Migrate from github.com/jackc/pgx to github.com/jackc/pglogrepl (#12)

* Migrate from github.com/jackc/pgx to github.com/jackc/pglogrepl

This commit migrates the PostgreSQL logical replication implementation
from the legacy pgx v3 API to the modern pglogrepl library with pgx/v5.

## Changes

### Dependencies (go.mod)
- Replaced github.com/jackc/pgx v3.6.2+incompatible with:
  - github.com/jackc/pglogrepl v0.0.0-20251213150135-2e8d0df862c1
  - github.com/jackc/pgx/v5 v5.7.4
- Removed obsolete indirect dependencies (cockroachdb/apd, jackc/fake, etc.)

### Main Application (cmd/pgoutbox/init.go)
- Created replicationConn wrapper struct that adapts *pgconn.PgConn to
  the replication interface expected by the listener
- Wrapper implements: CreateReplicationSlot, DropReplicationSlot,
  StartReplication, ReceiveMessage, SendStandbyStatusUpdate, IsAlive, Close
- Updated imports to use pgx/v5 and pglogrepl packages

### Listener (internal/listener/listener.go)
- Changed lsn field type from uint64 to pglogrepl.LSN
- Updated replication interface to use pglogrepl types:
  - CreateReplicationSlot returns pglogrepl.CreateReplicationSlotResult
  - StartReplication uses pglogrepl.LSN and pglogrepl.StartReplicationOptions
  - SendStandbyStatusUpdate uses pglogrepl.StandbyStatusUpdate
  - ReceiveMessage returns raw []byte instead of structured messages
- Rewrote processRawMessage to handle raw byte messages using
  pglogrepl.ParseXLogData and pglogrepl.ParsePrimaryKeepaliveMessage
- Updated SendStandbyStatus and AckWalMessage to take context parameter

### Repository (internal/listener/repository.go)
- Updated to pgx/v5 API (QueryRow instead of QueryRowEx)
- Close now takes context parameter
- IsAlive uses IsClosed() method

### Tests
- Updated all mock implementations for new interface signatures
- Rewrote test helper functions to use pglogrepl types
- Simplified test cases by removing obsolete NewStandbyStatus calls

All listener tests pass.

---------

Signed-off-by: Tamal Saha <tamal@appscode.com>
Signed-off-by: Imtiaz Uddin <imtiaz@appscode.com>
Co-authored-by: Imtiaz Uddin <imtiaz@appscode.com>

Author: tamalsaha

.github/copilot-instructions.md

@@ -0,0 +1,72 @@
+# pgoutbox - AI Coding Instructions
+
+## Architecture & Data Flow
+
+**pgoutbox** captures PostgreSQL changes via logical decoding and publishes to message brokers (NATS, Kafka, RabbitMQ, Google Pub/Sub).
+
+```
+PostgreSQL WAL → pgx replication → Parser.ParseWalMessage() → WAL object → filter → Event → Publisher.Publish() → broker
+```
+
+### Key Components
+- [internal/listener/listener.go](../internal/listener/listener.go) - Replication orchestration, slot/publication lifecycle
+- [internal/listener/transaction/parser.go](../internal/listener/transaction/parser.go) - WAL binary protocol decoding
+- [internal/publisher/](../internal/publisher/) - Broker adapters implementing `eventPublisher` interface
+- [apis/config.go](../apis/config.go) - Config types with Viper loading (env prefix: `WAL_`)
+- [apis/event.go](../apis/event.go) - Event struct with `SubjectName()` for topic construction
+
+## Developer Workflows
+
+```bash
+make build          # Build for current OS/ARCH (Docker containerized)
+make test           # Unit tests with race detector
+make lint           # golangci-lint with gofmt, goimports, unparam
+make ci             # verify + lint + build + unit-tests
+make fmt            # Format source code
+```
+
+All commands run in Docker (`ghcr.io/appscode/golang-dev:1.24`). Output: `bin/pgoutbox-{OS}-{ARCH}`.
+
+**Local PostgreSQL**: `docker/docker-compose.yml` + `docker/scripts/` for test DB setup.
+
+## Critical Patterns
+
+### Interface-Based Mocking
+Listener depends on interfaces (`eventPublisher`, `parser`, `replication`, `repository`). Mock implementations in `*_mock_test.go` files:
+```go
+// internal/listener/listener.go
+type eventPublisher interface {
+    Publish(context.Context, string, *apis.Event) error
+}
+```
+
+### Configuration
+- YAML config + environment overrides (prefix `WAL_`, e.g., `WAL_DATABASE_HOST`)
+- Struct tags: both `mapstructure` and `json` required
+- Publisher types: `nats`, `kafka`, `rabbitmq`, `google_pubsub`
+
+### Topic Naming
+Format: `{publisher.topic}.{publisher.topicPrefix}schemas.{schema}.tables.{table}`
+Override via `listener.topicsMap` in config.
+
+### Logging
+Use `log/slog` with injected `*slog.Logger`:
+```go
+l.log.Debug("message", slog.String("key", value))
+```
+
+## Common Tasks
+
+| Task | Files to Modify |
+|------|-----------------|
+| Add publisher | `internal/publisher/{broker}.go` (implement `eventPublisher`), `cmd/pgoutbox/init.go` |
+| Add filter logic | `apis/config.go` (`FilterStruct`), `internal/listener/transaction/parser.go` |
+| Extend WAL parsing | `internal/listener/transaction/parser.go`, `transaction/data.go` |
+| Add metrics | `apis/metrics.go` (Prometheus counters) |
+
+## Standards
+
+- **License**: Apache 2.0 headers required (see `hack/license/`)
+- **Errors**: Wrap with `fmt.Errorf("context: %w", err)`
+- **Publication name**: Hardcoded as `_pgoutbox_`
+- **Replication slot**: Configured via `listener.slotName`, auto-created on startup

