github.com/prometheus/procfs v0.6.0: FS.LoadAvg

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify github.com/prometheus/procfs.FS.LoadAvg in pkg:golang/github.com/prometheus/procfs@v0.6.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/prometheus/procfs@v0.6.0
Demonstrate these symbols/APIs:
  - github.com/prometheus/procfs.FS.LoadAvg

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:668f430745cd5eedeb0d2ebdba6d272a4772bb1491fe95df0e99ac89eff2e1eb","contract":["procfs.NewFS initializes an FS instance for a valid directory","FS.LoadAvg fails if loadavg file does not exist in mount directory","FS.LoadAvg returns error on malformed loadavg content","FS.LoadAvg parses 1m, 5m, and 15m load averages correctly","FS.LoadAvg ignores extraneous trailing fields such as runnable processes and last pid"],"goal":"verify github.com/prometheus/procfs.FS.LoadAvg in pkg:golang/github.com/prometheus/procfs@v0.6.0","kind":"HOW","packages":["pkg:golang/github.com/prometheus/procfs@v0.6.0"],"schemaVersion":1,"symbols":["github.com/prometheus/procfs.FS.LoadAvg"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/prometheus/procfs@v0.6.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/prometheus/procfs@v0.6.0","symbols":["github.com/prometheus/procfs.FS.LoadAvg"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require github.com/prometheus/procfs v0.6.0

require golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c // indirect

github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
github.com/prometheus/procfs v0.6.0 h1:mxy4L2jP6qMonqmq+aTtOx1ifVWUgG/TAmntgbh3xv4=
github.com/prometheus/procfs v0.6.0/go.mod h1:cz+aTbrPOrUb4q7XlbU9ygM+/jj0fzG6c1xBZuNvfVA=
golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c h1:VwygUrnw9jn88c4u8GD3rZQbqrP/tgas88tPUbBxQrk=
golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

package main

import (
	"fmt"
	"os"

	"github.com/prometheus/procfs"
)

func main() {
	fs, err := procfs.NewFS(procfs.DefaultMountPoint)
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to open procfs: %v\n", err)
		os.Exit(1)
	}

	loadavg, err := fs.LoadAvg()
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to read loadavg: %v\n", err)
		os.Exit(1)
	}

	fmt.Printf("LoadAvg: 1m=%.2f, 5m=%.2f, 15m=%.2f\n", loadavg.Load1, loadavg.Load5, loadavg.Load15)
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/prometheus/procfs.FS.LoadAvg in pkg:golang/github.com/prometheus/procfs@v0.6.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/prometheus/procfs@v0.6.0"
  ],
  "symbols": [
    "github.com/prometheus/procfs.FS.LoadAvg"
  ]
}

package main

import (
	"fmt"
	"math"
	"os"
	"path/filepath"

	"github.com/prometheus/procfs"
)

func floatEquals(a, b, tolerance float64) bool {
	return math.Abs(a-b) <= tolerance
}

func main() {
	// 1. procfs.NewFS initializes an FS instance for a valid directory
	mockDir, err := os.MkdirTemp("", "mock-procfs-*")
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to create mock directory: %v\n", err)
		os.Exit(1)
	}
	defer os.RemoveAll(mockDir)

	fs, err := procfs.NewFS(mockDir)
	if err != nil {
		fmt.Fprintf(os.Stderr, "expected NewFS to succeed for valid directory: %v\n", err)
		os.Exit(1)
	}

	// 2. FS.LoadAvg fails if loadavg file does not exist in mount directory
	_, err = fs.LoadAvg()
	if err == nil {
		fmt.Fprintf(os.Stderr, "expected LoadAvg to fail when loadavg file is missing, but got nil error\n")
		os.Exit(1)
	}

	// 3. FS.LoadAvg returns error on malformed loadavg content
	loadavgFile := filepath.Join(mockDir, "loadavg")
	if err := os.WriteFile(loadavgFile, []byte("0.10 0.20\n"), 0644); err != nil {
		fmt.Fprintf(os.Stderr, "failed to write malformed loadavg: %v\n", err)
		os.Exit(1)
	}
	_, err = fs.LoadAvg()
	if err == nil {
		fmt.Fprintf(os.Stderr, "expected LoadAvg to fail on fewer than 3 fields, but got nil error\n")
		os.Exit(1)
	}

	if err := os.WriteFile(loadavgFile, []byte("invalid non-numeric fields here\n"), 0644); err != nil {
		fmt.Fprintf(os.Stderr, "failed to write non-numeric loadavg: %v\n", err)
		os.Exit(1)
	}
	_, err = fs.LoadAvg()
	if err == nil {
		fmt.Fprintf(os.Stderr, "expected LoadAvg to fail on non-numeric fields, but got nil error\n")
		os.Exit(1)
	}

	// 4. FS.LoadAvg parses 1m, 5m, and 15m load averages correctly
	// 5. FS.LoadAvg ignores extraneous trailing fields such as runnable processes and last pid
	validContent := "0.02 0.04 0.05 1/502 33634\n"
	if err := os.WriteFile(loadavgFile, []byte(validContent), 0644); err != nil {
		fmt.Fprintf(os.Stderr, "failed to write valid loadavg: %v\n", err)
		os.Exit(1)
	}

	loadavg, err := fs.LoadAvg()
	if err != nil {
		fmt.Fprintf(os.Stderr, "expected LoadAvg to succeed: %v\n", err)
		os.Exit(1)
	}

	if !floatEquals(loadavg.Load1, 0.02, 1e-6) {
		fmt.Fprintf(os.Stderr, "expected Load1 0.02, got %v\n", loadavg.Load1)
		os.Exit(1)
	}
	if !floatEquals(loadavg.Load5, 0.04, 1e-6) {
		fmt.Fprintf(os.Stderr, "expected Load5 0.04, got %v\n", loadavg.Load5)
		os.Exit(1)
	}
	if !floatEquals(loadavg.Load15, 0.05, 1e-6) {
		fmt.Fprintf(os.Stderr, "expected Load15 0.05, got %v\n", loadavg.Load15)
		os.Exit(1)
	}

	fmt.Println("All procfs.FS.LoadAvg contract assertions passed.")
}