github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a

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@v0.0.0-20221227161230-091c0ba34f0a
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/jackc/pgservicefile@v0.0.0-20221227161230-091c0ba34f0a
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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:sha256:333ce46758059f0a5d006157f6d70172d85a51f7350ef7f8d6860689a18b28b4","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@v0.0.0-20221227161230-091c0ba34f0a","kind":"HOW","packages":["pkg:golang/github.com/jackc/pgservicefile@v0.0.0-20221227161230-091c0ba34f0a"],"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@v0.0.0-20221227161230-091c0ba34f0a"],"schemaVersion":1,"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a

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 v0.0.0-20221227161230-091c0ba34f0a h1:bbPeKD0xmW/Y25WS6cokEszi5g+S0QxI/d45PkRi7Nk=
github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a/go.mod h1:5TJZWKEWniPve33vlWYSoGYefn3gLQRzjfDlhSJ9ZKM=
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 v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

package main

import (
	"fmt"
	"io"
	"strings"

	"github.com/jackc/pgservicefile"
)

// ServiceConfigResolver manages PostgreSQL service file definitions and provides connection parameters.
type ServiceConfigResolver struct {
	serviceFile *pgservicefile.Servicefile
}

// NewServiceConfigResolverFromReader parses PostgreSQL service configuration from an io.Reader.
func NewServiceConfigResolverFromReader(r io.Reader) (*ServiceConfigResolver, error) {
	sf, err := pgservicefile.ParseServicefile(r)
	if err != nil {
		return nil, fmt.Errorf("failed to parse service file: %w", err)
	}
	return &ServiceConfigResolver{serviceFile: sf}, nil
}

// NewServiceConfigResolverFromFile loads and parses a PostgreSQL service configuration file from the filesystem.
func NewServiceConfigResolverFromFile(filePath string) (*ServiceConfigResolver, error) {
	sf, err := pgservicefile.ReadServicefile(filePath)
	if err != nil {
		return nil, fmt.Errorf("failed to read service file: %w", err)
	}
	return &ServiceConfigResolver{serviceFile: sf}, nil
}

// GetServiceSettings retrieves the key-value settings map for a named service.
func (r *ServiceConfigResolver) GetServiceSettings(name string) (map[string]string, error) {
	svc, err := r.serviceFile.GetService(name)
	if err != nil {
		return nil, fmt.Errorf("service %q not found: %w", name, err)
	}
	return svc.Settings, nil
}

// BuildConnString builds a standard PostgreSQL connection keyword/value string for a named service.
func (r *ServiceConfigResolver) BuildConnString(name string) (string, error) {
	settings, err := r.GetServiceSettings(name)
	if err != nil {
		return "", err
	}

	var parts []string
	for k, v := range settings {
		parts = append(parts, fmt.Sprintf("%s=%s", k, v))
	}
	return strings.Join(parts, " "), nil
}

func main() {
	sampleConfig := `
# Primary database service
[primary_db]
host=db.example.com
port=5432
dbname=production_app
user=app_user

# Analytics replica service
[analytics_db]
host=analytics.example.com
port=5433
dbname=analytics_warehouse
user=readonly_user
`

	resolver, err := NewServiceConfigResolverFromReader(strings.NewReader(sampleConfig))
	if err != nil {
		fmt.Printf("Error initializing resolver: %v\n", err)
		return
	}

	settings, err := resolver.GetServiceSettings("primary_db")
	if err != nil {
		fmt.Printf("Error retrieving service settings: %v\n", err)
		return
	}

	fmt.Printf("Resolved primary_db host: %s, dbname: %s\n", settings["host"], settings["dbname"])
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/jackc/pgservicefile@v0.0.0-20221227161230-091c0ba34f0a",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/jackc/pgservicefile@v0.0.0-20221227161230-091c0ba34f0a"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

package main

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

	"github.com/jackc/pgservicefile"
)

func main() {
	// Contract 1: ParseServicefile parses service definitions with multiple sections and key-value settings from io.Reader
	{
		content := `
# PostgreSQL service definitions
[primary_db]
host=db.example.com
port=5432
user=dbuser
dbname=appdb

