github.com/jackc/pgx/v5 v5.10.0: Parse PostgreSQL connection string using pgx.ParseConfig

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: Parse PostgreSQL connection string using pgx.ParseConfig
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/jackc/pgx/v5@v5.10.0
Demonstrate these symbols/APIs:
  - ParseConfig
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@11.8.0
  - runtime: node@24.13.1

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:bb4ab296bb22734c33878e5c1d11ddd79c2d351484432b95fd2dd735e0f58245","contract":["pgx.ParseConfig parses PostgreSQL connection URI into ConnConfig","pgx.ParseConfig extracts runtime parameters from query parameters","pgx.ParseConfig parses key-value DSN format","pgx.ParseConfig returns an error for invalid connection strings","pgx.ConnConfig.Copy creates an independent copy of configuration","pgx.NamedArgs rewrites named SQL parameters into positional placeholders","pgx.StrictNamedArgs returns an error when a query parameter is missing","pgx.Identifier sanitizes multi-part SQL identifiers and escapes embedded quotes"],"goal":"Parse PostgreSQL connection string using pgx.ParseConfig","kind":"HOW","packages":["pkg:golang/github.com/jackc/pgx/v5@v5.10.0"],"schemaVersion":1,"symbols":["pgx.ParseConfig","pgx.NamedArgs","pgx.StrictNamedArgs","pgx.Identifier"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","ecosystem":"golang","os":"windows","osVersionBucket":"11","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/jackc/pgx/v5@v5.10.0"],"schemaVersion":1,"symbols":["pgx.ParseConfig","pgx.NamedArgs","pgx.StrictNamedArgs","pgx.Identifier"],"verifierAdapter":"golang@1"}

module sample

go 1.26.5

require github.com/jackc/pgx/v5 v5.10.0

require (
	github.com/jackc/pgpassfile v1.0.0 // indirect
	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
	golang.org/x/text v0.29.0 // indirect
)

github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
github.com/jackc/pgpassfile v1.0.0/go.mod h1:CEx0iS5ambNFdcRtxPj5JhEz+xB6uRky5eyVu/W2HEg=
github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 h1:iCEnooe7UlwOQYpKFhBabPMi4aNAfoODPEFNiAnClxo=
github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761/go.mod h1:5TJZWKEWniPve33vlWYSoGYefn3gLQRzjfDlhSJ9ZKM=
github.com/jackc/pgx/v5 v5.10.0 h1:VhSvgU2jSli8o3AqIEOTJr7rZwAEUVo4E4XhR94Zfr0=
github.com/jackc/pgx/v5 v5.10.0/go.mod h1:mal1tBGAFfLHvZzaYh77YS/eC6IX9OWbRV1QIIM0Jn4=
github.com/jackc/puddle/v2 v2.2.2 h1:PR8nw+E/1w0GLuRFSmiioY6UooMp6KJv0/61nB7icHo=
github.com/jackc/puddle/v2 v2.2.2/go.mod h1:vriiEXHvEE654aYKXXjOvZM39qJ0q+azkZFrfEOc3H4=
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 v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
golang.org/x/sync v0.17.0 h1:l60nONMj9l5drqw6jlhIELNv9I0A4OFgRsG9k2oT9Ug=
golang.org/x/sync v0.17.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
golang.org/x/text v0.29.0 h1:1neNs90w9YzJ9BocxfsQNHKuAT4pkghyXc4nhZ6sJvk=
golang.org/x/text v0.29.0/go.mod h1:7MhJOA9CD2qZyOKYazxdYMF85OwPdEr9jTtBpO7ydH4=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/jackc/pgx/v5"
)

func main() {
	ctx := context.Background()

	// 1. Parse PostgreSQL connection URI
	uri := "postgres://sampleuser:secretpassword@localhost:5432/sampledb?sslmode=disable&application_name=sample_app"
	cfg, err := pgx.ParseConfig(uri)
	if err != nil {
		log.Fatalf("failed to parse URI: %v", err)
	}
	fmt.Printf("Host: %s, Port: %d, Database: %s, User: %s\n",
		cfg.Host, cfg.Port, cfg.Database, cfg.User)
	fmt.Printf("ApplicationName: %s\n", cfg.RuntimeParams["application_name"])

	// 2. Parse key-value DSN format
	dsn := "host=localhost port=5432 user=sampleuser dbname=sampledb password=secretpassword sslmode=disable"
	cfgDSN, err := pgx.ParseConfig(dsn)
	if err != nil {
		log.Fatalf("failed to parse DSN: %v", err)
	}
	fmt.Printf("DSN Database: %s\n", cfgDSN.Database)

	// 3. Rewrite queries with named arguments
	namedArgs := pgx.NamedArgs{
		"username": "alice",
		"status":   "active",
	}
	sqlQuery := "SELECT id, email FROM users WHERE username = @username AND status = @status"
	rewrittenSQL, args, err := namedArgs.RewriteQuery(ctx, nil, sqlQuery, nil)
	if err != nil {
		log.Fatalf("failed to rewrite query: %v", err)
	}
	fmt.Printf("Rewritten SQL: %s\n", rewrittenSQL)
	fmt.Printf("Positional Args: %v\n", args)

	// 4. Sanitize SQL identifiers
	ident := pgx.Identifier{"public", "user\"table"}
	fmt.Printf("Sanitized Identifier: %s\n", ident.Sanitize())
}

{
  "schemaVersion": 1,
  "goal": "Parse PostgreSQL connection string using pgx.ParseConfig",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/jackc/pgx/v5@v5.10.0"
  ],
  "symbols": [
    "ParseConfig"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@11.8.0",
    "runtime": "node@24.13.1"
  }
}

package main

import (
	"context"
	"fmt"
	"os"
	"strings"