.github/workflows/ci.yml

@@ -1,46 +1,25 @@
-name: CI
+name: ci
 
 on:
-  pull_request:
-    branches:
-      - "*"
   push:
-    branches:
-      - master
-  workflow_dispatch:
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
-  cancel-in-progress: true
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
 
 jobs:
+
   build:
-    name: Build
     runs-on: ubuntu-24.04
     steps:
-      - name: Set up Go 1.24
-        uses: actions/setup-go@v5
-        with:
-          go-version: '1.24'
-        id: go
+    - uses: actions/checkout@v4
 
-      - name: Use Node.js 20.x
-        uses: actions/setup-node@v4
-        with:
-          node-version: '20'
-          check-latest: true
+    - name: Set up Go
+      uses: actions/setup-go@v5
+      with:
+        go-version: '1.25'
 
-      - name: Check out code into the Go module directory
-        uses: actions/checkout@v4
+    - name: Build
+      run: go build -v ./...
 
-      - name: Prepare git
-        env:
-          GITHUB_USER: 1gtm
-          GITHUB_TOKEN: ${{ secrets.LGTM_GITHUB_TOKEN }}
-        run: |
-          set -x
-          git config --global user.name "${GITHUB_USER}"
-          git config --global user.email "${GITHUB_USER}@appscode.com"
-          git config --global \
-            url."https://${GITHUB_USER}:${GITHUB_TOKEN}@github.com".insteadOf \
-            "https://github.com"
+    - name: Test
+      run: go test -v ./...

apis/config_test.go

@@ -39,10 +39,11 @@ func TestConfig_Validate(t *testing.T) {
 					Password: "pass",
 				},
 				Publisher: &PublisherCfg{
-					Type:        "kafka",
-					Address:     "addr",
-					Topic:       "stream",
-					TopicPrefix: "prefix",
+					Type:         "kafka",
+					Address:      "addr",
+					Topic:        "stream",
+					TopicPrefix:  "prefix",
+					NatsCredPath: "/etc/nats/creds/admin.creds",
 				},
 			},
 			wantErr: nil,
@@ -65,13 +66,14 @@ func TestConfig_Validate(t *testing.T) {
 					Password: "pass",
 				},
 				Publisher: &PublisherCfg{
-					Type:        "kafka",
-					Address:     "addr",
-					Topic:       "stream",
-					TopicPrefix: "prefix",
+					Type:         "kafka",
+					Address:      "addr",
+					Topic:        "stream",
+					TopicPrefix:  "prefix",
+					NatsCredPath: "/etc/nats/creds/admin.creds",
 				},
 			},
-			wantErr: errors.New("Listener.RefreshConnection: non zero value required;Listener.SlotName: non zero value required"),
+			wantErr: errors.New("Listener.refreshConnection: non zero value required;Listener.slotName: non zero value required"),
 		},
 		{
 			name: "bad db cfg",
@@ -91,13 +93,14 @@ func TestConfig_Validate(t *testing.T) {
 					Password: "pass",
 				},
 				Publisher: &PublisherCfg{
-					Type:        "kafka",
-					Address:     "addr",
-					Topic:       "stream",
-					TopicPrefix: "prefix",
+					Type:         "kafka",
+					Address:      "addr",
+					Topic:        "stream",
+					TopicPrefix:  "prefix",
+					NatsCredPath: "/etc/nats/creds/admin.creds",
 				},
 			},
-			wantErr: errors.New("Database.Host: non zero value required;Database.Port: non zero value required"),
+			wantErr: errors.New("Database.host: non zero value required;Database.port: non zero value required"),
 		},
 		{
 			name: "empty publisher kind",
@@ -119,11 +122,12 @@ func TestConfig_Validate(t *testing.T) {
 					Password: "pass",
 				},
 				Publisher: &PublisherCfg{
-					Topic:       "stream",
-					TopicPrefix: "prefix",
+					Topic:        "stream",
+					TopicPrefix:  "prefix",
+					NatsCredPath: "/etc/nats/creds/admin.creds",
 				},
 			},
-			wantErr: errors.New("Publisher.Type: non zero value required"),
+			wantErr: errors.New("Publisher.address: non zero value required;Publisher.type: non zero value required"),
 		},
 	}
 

