Update Config module to current conventions

Why these changes are being introduced:
* Use a central Config class for dynamic access to
environment variables and simplify method for configuring
loggers.

How this addresses that need:
* Create a Config class for dynamically accessing environment variables
* Deprecate load_alma_config and update AlmaClient to use Config class to dynamically
set attributes (base_url, headers, timeout)
* Update configure_logger to use 'verbose' boolean flag
* Update CLI to accept '-v/--verbose' boolean option and remove '-l/--log-level' string option
* Add/update corresponding unit tests

Side effects of this change:
* Remove LOG_LEVEL as an optional environment variable

Relevant ticket(s):
* https://mitlibraries.atlassian.net/browse/IN-1065

ccslips/alma.py

@@ -5,7 +5,7 @@
 
 import requests
 
-from ccslips.config import load_alma_config
+from ccslips.config import Config
 
 logger = logging.getLogger(__name__)
 
@@ -24,16 +24,21 @@ class AlmaClient:
           {"total_record_count": 0} and these methods will return that object.
     """
 
-    def __init__(self) -> None:
-        """Initialize AlmaClient instance."""
-        alma_config = load_alma_config()
-        self.base_url = alma_config["BASE_URL"]
-        self.headers = {
-            "Authorization": f"apikey {alma_config['API_KEY']}",
+    @property
+    def base_url(self) -> str:
+        return Config().ALMA_API_URL
+
+    @property
+    def headers(self) -> dict:
+        return {
+            "Authorization": f"apikey {Config().ALMA_API_READ_KEY}",
             "Accept": "application/json",
             "Content-Type": "application/json",
         }
-        self.timeout = float(alma_config["TIMEOUT"])
+
+    @property
+    def timeout(self) -> float:
+        return float(Config().ALMA_API_TIMEOUT)
 
     def get_paged(
         self,

ccslips/cli.py

@@ -1,16 +1,17 @@
 import datetime
 import logging
-import os
 from time import perf_counter
 
 import click
 
-from ccslips.config import configure_logger, configure_sentry
+from ccslips.config import Config, configure_logger, configure_sentry
 from ccslips.email import Email
 from ccslips.polines import generate_credit_card_slips_html, process_po_lines
 
 logger = logging.getLogger(__name__)
 
+CONFIG = Config()
+
 
 @click.command()
 @click.option(
@@ -36,48 +37,51 @@
     "--date",
     help=(
         "Optional date of exports to process, in 'YYYY-MM-DD' format. Defaults to "
-        "yesterday's date if not provided."
+        "two (2) days before the date the application is run."
     ),
 )
 @click.option(
-    "-l",
-    "--log-level",
-    envvar="LOG_LEVEL",
-    help="Case-insensitive Python log level to use, e.g. debug or warning. Defaults to "
-    "INFO if not provided or found in ENV.",
+    "-v",
+    "--verbose",
+    is_flag=True,
+    help="Pass to set log level to DEBUG. Defaults to INFO.",
 )
 @click.pass_context
 def main(
     ctx: click.Context,
     source_email: str,
     recipient_email: list[str],
     date: str | None,
-    log_level: str | None,
+    *,
+    verbose: bool,
 ) -> None:
     start_time = perf_counter()
-    log_level = log_level or "INFO"
     root_logger = logging.getLogger()
-    logger.info(configure_logger(root_logger, log_level))
+    logger.info(configure_logger(root_logger, verbose=verbose))
     logger.info(configure_sentry())
-    logger.debug("Command called with options: %s", ctx.params)
+    CONFIG.check_required_env_vars()
 
