Encapsulate configuration functions in a class

Why these changes are being introduced:
* Streamline logging configuration and environment variable management

How this addresses that need:
* Create Config class
   * Clearly identify required vs. optional env vars
* Update dependent modules to use Config
   * Replace os.getenv() calls with Config.<ENV-VAR>
* Update unit tests in test_config

Side effects of this change:
* None

harvester/cli.py

@@ -10,11 +10,13 @@
 import click
 from sickle.oaiexceptions import NoRecordsMatch
 
-from harvester.config import configure_logger, configure_sentry
+from harvester.config import Config
 from harvester.oai import OAIClient, write_records, write_sets
 
 logger = logging.getLogger(__name__)
 
+CONFIG = Config()
+
 
 @click.group()
 @click.option(
@@ -40,10 +42,9 @@ def main(ctx: click.Context, host: str, output_file: str, verbose: bool) -> None
     ctx.obj["START_TIME"] = perf_counter()
     ctx.obj["HOST"] = host
     ctx.obj["OUTPUT_FILE"] = output_file
-
-    root_logger = logging.getLogger()
-    logger.info(configure_logger(root_logger, verbose))
-    logger.info(configure_sentry())
+    logger.info(CONFIG.configure_logger(verbose))
+    logger.info(CONFIG.configure_sentry())
+    CONFIG.check_required_env_vars()
 
 
 @main.command()

harvester/config.py

@@ -3,6 +3,7 @@
 """harvester.config module."""
 import logging
 import os
+from typing import Any
 
 import sentry_sdk
 
@@ -12,30 +13,60 @@
 MAX_ALLOWED_ERRORS = 10
 
 
-def configure_logger(logger: logging.Logger, verbose: bool) -> str:
-    if verbose:
-        logging.basicConfig(
-            format="%(asctime)s %(levelname)s %(name)s.%(funcName)s() line %(lineno)d: "
-            "%(message)s"
-        )
-        logger.setLevel(logging.DEBUG)
+class Config:
+    REQUIRED_ENV_VARS = ("WORKSPACE", "SENTRY_DSN")
+    OPTIONAL_ENV_VARS = ("RECORD_SKIP_LIST", "STATUS_UPDATE_INTERVAL")
+
+    def __init__(self, logger: logging.Logger | None = None):
+        """Set root logger as default when creating class instance."""
+        if logger is None:
+            self.logger = logging.getLogger()
+        else:
+            self.logger = logger
+
+    def check_required_env_vars(self) -> None:
+        """Method to raise exception if required env vars not set."""
+        missing_vars = [var for var in self.REQUIRED_ENV_VARS if not os.getenv(var)]
+        if missing_vars:
+            message = f"Missing required environment variables: {', '.join(missing_vars)}"
+            raise OSError(message)
+
+    def configure_logger(self, verbose: bool) -> str:
         for handler in logging.root.handlers:
-            handler.addFilter(logging.Filter("harvester"))
-    else:
-        logging.basicConfig(
-            format=("%(asctime)s %(levelname)s %(name)s.%(funcName)s(): %(message)s")
+            handler.filters.clear()
+        if verbose:
+            logging.basicConfig(
+                format="%(asctime)s %(levelname)s %(name)s.%(funcName)s() "
+                "line %(lineno)d: %(message)s"
+            )
+            self.logger.setLevel(logging.DEBUG)
+            for handler in logging.root.handlers:
+                handler.addFilter(logging.Filter("harvester"))
+        else:
+            logging.basicConfig(
+                format=("%(asctime)s %(levelname)s %(name)s.%(funcName)s(): %(message)s")
+            )
+            self.logger.setLevel(logging.INFO)
+        return (
+            f"Logger '{self.logger.name}' configured with level="
+            f"{logging.getLevelName(self.logger.getEffectiveLevel())}"
         )
-        logger.setLevel(logging.INFO)
-    return (
-        f"Logger '{logger.name}' configured with level="
-        f"{logging.getLevelName(logger.getEffectiveLevel())}"
-    )
-
-
-def configure_sentry() -> str:
-    env = os.getenv("WORKSPACE")
-    sentry_dsn = os.getenv("SENTRY_DSN")
-    if sentry_dsn and sentry_dsn.lower() != "none":
-        sentry_sdk.init(sentry_dsn, environment=env)
-        return f"Sentry DSN found, exceptions will be sent to Sentry with env={env}"
-    return "No Sentry DSN found, exceptions will not be sent to Sentry"
+
+    def configure_sentry(self) -> str:
+        sentry_dsn = self.SENTRY_DSN
+        if sentry_dsn and sentry_dsn.lower() != "none":
+            sentry_sdk.init(sentry_dsn, environment=self.WORKSPACE)
+            return (
+                "Sentry DSN found, exceptions will be sent to Sentry with env="
+                f"{self.WORKSPACE}"
+            )
+        return "No Sentry DSN found, exceptions will not be sent to Sentry"
+
+    def __getattr__(self, name: str) -> Any:  # noqa: ANN401
+        """Provide dot notation access to configurations and env vars on this class."""
+        if name in self.REQUIRED_ENV_VARS or name in self.OPTIONAL_ENV_VARS:
+            if name == "STATUS_UPDATE_INTERVAL":
+                return os.getenv(name, "1000")
+            return os.getenv(name)
+        message = f"'{name}' not a valid configuration variable"
+        raise AttributeError(message)

harvester/oai.py

@@ -4,7 +4,6 @@
 
 import json
 import logging
-import os
 from collections.abc import Iterator
 from typing import Any, Literal
 
