feat: add wal2json extension

Signed-off-by: Alper Kanat <me@alperkan.at>

Author: tunix

wal2json/Dockerfile

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+ARG BASE=ghcr.io/cloudnative-pg/postgresql:18-minimal-trixie
+FROM $BASE AS builder
+
+ARG PG_MAJOR
+ARG EXT_VERSION
+
+USER 0
+
+RUN apt-get update && \
+	apt-get install -y --no-install-recommends "postgresql-${PG_MAJOR}-wal2json=${EXT_VERSION}"
+
+FROM scratch
+ARG PG_MAJOR
+
+# Licenses
+COPY --from=builder /usr/share/doc/postgresql-${PG_MAJOR}-wal2json/copyright /licenses/postgresql-${PG_MAJOR}-wal2json/
+
+# Libraries
+COPY --from=builder /usr/lib/postgresql/${PG_MAJOR}/lib/wal2json* /lib/
+
+USER 65532:65532

wal2json/README.md

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+# wal2json
+
+[wal2json](https://github.com/eulerto/wal2json) is an open-source logical decoding
+output plugin for PostgreSQL that converts WAL (Write-Ahead Log) changes to JSON format.
+
+This image provides a convenient way to deploy and manage `wal2json` with
+[CloudNativePG](https://cloudnative-pg.io/).
+
+## Usage
+
+### 1. Add the wal2json plugin image to your Cluster
+
+Define the `wal2json` plugin under the `postgresql.extensions` section of
+your `Cluster` resource. For example:
+
+```yaml
+apiVersion: postgresql.cnpg.io/v1
+kind: Cluster
+metadata:
+  name: cluster-wal2json
+spec:
+  imageName: ghcr.io/cloudnative-pg/postgresql:18-minimal-trixie
+  instances: 1
+
+  storage:
+    size: 1Gi
+
+  postgresql:
+    parameters:
+      wal_level: logical
+
+    extensions:
+    - name: wal2json
+      image:
+        # renovate: suite=trixie-pgdg depName=postgresql-18-wal2json
+        reference: ghcr.io/cloudnative-pg/wal2json:2.6-18-trixie
+```
+
+### 2. Configure logical replication
+
+To use `wal2json`, you need to:
+
+1. Set `wal_level` to `logical` in your PostgreSQL configuration (as shown above)
+2. Create a logical replication slot using the `wal2json` output plugin
+
+Connect to your database and create a replication slot:
+
+```sql
+SELECT * FROM pg_create_logical_replication_slot('wal2json_slot', 'wal2json');
+```
+
+### 3. Use the replication slot
+
+You can now use the replication slot to stream changes in JSON format. For example,
+using `pg_recvlogical`:
+
+```bash
+pg_recvlogical -d your_database -h your_host -U your_user \
+  --slot wal2json_slot --start -f -
+```
+
+### 4. Verify installation
+
+To verify that `wal2json` is available, you can check the available output plugins:
+
+```sql
+SELECT * FROM pg_available_logical_replication_slots;
+```
+
+Or check if the library is loaded:
+
+```sql
+SELECT * FROM pg_show_replication_slots();
+```

wal2json/metadata.hcl

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+metadata = {
+  name                     = "wal2json"
+  sql_name                 = "wal2json"
+  image_name               = "wal2json"
+  shared_preload_libraries = []
+  extension_control_path   = []
+  dynamic_library_path     = []
+  ld_library_path          = []
+  auto_update_os_libs      = false
+
+  versions = {
+    bookworm = {
+      // renovate: suite=bookworm-pgdg depName=postgresql-18-wal2json
+      "18" = "2.6-3.pgdg12+1"
+    }
+    trixie = {
+      // renovate: suite=trixie-pgdg depName=postgresql-18-wal2json
+      "18" = "2.6-3.pgdg13+1"
+    }
+  }
+}