Repository: meltano/sdk (python)

Issue:
feat: allow target `MAX_SIZE_DEFAULT` to be externally configurable
In the base sink class we define a `MAX_SIZE_DEFAULT` thats set to 10,000 https://github.com/meltano/sdk/blob/e9f2c179fb3a8bcd103546209b4d1c4b8df78ec6/singer_sdk/sinks/core.py#L133. Thats a fine base default and target developers can override it if their target prefers smaller or larger batches.

The thing thats not supported today is the use case where I want to configure a target, say target-postgres, to output more frequently because my tap records are slow/expensive to get so the possibility of waiting until 10k records are retrieved, the batch is old enough to drain, or the sync completes, is undesirable. I might want to drain after every 50 records or so in some case.

One example that came up a while ago is from the map-gpt-embeddings plugin that requests from openai's api. It takes a while to embed all input data and each request costs money so preferably I'd drain as frequently as possible.

cc @edgarrmondragon 

Pull request description:
feat(targets): Targets now accept a `batch_size_rows` setting to configure how many rows are loaded in each record batch
This feature will allow target users the ability to set the batch size used to triggers a drain via the target's meltano confiig.

 ` batch_size_rows: 100000`

When a batch is full and a drain is triggered, the message logged will now state the size of the batch so the users has a visual confirmation that the batch size they configured is being utilized.

The code for this PR was pulled out of PR 1876.

Closes #2155

<!-- readthedocs-preview meltano-sdk start -->
----
📚 Documentation preview 📚: https://meltano-sdk--2248.org.readthedocs.build/en/2248/

<!-- readthedocs-preview meltano-sdk end -->

Patch:
diff --git a/cookiecutter/tap-template/{{cookiecutter.tap_id}}/{{cookiecutter.library_name}}/rest-client.py b/cookiecutter/tap-template/{{cookiecutter.tap_id}}/{{cookiecutter.library_name}}/rest-client.py
index 26c1447c..16ad9d23 100644
--- a/cookiecutter/tap-template/{{cookiecutter.tap_id}}/{{cookiecutter.library_name}}/rest-client.py
+++ b/cookiecutter/tap-template/{{cookiecutter.tap_id}}/{{cookiecutter.library_name}}/rest-client.py
@@ -22,7 +22,7 @@ from singer_sdk.pagination import BaseAPIPaginator  # noqa: TCH002
 from singer_sdk.streams import {{ cookiecutter.stream_type }}Stream
 
 {% elif cookiecutter.auth_method == "Basic Auth" -%}
-from singer_sdk.authenticators import BasicAuthenticator
+from requests.auth import HTTPBasicAuth
 from singer_sdk.helpers.jsonpath import extract_jsonpath
 from singer_sdk.pagination import BaseAPIPaginator  # noqa: TCH002
 from singer_sdk.streams import {{ cookiecutter.stream_type }}Stream
@@ -110,14 +110,13 @@ class {{ cookiecutter.source_name }}Stream({{ cookiecutter.stream_type }}Stream)
 {%- elif cookiecutter.auth_method == "Basic Auth" %}
 
     @property
-    def authenticator(self) -> BasicAuthenticator:
+    def authenticator(self) -> HTTPBasicAuth:
         """Return a new authenticator object.
 
         Returns:
             An authenticator instance.
         """
-        return BasicAuthenticator.create_for_stream(
-            self,
+        return HTTPBasicAuth(
             username=self.config.get("username", ""),
             password=self.config.get("password", ""),
         )
diff --git a/pyproject.toml b/pyproject.toml
index d22e6c69..5de8456b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -249,6 +249,10 @@ jsonl = "singer_sdk.contrib.batch_encoder_jsonl:JSONLinesBatcher"
 parquet = "singer_sdk.contrib.batch_encoder_parquet:ParquetBatcher"
 
 [tool.ruff]
+extend-exclude = [
+    "cookiecutter/*",
+    "*simpleeval*",
+]
 line-length = 88
 src = ["samples", "singer_sdk", "tests"]
 target-version = "py38"
@@ -257,10 +261,6 @@ target-version = "py38"
 docstring-code-format = true
 
 [tool.ruff.lint]
-exclude = [
-    "cookiecutter/*",
-    "*simpleeval*",
-]
 ignore = [
     "ANN101",  # Missing type annotation for `self` in method
     "ANN102",  # Missing type annotation for `cls` in class method
diff --git a/singer_sdk/authenticators.py b/singer_sdk/authenticators.py
index 82e0556b..faf34e85 100644
--- a/singer_sdk/authenticators.py
+++ b/singer_sdk/authenticators.py
@@ -5,6 +5,7 @@ from __future__ import annotations
 import base64
 import math
 import typing as t
+import warnings
 from datetime import timedelta
 from types import MappingProxyType
 from urllib.parse import parse_qs, urlencode, urlsplit, urlunsplit
@@ -297,7 +298,10 @@ class BearerTokenAuthenticator(APIAuthenticatorBase):
 class BasicAuthenticator(APIAuthenticatorBase):
     """Implements basic authentication for REST Streams.
 
