Defining Processor order as a string is silently ignored. Undefined Processor order runs in reverse.

[cruscio]

Relevant telegraf.conf

#`order` as a string. Expectation: Either an error is thrown or the string is converted to an int when parsing the config. Neither happens. 
#Keep in mind processors don't work as documented. In this example, `order` isn't being set, so the second processor runs before the first. Additional examples in the 'steps to reproduce' demonstrate that 
[agent]
  interval = "10s"
  omit_hostname = true

[[outputs.file]]
  files = ["stdout"]

[[inputs.mem]]
  taginclude   = []
  fieldpass = ["total"]

[[processors.rename]]
  order = "1"
  [[processors.rename.replace]]
    field = "total"
    dest = "total_renamed_once"

[[processors.rename]]
  order = "2"
  [[processors.rename.replace]]
    field = "total_renamed_once"
    dest = "total_renamed_twice"

Logs from Telegraf

See steps to reproduce for more examples. This is the log from the final example with a string-quoted `order` showing no error message, even with debug logging

telegraf --config ./telegraf.conf --test --debug
2023-03-15T15:31:25Z I! Starting Telegraf 1.25.1
2023-03-15T15:31:25Z I! Available plugins: 213 inputs, 9 aggregators, 26 processors, 21 parsers, 57 outputs, 2 secret-stores
2023-03-15T15:31:25Z I! Loaded inputs: mem
2023-03-15T15:31:25Z I! Loaded aggregators: 
2023-03-15T15:31:25Z I! Loaded processors: rename (2x)
2023-03-15T15:31:25Z I! Loaded secretstores: 
2023-03-15T15:31:25Z W! Outputs are not used in testing mode!
2023-03-15T15:31:25Z I! Tags enabled: 
2023-03-15T15:31:25Z D! [agent] Initializing plugins
2023-03-15T15:31:25Z D! [agent] Starting service inputs
2023-03-15T15:31:25Z D! [agent] Stopping service inputs
2023-03-15T15:31:25Z D! [agent] Input channel closed
2023-03-15T15:31:25Z D! [agent] Processor channel closed
2023-03-15T15:31:25Z D! [agent] Processor channel closed
2023-03-15T15:31:25Z D! [agent] Stopped Successfully
> mem total_renamed_once=17179869184i 1678894286000000000

System info

Telegraf 1.25.1

Docker

No response

Steps to reproduce

cat << EOF > ./telegraf.conf
#No explicit `order`, with processors defined in order in file: Doesn't work as documented. 
# Second processor didn't do its work because it was run before the first processor
[agent]
  interval = "10s"
  omit_hostname = true

[[outputs.file]]
  files = ["stdout"]

[[inputs.mem]]
  taginclude   = []
  fieldpass = ["total"]

[[processors.rename]]
  [[processors.rename.replace]]
    field = "total"
    dest = "total_renamed_once"

[[processors.rename]]
  [[processors.rename.replace]]
    field = "total_renamed_once"
    dest = "total_renamed_twice"
EOF
telegraf --config ./telegraf.conf --test
[...]
> mem total_renamed_once=17179869184i 1678893634000000000

cat << EOF > ./telegraf.conf
#No explicit `order`, with processors defined in reveres in file: Does not work as documented.
# Both processors run - second before the first
[agent]
  interval = "10s"
  omit_hostname = true

[[outputs.file]]
  files = ["stdout"]

[[inputs.mem]]
  taginclude   = []
  fieldpass = ["total"]

[[processors.rename]]
  [[processors.rename.replace]]
    field = "total_renamed_once"
    dest = "total_renamed_twice"

[[processors.rename]]
  [[processors.rename.replace]]
    field = "total"
    dest = "total_renamed_once"
EOF
telegraf --config ./telegraf.conf --test
[...]
> mem total_renamed_twice=17179869184i 1678893654000000000

cat << EOF > ./telegraf.conf
#`order` as an int: works as documented
[agent]
  interval = "10s"
  omit_hostname = true

[[outputs.file]]
  files = ["stdout"]

[[inputs.mem]]
  taginclude   = []
  fieldpass = ["total"]

[[processors.rename]]
  order = 1
  [[processors.rename.replace]]
    field = "total"
    dest = "total_renamed_once"

[[processors.rename]]
  order = 2
  [[processors.rename.replace]]
    field = "total_renamed_once"
    dest = "total_renamed_twice"
EOF
telegraf --config ./telegraf.conf --test
[...]
> mem total_renamed_twice=17179869184i 1678893671000000000

cat << EOF > ./telegraf.conf
#`order` as a string. Expectation: Either an error is thrown or the string is converted to 
# an int when parsing the config. Neither happens. Keep in mind processors don't work 
# as documented. In this example, `order` isn't being set, so the SECOND processor (with
# `order="2"`) runs BEFORE the FIRST processor (with `order="1"`)
[agent]
  interval = "10s"
  omit_hostname = true

[[outputs.file]]
  files = ["stdout"]

[[inputs.mem]]
  taginclude   = []
  fieldpass = ["total"]

[[processors.rename]]
  order = "1"
  [[processors.rename.replace]]
    field = "total"
    dest = "total_renamed_once"

[[processors.rename]]
  order = "2"
  [[processors.rename.replace]]
    field = "total_renamed_once"
    dest = "total_renamed_twice"
EOF
telegraf --config ./telegraf.conf --test
[...]
> mem total_renamed_once=17179869184i 1678893686000000000

Expected behavior

When order is defined in a processor, and config parsing cannot set a value, log an error. Maybe also attempt to first convert str to int before logging an error -- Either accept both str and int values, or log when the value isn't an int.

When order isn't defined, processors should run as ordered in the config file (per documentation )

Actual behavior

When order is defined as a string, the config parser silently fails, no value is set, and no error is logged.

When order isn't defined, Processors run in reverse order

Additional info

May be relevant:

• chore: Improve processor ordering by srebhan · Pull Request #12308 · influxdata/telegraf
• processors should run in the order they appear in the config · Issue #8016 · influxdata/telegraf
• New metrics created by starlark do not pass to downstream processors · Issue #12849 · influxdata/telegraf

[Hipska]

Good catch! Can you test the artifacts from #12880 (comment) and let us know if this is what you expected.

[cruscio]

$ ./telegraf --config ./telegraf.conf --test --debug
2023-03-21T14:11:37Z I! Loading config file: ./telegraf.conf
2023-03-21T14:11:37Z E! error loading config file ./telegraf.conf: error parsing rename, line 12:{150 185}: found unexpected format while parsing "order", expecting int

Looks good to me, @Hipska