github.com/jackc/pgservicefile v0.0.0-20200714003250-2b9c44734f2b

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 pkg:golang/github.com/jackc/pgservicefile@v0.0.0-20200714003250-2b9c44734f2b
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/jackc/pgservicefile@v0.0.0-20200714003250-2b9c44734f2b

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:a45baa4bca36cff233b8c210835fbfa4e62878906b84726d18b3ec8b552d5a4f","contract":["ParseServicefile parses service definitions with multiple sections and key-value settings from io.Reader","GetService retrieves existing service configuration with exact settings map and returns error for nonexistent service","ReadServicefile parses service definitions directly from a file path on disk","ParseServicefile correctly ignores comments and empty lines in service file definitions"],"goal":"verify pkg:golang/github.com/jackc/pgservicefile@v0.0.0-20200714003250-2b9c44734f2b","kind":"HOW","packages":["pkg:golang/github.com/jackc/pgservicefile@v0.0.0-20200714003250-2b9c44734f2b"],"schemaVersion":1},"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/jackc/pgservicefile@v0.0.0-20200714003250-2b9c44734f2b"],"schemaVersion":1,"subject":"pkg:golang/github.com/jackc/pgservicefile@v0.0.0-20200714003250-2b9c44734f2b","verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require github.com/jackc/pgservicefile v0.0.0-20200714003250-2b9c44734f2b

github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/jackc/pgservicefile v0.0.0-20200714003250-2b9c44734f2b h1:C8S2+VttkHFdOOCXJe+YGfa4vHYwlt4Zx+IVXQ97jYg=
github.com/jackc/pgservicefile v0.0.0-20200714003250-2b9c44734f2b/go.mod h1:vsD4gTJCa9TptPL8sPkXrLZ+hDuNrZCnj29CQpr4X1E=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

package main

import (
	"fmt"
	"io"
	"strings"

	"github.com/jackc/pgservicefile"
)

// ServiceConfig stores parsed configuration for PostgreSQL services.
type ServiceConfig struct {
	servicefile *pgservicefile.Servicefile
}

// LoadFromReader creates a ServiceConfig from an io.Reader.
func LoadFromReader(r io.Reader) (*ServiceConfig, error) {
	sf, err := pgservicefile.ParseServicefile(r)
	if err != nil {
		return nil, fmt.Errorf("parse servicefile failed: %w", err)
	}
	return &ServiceConfig{servicefile: sf}, nil
}

// LoadFromFile creates a ServiceConfig from a file path.
func LoadFromFile(path string) (*ServiceConfig, error) {
	sf, err := pgservicefile.ReadServicefile(path)
	if err != nil {
		return nil, fmt.Errorf("read servicefile failed: %w", err)
	}
	return &ServiceConfig{servicefile: sf}, nil
}

// LookupService returns the settings map for a named service.
func (c *ServiceConfig) LookupService(name string) (map[string]string, error) {
	svc, err := c.servicefile.GetService(name)
	if err != nil {
		return nil, fmt.Errorf("service lookup failed: %w", err)
	}
	return svc.Settings, nil
}

func main() {
	sample := `
# Example PostgreSQL service definition
[mydb]
host=db.example.com
port=5432
dbname=testdb
user=testuser
`
	cfg, err := LoadFromReader(strings.NewReader(sample))
	if err != nil {
		fmt.Printf("Error: %v\n", err)
		return
	}

	settings, err := cfg.LookupService("mydb")
	if err != nil {
		fmt.Printf("Error: %v\n", err)
		return
	}

	fmt.Printf("Database: %s@%s:%s\n", settings["dbname"], settings["host"], settings["port"])
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/jackc/pgservicefile@v0.0.0-20200714003250-2b9c44734f2b",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/jackc/pgservicefile@v0.0.0-20200714003250-2b9c44734f2b"
  ]
}

package main

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

	"github.com/jackc/pgservicefile"
)

func main() {
	// Assertion 1: ParseServicefile parses service definitions with sections and key-value pairs
	{
		content := `
# Service definitions
[db_primary]
host=primary.example.com
port=5432
user=dbuser
dbname=appdb