-    This Authenticator implements basic authentication by concatinating a
+    .. deprecated:: 0.36.0
+       Use :class:`requests.auth.HTTPBasicAuth` instead.
+
+    This Authenticator implements basic authentication by concatenating a
     username and password then base64 encoding the string. The resulting
     token will be merged with any HTTP headers specified on the stream.
     """
@@ -316,6 +320,13 @@ class BasicAuthenticator(APIAuthenticatorBase):
             password: API password.
         """
         super().__init__(stream=stream)
+        warnings.warn(
+            "BasicAuthenticator is deprecated. Use "
+            "requests.auth.HTTPBasicAuth instead.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+
         credentials = f"{username}:{password}".encode()
         auth_token = base64.b64encode(credentials).decode("ascii")
         auth_credentials = {"Authorization": f"Basic {auth_token}"}
diff --git a/singer_sdk/helpers/_flattening.py b/singer_sdk/helpers/_flattening.py
index 2a3e194d..9dcbf128 100644
--- a/singer_sdk/helpers/_flattening.py
+++ b/singer_sdk/helpers/_flattening.py
@@ -33,7 +33,7 @@ def get_flattening_options(
     Returns:
         A new FlatteningOptions object or None if flattening is disabled.
     """
-    if plugin_config.get("flattening_enabled"):
+    if plugin_config.get("flattening_enabled", False):
         return FlatteningOptions(max_level=int(plugin_config["flattening_max_depth"]))
 
     return None
diff --git a/singer_sdk/helpers/capabilities.py b/singer_sdk/helpers/capabilities.py
index b48d290a..f76400c5 100644
--- a/singer_sdk/helpers/capabilities.py
+++ b/singer_sdk/helpers/capabilities.py
@@ -152,6 +152,13 @@ TARGET_VALIDATE_RECORDS_CONFIG = PropertiesList(
         default=True,
     ),
 ).to_dict()
+TARGET_BATCH_SIZE_ROWS_CONFIG = PropertiesList(
+    Property(
+        "batch_size_rows",
+        IntegerType,
+        description="Maximum number of rows in each batch.",
+    ),
+).to_dict()
 
 
 class TargetLoadMethods(str, Enum):
diff --git a/singer_sdk/sinks/core.py b/singer_sdk/sinks/core.py
index e3535378..f41d3d97 100644
--- a/singer_sdk/sinks/core.py
+++ b/singer_sdk/sinks/core.py
@@ -182,6 +182,11 @@ class Sink(metaclass=abc.ABCMeta):
         self._batch_records_read: int = 0
         self._batch_dupe_records_merged: int = 0
 
+        # Batch full markers
+        self._batch_size_rows: int | None = target.config.get(
+            "batch_size_rows",
+        )
+
         self._validator: BaseJSONSchemaValidator | None = self.get_validator()
 
     @cached_property
@@ -249,15 +254,6 @@ class Sink(metaclass=abc.ABCMeta):
 
     # Size properties
 
-    @property
-    def max_size(self) -> int:
-        """Get max batch size.
-
-        Returns:
-            Max number of records to batch before `is_full=True`
-        """
-        return self.MAX_SIZE_DEFAULT
-
     @property
     def current_size(self) -> int:
         """Get current batch size.
@@ -269,13 +265,40 @@ class Sink(metaclass=abc.ABCMeta):
 
     @property
     def is_full(self) -> bool:
-        """Check against size limit.
+        """Check against the batch size limit.
 
         Returns:
             True if the sink needs to be drained.
         """
         return self.current_size >= self.max_size
 
+    @property
+    def batch_size_rows(self) -> int | None:
+        """The maximum number of rows a batch can accumulate before being processed.
+
+        Returns:
+            The max number of rows or None if not set.
+        """
+        return self._batch_size_rows
+
+    @property
+    def max_size(self) -> int:
+        """Get max batch size.
+
+        Returns:
+            Max number of records to batch before `is_full=True`
+
+        .. versionchanged:: 0.36.0
+           This property now takes into account the
+           :attr:`~singer_sdk.Sink.batch_size_rows` attribute and the corresponding
+           ``batch_size_rows`` target setting.
+        """
+        return (
+            self.batch_size_rows
+            if self.batch_size_rows is not None
+            else self.MAX_SIZE_DEFAULT
+        )
+
     # Tally methods
 
     @t.final
diff --git a/singer_sdk/target_base.py b/singer_sdk/target_base.py
index 5a78bf36..3c0d3723 100644
--- a/singer_sdk/target_base.py
+++ b/singer_sdk/target_base.py
@@ -18,6 +18,7 @@ from singer_sdk.helpers._classproperty import classproperty
 from singer_sdk.helpers.capabilities import (
     ADD_RECORD_METADATA_CONFIG,
     BATCH_CONFIG,
+    TARGET_BATCH_SIZE_ROWS_CONFIG,
     TARGET_HARD_DELETE_CONFIG,
     TARGET_LOAD_METHOD_CONFIG,
     TARGET_SCHEMA_CONFIG,
@@ -363,8 +364,9 @@ class Target(PluginBase, SingerReader, metaclass=abc.ABCMeta):
 
             if sink.is_full:
                 self.logger.info(
-                    "Target sink for '%s' is full. Draining...",
+                    "Target sink for '%s' is full. Current size is '%s'. Draining...",
                     sink.stream_name,
+                    sink.current_size,
                 )
                 self.drain_one(sink)
 
