Can't enable wal2json in postgres 12 docker image

Question

I'm trying to enable wal2json in an image extended from postgres:12 image. But i'm getting an error:

postgres=# create extension wal2json;
ERROR:  could not open extension control file "/usr/share/postgresql/12/extension/wal2json.control": No such file or directory

This might be because wal2json is also missing from pg_available_extensions:

postgres=# select * from pg_available_extensions where name ilike '%%json%%';
 name | default_version | installed_version | comment 
------+-----------------+-------------------+---------
(0 rows)

Dockerfile:

FROM postgres:12
RUN apt update && apt install -y postgresql-12-wal2json postgresql-contrib

postgres server logs:

db_1  | 2020-05-10 13:53:04.611 GMT [1] LOG:  database system is ready to accept connections
db_1  | 2020-05-10 13:54:03.587 GMT [83] ERROR:  could not open extension control file "/usr/share/postgresql/12/extension/wal2json.control": No such file or directory
db_1  | 2020-05-10 13:54:03.587 GMT [83] STATEMENT:  create extension wal2json;

the postgresql.conf file has been tweaked to

wal_level = logical     
shared_preload_libraries = 'wal2json'

Any help with getting this working will be appreciated.

Answer 1

2 years later, on postgresql-14 with wal2json. After installing with debezium docker image : https://hub.docker.com/r/debezium/postgres/tags

Which basically does what you did https://github.com/debezium/container-images/blob/023a7da62f802051b15e3991e2a28f8d705e8d40/postgres/14/Dockerfile

I'm able to use the wal2json extension through a repl slot

SELECT * FROM pg_create_logical_replication_slot('testing', 'wal2json')

without activating the extension with a CREATE EXTENSION

A user on the debezium gitter was mind blown by this. I don't know how if it's supposed to work like so; but it does apparently.