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feat(inputs.modbus): Add workaround for unusual string-byte locations (#14764)

This commit is contained in:
Sven Rebhan 2024-02-14 15:21:18 +01:00 committed by GitHub
parent e0ae43f4f4
commit f77049855b
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GPG Key ID: B5690EEEBB952194
9 changed files with 274 additions and 8 deletions
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10
plugins/inputs/modbus/README.md
View File

@ -357,6 +357,16 @@ See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
## coil registers. This is necessary for some devices see
## https://github.com/influxdata/telegraf/issues/8905
# read_coils_starting_at_zero = false
## String byte-location in registers AFTER byte-order conversion
## Some device (e.g. EM340) place the string byte in only the upper or
## lower byte location of a register see
## https://github.com/influxdata/telegraf/issues/14748
## Available settings:
## lower -- use only lower byte of the register i.e. 00XX 00XX 00XX 00XX
## upper -- use only upper byte of the register i.e. XX00 XX00 XX00 XX00
## By default both bytes of the register are used i.e. XXXX XXXX.
# string_register_location = ""
```
## Notes

9
plugins/inputs/modbus/configuration_metric.go
View File

@ -43,6 +43,13 @@ func (c *ConfigurationPerMetric) SampleConfigPart() string {
}
func (c *ConfigurationPerMetric) Check() error {
switch c.workarounds.StringRegisterLocation {
case "", "both", "lower", "upper":
// Do nothing as those are valid
default:
return fmt.Errorf("invalid 'string_register_location' %q", c.workarounds.StringRegisterLocation)
}
seed := maphash.MakeSeed()
seenFields := make(map[uint64]bool)
@ -302,7 +309,7 @@ func (c *ConfigurationPerMetric) newField(def metricFieldDefinition, mdef metric
return field{}, err
}
f.converter, err = determineConverter(inType, order, outType, def.Scale)
f.converter, err = determineConverter(inType, order, outType, def.Scale, c.workarounds.StringRegisterLocation)
if err != nil {
return field{}, err
}

9
plugins/inputs/modbus/configuration_register.go
View File

@ -35,6 +35,13 @@ func (c *ConfigurationOriginal) SampleConfigPart() string {
}
func (c *ConfigurationOriginal) Check() error {
switch c.workarounds.StringRegisterLocation {
case "", "both", "lower", "upper":
// Do nothing as those are valid
default:
return fmt.Errorf("invalid 'string_register_location' %q", c.workarounds.StringRegisterLocation)
}
if err := c.validateFieldDefinitions(c.DiscreteInputs, cDiscreteInputs); err != nil {
return err
}
@ -165,7 +172,7 @@ func (c *ConfigurationOriginal) newFieldFromDefinition(def fieldDefinition, type
return f, err
}
f.converter, err = determineConverter(inType, byteOrder, outType, def.Scale)
f.converter, err = determineConverter(inType, byteOrder, outType, def.Scale, c.workarounds.StringRegisterLocation)
if err != nil {
return f, err
}

9
plugins/inputs/modbus/configuration_request.go
View File

@ -46,6 +46,13 @@ func (c *ConfigurationPerRequest) SampleConfigPart() string {
}
func (c *ConfigurationPerRequest) Check() error {
switch c.workarounds.StringRegisterLocation {
case "", "both", "lower", "upper":
// Do nothing as those are valid
default:
return fmt.Errorf("invalid 'string_register_location' %q", c.workarounds.StringRegisterLocation)
}
seed := maphash.MakeSeed()
seenFields := make(map[uint64]bool)
@ -349,7 +356,7 @@ func (c *ConfigurationPerRequest) newFieldFromDefinition(def requestFieldDefinit
return field{}, err
}
f.converter, err = determineConverter(inType, order, outType, def.Scale)
f.converter, err = determineConverter(inType, order, outType, def.Scale, c.workarounds.StringRegisterLocation)
if err != nil {
return field{}, err
}

1
plugins/inputs/modbus/modbus.go
View File

@ -31,6 +31,7 @@ type ModbusWorkarounds struct {
CloseAfterGather bool `toml:"close_connection_after_gather"`
