windows_exporter/docs/collector.textfile.md

textfile collector

The textfile collector exposes metrics from files written by other processes.

Metric name prefix	textfile
Classes	None
Enabled by default?	No

Flags

--collector.textfile.directories

One or multiple directories containing the files to be ingested.

E.G. --collector.textfile.directories="C:\MyDir1,C:\MyDir2"

Default value: C:\Program Files\windows_exporter\textfile_inputs

Required: No

Note:

• If there are duplicated filenames among the directories, only the first one found will be read. For any other files with the same name, the windows_textfile_scrape_error metric will be set to 1 and a error message will be logged.
• Only files with the extension .prom are read. The .prom file must end with an empty line feed to work properly.

Metrics will primarily come from the files on disk. The below listed metrics are collected to give information about the reading of the metrics themselves.

Name	Description	Type	Labels
windows_textfile_scrape_error	1 if there was an error opening or reading a file, 0 otherwise	gauge	None
windows_textfile_mtime_seconds	Unix epoch-formatted mtime (modified time) of textfiles successfully read	gauge	file

Example metric

A scheduled collector should expose a completion timestamp that is updated only after a successful collection. For example:

# HELP example_collection_timestamp_seconds Unix time when the scheduled collection last completed successfully.
# TYPE example_collection_timestamp_seconds gauge
example_collection_timestamp_seconds 1789891200

If collection fails before publication, the previous value remains visible and becomes stale instead of falsely reporting a fresh success.

Useful queries

Use time() - example_collection_timestamp_seconds to measure the age of the last successful collection. time() - windows_textfile_mtime_seconds measures the age of each successfully read file, but should only be used for files that are expected to be rewritten; intentionally static files would appear stale by design. windows_textfile_scrape_error detects files that cannot be opened or parsed, not successfully parsed files whose producer stopped updating them.

Alerting examples

Add one alerting-rule group:

groups:
  - name: windows-textfile-freshness
    rules:
      - alert: WindowsTextfileScrapeError
        expr: windows_textfile_scrape_error == 1
        for: 5m
        labels:
          severity: warning
        annotations:
          description: A textfile cannot be opened or parsed.
      - alert: WindowsTextfileCollectionStale
        expr: time() - example_collection_timestamp_seconds > 300
        for: 2m
        labels:
          severity: warning
        annotations:
          description: The scheduled collection has not completed for more than five minutes and the producer or publication step may have failed.
      - alert: WindowsTextfileCollectionMissing
        expr: up{job="windows-exporter"} == 1 unless on (job, instance) example_collection_timestamp_seconds
        for: 5m
        labels:
          severity: warning
        annotations:
          description: The exporter is reachable but the expected completion metric is missing.

Exporter-down alerting (up == 0) remains separate; metric names, job labels and thresholds must be adapted to the deployment.

Example use

This Powershell script, when run in the --collector.textfile.directories (default C:\Program Files\windows_exporter\textfile_inputs), generates a valid .prom file that should successfully ingested by windows_exporter.

$alpha = 42
$beta = @{ left=3.1415; right=2.718281828; }

$timestamp = [DateTimeOffset]::UtcNow.ToUnixTimeSeconds()

$lines = @(
  "# HELP test_alpha_total Some random metric."
  "# TYPE test_alpha_total counter"
  "test_alpha_total ${alpha}"
  "# HELP test_beta_bytes Some other metric."
  "# TYPE test_beta_bytes gauge"
)
foreach ($k in $beta.Keys) {
  $lines += "test_beta_bytes{spin=""${k}""} $( $beta[$k] )"
}
$lines += "# HELP example_collection_timestamp_seconds Unix time when the scheduled collection last completed successfully."
$lines += "# TYPE example_collection_timestamp_seconds gauge"
$lines += "example_collection_timestamp_seconds $timestamp"

Set-Content -Path test1.prom.tmp -Encoding Ascii -NoNewline -Value (($lines -join "`n") + "`n")
Move-Item -LiteralPath test1.prom.tmp -Destination test1.prom -Force