Possible bug in "DEBUG vector::utilization" message formatting

[gwk]

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I am a new vector user, trying to get my desired configuration running properly. I just discovered the VECTOR_LOG=debug environment variable, and I am observing some odd behavior in the debug logs for utilization. The utilization is close to zero, and adds another leading zero for every new message, as if it is dividing by ten every five seconds. It almost looks like there is some arbitrary precision float math being used that is causing ever-longer numbers to be printed to the log. It appears to go on like this indefinitely.

### Problem

2025-09-22T16:00:08.716762Z  INFO vector::topology::builder: Healthcheck passed.
2025-09-22T16:00:13.601127Z DEBUG vector::utilization: utilization=0.09408874719071758
2025-09-22T16:00:18.600407Z DEBUG vector::utilization: utilization=0.009408874719071756
2025-09-22T16:00:23.600468Z DEBUG vector::utilization: utilization=0.0009408874719071754
2025-09-22T16:00:28.601191Z DEBUG vector::utilization: utilization=0.00009408874719071751
2025-09-22T16:00:33.601908Z DEBUG vector::utilization: utilization=0.000009408874719071749
2025-09-22T16:00:38.600959Z DEBUG vector::utilization: utilization=0.0000009408874719071747
2025-09-22T16:00:43.600780Z DEBUG vector::utilization: utilization=0.00000009408874719071745
2025-09-22T16:00:48.600786Z DEBUG vector::utilization: utilization=0.000000009408874719071742
2025-09-22T16:00:53.600754Z DEBUG vector::utilization: utilization=0.000000000940887471907174
2025-09-22T16:00:58.600750Z DEBUG vector::utilization: utilization=0.00000000009408874719071739
2025-09-22T16:01:03.600689Z DEBUG vector::utilization: utilization=0.000000000009408874719071737
2025-09-22T16:01:08.600565Z DEBUG vector::utilization: utilization=0.0000000000009408874719071735
2025-09-22T16:01:13.601139Z DEBUG vector::utilization: utilization=0.00000000000009408874719071733
2025-09-22T16:01:18.600549Z DEBUG vector::utilization: utilization=0.000000000000009408874719071732
2025-09-22T16:01:23.600552Z DEBUG vector::utilization: utilization=0.000000000000000940887471907173
2025-09-22T16:01:28.600630Z DEBUG vector::utilization: utilization=0.00000000000000009408874719071729
2025-09-22T16:01:33.600800Z DEBUG vector::utilization: utilization=0.000000000000000009408874719071727
2025-09-22T16:01:38.601093Z DEBUG vector::utilization: utilization=0.0000000000000000009408874719071726
2025-09-22T16:01:43.601020Z DEBUG vector::utilization: utilization=0.00000000000000000009408874719071723
2025-09-22T16:01:48.600741Z DEBUG vector::utilization: utilization=0.000000000000000000009408874719071722
2025-09-22T16:01:53.600544Z DEBUG vector::utilization: utilization=0.000000000000000000000940887471907172
2025-09-22T16:01:58.600783Z DEBUG vector::utilization: utilization=0.00000000000000000000009408874719071718
2025-09-22T16:02:03.600842Z DEBUG vector::utilization: utilization=0.000000000000000000000009408874719071716
2025-09-22T16:02:08.601026Z DEBUG vector::utilization: utilization=0.0000000000000000000000009408874719071713
2025-09-22T16:02:13.600961Z DEBUG vector::utilization: utilization=0.00000000000000000000000009408874719071712
2025-09-22T16:02:18.600818Z DEBUG vector::utilization: utilization=0.00000000000000000000000000940887471907171
2025-09-22T16:02:23.600790Z DEBUG vector::utilization: utilization=0.0000000000000000000000000009408874719071708
2025-09-22T16:02:28.600940Z DEBUG vector::utilization: utilization=0.00000000000000000000000000009408874719071707
2025-09-22T16:02:33.600846Z DEBUG vector::utilization: utilization=0.000000000000000000000000000009408874719071704
2025-09-22T16:02:38.600823Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000009408874719071702
2025-09-22T16:02:43.600591Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000009408874719071699
2025-09-22T16:02:48.600801Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000009408874719071697
2025-09-22T16:02:53.600580Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000009408874719071694
2025-09-22T16:02:58.600525Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000009408874719071692
2025-09-22T16:03:03.600419Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000940887471907169
2025-09-22T16:03:08.600974Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000009408874719071687
2025-09-22T16:03:13.600372Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000009408874719071684
2025-09-22T16:03:18.600330Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000009408874719071682
2025-09-22T16:03:23.601036Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000940887471907168
2025-09-22T16:03:28.601076Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000009408874719071679
2025-09-22T16:03:33.601096Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000009408874719071676
2025-09-22T16:03:38.600674Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000009408874719071673
2025-09-22T16:03:43.600714Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000009408874719071672
2025-09-22T16:03:48.600765Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000940887471907167
2025-09-22T16:03:53.600515Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000009408874719071668
2025-09-22T16:03:58.600567Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000009408874719071665
2025-09-22T16:04:03.600523Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000009408874719071663
2025-09-22T16:04:08.600248Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000009408874719071661
2025-09-22T16:04:13.600156Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000009408874719071659
2025-09-22T16:04:18.601139Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000009408874719071657
2025-09-22T16:04:23.600907Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000009408874719071654
2025-09-22T16:04:28.600753Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000009408874719071652
2025-09-22T16:04:33.600869Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000940887471907165
2025-09-22T16:04:38.600248Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000009408874719071648
2025-09-22T16:04:43.600928Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000009408874719071646
2025-09-22T16:04:48.601208Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000009408874719071644
2025-09-22T16:04:53.601004Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000009408874719071643
2025-09-22T16:04:58.601133Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000009408874719071641
2025-09-22T16:05:03.601080Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000009408874719071639
2025-09-22T16:05:08.600388Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000009408874719071637
2025-09-22T16:05:13.600741Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000000009408874719071636
2025-09-22T16:05:18.600957Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000009408874719071634
2025-09-22T16:05:23.600781Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000000009408874719071632
2025-09-22T16:05:28.600645Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000000000940887471907163
2025-09-22T16:05:33.600670Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000009408874719071627
2025-09-22T16:05:38.600556Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000000000009408874719071625
2025-09-22T16:05:43.600778Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000000000000009408874719071624
2025-09-22T16:05:48.600353Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000009408874719071622
2025-09-22T16:05:53.600338Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000000940887471907162
2025-09-22T16:05:58.600438Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000000000000000009408874719071618
2025-09-22T16:06:03.600662Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000000009408874719071616
2025-09-22T16:06:08.600721Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000000000000000009408874719071613
2025-09-22T16:06:13.601082Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000000000000000000009408874719071611
2025-09-22T16:06:18.600788Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000000000000000000000940887471907161
2025-09-22T16:06:23.600721Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000000000000000000009408874719071607
2025-09-22T16:06:28.600534Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000000000000000000000009408874719071605
2025-09-22T16:06:33.600535Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071603
2025-09-22T16:06:38.600644Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071602
2025-09-22T16:06:43.600937Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000000000000000094088747190716
2025-09-22T16:06:48.600423Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071598
2025-09-22T16:06:53.600169Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071595
2025-09-22T16:06:58.601012Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071594
2025-09-22T16:07:03.601186Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071591
2025-09-22T16:07:08.600179Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000940887471907159
2025-09-22T16:07:13.601015Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071588
2025-09-22T16:07:18.601157Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071585
2025-09-22T16:07:23.600948Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071583
2025-09-22T16:07:28.601010Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000940887471907158
2025-09-22T16:07:33.600984Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000940887471907158
2025-09-22T16:07:38.600692Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071577
2025-09-22T16:07:43.600704Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071575
2025-09-22T16:07:48.600346Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071573
2025-09-22T16:07:53.601199Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000940887471907157
2025-09-22T16:07:58.600311Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071568
2025-09-22T16:08:03.601022Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071567
2025-09-22T16:08:08.601134Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071564
2025-09-22T16:08:13.600948Z DEBUG vector::utilization: utilization=0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071561
2025-09-22T16:08:18.600753Z DEBUG vector::utilization: utilization=0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071559
2025-09-22T16:08:23.600329Z DEBUG vector::utilization: utilization=0.0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000009408874719071558

