github.com/jackc/pgconn v1.14.3: parse postgresql connection config and inspect pgconn types with pgconn.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 config and inspect pgconn types with pgconn.ParseConfig
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/jackc/pgconn@v1.14.3
Demonstrate these symbols/APIs:
  - pgconn.CommandTag
  - pgconn.Config
  - pgconn.NetworkAddress
  - pgconn.ParseConfig
  - pgconn.PgError
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:bbc8af01bedc2b23564b7028216ce80d15973bcb68c6cc2ccf3ea7129d9e7646","contract":["pgconn.ParseConfig parses PostgreSQL URL connection string with host, port, user, password, and options","pgconn.ParseConfig parses PostgreSQL DSN key-value connection string","pgconn.Config.Copy creates an independent deep copy of runtime parameters","pgconn.NetworkAddress formats TCP hostname and IP address with port correctly","pgconn.CommandTag parses SQL execution tag, command type, and affected rows count","pgconn.PgError formats error message and exposes SQLState code","pgconn.Timeout and pgconn.SafeToRetry evaluate error retryability"],"goal":"parse postgresql connection config and inspect pgconn types with pgconn.ParseConfig","kind":"HOW","packages":["pkg:golang/github.com/jackc/pgconn@v1.14.3"],"schemaVersion":1,"symbols":["pgconn.CommandTag","pgconn.Config","pgconn.NetworkAddress","pgconn.ParseConfig","pgconn.PgError"]},"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/pgconn@v1.14.3"],"schemaVersion":1,"subject":"pkg:golang/github.com/jackc/pgconn@v1.14.3","symbols":["pgconn.CommandTag","pgconn.Config","pgconn.NetworkAddress","pgconn.ParseConfig","pgconn.PgError"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require github.com/jackc/pgconn v1.14.3

require (
	github.com/jackc/chunkreader/v2 v2.0.1 // indirect
	github.com/jackc/pgio v1.0.0 // indirect
	github.com/jackc/pgpassfile v1.0.0 // indirect
	github.com/jackc/pgproto3/v2 v2.3.3 // indirect
	github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a // indirect
	golang.org/x/crypto v0.20.0 // indirect
	golang.org/x/text v0.14.0 // 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/chunkreader/v2 v2.0.0/go.mod h1:odVSm741yZoC3dpHEUXIqA9tQRhFrgOHwnPIn9lDKlk=
github.com/jackc/chunkreader/v2 v2.0.1 h1:i+RDz65UE+mmpjTfyz0MoVTnzeYxroil2G82ki7MGG8=
github.com/jackc/chunkreader/v2 v2.0.1/go.mod h1:odVSm741yZoC3dpHEUXIqA9tQRhFrgOHwnPIn9lDKlk=
github.com/jackc/pgconn v1.14.3 h1:bVoTr12EGANZz66nZPkMInAV/KHD2TxH9npjXXgiB3w=
github.com/jackc/pgconn v1.14.3/go.mod h1:RZbme4uasqzybK2RK5c65VsHxoyaml09lx3tXOcO/VM=
github.com/jackc/pgio v1.0.0 h1:g12B9UwVnzGhueNavwioyEEpAmqMe1E/BN9ES+8ovkE=
github.com/jackc/pgio v1.0.0/go.mod h1:oP+2QK2wFfUWgr+gxjoBH9KGBb31Eio69xUb0w5bYf8=
github.com/jackc/pgmock v0.0.0-20210724152146-4ad1a8207f65 h1:DadwsjnMwFjfWc9y5Wi/+Zz7xoE5ALHsRQlOctkOiHc=
github.com/jackc/pgmock v0.0.0-20210724152146-4ad1a8207f65/go.mod h1:5R2h2EEX+qri8jOWMbJCtaPWkrrNc7OHwsp2TCqp7ak=
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/pgproto3/v2 v2.3.3 h1:1HLSx5H+tXR9pW3in3zaztoEwQYRC9SQaYUHjTSUOag=
github.com/jackc/pgproto3/v2 v2.3.3/go.mod h1:WfJCnwN3HIg9Ish/j3sgWXnAfK8A9Y0bwXYU5xKaEdA=
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 v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
golang.org/x/crypto v0.20.0 h1:jmAMJJZXr5KiCw05dfYK9QnqaqKLYXijU23lsEdcQqg=
golang.org/x/crypto v0.20.0/go.mod h1:Xwo95rrVNIoSMx9wa1JroENMToLWn3RNVrTBpLHgZPQ=
golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
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=

{
  "schemaVersion": 1,
  "goal": "parse postgresql connection config and inspect pgconn types with pgconn.ParseConfig",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/jackc/pgconn@v1.14.3"
  ],
  "symbols": [
    "pgconn.CommandTag",
    "pgconn.Config",
    "pgconn.NetworkAddress",
    "pgconn.ParseConfig",
    "pgconn.PgError"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

package main

import (
	"errors"
	"fmt"
	"os"
	"time"

