputs/modbus/modbus.go:205 +0x205
github.com/influxdata/telegraf/agent.(*Agent).testRunInputs.func2(0xc000518d70)
	github.com/influxdata/telegraf/agent/agent.go:508 +0x2f8
created by github.com/influxdata/telegraf/agent.(*Agent).testRunInputs
	github.com/influxdata/telegraf/agent/agent.go:477 +0xc8

System info

Latest

Docker

No response

Steps to reproduce

Run Modbus simulator

Create two registers at address 0 and 1

Run config.

Expected behavior

Panic.

Actual behavior

Offical behaviour should be a config error.

Additional info

No response