initial commit

.editorconfig

@@ -0,0 +1,27 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 4
+tab_width = 4
+indent_style = space
+insert_final_newline = false
+max_line_length = 120
+trim_trailing_whitespace = true
+
+[*.go]
+indent_style = tab
+ij_smart_tabs = true
+ij_go_GROUP_CURRENT_PROJECT_IMPORTS = true
+ij_go_group_stdlib_imports = true
+ij_go_import_sorting = goimports
+ij_go_local_group_mode = project
+ij_go_move_all_imports_in_one_declaration = true
+ij_go_move_all_stdlib_imports_in_one_group = true
+ij_go_remove_redundant_import_aliases = true
+
+[*.{yml,yaml}]
+indent_size = 2
+tab_width = 2
+insert_final_newline = true

.gitignore

@@ -0,0 +1,2 @@
+out/
+.idea/

Dockerfile

@@ -0,0 +1,26 @@
+FROM docker.io/golang:1.24-alpine AS builder
+
+ENV CGO_ENABLED=0
+
+WORKDIR /src
+
+RUN \
+    --mount=type=cache,target=/go/pkg/mod \
+    --mount=type=bind,source=./go.mod,target=./go.mod,rw=false \
+    --mount=type=bind,source=./go.sum,target=./go.sum,rw=false \
+    go mod download
+
+COPY . ./
+
+RUN --mount=type=cache,target=/root/.cache/go-build \
+    --mount=type=cache,target=/go/pkg/mod \
+    mkdir -p ./out && \
+    go build -o ./out/pg_v_man -trimpath -ldflags '-s -w' main.go
+
+FROM gcr.io/distroless/static:nonroot
+
+WORKDIR /app
+
+COPY --from=builder /src/out/pg_v_man ./
+
+ENTRYPOINT ["/app/pg_v_man"]

README.md

@@ -0,0 +1,14 @@
+# pg_v_man
+
+## Getting started
+
+To get started, simply start the Docker Compose stack:
+
+```bash
+docker compose up
+```
+
+You can then open the [RabbitMQ management UI](http://localhost:15672) and watch messages coming in in the `letterbox` queue whenever you manipulate any data in the database.
+The database port is by default 5432 (as always) and credentials can be found in the [compose.yml](./compose.yml).
+
+Right now no pgAdmin/cloud-beaver or anything are part of the stack, feel free to use whatever Postgres tool you prefer :).

assets/db/01_init.sql

@@ -0,0 +1,59 @@
+CREATE PUBLICATION v_man_1 FOR ALL TABLES;
+
+create extension pgcrypto;
+
+create table users (
+    id bigint primary key generated always as identity,
+    username text not null unique,
+    email text not null unique,
+    password_hash text not null
+);
+
+create table categories (
+    id bigint primary key generated always as identity,
+    name text not null unique
+);
+
+create table lists (
+    id bigint primary key generated always as identity,
+    user_id bigint not null references users (id),
+    name text not null
+);
+
+create table tasks (
+    id bigint primary key generated always as identity,
+    list_id bigint not null references lists (id),
+    category_id bigint references categories (id),
+    title text not null,
+    description text,
+    due_date date,
+    priority int,
+    completed boolean default false
+);
+
+INSERT INTO
+    users (username, email, password_hash)
+VALUES
+    (
+        'ted.tester',
+        'ted.tester@example.com',
+        crypt ('password', gen_salt ('bf'))
+    );
+
+INSERT INTO
+    categories (name)
+VALUES
+    ('Groceries'),
+    ('Work'),
+    ('Personal'),
+    ('Other');
+
+INSERT INTO
+    public.lists (user_id, name)
+VALUES
+    (1, 'Groceries');
+
+INSERT INTO
+    public.tasks (list_id, category_id, title)
+VALUES
+    (1, 1, 'Orange Juice');