@@ -19,12 +18,15 @@
     MAX_ALLOWED_ERRORS,
     MAX_RETRIES,
     RETRY_STATUS_CODES,
+    Config,
 )
 from harvester.exceptions import MaxAllowedErrorsReached
 from harvester.utils import send_sentry_message
 
 logger = logging.getLogger(__name__)
 
+CONFIG = Config()
+
 
 class OAIClient:
     def __init__(
@@ -157,7 +159,7 @@ def write_records(records: Iterator, filepath: str) -> int:
         for record in records:
             file.write("  ".encode() + record.raw.encode() + "\n".encode())
             count += 1
-            if count % int(os.getenv("STATUS_UPDATE_INTERVAL", "1000")) == 0:
+            if count % int(CONFIG.STATUS_UPDATE_INTERVAL) == 0:
                 logger.info(
                     "Status update: %s records written to output file so far!",
                     count,

tests/conftest.py

@@ -3,12 +3,20 @@
 import pytest
 from click.testing import CliRunner
 
+from harvester.config import Config
+
 
 @pytest.fixture(autouse=True)
 def _test_env(monkeypatch):
+    monkeypatch.setenv("SENTRY_DSN", "None")
     monkeypatch.setenv("WORKSPACE", "test")
 
 
+@pytest.fixture
+def config():
+    return Config()
+
+
 @pytest.fixture
 def runner():
     return CliRunner()

tests/test_config.py

@@ -1,35 +1,70 @@
 import logging
 
-from harvester.config import configure_logger, configure_sentry
+import pytest
 
+from harvester.config import Config
 
-def test_configure_logger_not_verbose():
-    logger = logging.getLogger(__name__)
-    result = configure_logger(logger, verbose=False)
-    assert logger.getEffectiveLevel() == int(logging.INFO)
-    assert result == "Logger 'tests.test_config' configured with level=INFO"
+
+def test_configure_logger_defaults_to_root_logger():
+    config = Config(logger=None)
+    assert config.logger.name == "root"
 
 
-def test_configure_logger_verbose(caplog):
+def test_configure_logger_accepts_specific_logger():
     logger = logging.getLogger(__name__)
-    result = configure_logger(logger, verbose=True)
-    assert logger.getEffectiveLevel() == int(logging.DEBUG)
-    assert result == "Logger 'tests.test_config' configured with level=DEBUG"
+    config = Config(logger=logger)
+    assert config.logger.name == "tests.test_config"
+
+
+def test_configure_logger_not_verbose(config):
+    result = config.configure_logger(verbose=False)
+    assert config.logger.getEffectiveLevel() == int(logging.INFO)
+    assert result == "Logger 'root' configured with level=INFO"
 
 
-def test_configure_sentry_no_env_variable(monkeypatch):
+def test_configure_logger_verbose(config):
+    result = config.configure_logger(verbose=True)
+    assert config.logger.getEffectiveLevel() == int(logging.DEBUG)
+    assert result == "Logger 'root' configured with level=DEBUG"
+
+
+def test_configure_sentry_no_env_variable(config, monkeypatch):
+    config.configure_logger(verbose=False)
     monkeypatch.delenv("SENTRY_DSN", raising=False)
-    result = configure_sentry()
+    result = config.configure_sentry()
     assert result == "No Sentry DSN found, exceptions will not be sent to Sentry"
 
 
-def test_configure_sentry_env_variable_is_none(monkeypatch):
+def test_configure_sentry_env_variable_is_none(config, monkeypatch):
     monkeypatch.setenv("SENTRY_DSN", "None")
-    result = configure_sentry()
+    result = config.configure_sentry()
     assert result == "No Sentry DSN found, exceptions will not be sent to Sentry"
 
 
-def test_configure_sentry_env_variable_is_dsn(monkeypatch):
+def test_configure_sentry_env_variable_is_dsn(config, monkeypatch):
     monkeypatch.setenv("SENTRY_DSN", "https://1234567890@00000.ingest.sentry.io/123456")
-    result = configure_sentry()
+    result = config.configure_sentry()
     assert result == "Sentry DSN found, exceptions will be sent to Sentry with env=test"
+
+
+def test_config_check_required_env_vars_success(config):
+    config.check_required_env_vars()
+
+
+def test_config_check_required_env_vars_error(config, monkeypatch):
+    monkeypatch.delenv("SENTRY_DSN")
+    with pytest.raises(
+        OSError, match="Missing required environment variables: SENTRY_DSN"
+    ):
+        config.check_required_env_vars()
+
+
+def test_config_env_var_access_success(config):
+    assert config.STATUS_UPDATE_INTERVAL == "1000"
+
+
+def test_config_env_var_access_error(config):
+    with pytest.raises(
+        AttributeError, match="'DOES_NOT_EXIST' not a valid configuration variable"
+    ):
+        _ = config.DOES_NOT_EXIST