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moon-prometheus

prometheus
metrics
observability
moon add mohongquan0630/moon-prometheus@0.2.6
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Version
0.2.6
License
Apache-2.0
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Last updated
16 hours ago
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README

#moon-prometheus

moon-prometheus is a MoonBit metrics library for service instrumentation, CLI tooling, batch jobs, and edge workloads. It provides metric types, validated multidimensional labels, a registry, Prometheus text exposition, PushGateway payload helpers, portable process samples, and deterministic benchmark fixtures.

This repository is prepared for MoonBit OSC2026 acceptance. It is public, Apache-2.0 licensed, tested with MoonBit, and includes CI plus generated public API information.

#Features

  • Standard Metrics Types:
    • Counter: A monotonically increasing cumulative metric (e.g., total requests, errors).
    • Gauge: A single numerical value that can arbitrarily go up and down (e.g., memory usage, concurrent connections).
    • Histogram: Samples observations (e.g., request durations) and counts them in configurable buckets.
    • Summary: Stores observations in memory and exposes configured quantiles plus aggregate sum/count values.
  • Metric Registry: Central registry for metrics registration and text exposition.
  • Multidimensional Labels: Validates names, escapes control characters, normalizes label order, and supports lookup/merge.
  • Metric Contracts: MetricDescriptor documents a metric family and checks its label set before registration.
  • Prometheus Serializer: Emits HELP, TYPE, cumulative histogram buckets, summary quantiles, and escaped labels.
  • Ecosystem Integrations:
    • Crescent Middleware: Native bobzhang/crescent@0.11.0 middleware, /metrics handler, and app installer.
    • PushGateway Exporter: Construct payloads to push metrics for ephemeral or batch jobs.
    • ProcessCollector: Portable CPU, virtual-memory, and open-file-descriptor samples that the host runtime can update.
  • Deterministic Benchmark Suite: Exercises counter, histogram, and summary workloads and reports observations, serialized bytes, and checksums.

#Installation

Add the package to your MoonBit project:

moon add mohongquan0630/moon-prometheus

The optional Crescent adapter is native-only and uses the compatible bobzhang/crescent@0.11.0 package:

moon add bobzhang/crescent@0.11.0

#Usage

let registry = Registry::new()

let counter = Counter::new("http_requests_total", "Total number of HTTP requests")
counter.add(3.0)
registry.register_counter(counter)

let gauge = Gauge::new("memory_usage_bytes", "Current memory usage")
gauge.set(1024.0)
registry.register_gauge(gauge)

println(registry.to_text_format())

For a Crescent application, import the adapter package and install it on the app. The adapter increments http_requests_total and serves the registry at /metrics:

import {
  "mohongquan0630/moon-prometheus/src/prometheus" @prometheus,
  "mohongquan0630/moon-prometheus/src/prometheus/crescent" @metrics_crescent,
  "bobzhang/crescent" @web,
}

let registry = @prometheus.Registry::new()
let app = @web.App()
@metrics_crescent.install(app, registry)

Run the native integration tests with moon test --target native; the adapter package contains tests for delegation, request counting, exposition output, and route registration.

Run the included demo:

moon run cmd/main

#Development and Testing

Verify the codebase:

moon fmt --check
moon check --deny-warn
moon test --deny-warn
moon info --target all

The CI workflow runs the checks on Linux, macOS, and Windows. It installs the official MoonBit toolchain, checks formatting with moon fmt --check, checks all supported targets, verifies generated .mbti files, and builds the native target with a platform compiler.

#Acceptance Notes

  • Public repository: https://gitlink.org.cn/mohongquan0630/moon-prometheus
  • Package name: mohongquan0630/moon-prometheus
  • License: Apache-2.0
  • CI: .github/workflows/test.yml
  • Publish workflow: .github/workflows/publish.yml
  • Generated API: src/prometheus/pkg.generated.mbti
  • Runnable example: moon run cmd/main

#Source Statement

The implementation is original MoonBit code for this repository. API names and text exposition concepts follow the public Prometheus/OpenMetrics model, but no third-party source code is copied into this project.

#Current Scope

The parent package focuses on deterministic metric construction and exposition. The separate Crescent adapter performs framework registration but leaves socket serving to Crescent. ProcessCollector remains portable: a host runtime supplies the process samples rather than relying on OS-specific probing.

#Reproducible benchmark data

The benchmark suite is a deterministic workload, not a wall-clock claim. It records exact operation counts, serialized output size, and a checksum so CI and reviewers can compare behavior across MoonBit backends without machine-dependent timing noise.

moon run cmd/main

#Release Checklist

moon fmt --check
moon check --deny-warn
moon test --deny-warn
moon info --target all
git diff --exit-code

#License

This project is licensed under the Apache License 2.0. See LICENSE for details.

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