#moonopenmetrics

#What it provides

• HELP, TYPE, UNIT, sample, exemplar, timestamp, comment, and EOF parsing
• Counter, gauge, histogram, gauge-histogram, summary, info, state-set, and unknown family models
• OpenMetrics NaN, +Inf, -Inf, decimal, and scientific numbers
• Quoted label escaping and HELP escaping with useful line/column failures
• Canonical output with stable family, sample, and label order
• Semantic checks for family suffixes, duplicate series/labels, counter totals, metric/family/point interleaving, cumulative histogram buckets/counts, summary quantiles, created/timestamp ordering, info/state-set values, exemplar placement/size, unit naming, family-name collisions, and mandatory EOF
• An in-memory registry with counter, gauge, histogram, gauge-histogram, summary, info, and state-set collectors
• Snapshot merge policies, family selection, label selection, and structural summary reports
• A runnable validate / normalize command demonstration
• Black-box tests for valid inputs, malformed inputs, edge cases, round trips, validation diagnostics, and registry aggregation

#Install

moon add JYPeng487/moonopenmetrics

import {
  "JYPeng487/moonopenmetrics",
}

#Parse, validate, and normalize

///|
test {
  let input =
    #|# TYPE requests counter
    #|# HELP requests processed requests
    #|requests_total{method="GET"} 3
    #|# EOF
    #|
  let document = match @moonopenmetrics.parse(input) {
    Ok(document) => document
    Err(error) => fail(error.to_string())
  }
  let report = @moonopenmetrics.validate(document)
  inspect(report.error_count, content="0")
  inspect(document.families.length(), content="1")
  inspect(@moonopenmetrics.encode(document).contains("# EOF"), content="true")
}

#Record application metrics

///|
test {
  let registry = @moonopenmetrics.Registry::new()
  match registry.register("requests", Counter, help="processed requests") {
    Ok(_) => ()
    Err(error) => fail(error)
  }
  match
    registry.increment_counter("requests", delta=2.0, labels=[
      @moonopenmetrics.Label::new("method", "GET"),
    ]) {
    Ok(_) => ()
    Err(error) => fail(error)
  }
  let text = registry.to_text()
  inspect(text.contains("requests_total{method=\"GET\"} 2"), content="true")
  inspect(
    @moonopenmetrics.validate(registry.snapshot()).error_count,
    content="0",
  )
}

///|
test {
  let registry = @moonopenmetrics.Registry::new()
  match
    registry.register(
      "latency_seconds",
      Histogram,
      help="request latency",
      unit="seconds",
    ) {
    Ok(_) => ()
    Err(error) => fail(error)
  }
  match registry.observe_histogram("latency_seconds", 0.2, [0.1, 0.5, 1.0]) {
    Ok(_) => ()
    Err(error) => fail(error)
  }
  inspect(
    registry.to_text().contains("latency_seconds_bucket{le=\"+Inf\"} 1"),
    content="true",
  )
}

#Runnable command

moon run cmd/main

moon run cmd/main -- validate
moon run cmd/main -- normalize
moon run cmd/main -- help

moon run cmd/main -- validate "# EOF"

#Data model

#Originality, specification source, and related work

#Compatibility boundary

• metric: [A-Za-z_:][A-Za-z0-9_:]*
• label: [A-Za-z_][A-Za-z0-9_]*

#Reproduce locally

moon fmt --check
moon info --target all
moon check --target all --deny-warn
moon test --target all --deny-warn
moon build --target all
moon run cmd/main
moon package

#Project layout

model.mbt                    public domain model
text.mbt / number.mbt        lexical rules and escaping
labels.mbt                   label parser and encoder
sample_parser.mbt            sample, timestamp, and exemplar grammar
parser.mbt / encoder.mbt     complete document conversion
validation.mbt               cross-line semantic checks
registry.mbt                 deterministic aggregation
merge.mbt                    snapshot merge and selection
report.mbt                   structural and diagnostic reports
cmd/main                     runnable validator/normalizer
examples/complete.om         reproducible fixture

#License