refactor: Use SQLConnector.jsonschema_to_sql to map JSON schema typ…

…es to SQL data types (MeltanoLabs#469)

Related:

- meltano/sdk#2732

target_postgres/connector.py

@@ -17,7 +17,7 @@
 import simplejson
 import sqlalchemy as sa
 from singer_sdk import SQLConnector
-from singer_sdk import typing as th
+from singer_sdk.connectors.sql import JSONSchemaToSQL
 from sqlalchemy.dialects.postgresql import ARRAY, BIGINT, BYTEA, JSONB, UUID
 from sqlalchemy.engine import URL
 from sqlalchemy.engine.url import make_url
@@ -30,7 +30,6 @@
     TEXT,
     TIME,
     TIMESTAMP,
-    VARCHAR,
     TypeDecorator,
 )
 from sshtunnel import SSHTunnelForwarder
@@ -39,6 +38,22 @@
     from singer_sdk.connectors.sql import FullyQualifiedName
 
 
+class JSONSchemaToPostgres(JSONSchemaToSQL):
+    """Convert JSON Schema types to Postgres types."""
+
+    def __init__(self, *, content_encoding: bool = True) -> None:
+        """Initialize the JSONSchemaToPostgres instance."""
+        super().__init__()
+        self.content_encoding = content_encoding
+
+    def handle_raw_string(self, schema):
+        """Handle a raw string type."""
+        if self.content_encoding and schema.get("contentEncoding") == "base16":
+            return HexByteString()
+
+        return TEXT()
+
+
 class PostgresConnector(SQLConnector):
     """Sets up SQL Alchemy, and other Postgres related stuff."""
 
@@ -223,7 +238,50 @@ def clone_table(
         new_table.create(bind=connection)
         return new_table
 
-    def to_sql_type(self, jsonschema_type: dict) -> sa.types.TypeEngine:  # type: ignore[override]
+    def _handle_array_type(self, jsonschema: dict) -> ARRAY | JSONB:
+        """Handle array type."""
+        items = jsonschema.get("items")
+        # Case 1: items is a string
+        if isinstance(items, str):
+            return ARRAY(self.to_sql_type({"type": items}))
+
+        # Case 2: items are more complex
+        if isinstance(items, dict):
+            # Case 2.1: items are variants
+            if "type" not in items:
+                return ARRAY(JSONB())
+
+            items_type = items["type"]
+
+            # Case 2.2: items are a single type
+            if isinstance(items_type, str):
+                return ARRAY(self.to_sql_type({"type": items_type}))
+
+            # Case 2.3: items are a list of types
+            if isinstance(items_type, list):
+                return ARRAY(self.to_sql_type({"type": items_type}))
+
+        # Case 3: tuples
+        return ARRAY(JSONB()) if isinstance(items, list) else JSONB()
+
+    @cached_property
+    def jsonschema_to_sql(self) -> JSONSchemaToSQL:
+        """Return a JSONSchemaToSQL instance with custom type handling."""
+        to_sql = JSONSchemaToPostgres(content_encoding=self.interpret_content_encoding)
+        to_sql.fallback_type = TEXT
+        to_sql.register_type_handler("integer", BIGINT)
+        to_sql.register_type_handler("object", JSONB)
+        to_sql.register_type_handler("array", self._handle_array_type)
+        to_sql.register_format_handler("date-time", TIMESTAMP)
+        to_sql.register_format_handler("uuid", UUID)
+        to_sql.register_format_handler("email", TEXT)
+        to_sql.register_format_handler("uri", TEXT)
+        to_sql.register_format_handler("hostname", TEXT)
+        to_sql.register_format_handler("ipv4", TEXT)
+        to_sql.register_format_handler("ipv6", TEXT)
+        return to_sql
+
+    def to_sql_type(self, jsonschema_type: dict) -> sa.types.TypeEngine:
         """Return a JSON Schema representation of the provided type.
 
         By default will call `typing.to_sql_type()`.
@@ -279,7 +337,7 @@ def to_sql_type(self, jsonschema_type: dict) -> sa.types.TypeEngine:  # type: ig
 
         return PostgresConnector.pick_best_sql_type(sql_type_array=sql_type_array)
 
-    def pick_individual_type(self, jsonschema_type: dict):  # noqa: PLR0911
+    def pick_individual_type(self, jsonschema_type: dict):
         """Select the correct sql type assuming jsonschema_type has only a single type.
 
         Args:
@@ -290,47 +348,8 @@ def pick_individual_type(self, jsonschema_type: dict):  # noqa: PLR0911
         """
         if "null" in jsonschema_type["type"]:
             return None
-        if "integer" in jsonschema_type["type"]:
-            return BIGINT()
-        if "object" in jsonschema_type["type"]:
-            return JSONB()
-        if "array" in jsonschema_type["type"]:
-            items = jsonschema_type.get("items")
-            # Case 1: items is a string
-            if isinstance(items, str):
-                return ARRAY(self.to_sql_type({"type": items}))
-
-            # Case 2: items are more complex
-            if isinstance(items, dict):
-                # Case 2.1: items are variants
-                if "type" not in items:
-                    return ARRAY(JSONB())
-
-                items_type = items["type"]
-
-                # Case 2.2: items are a single type
-                if isinstance(items_type, str):
-                    return ARRAY(self.to_sql_type({"type": items_type}))
-
-                # Case 2.3: items are a list of types
-                if isinstance(items_type, list):
-                    return ARRAY(self.to_sql_type({"type": items_type}))
-
-            # Case 3: tuples
-            return ARRAY(JSONB()) if isinstance(items, list) else JSONB()
-
-        # string formats
-        if jsonschema_type.get("format") == "date-time":
-            return TIMESTAMP()
-        if jsonschema_type.get("format") == "uuid":
-            return UUID()
-        if (
-            self.interpret_content_encoding
-            and jsonschema_type.get("contentEncoding") == "base16"
-        ):
-            return HexByteString()
-        individual_type = th.to_sql_type(jsonschema_type)
-        return TEXT() if isinstance(individual_type, VARCHAR) else individual_type
+
+        return self.jsonschema_to_sql.to_sql_type(jsonschema_type)
 
     @staticmethod
     def pick_best_sql_type(sql_type_array: list):