Rename private functions

Rename __cdb_* "private" functions to __ft_*, kind of a namespace to
avoid name clashing.

scripts-available/CDB_PG_Federated_Tables.sql

@@ -0,0 +1,72 @@
+----------------------------------------------------------------------
+-- Federated Tables management functions
+----------------------------------------------------------------------
+
+-- Take a config jsonb and transform it to an input suitable for
+-- _CDB_SetUp_User_PG_FDW_Server
+CREATE OR REPLACE FUNCTION @extschema@.__ft_credentials_to_user_mapping(input_config jsonb)
+RETURNS jsonb
+AS $$
+DECLARE
+    user_mapping jsonb;
+BEGIN
+    user_mapping := json_build_object('user_mapping',
+        jsonb_build_object(
+            'user', input_config->'credentials'->'username',
+            'password', input_config->'credentials'->'password'
+        )
+    );
+    RETURN (input_config - 'credentials')::jsonb || user_mapping;
+END
+$$
+LANGUAGE PLPGSQL IMMUTABLE PARALLEL SAFE;
+
+
+-- Take a config jsonb as input and return it augmented with default
+-- options
+CREATE OR REPLACE FUNCTION @extschema@.__ft_add_default_options(input_config jsonb)
+RETURNS jsonb
+AS $$
+DECLARE
+    default_options jsonb := '{
+        "extensions": "postgis",
+        "updatable": "false",
+        "use_remote_estimate": "true",
+        "fetch_size": "1000"
+    }';
+    server_config jsonb;
+BEGIN
+    server_config := default_options || to_jsonb(input_config->'server');
+    RETURN jsonb_set(input_config, '{server}'::text[], server_config);
+END
+$$
+LANGUAGE PLPGSQL IMMUTABLE PARALLEL SAFE;
+
+
+--
+-- Set up a federated server for later connection of tables/views
+-- E.g:
+-- SELECT cartodb.CDB_SetUp_PG_Federated_Server('amazon', '{
+--    "server": {
+--      "dbname": "testdb",
+--      "host": "myhostname.us-east-2.rds.amazonaws.com",
+--      "port": "5432"
+--    },
+--    "credentials": {
+--      "username": "read_only_user",
+--      "password": "secret"
+--    }
+-- }');
+CREATE OR REPLACE FUNCTION @extschema@.CDB_SetUp_PG_Federated_Server(server_alias text, server_config jsonb)
+RETURNS void
+AS $$
+DECLARE
+    final_config jsonb;
+BEGIN
+    final_config := @extschema@.__ft_credentials_to_user_mapping(
+        @extschema@.__ft_add_default_options(server_config)
+    );
+    PERFORM cartodb._CDB_SetUp_User_PG_FDW_Server(server_alias, final_config::json);
+END
+$$
+LANGUAGE PLPGSQL VOLATILE PARALLEL UNSAFE;

scripts-enabled/255-CDB_PG_Federated_Tables.sql

@@ -0,0 +1 @@
+../scripts-available/CDB_PG_Federated_Tables.sql

test/extension/test.sh

@@ -502,10 +502,11 @@ function test_cdb_querytables_happy_cases() {
     sql postgres 'DROP SCHEMA foo;'
 }
 
-function test_foreign_tables() {
+function setup_fdw_target() {
+    local DATABASE=fdw_target
 
-    DATABASE=fdw_target setup_database
-    DATABASE=fdw_target sql postgres "DO
+    setup_database
+    sql postgres "DO
 \$\$
 BEGIN
    IF NOT EXISTS (
@@ -518,19 +519,36 @@ BEGIN
 END
 \$\$;"
 
-    DATABASE=fdw_target sql postgres 'CREATE SCHEMA test_fdw;'
-    DATABASE=fdw_target sql postgres 'CREATE TABLE test_fdw.foo (a int);'
-    DATABASE=fdw_target sql postgres 'INSERT INTO test_fdw.foo (a) values (42);'
-    DATABASE=fdw_target sql postgres 'CREATE TABLE test_fdw.foo2 (a int);'
-    DATABASE=fdw_target sql postgres 'INSERT INTO test_fdw.foo2 (a) values (42);'
-    DATABASE=fdw_target sql postgres "CREATE USER fdw_user WITH PASSWORD 'foobarino';"
-    DATABASE=fdw_target sql postgres 'GRANT USAGE ON SCHEMA test_fdw TO fdw_user;'
-    DATABASE=fdw_target sql postgres 'GRANT SELECT ON TABLE test_fdw.foo TO fdw_user;'
-    DATABASE=fdw_target sql postgres 'GRANT SELECT ON TABLE test_fdw.foo2 TO fdw_user;'
-    DATABASE=fdw_target sql postgres 'GRANT SELECT ON cdb_tablemetadata_text TO fdw_user;'
+    sql postgres 'CREATE SCHEMA test_fdw;'
+    sql postgres 'CREATE TABLE test_fdw.foo (a int);'
+    sql postgres 'INSERT INTO test_fdw.foo (a) values (42);'
+    sql postgres 'CREATE TABLE test_fdw.foo2 (a int);'
+    sql postgres 'INSERT INTO test_fdw.foo2 (a) values (42);'
+    sql postgres "CREATE USER fdw_user WITH PASSWORD 'foobarino';"
+    sql postgres 'GRANT USAGE ON SCHEMA test_fdw TO fdw_user;'
+    sql postgres 'GRANT SELECT ON TABLE test_fdw.foo TO fdw_user;'
+    sql postgres 'GRANT SELECT ON TABLE test_fdw.foo2 TO fdw_user;'
+    sql postgres 'GRANT SELECT ON cdb_tablemetadata_text TO fdw_user;'
 
