Fix docs generating for cross-db sources (#2)

Co-authored-by: kostkaw <wojciech.kostka@contractors.roche.com>

core/dbt/adapters/base/relation.py

@@ -433,13 +433,14 @@ class SchemaSearchMap(Dict[InformationSchema, Set[Optional[str]]]):
             for schema in schemas:
                 yield information_schema_name, schema
 
-    def flatten(self):
+    def flatten(self, allow_multiple_databases: bool=False):
         new = self.__class__()
 
-        # make sure we don't have duplicates
-        seen = {r.database.lower() for r in self if r.database}
-        if len(seen) > 1:
-            dbt.exceptions.raise_compiler_error(str(seen))
+        # make sure we don't have multiple databases if allow_multiple_databases is set to False
+        if not allow_multiple_databases:
+            seen = {r.database.lower() for r in self if r.database}
+            if len(seen) > 1:
+                dbt.exceptions.raise_compiler_error(str(seen))
 
         for information_schema_name, schema in self.search():
             path = {

plugins/postgres/dbt/adapters/postgres/impl.py

@@ -112,7 +112,7 @@ class PostgresAdapter(SQLAdapter):
                 self.cache.add_link(referenced, dependent)
 
     def _get_catalog_schemas(self, manifest):
-        # postgres/redshift only allow one database (the main one)
+        # postgres only allow one database (the main one)
         schemas = super()._get_catalog_schemas(manifest)
         try:
             return schemas.flatten()

plugins/redshift/dbt/adapters/redshift/connections.py

@@ -49,6 +49,7 @@ class RedshiftCredentials(PostgresCredentials):
     keepalives_idle: int = 240
     autocreate: bool = False
     db_groups: List[str] = field(default_factory=list)
+    ra3_node: Optional[bool] = False
 
     @property
     def type(self):

plugins/redshift/dbt/adapters/redshift/impl.py

@@ -1,11 +1,14 @@
 from dataclasses import dataclass
 from typing import Optional
 from dbt.adapters.base.impl import AdapterConfig
+from dbt.adapters.sql import SQLAdapter
+from dbt.adapters.base.meta import available
 from dbt.adapters.postgres import PostgresAdapter
 from dbt.adapters.redshift import RedshiftConnectionManager
 from dbt.adapters.redshift import RedshiftColumn
 from dbt.adapters.redshift import RedshiftRelation
 from dbt.logger import GLOBAL_LOGGER as logger  # noqa
+import dbt.exceptions
 
 
 @dataclass
@@ -16,7 +19,7 @@ class RedshiftConfig(AdapterConfig):
     bind: Optional[bool] = None
 
 
-class RedshiftAdapter(PostgresAdapter):
+class RedshiftAdapter(PostgresAdapter, SQLAdapter):
     Relation = RedshiftRelation
     ConnectionManager = RedshiftConnectionManager
     Column = RedshiftColumn
@@ -57,3 +60,30 @@ class RedshiftAdapter(PostgresAdapter):
     @classmethod
     def convert_time_type(cls, agate_table, col_idx):
         return "varchar(24)"
+
+    @available
+    def verify_database(self, database):
+        if database.startswith('"'):
+            database = database.strip('"')
+        expected = self.config.credentials.database
+        ra3_node = self.config.credentials.ra3_node
+    
+        if database.lower() != expected.lower() and not ra3_node:
+            raise dbt.exceptions.NotImplementedException(
+               'Cross-db references allowed only in RA3.* node. ({} vs {})'
+               .format(database, expected)
+            )
+        # return an empty string on success so macros can call this
+        return ''
+
+    def _get_catalog_schemas(self, manifest):
+        # redshift(besides ra3) only allow one database (the main one)
+        schemas = super(SQLAdapter, self)._get_catalog_schemas(manifest)
+        try:
+            return schemas.flatten(allow_multiple_databases=self.config.credentials.ra3_node)
+        except dbt.exceptions.RuntimeException as exc:
+            dbt.exceptions.raise_compiler_error(
+                'Cross-db references not allowed in adapter {}: Got {}'.format(
+                    self.type(), exc.msg
+                )
+            )