Make email template placeholders configurable via environment variables

scraibe/email_sender.py

@@ -4,6 +4,7 @@ Email sender module for ScrAIbe.
 Sends transcription outputs (TXT, JSON, etc.) via SMTP.
 All credentials are configured via environment variables.
 Supports both plain text and HTML email bodies.
+Template placeholders are primarily filled via environment variables.
 """
 
 import os
@@ -13,7 +14,7 @@ from email import encoders
 from email.mime.base import MIMEBase
 from email.mime.multipart import MIMEMultipart
 from email.mime.text import MIMEText
-from typing import List, Optional
+from typing import List, Optional, Dict, Any
 
 logger = logging.getLogger("scraibe.email_sender")
 
@@ -52,7 +53,31 @@ def get_email_config():
     }
 
 
-def load_template(template_name: str, **kwargs) -> str:
+def build_template_context(**runtime_kwargs: Any) -> Dict[str, Any]:
+    """
+    Build a context dict for templates from:
+      - environment variables (base, customizable)
+      - runtime-provided values (override env if present)
+
+    Environment variables:
+      - EMAIL_CONTACT_ADDRESS: value for {contact_email}
+      - EMAIL_CSS_PATH: value for {css_path}
+
+    Runtime kwargs are merged on top (e.g. queue_position, exception).
+    """
+    ctx: Dict[str, Any] = {
+        "contact_email": os.getenv("EMAIL_CONTACT_ADDRESS", "support@example.com"),
+        "css_path": os.getenv("EMAIL_CSS_PATH", ""),
+    }
+
+    # Runtime values override env if provided
+    if runtime_kwargs:
+        ctx.update(runtime_kwargs)
+
+    return ctx
+
+
+def load_template(template_name: str, **runtime_kwargs: Any) -> str:
     """
     Load an HTML email template from misc/ and render placeholders.
 
@@ -70,9 +95,12 @@ def load_template(template_name: str, **kwargs) -> str:
     with open(path, "r", encoding="utf-8") as f:
         template = f.read()
 
+    # Build context from env + runtime
+    ctx = build_template_context(**runtime_kwargs)
+
     # Replace {placeholder} style variables safely
     try:
-        return template.format(**kwargs)
+        return template.format(**ctx)
     except KeyError as e:
         raise EmailError(f"Missing template variable: {e}")