Configuration

[sources.journald]
  type = "journald"
  include_units  = ["sshd", "sshd-session", "webapp"]
  data_dir = "/service/vector/data"

[sinks.cloudwatch]
  type = "aws_cloudwatch_logs"
  inputs = ["journald"]
  encoding.codec = "json"
  compression = "zstd"
  create_missing_group = false
  create_missing_stream = true
  group_name = "xyz"
  region = "us-guess-1"
  stream_name = "{{ host }}"
  auth.credentials_file = "/service/vector/creds/vector-aws.ini"

Version

vector 0.49.0 (x86_64-unknown-linux-gnu dc7e792 2025-08-12 13:47:08.632326804)

Debug Output

Example Data

No response

Additional Context

No response

References

No response

[pront]

Hi @gwk, this comes from this line:

vector/src/utilization.rs

Line 125 in be2dde4

debug!(utilization = %avg);

(should probably limit the precision)

The line above is only debugging purposes. What I am more interested in is the actual utilization metric value, for example:

{"name":"utilization","namespace":"vector","tags":{"component_id":"abc","component_kind":"sink","component_type":"file","host":"somehost"},"timestamp":"2025-09-22T19:09:08.106930Z","kind":"absolute","gauge":{"value":4.642872610453016e-6}}

The actual value is in gauge.value. You can observe these values with the internal_metrics source (see guide here).