[replica_db]
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 error: %v\n", err)
			os.Exit(1)
		}
		if sf == nil {
			fmt.Fprintf(os.Stderr, "FAIL: expected non-nil Servicefile\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 != "primary_db" || sf.Services[1].Name != "replica_db" {
			fmt.Fprintf(os.Stderr, "FAIL: unexpected service names: %s, %s\n", sf.Services[0].Name, sf.Services[1].Name)
			os.Exit(1)
		}
	}

	// Contract 2: GetService retrieves existing service configuration with exact settings map and returns error for nonexistent service
	{
		content := `
[app_service]
host=localhost
port=5432
dbname=mydb
user=postgres
sslmode=verify-full
`
		sf, err := pgservicefile.ParseServicefile(strings.NewReader(content))
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: ParseServicefile error: %v\n", err)
			os.Exit(1)
		}

		svc, err := sf.GetService("app_service")
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: GetService failed for existing service: %v\n", err)
			os.Exit(1)
		}
		if svc.Name != "app_service" {
			fmt.Fprintf(os.Stderr, "FAIL: expected service name 'app_service', got %q\n", svc.Name)
			os.Exit(1)
		}
		expectedSettings := map[string]string{
			"host":    "localhost",
			"port":    "5432",
			"dbname":  "mydb",
			"user":    "postgres",
			"sslmode": "verify-full",
		}
		for k, expectedVal := range expectedSettings {
			if actualVal, ok := svc.Settings[k]; !ok || actualVal != expectedVal {
				fmt.Fprintf(os.Stderr, "FAIL: setting %q mismatch: got %q, expected %q\n", k, actualVal, expectedVal)
				os.Exit(1)
			}
		}

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

	// Contract 3: ReadServicefile parses service definitions directly from a file path on disk
	{
		tmpDir, err := os.MkdirTemp("", "pgservicefile_test_*")
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: failed to create temp directory: %v\n", err)
			os.Exit(1)
		}
		defer os.RemoveAll(tmpDir)

		filePath := filepath.Join(tmpDir, ".pg_service.conf")
		fileContent := `
[metrics_db]
host=metrics.example.com
port=5432
dbname=metrics
user=collector
`
		if err := os.WriteFile(filePath, []byte(fileContent), 0600); err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: failed to write temp file: %v\n", err)
			os.Exit(1)
		}

		sf, err := pgservicefile.ReadServicefile(filePath)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: ReadServicefile error: %v\n", err)
			os.Exit(1)
		}
		svc, err := sf.GetService("metrics_db")
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: GetService for metrics_db error: %v\n", err)
			os.Exit(1)
		}
		if svc.Settings["host"] != "metrics.example.com" || svc.Settings["dbname"] != "metrics" {
			fmt.Fprintf(os.Stderr, "FAIL: unexpected service settings: %+v\n", svc.Settings)
			os.Exit(1)
		}

		// Nonexistent file should return error
		_, err = pgservicefile.ReadServicefile(filepath.Join(tmpDir, "missing.conf"))
		if err == nil {
			fmt.Fprintf(os.Stderr, "FAIL: expected error for missing file, got nil\n")
			os.Exit(1)
		}
	}

	// Contract 4: ParseServicefile correctly ignores comments and empty lines in service file definitions
	{
		contentWithComments := `
# Header comments
# Another comment line

[comment_test]
# Inline parameter comments
host=db.example.com

# Blank lines between keys
port=5432

# Trailing comments
`
		sf, err := pgservicefile.ParseServicefile(strings.NewReader(contentWithComments))
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: ParseServicefile with comments error: %v\n", err)
			os.Exit(1)
		}
		svc, err := sf.GetService("comment_test")
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: GetService comment_test error: %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)
		}
		if svc.Settings["host"] != "db.example.com" || svc.Settings["port"] != "5432" {
			fmt.Fprintf(os.Stderr, "FAIL: unexpected settings in comment_test: %+v\n", svc.Settings)
			os.Exit(1)
		}
	}

	fmt.Println("PASS: github.com/jackc/pgservicefile contract passed")
}