assets/rabbitmq/definitions.json

@@ -0,0 +1,80 @@
+{
+    "rabbit_version": "4.0.5",
+    "rabbitmq_version": "4.0.5",
+    "product_name": "RabbitMQ",
+    "product_version": "4.0.5",
+    "rabbitmq_definition_format": "cluster",
+    "original_cluster_name": "rabbit@553990bf8169",
+    "explanation": "Definitions of cluster 'rabbit@553990bf8169'",
+    "users": [
+        {
+            "name": "v_man",
+            "password_hash": "ASzCoAwdiANYvE0ySlYTw76+1u6Vda24cyafLJfSb8eiVmKp",
+            "hashing_algorithm": "rabbit_password_hashing_sha256",
+            "tags": ["administrator"],
+            "limits": {}
+        }
+    ],
+    "vhosts": [
+        {
+            "name": "/",
+            "description": "Default virtual host",
+            "metadata": {
+                "description": "Default virtual host",
+                "tags": [],
+                "default_queue_type": "classic"
+            },
+            "tags": [],
+            "default_queue_type": "classic"
+        }
+    ],
+    "permissions": [
+        {
+            "user": "v_man",
+            "vhost": "/",
+            "configure": ".*",
+            "write": ".*",
+            "read": ".*"
+        }
+    ],
+    "topic_permissions": [],
+    "parameters": [],
+    "global_parameters": [
+        { "name": "cluster_tags", "value": [] },
+        {
+            "name": "internal_cluster_id",
+            "value": "rabbitmq-cluster-id-zBQKaZR5QrD8CTz1RhYHag"
+        }
+    ],
+    "policies": [],
+    "queues": [
+        {
+            "name": "letterbox",
+            "vhost": "/",
+            "durable": true,
+            "auto_delete": false,
+            "arguments": { "x-max-length": 1000, "x-queue-type": "classic" }
+        }
+    ],
+    "exchanges": [
+        {
+            "name": "pg_v_man",
+            "vhost": "/",
+            "type": "topic",
+            "durable": true,
+            "auto_delete": false,
+            "internal": false,
+            "arguments": {}
+        }
+    ],
+    "bindings": [
+        {
+            "source": "pg_v_man",
+            "vhost": "/",
+            "destination": "letterbox",
+            "destination_type": "queue",
+            "routing_key": "*",
+            "arguments": {}
+        }
+    ]
+}

assets/rabbitmq/enabled_plugins

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+[rabbitmq_management,rabbitmq_prometheus].

assets/rabbitmq/rabbitmq.conf

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+default_user = $(RABBITMQ_DEFAULT_USER)
+default_pass = $(RABBITMQ_DEFAULT_PASS)
+
+definitions.import_backend = local_filesystem
+definitions.local.path = /etc/rabbitmq/definitions.json
+
+log.console = true

cmd/app.go

@@ -0,0 +1,59 @@
+package cmd
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log/slog"
+	"os"
+
+	"github.com/alecthomas/kong"
+
+	"code.icb4dc0.de/prskr/pg_v_man/infrastructure/config"
+	"code.icb4dc0.de/prskr/pg_v_man/infrastructure/db"
+	"code.icb4dc0.de/prskr/pg_v_man/infrastructure/rabbitmq"
+)
+
+func RunApp(ctx context.Context) error {
+	var app App
+
+	return kong.Parse(
+		&app,
+		kong.Name("replication-emitter"),
+		kong.BindTo(ctx, (*context.Context)(nil)),
+	).Run()
+}
+
+type App struct {
+	Logging  config.Logging  `embed:"" prefix:"logging."`
+	DB       config.DB       `embed:"" prefix:"db."`
+	RabbitMQ config.RabbitMQ `embed:"" prefix:"rabbitmq."`
+}
+
+func (a *App) Run(ctx context.Context) (err error) {
+	publisher, err := rabbitmq.NewPublishingEventConsumer(ctx, a.RabbitMQ)
+	if err != nil {
+		return fmt.Errorf("could not create publishing event consumer: %w", err)
+	}
+
+	replClient, err := db.NewReplicationClient(ctx, a.DB, publisher)
+	if err != nil {
+		return fmt.Errorf("could not create replication client: %w", err)
+	}
+
+	defer func() {
+		err = errors.Join(err, replClient.Close(context.Background()))
+	}()
+
+	return replClient.Receive(ctx)
+}
+
+func (a *App) AfterApply(kongCtx *kong.Context) error {
+	defaultLogger := slog.New(slog.NewJSONHandler(os.Stderr, a.Logging.Options()))
+
+	slog.SetDefault(defaultLogger)
+
+	kongCtx.Bind(defaultLogger)
+
+	return nil
+}

