Email: add possibility to easily load templates from a directory

mylib/email.py

@@ -46,15 +46,18 @@ class EmailClient(
         "encoding": "utf-8",
         "catch_all_addr": None,
         "just_try": False,
+        "templates_path": None,
     }
 
     templates = {}
 
-    def __init__(self, templates=None, **kwargs):
+    def __init__(self, templates=None, initialize=False, **kwargs):
         super().__init__(**kwargs)
 
         assert templates is None or isinstance(templates, dict)
         self.templates = templates if templates else {}
+        if initialize:
+            self.initialize()
 
     # pylint: disable=arguments-differ,arguments-renamed
     def configure(self, use_smtp=True, just_try=True, **kwargs):
@@ -137,8 +140,40 @@ class EmailClient(
                 comment="Just-try mode: do not really send emails",
             )
 
+        section.add_option(
+            StringOption,
+            "templates_path",
+            comment="Path to templates directory",
+        )
+
         return section
 
+    def initialize(self, *args, **kwargs):  # pylint: disable=arguments-differ
+        """Configuration initialized hook"""
+        super().initialize(*args, **kwargs)
+        self.load_templates_directory()
+
+    def load_templates_directory(self, templates_path=None):
+        """Load templates from specified directory"""
+        if templates_path is None:
+            templates_path = self._get_option("templates_path")
+        if not templates_path:
+            return
+        log.debug("Load email templates from %s directory", templates_path)
+        for filename in os.listdir(templates_path):
+            filepath = os.path.join(templates_path, filename)
+            if not os.path.isfile(filepath):
+                continue
+            template_name, template_type = os.path.splitext(filename)
+            if template_type not in [".html", ".txt", ".subject"]:
+                continue
+            template_type = "text" if template_type == ".txt" else template_type[1:]
+            if template_name not in self.templates:
+                self.templates[template_name] = {}
+            log.debug("Load email template %s %s from %s", template_name, template_type, filepath)
+            with open(filepath, encoding="utf8") as file_desc:
+                self.templates[template_name][template_type] = MakoTemplate(file_desc.read())
+
     def forge_message(
         self,
         rcpt_to,
@@ -179,7 +214,11 @@ class EmailClient(
             )
         )
         if subject:
-            msg["Subject"] = subject.format(**template_vars)
+            msg["Subject"] = (
+                subject.render(**template_vars)
+                if isinstance(subject, MakoTemplate)
+                else subject.format(**template_vars)
+            )
         msg["Date"] = email.utils.formatdate(None, True)
         encoding = encoding if encoding else self._get_option("encoding")
         if template:
@@ -189,7 +228,11 @@ class EmailClient(
                 assert self.templates[template].get(
                     "subject"
                 ), f"No subject defined in template {template}"
-                msg["Subject"] = self.templates[template]["subject"].format(**template_vars)
+                msg["Subject"] = (
+                    self.templates[template]["subject"].render(**template_vars)
+                    if isinstance(self.templates[template]["subject"], MakoTemplate)
+                    else self.templates[template]["subject"].format(**template_vars)
+                )
 
             # Put HTML part in last one to prefered it
             parts = []

mylib/scripts/email_templates/test.html

@@ -0,0 +1 @@
+<strong>Just a test email.</strong> <small>(sent at ${sent_date})</small>

mylib/scripts/email_templates/test.subject

@@ -0,0 +1 @@
+Test email

mylib/scripts/email_templates/test.txt

@@ -0,0 +1 @@
+Just a test email sent at ${sent_date}.

mylib/scripts/email_test.py

@@ -2,10 +2,9 @@
 import datetime
 import getpass
 import logging
+import os
 import sys
 
-from mako.template import Template as MakoTemplate
-
 from mylib.scripts.helpers import add_email_opts, get_opts_parser, init_email_client, init_logging
 
 log = logging.getLogger("mylib.scripts.email_test")
@@ -18,7 +17,10 @@ def main(argv=None):  # pylint: disable=too-many-locals,too-many-statements
 
     # Options parser
     parser = get_opts_parser(just_try=True)
-    add_email_opts(parser)
+    add_email_opts(
+        parser,
+        templates_path=os.path.join(os.path.dirname(os.path.realpath(__file__)), "email_templates"),
+    )
 
     test_opts = parser.add_argument_group("Test email options")
 