+    logger.debug("Command called with options: %s", ctx.params)
     logger.info("Starting credit card slips process")
-    date = date or (
+
+    # creation date of retrieved PO lines
+    created_date = date or (
         datetime.datetime.now(tz=datetime.UTC) - datetime.timedelta(days=2)
     ).strftime("%Y-%m-%d")
-    credit_card_slips_data = process_po_lines(date)
+
+    credit_card_slips_data = process_po_lines(created_date)
+
     email_content = generate_credit_card_slips_html(credit_card_slips_data)
     email = Email()
-    env = os.environ["WORKSPACE"]
-    subject_prefix = f"{env.upper()} " if env != "prod" else ""
+    subject_prefix = f"{CONFIG.WORKSPACE.upper()} " if CONFIG.WORKSPACE != "prod" else ""
     email.populate(
         from_address=source_email,
         to_addresses=",".join(recipient_email),
-        subject=f"{subject_prefix}Credit card slips {date}",
+        subject=f"{subject_prefix}Credit card slips {created_date}",
         attachments=[
             {
                 "content": email_content,
-                "filename": f"{date}_credit_card_slips.htm",
+                "filename": f"{created_date}_credit_card_slips.htm",
             }
         ],
     )
@@ -86,10 +90,8 @@ def main(
 
     elapsed_time = perf_counter() - start_time
     logger.info(
-        "Credit card slips processing complete for date %s. Email sent to recipient(s) "
-        "%s with SES message ID '%s'. Total time to complete process: %s",
-        date,
-        recipient_email,
-        response["MessageId"],
-        str(datetime.timedelta(seconds=elapsed_time)),
+        f"Credit card slips processing complete for date {created_date}. "
+        f"Email sent to recipient(s) {recipient_email} "
+        f"with SES message ID {response["MessageId"]}. "
+        f"Total time to complete process: {datetime.timedelta(seconds=elapsed_time)}"
     )

ccslips/config.py

@@ -1,27 +1,48 @@
 import logging
 import os
+from typing import Any
 
 import sentry_sdk
 
 
-def configure_logger(logger: logging.Logger, log_level_string: str) -> str:
-    if log_level_string.upper() not in logging.getLevelNamesMapping():
-        message = f"'{log_level_string}' is not a valid Python logging level"
-        raise ValueError(message)
-    log_level = logging.getLevelName(log_level_string.upper())
-    if log_level < 20:  # noqa: PLR2004
+class Config:
+    REQUIRED_ENV_VARS = ("ALMA_API_URL", "ALMA_API_READ_KEY", "SENTRY_DSN", "WORKSPACE")
+
+    OPTIONAL_ENV_VARS = (
+        "ALMA_API_TIMEOUT",
+        "SES_RECIPIENT_EMAIL",
+        "SES_SEND_FROM_EMAIL",
+    )
+
+    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 __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:
+            return os.getenv(name)
+        message = f"'{name}' not a valid configuration variable"
+        raise AttributeError(message)
+
+
+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(log_level)
+        logger.setLevel(logging.DEBUG)
         for handler in logging.root.handlers:
             handler.addFilter(logging.Filter("ccslips"))
     else:
         logging.basicConfig(
             format="%(asctime)s %(levelname)s %(name)s.%(funcName)s(): %(message)s"
         )
-        logger.setLevel(log_level)
+        logger.setLevel(logging.INFO)
     return (
         f"Logger '{logger.name}' configured with level="
         f"{logging.getLevelName(logger.getEffectiveLevel())}"
@@ -35,11 +56,3 @@ def configure_sentry() -> str:
         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 load_alma_config() -> dict[str, str]:
-    return {
-        "API_KEY": os.environ["ALMA_API_READ_KEY"],
-        "BASE_URL": os.environ["ALMA_API_URL"],
-        "TIMEOUT": os.getenv("ALMA_API_TIMEOUT", "30"),
-    }

tests/conftest.py

@@ -7,6 +7,7 @@
 from moto import mock_aws
 
 from ccslips.alma import AlmaClient
+from ccslips.config import Config
 
 
 # Env fixtures
@@ -21,10 +22,11 @@ def _test_environment(monkeypatch):
     )
     monkeypatch.setenv("SENTRY_DSN", "None")
     monkeypatch.setenv("WORKSPACE", "test")
-    monkeypatch.setenv("AWS_ACCESS_KEY_ID", "testing")
-    monkeypatch.setenv("AWS_SECRET_ACCESS_KEY", "testing")
-    monkeypatch.setenv("AWS_SECURITY_TOKEN", "testing")
-    monkeypatch.setenv("AWS_SESSION_TOKEN", "testing")
+
+
+@pytest.fixture
+def config_instance() -> Config:
+    return Config()
 