compose.yml

@@ -0,0 +1,70 @@
+services:
+  pg_v_man:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    environment:
+      DB_CONNECTION_STRING: postgresql://postgres:postgres@postgres:5432/postgres?replication=database
+      DB_PUBLICATION: v_man_1
+      RABBITMQ_CONNECTION_STRING: amqp://v_man:ies6ohF8@rabbitmq:5672/
+    restart: always
+    depends_on:
+      - rabbitmq
+      - postgres
+
+  postgres:
+    image: postgres:17.3
+    command:
+      - "postgres"
+      - "-c"
+      - "wal_level=logical"
+    ports:
+      - target: 5432
+        published: 5432
+        protocol: tcp
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_DB: postgres
+    volumes:
+      - type: bind
+        source: ./assets/db
+        target: /docker-entrypoint-initdb.d
+      - type: volume
+        source: postgres-data
+        target: /var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+  rabbitmq:
+    image: rabbitmq:4-management-alpine
+    ports:
+      - target: 5672
+        published: 5672
+        protocol: tcp
+      - target: 15672
+        published: 15672
+        protocol: tcp
+    environment:
+      RABBITMQ_DEFAULT_USER: v_man
+      RABBITMQ_DEFAULT_PASS: ies6ohF8
+      RABBITMQ_DEFAULT_VHOST: /
+    volumes:
+      - type: bind
+        source: ./assets/rabbitmq
+        target: /etc/rabbitmq
+      - type: volume
+        source: rabbitmq-data
+        target: /var/lib/rabbitmq
+    healthcheck:
+      test: rabbitmq-diagnostics -q ping
+      interval: 30s
+      timeout: 25s
+      retries: 3
+
+volumes:
+  rabbitmq-data:
+  postgres-data:

core/domain/repl_event.go

@@ -0,0 +1,44 @@
+package domain
+
+type EventType string
+
+func (e EventType) String() string {
+	return string(e)
+}
+
+const (
+	EventTypeInsert   EventType = "INSERT"
+	EventTypeUpdate   EventType = "UPDATE"
+	EventTypeDelete   EventType = "DELETE"
+	EventTypeTruncate EventType = "TRUNCATE"
+)
+
+func NewValues() *Values {
+	return &Values{
+		Key:  make(map[string]any),
+		Data: make(map[string]any),
+	}
+}
+
+func (v *Values) AddValue(partOfKey bool, key string, value any) {
+	if partOfKey {
+		v.Key[key] = value
+	} else {
+		v.Data[key] = value
+	}
+}
+
+type Values struct {
+	Key  map[string]any
+	Data map[string]any
+}
+
+type ReplicationEvent struct {
+	EventType     EventType `json:"eventType"`
+	TransactionId uint32    `json:"transactionId"`
+	DBName        string    `json:"dbName"`
+	Namespace     string    `json:"namespace"`
+	Relation      string    `json:"relation"`
+	NewValues     *Values   `json:"newValues,omitempty"`
+	OldValues     *Values   `json:"oldValues,omitempty"`
+}

core/ports/repl_event_consumer.go

@@ -0,0 +1,11 @@
+package ports
+
+import (
+	"context"
+
+	"code.icb4dc0.de/prskr/pg_v_man/core/domain"
+)
+
+type ReplicationEventConsumer interface {
+	OnDataChange(ctx context.Context, ev domain.ReplicationEvent) error
+}

go.mod

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+module code.icb4dc0.de/prskr/pg_v_man
+
+go 1.24
+
+toolchain go1.24.0
+
+require (
+	github.com/alecthomas/kong v0.9.0
+	github.com/google/uuid v1.6.0
+	github.com/jackc/pglogrepl v0.0.0-20240307033717-828fbfe908e9
+	github.com/jackc/pgx/v5 v5.6.0
+	github.com/wagslane/go-rabbitmq v0.13.0
+)
+
+require (
+	github.com/jackc/pgio v1.0.0 // indirect
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
+	github.com/rabbitmq/amqp091-go v1.10.0 // indirect
+	golang.org/x/crypto v0.24.0 // indirect
+	golang.org/x/text v0.16.0 // indirect
+)

go.sum

@@ -0,0 +1,48 @@
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