cmd/pgoutbox/init.go

@@ -25,35 +25,83 @@ import (
 	"kubeops.dev/pgoutbox/apis"
 	"kubeops.dev/pgoutbox/internal/publisher"
 
-	"github.com/jackc/pgx"
+	"github.com/jackc/pglogrepl"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
+	"github.com/jackc/pgx/v5/pgproto3"
 	"github.com/nats-io/nats.go"
 	"k8s.io/apimachinery/pkg/util/wait"
 )
 
+// replicationConn wraps pgconn.PgConn to implement the replication interface expected by the listener.
+type replicationConn struct {
+	conn *pgconn.PgConn
+}
+
+func newReplicationConn(conn *pgconn.PgConn) *replicationConn {
+	return &replicationConn{conn: conn}
+}
+
+func (r *replicationConn) CreateReplicationSlot(ctx context.Context, slotName, outputPlugin string) (pglogrepl.CreateReplicationSlotResult, error) {
+	return pglogrepl.CreateReplicationSlot(ctx, r.conn, slotName, outputPlugin, pglogrepl.CreateReplicationSlotOptions{})
+}
+
+func (r *replicationConn) DropReplicationSlot(ctx context.Context, slotName string) error {
+	return pglogrepl.DropReplicationSlot(ctx, r.conn, slotName, pglogrepl.DropReplicationSlotOptions{})
+}
+
+func (r *replicationConn) StartReplication(ctx context.Context, slotName string, startLsn pglogrepl.LSN, options pglogrepl.StartReplicationOptions) error {
+	return pglogrepl.StartReplication(ctx, r.conn, slotName, startLsn, options)
+}
+
+func (r *replicationConn) ReceiveMessage(ctx context.Context) ([]byte, error) {
+	rawMsg, err := r.conn.ReceiveMessage(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	if errMsg, ok := rawMsg.(*pgproto3.ErrorResponse); ok {
+		return nil, fmt.Errorf("received error from postgres: %s", errMsg.Message)
+	}
+
+	msg, ok := rawMsg.(*pgproto3.CopyData)
+	if !ok {
+		return nil, nil
+	}
+
+	return msg.Data, nil
+}
+
+func (r *replicationConn) SendStandbyStatusUpdate(ctx context.Context, status pglogrepl.StandbyStatusUpdate) error {
+	return pglogrepl.SendStandbyStatusUpdate(ctx, r.conn, status)
+}
+
+func (r *replicationConn) IsAlive() bool {
+	return !r.conn.IsClosed()
+}
+
+func (r *replicationConn) Close() error {
+	return r.conn.Close(context.Background())
+}
+
 // initPgxConnections initialise db and replication connections.
-func initPgxConnections(cfg *apis.DatabaseCfg, logger *slog.Logger, timeout time.Duration) (*pgx.Conn, *pgx.ReplicationConn, error) {
+func initPgxConnections(cfg *apis.DatabaseCfg, logger *slog.Logger, timeout time.Duration) (*pgx.Conn, *pgconn.PgConn, error) {
 	var pgConn *pgx.Conn
-	var pgReplicationConn *pgx.ReplicationConn
-
-	pgxConf := pgx.ConnConfig{
-		LogLevel: pgx.LogLevelInfo,
-		Logger:   pgxLogger{logger},
-		Host:     cfg.Host,
-		Port:     cfg.Port,
-		Database: cfg.Name,
-		User:     cfg.User,
-		Password: cfg.Password,
-	}
+	var pgReplConn *pgconn.PgConn
+
+	connString := fmt.Sprintf("host=%s port=%d dbname=%s user=%s password=%s",
+		cfg.Host, cfg.Port, cfg.Name, cfg.User, cfg.Password)
+	replConnString := connString + " replication=database"
 