	"github.com/jackc/pgx/v5"
)

func main() {
	ctx := context.Background()

	// Assertion 1: pgx.ParseConfig parses PostgreSQL connection URI into ConnConfig
	uri := "postgres://sampleuser:secretpassword@localhost:5432/sampledb?sslmode=disable&application_name=sample_app"
	cfg, err := pgx.ParseConfig(uri)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected pgx.ParseConfig to succeed on valid URI, got: %v\n", err)
		os.Exit(1)
	}
	if cfg.Host != "localhost" {
		fmt.Fprintf(os.Stderr, "FAIL: expected Host 'localhost', got '%s'\n", cfg.Host)
		os.Exit(1)
	}
	if cfg.Port != 5432 {
		fmt.Fprintf(os.Stderr, "FAIL: expected Port 5432, got %d\n", cfg.Port)
		os.Exit(1)
	}
	if cfg.Database != "sampledb" {
		fmt.Fprintf(os.Stderr, "FAIL: expected Database 'sampledb', got '%s'\n", cfg.Database)
		os.Exit(1)
	}
	if cfg.User != "sampleuser" {
		fmt.Fprintf(os.Stderr, "FAIL: expected User 'sampleuser', got '%s'\n", cfg.User)
		os.Exit(1)
	}
	if cfg.Password != "secretpassword" {
		fmt.Fprintf(os.Stderr, "FAIL: expected Password 'secretpassword', got '%s'\n", cfg.Password)
		os.Exit(1)
	}

	// Assertion 2: pgx.ParseConfig extracts runtime parameters from query parameters
	if cfg.RuntimeParams == nil || cfg.RuntimeParams["application_name"] != "sample_app" {
		fmt.Fprintf(os.Stderr, "FAIL: expected application_name 'sample_app', got %v\n", cfg.RuntimeParams)
		os.Exit(1)
	}

	// Assertion 3: pgx.ParseConfig parses key-value DSN format
	dsn := "host=localhost port=5432 user=sampleuser dbname=sampledb password=secretpassword sslmode=disable"
	cfgDSN, err := pgx.ParseConfig(dsn)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected pgx.ParseConfig to succeed on valid DSN, got: %v\n", err)
		os.Exit(1)
	}
	if cfgDSN.Host != "localhost" || cfgDSN.Port != 5432 || cfgDSN.Database != "sampledb" || cfgDSN.User != "sampleuser" || cfgDSN.Password != "secretpassword" {
		fmt.Fprintf(os.Stderr, "FAIL: DSN fields mismatch: %+v\n", cfgDSN)
		os.Exit(1)
	}

	// Assertion 4: pgx.ParseConfig returns an error for invalid connection strings
	_, errInvalid := pgx.ParseConfig("postgres://localhost:invalid_port/sampledb")
	if errInvalid == nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected error for invalid port in URI, got nil\n")
		os.Exit(1)
	}

	// Assertion 5: pgx.ConnConfig.Copy creates an independent copy of configuration
	cfgCopy := cfg.Copy()
	if cfgCopy == nil || cfgCopy.Host != cfg.Host || cfgCopy.Port != cfg.Port {
		fmt.Fprintf(os.Stderr, "FAIL: expected cfgCopy to match cfg\n")
		os.Exit(1)
	}
	cfgCopy.RuntimeParams["custom_setting"] = "enabled"
	if _, exists := cfg.RuntimeParams["custom_setting"]; exists {
		fmt.Fprintf(os.Stderr, "FAIL: mutating cfgCopy.RuntimeParams mutated original cfg\n")
		os.Exit(1)
	}

	// Assertion 6: pgx.NamedArgs rewrites named SQL parameters into positional placeholders
	namedArgs := pgx.NamedArgs{
		"username": "alice",
		"status":   "active",
	}
	rewrittenSQL, args, err := namedArgs.RewriteQuery(ctx, nil, "SELECT id, email FROM users WHERE username = @username AND status = @status", nil)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: NamedArgs.RewriteQuery error: %v\n", err)
		os.Exit(1)
	}
	if rewrittenSQL != "SELECT id, email FROM users WHERE username = $1 AND status = $2" {
		fmt.Fprintf(os.Stderr, "FAIL: expected rewritten SQL with placeholders $1 and $2, got: %s\n", rewrittenSQL)
		os.Exit(1)
	}
	if len(args) != 2 || args[0] != "alice" || args[1] != "active" {
		fmt.Fprintf(os.Stderr, "FAIL: unexpected args from NamedArgs: %v\n", args)
		os.Exit(1)
	}

	// Assertion 7: pgx.StrictNamedArgs returns an error when a query parameter is missing
	strictIncomplete := pgx.StrictNamedArgs{
		"limit": 10,
	}
	_, _, err = strictIncomplete.RewriteQuery(ctx, nil, "SELECT id FROM items LIMIT @limit OFFSET @offset", nil)
	if err == nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected error for missing parameter in StrictNamedArgs, got nil\n")
		os.Exit(1)
	}
	if !strings.Contains(err.Error(), "offset") {
		fmt.Fprintf(os.Stderr, "FAIL: expected error to mention 'offset', got: %v\n", err)
		os.Exit(1)
	}

	// Assertion 8: pgx.Identifier sanitizes multi-part SQL identifiers and escapes embedded quotes
	ident := pgx.Identifier{"public", "user\"table"}
	sanitized := ident.Sanitize()
	expectedIdent := `"public"."user""table"`
	if sanitized != expectedIdent {
		fmt.Fprintf(os.Stderr, "FAIL: expected sanitized identifier %s, got: %s\n", expectedIdent, sanitized)
		os.Exit(1)
	}

	fmt.Println("PASS: all contract assertions passed for pkg:golang/github.com/jackc/pgx/v5@v5.10.0")
}