OnRequestPerField bool `toml:"one_request_per_field"`
ReadCoilsStartingAtZero bool `toml:"read_coils_starting_at_zero"`
StringRegisterLocation string `toml:"string_register_location"`
}
// According to github.com/grid-x/serial

177
plugins/inputs/modbus/modbus_test.go
View File

@ -16,6 +16,7 @@ import (
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/config"
"github.com/influxdata/telegraf/metric"
"github.com/influxdata/telegraf/plugins/inputs"
"github.com/influxdata/telegraf/plugins/parsers/influx"
"github.com/influxdata/telegraf/testutil"
@ -570,3 +571,179 @@ func TestRequestsWorkaroundsReadCoilsStartingAtZeroRegister(t *testing.T) {
require.Equal(t, maxQuantityCoils, plugin.requests[1].coil[1].address)
require.Equal(t, uint16(1), plugin.requests[1].coil[1].length)
}
func TestWorkaroundsStringRegisterLocation(t *testing.T) {
tests := []struct {
name string
location string
order string
content []byte
expected string
}{
{
name: "default big-endian",
order: "ABCD",
content: []byte{
0x4d, 0x6f, 0x64, 0x62, 0x75, 0x73, 0x20, 0x53,
0x74, 0x72, 0x69, 0x6e, 0x67, 0x00,
},
expected: "Modbus String",
},
{
name: "default little-endian",
order: "DCBA",
content: []byte{
0x6f, 0x4d, 0x62, 0x64, 0x73, 0x75, 0x53, 0x20,
0x72, 0x74, 0x6e, 0x69, 0x00, 0x67,
},
expected: "Modbus String",
},
{
name: "both big-endian",
location: "both",
order: "ABCD",
content: []byte{
0x4d, 0x6f, 0x64, 0x62, 0x75, 0x73, 0x20, 0x53,
0x74, 0x72, 0x69, 0x6e, 0x67, 0x00,
},
expected: "Modbus String",
},
{
name: "both little-endian",
location: "both",
order: "DCBA",
content: []byte{
0x6f, 0x4d, 0x62, 0x64, 0x73, 0x75, 0x53, 0x20,
0x72, 0x74, 0x6e, 0x69, 0x00, 0x67,
},
expected: "Modbus String",
},
{
name: "lower big-endian",
location: "lower",
order: "ABCD",
content: []byte{
0x00, 0x4d, 0x00, 0x6f, 0x00, 0x64, 0x00, 0x62,
0x00, 0x75, 0x00, 0x73, 0x00, 0x20, 0x00, 0x53,
0x00, 0x74, 0x00, 0x72, 0x00, 0x69, 0x00, 0x6e,
0x00, 0x67, 0x00, 0x00,
},
expected: "Modbus String",
},
{
name: "lower little-endian",
location: "lower",
order: "DCBA",
content: []byte{
0x4d, 0x00, 0x6f, 0x00, 0x64, 0x00, 0x62, 0x00,
0x75, 0x00, 0x73, 0x00, 0x20, 0x00, 0x53, 0x00,
0x74, 0x00, 0x72, 0x00, 0x69, 0x00, 0x6e, 0x00,
0x67, 0x00, 0x00, 0x00,
},
expected: "Modbus String",
},
{
name: "upper big-endian",
location: "upper",
order: "ABCD",
content: []byte{
0x4d, 0x00, 0x6f, 0x00, 0x64, 0x00, 0x62, 0x00,
0x75, 0x00, 0x73, 0x00, 0x20, 0x00, 0x53, 0x00,
0x74, 0x00, 0x72, 0x00, 0x69, 0x00, 0x6e, 0x00,
0x67, 0x00, 0x00, 0x00,
},
expected: "Modbus String",
},
{
name: "upper little-endian",
location: "upper",
order: "DCBA",
content: []byte{
0x00, 0x4d, 0x00, 0x6f, 0x00, 0x64, 0x00, 0x62,
0x00, 0x75, 0x00, 0x73, 0x00, 0x20, 0x00, 0x53,
0x00, 0x74, 0x00, 0x72, 0x00, 0x69, 0x00, 0x6e,
0x00, 0x67, 0x00, 0x00,
},
expected: "Modbus String",
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
const addr = uint16(8)
length := uint16(len(tt.content) / 2)
expected := []telegraf.Metric{
metric.New(
"modbus",
map[string]string{
"name": "Test",
"slave_id": "1",
"type": "holding_register",
},
map[string]interface{}{
"value": tt.expected,
},
time.Unix(0, 0),
),
}
plugin := &Modbus{
Name: "Test",
Controller: "tcp://localhost:1502",
ConfigurationType: "request",
Log: testutil.Logger{},
Workarounds: ModbusWorkarounds{StringRegisterLocation: tt.location},
ConfigurationPerRequest: ConfigurationPerRequest{
Requests: []requestDefinition{
{
SlaveID: 1,
ByteOrder: tt.order,
RegisterType: "holding",
Fields: []requestFieldDefinition{
{
Address: addr,
Name: "value",
InputType: "STRING",
Length: length,
},
},
},
},
},
}
require.NoError(t, plugin.Init())
// Create a mock server and fill in the data
serv := mbserver.NewServer()
require.NoError(t, serv.ListenTCP("localhost:1502"))
defer serv.Close()
handler := mb.NewTCPClientHandler("localhost:1502")
require.NoError(t, handler.Connect())