@@ -610,6 +612,7 @@ class Target(PluginBase, SingerReader, metaclass=abc.ABCMeta):
 
         _merge_missing(ADD_RECORD_METADATA_CONFIG, config_jsonschema)
         _merge_missing(TARGET_LOAD_METHOD_CONFIG, config_jsonschema)
+        _merge_missing(TARGET_BATCH_SIZE_ROWS_CONFIG, config_jsonschema)
 
         capabilities = cls.capabilities
 


Test patch:
diff --git a/tests/core/rest/test_authenticators.py b/tests/core/rest/test_authenticators.py
index 7e1da91e..d95d69ed 100644
--- a/tests/core/rest/test_authenticators.py
+++ b/tests/core/rest/test_authenticators.py
@@ -21,7 +21,11 @@ from cryptography.hazmat.primitives.serialization import (
 )
 from requests.auth import HTTPProxyAuth, _basic_auth_str
 
-from singer_sdk.authenticators import OAuthAuthenticator, OAuthJWTAuthenticator
+from singer_sdk.authenticators import (
+    BasicAuthenticator,
+    OAuthAuthenticator,
+    OAuthJWTAuthenticator,
+)
 
 if t.TYPE_CHECKING:
     import requests_mock
@@ -218,3 +222,13 @@ def test_requests_library_auth(rest_tap: Tap):
 
     assert isinstance(stream.authenticator, HTTPProxyAuth)
     assert r.headers["Proxy-Authorization"] == _basic_auth_str("username", "password")
+
+
+def test_basic_auth_deprecation_warning(rest_tap: Tap):
+    """Validate that a warning is emitted when using BasicAuthenticator."""
+    stream: RESTStream = rest_tap.streams["some_stream"]
+    with pytest.deprecated_call(match="BasicAuthenticator is deprecated") as recorder:
+        BasicAuthenticator(stream=stream, username="username", password="password")  # noqa: S106
+
+    assert len(recorder.list) == 1
+    assert recorder.list[0].filename.endswith("test_authenticators.py")
diff --git a/tests/core/targets/test_target_sql.py b/tests/core/targets/test_target_sql.py
index fd71c0ae..e47845a7 100644
--- a/tests/core/targets/test_target_sql.py
+++ b/tests/core/targets/test_target_sql.py
@@ -46,5 +46,9 @@ def test_target_about_info(
         pass
 
     about = MyTarget._get_about_info()
-    default_settings = {"add_record_metadata", "load_method"}
+    default_settings = {
+        "add_record_metadata",
+        "load_method",
+        "batch_size_rows",
+    }
     assert set(about.settings["properties"]) == expected_settings | default_settings
diff --git a/tests/core/test_target_base.py b/tests/core/test_target_base.py
index eaff6d6a..f9bcdb87 100644
--- a/tests/core/test_target_base.py
+++ b/tests/core/test_target_base.py
@@ -77,6 +77,7 @@ def test_target_about_info():
     assert "flattening_max_depth" in about.settings["properties"]
     assert "batch_config" in about.settings["properties"]
     assert "add_record_metadata" in about.settings["properties"]
+    assert "batch_size_rows" in about.settings["properties"]
 
 
 def test_sql_get_sink():
@@ -142,3 +143,40 @@ def test_add_sqlsink_and_get_sink():
         target.get_sink(
             "bar",
         )
+
+
+def test_batch_size_rows_and_max_size():
+    input_schema_1 = {
+        "properties": {
+            "id": {
+                "type": ["string", "null"],
+            },
+            "col_ts": {
+                "format": "date-time",
+                "type": ["string", "null"],
+            },
+        },
+    }
+    key_properties = []
+    target_default = TargetMock()
+    sink_default = BatchSinkMock(
+        target=target_default,
+        stream_name="foo",
+        schema=input_schema_1,
+        key_properties=key_properties,
+    )
+    target_set = TargetMock(config={"batch_size_rows": 100000})
+    sink_set = BatchSinkMock(
+        target=target_set,
+        stream_name="bar",
+        schema=input_schema_1,
+        key_properties=key_properties,
+    )
+    assert sink_default.stream_name == "foo"
+    assert sink_default._batch_size_rows is None
+    assert sink_default.batch_size_rows is None
+    assert sink_default.max_size == 10000
+    assert sink_set.stream_name == "bar"
+    assert sink_set._batch_size_rows == 100000
+    assert sink_set.batch_size_rows == 100000
+    assert sink_set.max_size == 100000