CREATE EXTENSION etcd_fdw;

CREATE FOREIGN DATA WRAPPER etcd_fdw
  HANDLER etcd_fdw_handler
  VALIDATOR etcd_fdw_validator;

-- Basic connection
CREATE SERVER etcd_plain
  FOREIGN DATA WRAPPER etcd_fdw
  OPTIONS (connstr '127.0.0.1:2379');

-- Production etcd with authentication and SSL
CREATE SERVER etcd FOREIGN DATA WRAPPER etcd_fdw OPTIONS (
    connstr '127.0.0.1:2379',
    username 'root',
    password 'Etcd.Root',
    ssl_ca '/pg/cert/ca.crt',
    ssl_cert '/pg/cert/server.crt',
    ssl_key '/pg/cert/server.key'
);

-- Basic table mapping all keys
CREATE FOREIGN TABLE etcd_kv (key TEXT, value TEXT) SERVER etcd OPTIONS (rowid_column 'key');

-- Table with prefix filter (only keys starting with '/config/')
CREATE FOREIGN TABLE etcd_config (key TEXT, value TEXT)
  SERVER etcd OPTIONS (rowid_column 'key', prefix '/config/');

-- Read all keys
SELECT * FROM etcd_kv;

-- Filter by key pattern (pushdown supported)
SELECT * FROM etcd_kv WHERE key LIKE '/app/%';

-- Range query
SELECT * FROM etcd_kv WHERE key >= '/a' AND key < '/b';

-- Insert new key
INSERT INTO etcd_kv (key, value) VALUES ('/mykey', 'myvalue');

-- Delete key
DELETE FROM etcd_kv WHERE key = '/mykey';

# Insert via etcdctl
etcdctl put '/config/db_pool_size' '20'

-- Instantly visible in PostgreSQL
SELECT * FROM etcd_config;
     key               | value
-----------------------+-------
 /config/db_pool_size  | 20
(1 row)