[db_replica]
host=replica.example.com
port=5433
user=readonly_user
dbname=appdb
`
		sf, err := pgservicefile.ParseServicefile(strings.NewReader(content))
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: ParseServicefile failed: %v\n", err)
			os.Exit(1)
		}
		if sf == nil {
			fmt.Fprintf(os.Stderr, "FAIL: nil Servicefile returned\n")
			os.Exit(1)
		}
		if len(sf.Services) != 2 {
			fmt.Fprintf(os.Stderr, "FAIL: expected 2 services, got %d\n", len(sf.Services))
			os.Exit(1)
		}
		if sf.Services[0].Name != "db_primary" || sf.Services[1].Name != "db_replica" {
			fmt.Fprintf(os.Stderr, "FAIL: unexpected service names: %q, %q\n", sf.Services[0].Name, sf.Services[1].Name)
			os.Exit(1)
		}
	}

	// Assertion 2: GetService returns configuration settings for an existing service and errors on nonexistent service
	{
		content := `
[app_svc]
host=localhost
port=5432
dbname=demodb
sslmode=disable
`
		sf, err := pgservicefile.ParseServicefile(strings.NewReader(content))
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: ParseServicefile failed: %v\n", err)
			os.Exit(1)
		}

		svc, err := sf.GetService("app_svc")
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: GetService failed: %v\n", err)
			os.Exit(1)
		}
		if svc.Name != "app_svc" {
			fmt.Fprintf(os.Stderr, "FAIL: expected service name app_svc, got %q\n", svc.Name)
			os.Exit(1)
		}
		if svc.Settings["host"] != "localhost" || svc.Settings["port"] != "5432" || svc.Settings["dbname"] != "demodb" || svc.Settings["sslmode"] != "disable" {
			fmt.Fprintf(os.Stderr, "FAIL: unexpected settings values: %+v\n", svc.Settings)
			os.Exit(1)
		}

		_, err = sf.GetService("missing_svc")
		if err == nil {
			fmt.Fprintf(os.Stderr, "FAIL: expected error for nonexistent service, got nil\n")
			os.Exit(1)
		}
	}

	// Assertion 3: ReadServicefile reads and parses service definitions from a file
	{
		dir, err := os.MkdirTemp("", "pgservicefile_test_*")
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: os.MkdirTemp failed: %v\n", err)
			os.Exit(1)
		}
		defer os.RemoveAll(dir)

		confPath := filepath.Join(dir, "pg_service.conf")
		confContent := `
[file_svc]
host=filehost.example.com
port=6432
dbname=filedb
`
		if err := os.WriteFile(confPath, []byte(confContent), 0600); err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: os.WriteFile failed: %v\n", err)
			os.Exit(1)
		}

		sf, err := pgservicefile.ReadServicefile(confPath)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: ReadServicefile failed: %v\n", err)
			os.Exit(1)
		}
		svc, err := sf.GetService("file_svc")
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: GetService on ReadServicefile failed: %v\n", err)
			os.Exit(1)
		}
		if svc.Settings["host"] != "filehost.example.com" || svc.Settings["dbname"] != "filedb" {
			fmt.Fprintf(os.Stderr, "FAIL: unexpected settings: %+v\n", svc.Settings)
			os.Exit(1)
		}

		_, err = pgservicefile.ReadServicefile(filepath.Join(dir, "nonexistent.conf"))
		if err == nil {
			fmt.Fprintf(os.Stderr, "FAIL: expected error reading nonexistent file\n")
			os.Exit(1)
		}
	}

	// Assertion 4: ParseServicefile handles comments and empty lines properly
	{
		content := `
# Comment line at start

[spaced_svc]
# Inline comment
host=example.com

# Another blank and comment
port=5432
`
		sf, err := pgservicefile.ParseServicefile(strings.NewReader(content))
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: ParseServicefile with comments failed: %v\n", err)
			os.Exit(1)
		}
		svc, err := sf.GetService("spaced_svc")
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: GetService failed: %v\n", err)
			os.Exit(1)
		}
		if len(svc.Settings) != 2 {
			fmt.Fprintf(os.Stderr, "FAIL: expected 2 settings, got %d: %+v\n", len(svc.Settings), svc.Settings)
			os.Exit(1)
		}
	}

	fmt.Println("PASS: pgservicefile contract passed")
}