-    DATABASE=fdw_target sql postgres "SELECT cdb_tablemetadatatouch('test_fdw.foo'::regclass);"
-    DATABASE=fdw_target sql postgres "SELECT cdb_tablemetadatatouch('test_fdw.foo2'::regclass);"
+    sql postgres "SELECT cdb_tablemetadatatouch('test_fdw.foo'::regclass);"
+    sql postgres "SELECT cdb_tablemetadatatouch('test_fdw.foo2'::regclass);"
+}
+
+function tear_down_fdw_target() {
+    local DATABASE=fdw_target
+
+    sql postgres 'REVOKE USAGE ON SCHEMA test_fdw FROM fdw_user;'
+    sql postgres 'REVOKE SELECT ON test_fdw.foo FROM fdw_user;'
+    sql postgres 'REVOKE SELECT ON test_fdw.foo2 FROM fdw_user;'
+    sql postgres 'REVOKE SELECT ON cdb_tablemetadata_text FROM fdw_user;'
+    sql postgres 'DROP ROLE fdw_user;'
+
+    DATABASE=test_extension sql postgres "select pg_terminate_backend(pid) from pg_stat_activity where datname='fdw_target';"
+    DATABASE=fdw_target tear_down_database
+}
+
+function test_foreign_tables() {
+    setup_fdw_target
 
     # Add PGPORT to conf if it is set
     PORT_SPEC=""
@@ -651,16 +669,82 @@ EOF
     sql cdb_testmember_1 "SELECT cartodb.CDB_SetUp_User_PG_FDW_Table('another_user_defined_test', 'test_fdw', 'foo');"
     sql postgres "SELECT cartodb._CDB_Drop_User_PG_FDW_Server('another_user_defined_test', /* force = */ true)"
 
+    tear_down_fdw_target
+}
+
+function test_federated_tables() {
+    setup_fdw_target
+
+    # Federated server configuration for tests
+    read -d '' federated_server_config <<- EOF
+{
+    "server": {
+        "dbname": "fdw_target",
+        "host": "localhost",
+        "port": ${PGPORT:-5432}
+    },
+    "credentials": {
+        "username": "fdw_user",
+        "password": "foobarino"
+    }
+}
+EOF
+
+    # Unit-test __ft_credentials_to_user_mapping
+    read -d '' expected_user_mapping <<- EOF
+{
+    "server": {
+        "dbname": "fdw_target",
+        "host": "localhost",
+        "port": ${PGPORT:-5432}
+    },
+    "user_mapping": {
+        "user": "fdw_user",
+        "password": "foobarino"
+    }
+}
+EOF
+    sql postgres "SELECT cartodb.__ft_credentials_to_user_mapping('$federated_server_config') = '$expected_user_mapping'" \
+        should 't'
+
+    # Unit-test __ft_add_default_options
+    read -d '' expected_default_options <<- EOF
+{
+    "server": {
+        "dbname": "fdw_target",
+        "host": "localhost",
+        "port": ${PGPORT:-5432},
+        "extensions": "postgis",
+        "updatable": "false",
+        "use_remote_estimate": "true",
+        "fetch_size": "1000"
+    },
+    "credentials": {
+        "username": "fdw_user",
+        "password": "foobarino"
+    }
+}
+EOF
+    sql postgres "SELECT cartodb.__ft_add_default_options('$federated_server_config') = '$expected_default_options'" \
+        should 't'
+
+    # There must be a function with the expected interface
+    sql postgres "SELECT cartodb.CDB_SetUp_PG_Federated_Server('my_server', '$federated_server_config');"
+
+    # It must be possible to use the created server and user mapping
+    # to connect and use a foreign table
+    sql postgres 'GRANT "cdb_fdw_my_server" TO cdb_testmember_1 WITH ADMIN OPTION;'
+    sql cdb_testmember_1 "SELECT cartodb.CDB_SetUp_User_PG_FDW_Table('my_server', 'test_fdw', 'foo');"
+    sql cdb_testmember_1 'SELECT * from "cdb_fdw_my_server".foo;'
+    sql cdb_testmember_1 'SELECT a from "cdb_fdw_my_server".foo LIMIT 1;' should 42
+
+    # It must apply some sensible defaults
+    sql postgres "SELECT srvoptions FROM pg_foreign_server WHERE srvname = 'cdb_fdw_my_server'" \
+        should '{host=localhost,port=5432,dbname=fdw_target,updatable=false,extensions=postgis,fetch_size=1000,use_remote_estimate=true}'
 
     # Tear down
-    DATABASE=fdw_target sql postgres 'REVOKE USAGE ON SCHEMA test_fdw FROM fdw_user;'
-    DATABASE=fdw_target sql postgres 'REVOKE SELECT ON test_fdw.foo FROM fdw_user;'
-    DATABASE=fdw_target sql postgres 'REVOKE SELECT ON test_fdw.foo2 FROM fdw_user;'
-    DATABASE=fdw_target sql postgres 'REVOKE SELECT ON cdb_tablemetadata_text FROM fdw_user;'
-    DATABASE=fdw_target sql postgres 'DROP ROLE fdw_user;'
-
-    sql postgres "select pg_terminate_backend(pid) from pg_stat_activity where datname='fdw_target';"
-    DATABASE=fdw_target tear_down_database
+    sql postgres "SELECT cartodb._CDB_Drop_User_PG_FDW_Server('my_server', /* force = */ true)"
+    tear_down_fdw_target
 }
 
 function test_cdb_catalog_basic_node() {