 	err := wait.PollUntilContextTimeout(context.TODO(), 5*time.Second, timeout, true, func(ctx context.Context) (bool, error) {
 		var err error
-		pgConn, err = pgx.Connect(pgxConf)
+		pgConn, err = pgx.Connect(ctx, connString)
 		if err != nil {
 			logger.Error("db connection:", slog.String("error", err.Error()))
 			return false, nil
 		}
 
-		pgReplicationConn, err = pgx.ReplicationConnect(pgxConf)
+		pgReplConn, err = pgconn.Connect(ctx, replConnString)
 		if err != nil {
 			logger.Error("db replication connection:", slog.String("error", err.Error()))
 			return false, nil
@@ -65,12 +113,12 @@ func initPgxConnections(cfg *apis.DatabaseCfg, logger *slog.Logger, timeout time
 		return nil, nil, fmt.Errorf("wait for db connection: %w", err)
 	}
 
-	return pgConn, pgReplicationConn, nil
+	return pgConn, pgReplConn, nil
 }
 
-func configureReplicaIdentityToFull(pgConn *pgx.Conn, filterTables apis.FilterStruct) error {
+func configureReplicaIdentityToFull(ctx context.Context, pgConn *pgx.Conn, filterTables apis.FilterStruct) error {
 	for table := range filterTables.Tables {
-		_, err := pgConn.Exec(fmt.Sprintf("ALTER TABLE %s REPLICA IDENTITY FULL;", table))
+		_, err := pgConn.Exec(ctx, fmt.Sprintf("ALTER TABLE %s REPLICA IDENTITY FULL;", table))
 		if err != nil {
 			return fmt.Errorf("change replica identity to FULL for table %s: %w", table, err)
 		}
@@ -79,15 +127,6 @@ func configureReplicaIdentityToFull(pgConn *pgx.Conn, filterTables apis.FilterSt
 	return nil
 }
 
-type pgxLogger struct {
-	logger *slog.Logger
-}
-
-// Log DB message.
-func (l pgxLogger) Log(_ pgx.LogLevel, msg string, _ map[string]any) {
-	l.logger.Debug(msg)
-}
-
 type eventPublisher interface {
 	Publish(context.Context, string, *apis.Event) error
 	Close() error

cmd/pgoutbox/main.go

@@ -35,7 +35,7 @@ import (
 
 // GetVersion returns latest git hash of commit.
 func GetVersion() string {
-	var version = "unknown"
+	version := "unknown"
 
 	info, ok := debug.ReadBuildInfo()
 	if ok {
@@ -85,12 +85,12 @@ func main() {
 
 			logger := apis.InitSlog(cfg.Logger, version, false)
 
-			conn, rConn, err := initPgxConnections(cfg.Database, logger, time.Minute*10)
+			pgxConn, pgConn, err := initPgxConnections(cfg.Database, logger, time.Minute*10)
 			if err != nil {
 				return fmt.Errorf("pgx connection: %w", err)
 			}
 
-			if err = configureReplicaIdentityToFull(conn, cfg.Listener.Filter); err != nil {
+			if err = configureReplicaIdentityToFull(ctx, pgxConn, cfg.Listener.Filter); err != nil {
 				return fmt.Errorf("configure replica identity: %w", err)
 			}
 			pub, err := factoryPublisher(ctx, cfg.Publisher, logger)
@@ -107,8 +107,8 @@ func main() {
 			svc := listener.NewWalListener(
 				cfg,
 				logger,
-				listener.NewRepository(conn),
-				rConn,
+				listener.NewRepository(pgxConn),
+				newReplicationConn(pgConn),
 				pub,
 				transaction.NewBinaryParser(logger, binary.BigEndian),
 				apis.NewMetrics(),