	"github.com/jackc/pgconn"
)

func main() {
	if err := runTests(); err != nil {
		fmt.Fprintf(os.Stderr, "Contract test failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("All contract tests passed successfully.")
}

func runTests() error {
	// 1. Test ParseConfig with URL format
	urlConnStr := "postgres://sample_user:sample_pass@localhost:5432/sample_db?sslmode=disable&application_name=sample_app&connect_timeout=10"
	cfg1, err := pgconn.ParseConfig(urlConnStr)
	if err != nil {
		return fmt.Errorf("ParseConfig(URL) failed: %w", err)
	}
	if cfg1.Host != "localhost" {
		return fmt.Errorf("cfg1.Host = %q, want 'localhost'", cfg1.Host)
	}
	if cfg1.Port != 5432 {
		return fmt.Errorf("cfg1.Port = %d, want 5432", cfg1.Port)
	}
	if cfg1.User != "sample_user" {
		return fmt.Errorf("cfg1.User = %q, want 'sample_user'", cfg1.User)
	}
	if cfg1.Password != "sample_pass" {
		return fmt.Errorf("cfg1.Password = %q, want 'sample_pass'", cfg1.Password)
	}
	if cfg1.Database != "sample_db" {
		return fmt.Errorf("cfg1.Database = %q, want 'sample_db'", cfg1.Database)
	}
	if cfg1.ConnectTimeout != 10*time.Second {
		return fmt.Errorf("cfg1.ConnectTimeout = %v, want 10s", cfg1.ConnectTimeout)
	}
	if cfg1.RuntimeParams["application_name"] != "sample_app" {
		return fmt.Errorf("cfg1.RuntimeParams['application_name'] = %q, want 'sample_app'", cfg1.RuntimeParams["application_name"])
	}

	// 2. Test ParseConfig with DSN / key-value format
	dsnConnStr := "host=127.0.0.1 port=5433 user=sample_admin password=sample_secret dbname=sample_analytics sslmode=disable application_name=sample_worker"
	cfg2, err := pgconn.ParseConfig(dsnConnStr)
	if err != nil {
		return fmt.Errorf("ParseConfig(DSN) failed: %w", err)
	}
	if cfg2.Host != "127.0.0.1" || cfg2.Port != 5433 || cfg2.User != "sample_admin" || cfg2.Database != "sample_analytics" {
		return fmt.Errorf("cfg2 parsed fields unexpected: %+v", cfg2)
	}
	if cfg2.RuntimeParams["application_name"] != "sample_worker" {
		return fmt.Errorf("cfg2 application_name = %q, want 'sample_worker'", cfg2.RuntimeParams["application_name"])
	}

	// 3. Test Config.Copy creates an independent deep copy of runtime parameters
	copiedCfg := cfg1.Copy()
	if copiedCfg == cfg1 {
		return fmt.Errorf("Config.Copy returned identical pointer")
	}
	if copiedCfg.Host != cfg1.Host || copiedCfg.Port != cfg1.Port || copiedCfg.User != cfg1.User {
		return fmt.Errorf("copiedCfg values do not match original")
	}
	copiedCfg.RuntimeParams["application_name"] = "modified_app"
	if cfg1.RuntimeParams["application_name"] == "modified_app" {
		return fmt.Errorf("modifying copied Config affected original Config RuntimeParams")
	}

	// 4. Test NetworkAddress formats host and port correctly
	netType, addr := pgconn.NetworkAddress("db.example.com", 5432)
	if netType != "tcp" || addr != "db.example.com:5432" {
		return fmt.Errorf("NetworkAddress('db.example.com', 5432) = (%q, %q), want ('tcp', 'db.example.com:5432')", netType, addr)
	}
	netTypeIP, addrIP := pgconn.NetworkAddress("127.0.0.1", 5432)
	if netTypeIP != "tcp" || addrIP != "127.0.0.1:5432" {
		return fmt.Errorf("NetworkAddress('127.0.0.1', 5432) = (%q, %q), want ('tcp', '127.0.0.1:5432')", netTypeIP, addrIP)
	}

	// 5. Test CommandTag inspects SQL execution tag results
	insertTag := pgconn.CommandTag("INSERT 0 42")
	if !insertTag.Insert() || insertTag.RowsAffected() != 42 || insertTag.String() != "INSERT 0 42" {
		return fmt.Errorf("CommandTag('INSERT 0 42') unexpected: Insert=%v, RowsAffected=%d", insertTag.Insert(), insertTag.RowsAffected())
	}
	updateTag := pgconn.CommandTag("UPDATE 7")
	if !updateTag.Update() || updateTag.RowsAffected() != 7 {
		return fmt.Errorf("CommandTag('UPDATE 7') unexpected: Update=%v, RowsAffected=%d", updateTag.Update(), updateTag.RowsAffected())
	}
	deleteTag := pgconn.CommandTag("DELETE 3")
	if !deleteTag.Delete() || deleteTag.RowsAffected() != 3 {
		return fmt.Errorf("CommandTag('DELETE 3') unexpected: Delete=%v, RowsAffected=%d", deleteTag.Delete(), deleteTag.RowsAffected())
	}
	selectTag := pgconn.CommandTag("SELECT 100")
	if !selectTag.Select() || selectTag.RowsAffected() != 100 {
		return fmt.Errorf("CommandTag('SELECT 100') unexpected: Select=%v, RowsAffected=%d", selectTag.Select(), selectTag.RowsAffected())
	}

	// 6. Test PgError formats error message and extracts SQLState
	pgErr := &pgconn.PgError{
		Severity:  "ERROR",
		Code:      "23505",
		Message:   "duplicate key value violates unique constraint",
		Detail:    "Key (id)=(1) already exists.",
		TableName: "items",
	}
	if pgErr.SQLState() != "23505" {
		return fmt.Errorf("PgError.SQLState() = %q, want '23505'", pgErr.SQLState())
	}
	if pgErr.Error() == "" {
		return fmt.Errorf("PgError.Error() returned empty string")
	}

	// 7. Test Timeout and SafeToRetry helper behavior on errors
	if pgconn.Timeout(errors.New("generic error")) {
		return fmt.Errorf("Timeout returned true for non-timeout error")
	}
	if pgconn.SafeToRetry(nil) {
		return fmt.Errorf("SafeToRetry returned true for nil error")
	}

	return nil
}