Refactoring exception handling

With this commit I wanted to make sure that modules weren't raising
ClickExceptions and instead were raising their own exception types to
reducing coupling.

Author: travishathaway

latz/cli.py

@@ -5,7 +5,7 @@
 from pydantic import create_model, validator
 
 from .commands import search_command, config_group
-from .config import get_app_config, BaseAppConfig
+from .config import get_app_config, BaseAppConfig, ConfigError
 from .constants import CONFIG_FILES
 from .plugins.manager import get_plugin_manager
 
@@ -45,7 +45,10 @@ def cli(ctx):
 
     # Creates the actual config object which parses all possible configuration sources
     # listed in ``CONFIG_FILES``.
-    app_config = get_app_config(CONFIG_FILES, AppConfig)
+    try:
+        app_config = get_app_config(CONFIG_FILES, AppConfig)
+    except ConfigError as exc:
+        raise click.ClickException(str(exc))
 
     # Attach several properties to click's ``ctx`` object so that we have access to it
     # in our sub-commands.

latz/commands/config/commands.py

@@ -4,7 +4,7 @@
 from rich import print as rprint
 
 from ...constants import CONFIG_FILE_CWD, CONFIG_FILE_HOME_DIR
-from ...config.main import parse_config_file_as_json, write_config_file
+from ...config import parse_config_file_as_json, write_config_file, ConfigError
 from .validators import validate_and_parse_config_values
 
 
@@ -42,10 +42,10 @@ def set_command(home, config_values):
     # Merge the new values and old values; new overwrites the old
     new_config_file_data = {**parsed_config.data, **config_values}
 
-    error = write_config_file(new_config_file_data, config_file)
-
-    if error:
-        raise click.ClickException(error)
+    try:
+        write_config_file(new_config_file_data, config_file)
+    except ConfigError as exc:
+        raise click.ClickException(str(exc))
 
 
 group.add_command(show_command)

latz/commands/search.py

@@ -2,6 +2,7 @@
 from typing import cast, ContextManager, Any
 
 import click
+import httpx
 from rich import print as rprint
 
 from ..image import ImageAPI
@@ -19,7 +20,10 @@ def command(ctx, query: str):
     )
 
     with image_api_context_manager(ctx.obj.config) as api:
-        result_set = api.search(query)
+        try:
+            result_set = api.search(query)
+        except httpx.HTTPError as exc:
+            raise click.ClickException(str(exc))
 
         for res in result_set.results:
             rprint(res)

latz/config/__init__.py

@@ -1,2 +1,7 @@
-from .main import get_app_config  # noqa: F401
+from .main import (  # noqa: F401
+    get_app_config,
+    parse_config_file_as_json,
+    write_config_file,
+    ConfigError,
+)
 from .models import BaseAppConfig  # noqa: F401

latz/config/main.py

@@ -8,14 +8,17 @@
 from typing import NamedTuple, Any
 
 from pydantic import ValidationError
-from click import ClickException
 
 from .models import BaseAppConfig
 from .errors import format_validation_error, format_all_validation_errors
 
 logger = logging.getLogger(__name__)
 
 
+class ConfigError(Exception):
+    pass
+
+
 class ParsedConfigFile(NamedTuple):
     #: Path to the configuration file
     path: Path
@@ -123,11 +126,11 @@ def get_app_config(
     Given a sequence of ``paths`` first attempts to parse these as JSON and then
     attempts to parse valid JSON objects as ``AppConfig`` objects.
 
-    :raises ClickException: Happens when any errors are encountered during config parsing
+    :raises ConfigError: Happens when any errors are encountered during config parsing
     """
     parsed_config_files = parse_config_files(paths)
 
-    # No files were found 🤷‍
+    # No files were found 🤷‍; let's return a default config object
     if parsed_config_files is None:
         return model_class()
 
@@ -140,7 +143,7 @@ def get_app_config(
 
     # Fail loudly if any errors
     if len(errors) > 0:
-        raise ClickException(format_all_validation_errors(errors))
+        raise ConfigError(format_all_validation_errors(errors))
 
     # Gather configs
     app_configs = tuple(parsed.model for parsed in parsed_config_files if parsed.model)
@@ -153,14 +156,14 @@ def get_app_config(
     return merge_app_configs(app_configs, model_class)
 
 
-def write_config_file(
-    config_file_data: dict[str, Any], config_file: Path
-) -> str | None:
+def write_config_file(config_file_data: dict[str, Any], config_file: Path) -> None:
     """
-    Attempts to write a
+    Attempts to write config file and returns the exception as a string if it failed.
+
+    :raises ConfigError: Raised when we are not able to write our config file.
     """
     try:
         with config_file.open("w") as fp:
             json.dump(config_file_data, fp, indent=2)
     except OSError as exc:
-        return str(exc)
+        raise ConfigError(str(exc))

latz/plugins/image/unsplash.py

@@ -2,8 +2,7 @@
 
 import urllib.parse
 
-import click
-from httpx import Client, HTTPError, Headers
+from httpx import Client, Headers
 from pydantic import BaseModel, Field
 
 from ...image import (
@@ -47,24 +46,26 @@ class UnsplashImageAPI(ImageAPI):
     #: Base URL for the Unsplash API
     base_url = "https://api.unsplash.com/"
 
-    def __init__(self, client_id: str, client):
+    #: Endpoint used for searching images
+    search_endpoint = "/search/photos"
+
+    def __init__(self, client_id: str, client: Client):
         """We use this initialization method to properly configure the ``httpx.Client`` object"""
         self._client_id = client_id
         self._headers = {"Authorization": f"Client-ID {client_id}"}
-        self._client: Client = client
+        self._client = client
         self._client.headers = Headers(self._headers)
 
     def search(self, query: str) -> ImageSearchResultSet:
         """
         Find images based on a ``search_term`` and return an ``ImageSearchResultSet``
+
+        :raises HTTPError: Encountered during problems querying the API
         """
-        search_url = urllib.parse.urljoin(self.base_url, "/search/photos")
+        search_url = urllib.parse.urljoin(self.base_url, self.search_endpoint)
 
-        try:
-            resp = self._client.get(search_url, params={"query": query})
-            resp.raise_for_status()
-        except HTTPError as exc:
-            raise click.ClickException(str(exc))
+        resp = self._client.get(search_url, params={"query": query})
+        resp.raise_for_status()
 
         json_data = resp.json()