AI Implementation feature(1089): Scheduled Execution with Cron and Retry Handling (#9)

src/tenbackward/config.py

@@ -13,10 +13,10 @@ from dotenv import dotenv_values, load_dotenv
 REQUIRED_KEYS = (
     "MASTODON_BASE_URL",
     "MASTODON_ACCESS_TOKEN",
-    "VISIBILITY",
+    "MASTODON_VISIBILITY",
     "SITE_URL",
     "HASHTAGS",
-    "THROWNBACK_PREFIX",
+    "THROWBACK_PREFIX",
     "MAX_RETRIES",
     "RUN_AT",
     "TZ",
@@ -25,11 +25,7 @@ REQUIRED_KEYS = (
 OPTIONAL_KEYS: tuple[str, ...] = ("BLOG_REPO_URL", "BLOG_DIR")
 
 DEFAULTS = {
-    "VISIBILITY": "public",
-    "THROWNBACK_PREFIX": "Heute vor 10 Jahren:",
-    "MAX_RETRIES": "3",
-    "TZ": "Europe/Berlin",
-    "RUN_AT": "09:00",
+    "MAX_RETRIES": "5",
     "BLOG_REPO_URL": "https://git.chaospott.de/Chaospott/site",
     "BLOG_DIR": "blog",
 }
@@ -46,7 +42,7 @@ class ConfigError(ValueError):
 class Config:
     mastodon_base_url: str
     mastodon_access_token: str
-    visibility: str
+    mastodon_visibility: str
     site_url: str
     hashtags: str
     throwback_prefix: str
@@ -67,6 +63,9 @@ class Config:
         return self.run_at.split(":", 1)[1]
 
 
+DEFAULT_DOTENV_PATH = Path("/app/.env")
+
+
 def _read_dotenv(dotenv_path: Optional[Path]) -> dict[str, str]:
     if dotenv_path is None:
         return {}
@@ -88,19 +87,38 @@ def _values_from_env() -> dict[str, str]:
 def load_config(dotenv_path: Optional[Path] = None) -> Config:
     """Load configuration from a dotenv file and the process environment.
 
-    Environment variables take precedence over the dotenv file so a mounted
-    `.env` can be supplemented by Compose-level overrides.
+    The .env file is loaded via python-dotenv at startup so the bind-mounted
+    runtime secrets are visible to the process. Environment variables take
+    precedence over the dotenv file so a mounted `.env` can be supplemented
+    by Compose-level overrides.
+
+    Required keys are validated against the **raw** merged map (dotenv +
+    process env) before any defaults are applied. Defaults are only used
+    for the retry budget and the optional Jekyll blog source so a missing
+    Mastodon/secret/URL/etc. fails fast with a clear error.
     """
+    if dotenv_path is None:
+        dotenv_path = DEFAULT_DOTENV_PATH if DEFAULT_DOTENV_PATH.exists() else None
+
     if dotenv_path is not None:
         load_dotenv(dotenv_path=str(dotenv_path), override=False)
 
     file_values = _read_dotenv(dotenv_path)
     env_values = _values_from_env()
 
-    merged: dict[str, str] = {}
-    merged.update(file_values)
-    merged.update(env_values)
+    raw: dict[str, str] = {}
+    raw.update(file_values)
+    raw.update(env_values)
 
+    # MAX_RETRIES is the only required key that has a permitted default
+    # (5 attempts per the Job). Apply it before the required-key check so a
+    # missing value uses the documented default rather than failing fast.
+    if not raw.get("MAX_RETRIES"):
+        raw["MAX_RETRIES"] = DEFAULTS["MAX_RETRIES"]
+
+    validate_required(raw)
+
+    merged = dict(raw)
     apply_defaults(merged)
 
     validate_config(merged)
@@ -119,10 +137,10 @@ def load_config(dotenv_path: Optional[Path] = None) -> Config:
     return Config(
         mastodon_base_url=merged["MASTODON_BASE_URL"],
         mastodon_access_token=merged["MASTODON_ACCESS_TOKEN"],
-        visibility=merged["VISIBILITY"],
+        mastodon_visibility=merged["MASTODON_VISIBILITY"],
         site_url=merged["SITE_URL"],
         hashtags=merged["HASHTAGS"],
-        throwback_prefix=merged["THROWNBACK_PREFIX"],
+        throwback_prefix=merged["THROWBACK_PREFIX"],
         max_retries=_parse_max_retries(merged["MAX_RETRIES"]),
         run_at=merged["RUN_AT"],
         tz=merged["TZ"],
@@ -138,13 +156,23 @@ def apply_defaults(values: dict[str, str]) -> None:
         values.setdefault(key, default)
 
 
-def validate_config(values: dict[str, str]) -> None:
-    errors: list[str] = []
+def validate_required(values: dict[str, str]) -> None:
+    """Validate that every required key is present and non-empty in ``values``.
 
+    Called against the raw (no-default) merged map so a missing key always
+    surfaces as a startup error rather than being silently substituted.
+    """
+    errors: list[str] = []
     for key in REQUIRED_KEYS:
         raw = values.get(key, "")
         if not raw:
             errors.append(f"missing required configuration key: {key}")
+    if errors:
+        raise ConfigError("; ".join(errors))
+
+
+def validate_config(values: dict[str, str]) -> None:
+    errors: list[str] = []
 
     run_at = values.get("RUN_AT", "")
     if run_at and not _is_valid_hhmm(run_at):
@@ -158,10 +186,10 @@ def validate_config(values: dict[str, str]) -> None:
     if site_url and not _is_valid_url(site_url):
         errors.append(f"SITE_URL={site_url!r} must be a valid http(s) URL")
 
-    visibility = values.get("VISIBILITY", "")
+    visibility = values.get("MASTODON_VISIBILITY", "")
     if visibility and not _is_valid_visibility(visibility):
         errors.append(
-            f"VISIBILITY={visibility!r} must be one of: {sorted(ALLOWED_VISIBILITY)}"
+            f"MASTODON_VISIBILITY={visibility!r} must be one of: {sorted(ALLOWED_VISIBILITY)}"
         )
 
     blog_repo_url = values.get("BLOG_REPO_URL", "")