defer handler.Close()
client := mb.NewClient(handler)
_, err := client.WriteMultipleRegisters(addr, length, tt.content)
require.NoError(t, err)
// Gather the data
var acc testutil.Accumulator
require.NoError(t, plugin.Gather(&acc))
// Compare
actual := acc.GetTelegrafMetrics()
testutil.RequireMetricsEqual(t, expected, actual, testutil.IgnoreTime())
})
}
}
func TestWorkaroundsStringRegisterLocationInvalid(t *testing.T) {
plugin := &Modbus{
Name: "Test",
Controller: "tcp://localhost:1502",
ConfigurationType: "request",
Log: testutil.Logger{},
Workarounds: ModbusWorkarounds{StringRegisterLocation: "foo"},
}
require.ErrorContains(t, plugin.Init(), `invalid 'string_register_location'`)
}

12
plugins/inputs/modbus/sample_general_end.conf
View File

@ -38,4 +38,14 @@
## Enforce the starting address to be zero for the first request on
## coil registers. This is necessary for some devices see
## https://github.com/influxdata/telegraf/issues/8905
# read_coils_starting_at_zero = false
# read_coils_starting_at_zero = false
## String byte-location in registers AFTER byte-order conversion
## Some device (e.g. EM340) place the string byte in only the upper or
## lower byte location of a register see
## https://github.com/influxdata/telegraf/issues/14748
## Available settings:
## lower -- use only lower byte of the register i.e. 00XX 00XX 00XX 00XX
## upper -- use only upper byte of the register i.e. XX00 XX00 XX00 XX00
## By default both bytes of the register are used i.e. XXXX XXXX.
# string_register_location = ""

17
plugins/inputs/modbus/type_conversions.go
View File

@ -18,8 +18,19 @@ func determineUntypedConverter(outType string) (fieldConverterFunc, error) {
return nil, fmt.Errorf("invalid output data-type: %s", outType)
}
func determineConverter(inType, byteOrder, outType string, scale float64) (fieldConverterFunc, error) {
if scale != 0.0 && inType != "STRING" {
func determineConverter(inType, byteOrder, outType string, scale float64, strloc string) (fieldConverterFunc, error) {
if inType == "STRING" {
switch strloc {
case "", "both":
return determineConverterString(byteOrder)
case "lower":
return determineConverterStringLow(byteOrder)
case "upper":
return determineConverterStringHigh(byteOrder)
}
}
if scale != 0.0 {
return determineConverterScale(inType, byteOrder, outType, scale)
}
return determineConverterNoScale(inType, byteOrder, outType)
@ -85,8 +96,6 @@ func determineConverterNoScale(inType, byteOrder, outType string) (fieldConverte
return determineConverterF32(outType, byteOrder)
case "FLOAT64":
return determineConverterF64(outType, byteOrder)
case "STRING":
return determineConverterString(byteOrder)
}
return nil, fmt.Errorf("invalid input data-type: %s", inType)
}

38
plugins/inputs/modbus/type_conversions_string.go
View File

@ -23,3 +23,41 @@ func determineConverterString(byteOrder string) (fieldConverterFunc, error) {
return string(s)
}, nil
}
func determineConverterStringLow(byteOrder string) (fieldConverterFunc, error) {
tohost, err := endiannessConverter16(byteOrder)
if err != nil {
return nil, err
}
return func(b []byte) interface{} {
// Swap the bytes according to endianness
var buf bytes.Buffer
for i := 0; i < len(b); i += 2 {
v := tohost(b[i : i+2])
buf.WriteByte(byte(v & 0xFF))
}
// Remove everything after null-termination
s, _ := bytes.CutSuffix(buf.Bytes(), []byte{0x00})
return string(s)
}, nil
}
func determineConverterStringHigh(byteOrder string) (fieldConverterFunc, error) {
tohost, err := endiannessConverter16(byteOrder)
if err != nil {
return nil, err
}
return func(b []byte) interface{} {
// Swap the bytes according to endianness
var buf bytes.Buffer
for i := 0; i < len(b); i += 2 {
v := tohost(b[i : i+2])
buf.WriteByte(byte(v >> 8))
}
// Remove everything after null-termination
s, _ := bytes.CutSuffix(buf.Bytes(), []byte{0x00})
return string(s)
}, nil
}