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

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/jackc/pgservicefile.Servicefile in 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
Demonstrate these symbols/APIs:
  - github.com/jackc/pgservicefile.Servicefile

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:be8ed258148c83792dbf69fc4134b8f07b818db352bdf0da8717613c6f70e006","contract":["ParseServicefile parses service definitions and key-value settings into Servicefile","Servicefile.Services preserves all parsed service definitions in order","Servicefile.GetService returns existing service by name with configured settings","Servicefile.GetService returns not found error for undefined service name"],"goal":"verify github.com/jackc/pgservicefile.Servicefile in 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,"symbols":["github.com/jackc/pgservicefile.Servicefile"]},"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","symbols":["github.com/jackc/pgservicefile.Servicefile"],"verifierAdapter":"golang@1"}

module sample

go 1.22

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 sample

import (
	"strings"

	"github.com/jackc/pgservicefile"
)

// ParseConfig parses PostgreSQL service file configuration text into a Servicefile.
func ParseConfig(content string) (*pgservicefile.Servicefile, error) {
	return pgservicefile.ParseServicefile(strings.NewReader(content))
}

// LookupService retrieves a service by name from the Servicefile.
func LookupService(sf *pgservicefile.Servicefile, serviceName string) (*pgservicefile.Service, error) {
	return sf.GetService(serviceName)
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/jackc/pgservicefile.Servicefile in 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"
  ],
  "symbols": [
    "github.com/jackc/pgservicefile.Servicefile"
  ]
}

package main

import (
	"fmt"
	"os"

	"sample"
)

func main() {
	configData := `# PostgreSQL service configuration
[db_primary]
host = localhost
port = 5432
dbname = testdb
user = appuser

[db_replica]
host = replica.example.com
port = 5433
dbname = testdb_ro
user = readonly_user
`

	// 1. Assert ParseConfig parses the configuration into a Servicefile
	sf, err := sample.ParseConfig(configData)
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to parse service file: %v\n", err)
		os.Exit(1)
	}
	if sf == nil {
		fmt.Fprintf(os.Stderr, "expected non-nil Servicefile\n")
		os.Exit(1)
	}

	// 2. Assert Servicefile.Services preserves all parsed service definitions
	if len(sf.Services) != 2 {
		fmt.Fprintf(os.Stderr, "expected 2 services in Servicefile, 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, "unexpected service order or names: %s, %s\n", sf.Services[0].Name, sf.Services[1].Name)
		os.Exit(1)
	}

	// 3. Assert Servicefile.GetService returns existing service by name
	primary, err := sample.LookupService(sf, "db_primary")
	if err != nil {
		fmt.Fprintf(os.Stderr, "expected to find db_primary service, got err: %v\n", err)
		os.Exit(1)
	}
	if primary.Settings["host"] != "localhost" {
		fmt.Fprintf(os.Stderr, "expected host 'localhost', got '%s'\n", primary.Settings["host"])
		os.Exit(1)
	}
	if primary.Settings["port"] != "5432" {
		fmt.Fprintf(os.Stderr, "expected port '5432', got '%s'\n", primary.Settings["port"])
		os.Exit(1)
	}
	if primary.Settings["dbname"] != "testdb" {
		fmt.Fprintf(os.Stderr, "expected dbname 'testdb', got '%s'\n", primary.Settings["dbname"])
		os.Exit(1)
	}
	if primary.Settings["user"] != "appuser" {
		fmt.Fprintf(os.Stderr, "expected user 'appuser', got '%s'\n", primary.Settings["user"])
		os.Exit(1)
	}

	replica, err := sample.LookupService(sf, "db_replica")
	if err != nil {
		fmt.Fprintf(os.Stderr, "expected to find db_replica service, got err: %v\n", err)
		os.Exit(1)
	}
	if replica.Settings["host"] != "replica.example.com" {
		fmt.Fprintf(os.Stderr, "expected host 'replica.example.com', got '%s'\n", replica.Settings["host"])
		os.Exit(1)
	}
	if replica.Settings["port"] != "5433" {
		fmt.Fprintf(os.Stderr, "expected port '5433', got '%s'\n", replica.Settings["port"])
		os.Exit(1)
	}

	// 4. Assert Servicefile.GetService returns error for undefined service name
	missing, err := sample.LookupService(sf, "db_nonexistent")
	if err == nil {
		fmt.Fprintf(os.Stderr, "expected error for non-existent service, got nil with service: %v\n", missing)
		os.Exit(1)
	}

	fmt.Println("All github.com/jackc/pgservicefile.Servicefile contract assertions passed.")
}