 
 # CLI fixture

tests/test_alma.py

@@ -1,7 +1,7 @@
 from ccslips.alma import AlmaClient
 
 
-def test_client_initializes_with_expected_values():
+def test_client_initializes_with_expected_values(monkeypatch):
     client = AlmaClient()
     assert client.base_url == "https://example.com"
     assert client.headers == {

tests/test_cli.py

@@ -30,16 +30,15 @@ def test_cli_all_options_passed(caplog, runner):
             "recipient2@example.com",
             "--date",
             "2023-01-02",
-            "--log-level",
-            "debug",
+            "--verbose",
         ],
     )
     assert result.exit_code == 0
     assert "Logger 'root' configured with level=DEBUG" in caplog.text
     assert (
         "Command called with options: {'source_email': 'from@example.com', "
         "'recipient_email': ('recipient1@example.com', 'recipient2@example.com'), "
-        "'date': '2023-01-02', 'log_level': 'debug'}" in caplog.text
+        "'date': '2023-01-02', 'verbose': True}" in caplog.text
     )
     assert (
         "Credit card slips processing complete for date 2023-01-02. Email sent to "

tests/test_config.py

@@ -2,26 +2,20 @@
 
 import pytest
 
-from ccslips.config import configure_logger, configure_sentry, load_alma_config
+from ccslips.config import configure_logger, configure_sentry
 
 
-def test_configure_logger_with_invalid_level_raises_error():
+def test_configure_logger_not_verbose():
     logger = logging.getLogger(__name__)
-    with pytest.raises(ValueError, match="'oops' is not a valid Python logging level"):
-        configure_logger(logger, log_level_string="oops")
-
-
-def test_configure_logger_info_level_or_higher():
-    logger = logging.getLogger(__name__)
-    result = configure_logger(logger, log_level_string="info")
-    assert logger.getEffectiveLevel() == 20  # noqa: PLR2004
+    result = configure_logger(logger, verbose=False)
+    assert logger.getEffectiveLevel() == logging.INFO
     assert result == "Logger 'tests.test_config' configured with level=INFO"
 
 
-def test_configure_logger_debug_level_or_lower():
+def test_configure_logger_verbose():
     logger = logging.getLogger(__name__)
-    result = configure_logger(logger, log_level_string="DEBUG")
-    assert logger.getEffectiveLevel() == 10  # noqa: PLR2004
+    result = configure_logger(logger, verbose=True)
+    assert logger.getEffectiveLevel() == logging.DEBUG
     assert result == "Logger 'tests.test_config' configured with level=DEBUG"
 
 
@@ -43,18 +37,22 @@ def test_configure_sentry_env_variable_is_dsn(monkeypatch):
     assert result == "Sentry DSN found, exceptions will be sent to Sentry with env=test"
 
 
-def test_load_alma_config_from_env():
-    assert load_alma_config() == {
-        "API_KEY": "just-for-testing",
-        "BASE_URL": "https://example.com",
-        "TIMEOUT": "10",
-    }
+def test_config_env_var_access_success(config_instance):
+    assert config_instance.WORKSPACE == "test"
+
+
+def test_config_env_var_access_error(config_instance):
+    with pytest.raises(
+        AttributeError, match="'DOES_NOT_EXIST' not a valid configuration variable"
+    ):
+        _ = config_instance.DOES_NOT_EXIST
+
+
+def test_config_check_required_env_vars_success(config_instance):
+    _ = config_instance.check_required_env_vars
 
 
-def test_load_alma_config_from_defaults(monkeypatch):
-    monkeypatch.delenv("ALMA_API_TIMEOUT", raising=False)
-    assert load_alma_config() == {
-        "API_KEY": "just-for-testing",
-        "BASE_URL": "https://example.com",
-        "TIMEOUT": "30",
-    }
+def test_config_check_required_env_vars_error(monkeypatch, config_instance):
+    monkeypatch.delenv("ALMA_API_URL")
+    with pytest.raises(OSError, match="Missing required environment variables"):
+        config_instance.check_required_env_vars()