@@ -31,6 +33,15 @@ def main(argv=None):  # pylint: disable=too-many-locals,too-many-statements
         help="Test email recipient",
     )
 
+    test_opts.add_argument(
+        "-T",
+        "--template",
+        action="store_true",
+        dest="template",
+        help="Template name to send (default: test)",
+        default="test",
+    )
+
     test_opts.add_argument(
         "-m",
         "--mako",
@@ -51,26 +62,7 @@ def main(argv=None):  # pylint: disable=too-many-locals,too-many-statements
     if options.email_smtp_user and not options.email_smtp_password:
         options.email_smtp_password = getpass.getpass("Please enter SMTP password: ")
 
-    email_client = init_email_client(
+    email_client = init_email_client(options)
-        options,
-        templates=dict(
-            test=dict(
-                subject="Test email",
-                text=(
-                    "Just a test email sent at {sent_date}."
-                    if not options.test_mako
-                    else MakoTemplate("Just a test email sent at ${sent_date}.")
-                ),
-                html=(
-                    "<strong>Just a test email.</strong> <small>(sent at {sent_date})</small>"
-                    if not options.test_mako
-                    else MakoTemplate(
-                        "<strong>Just a test email.</strong> <small>(sent at ${sent_date})</small>"
-                    )
-                ),
-            )
-        ),
-    )
 
     log.info("Send a test email to %s", options.test_to)
     if email_client.send(options.test_to, template="test", sent_date=datetime.datetime.now()):

mylib/scripts/email_test_with_config.py

@@ -1,10 +1,9 @@
 """ Test Email client using mylib.config.Config for configuration """
 import datetime
 import logging
+import os
 import sys
 
-from mako.template import Template as MakoTemplate
-
 from mylib.config import Config
 from mylib.email import EmailClient
 
@@ -20,6 +19,11 @@ def main(argv=None):  # pylint: disable=too-many-locals,too-many-statements
 
     email_client = EmailClient(config=config)
     email_client.configure()
+    config.set_default(
+        "email",
+        "templates_path",
+        os.path.join(os.path.dirname(os.path.realpath(__file__)), "email_templates"),
+    )
 
     # Options parser
     parser = config.get_arguments_parser(description=__doc__)
@@ -35,6 +39,15 @@ def main(argv=None):  # pylint: disable=too-many-locals,too-many-statements
         help="Test email recipient",
     )
 
+    test_opts.add_argument(
+        "-T",
+        "--template",
+        action="store_true",
+        dest="template",
+        help="Template name to send (default: test)",
+        default="test",
+    )
+
     test_opts.add_argument(
         "-m",
         "--mako",
@@ -49,24 +62,6 @@ def main(argv=None):  # pylint: disable=too-many-locals,too-many-statements
         parser.error("You must specify test email recipient using -t/--to parameter")
         sys.exit(1)
 
-    email_client.templates = dict(
-        test=dict(
-            subject="Test email",
-            text=(
-                "Just a test email sent at {sent_date}."
-                if not options.test_mako
-                else MakoTemplate("Just a test email sent at ${sent_date}.")
-            ),
-            html=(
-                "<strong>Just a test email.</strong> <small>(sent at {sent_date})</small>"
-                if not options.test_mako
-                else MakoTemplate(
-                    "<strong>Just a test email.</strong> <small>(sent at ${sent_date})</small>"
-                )
-            ),
-        )
-    )
-
     logging.info("Send a test email to %s", options.test_to)
     if email_client.send(options.test_to, template="test", sent_date=datetime.datetime.now()):
         logging.info("Test email sent")

mylib/scripts/helpers.py

@@ -87,7 +87,7 @@ def get_opts_parser(desc=None, just_try=False, just_one=False, progress=False, c
     return parser
 
 
-def add_email_opts(parser, config=None):
+def add_email_opts(parser, config=None, **defaults):
     """Add email options"""
     email_opts = parser.add_argument_group("Email options")
 
@@ -103,7 +103,9 @@ def add_email_opts(parser, config=None):
         sender_name=getpass.getuser(),
         sender_email=f"{getpass.getuser()}@{socket.gethostname()}",
         catch_all=False,
+        templates_path=None,
     )
+    default_config.update(defaults)
 
     email_opts.add_argument(
         "--smtp-host",
@@ -220,6 +222,18 @@ def add_email_opts(parser, config=None):
         default=get_default_opt_value(config, default_config, "catch_all"),
     )
 
+    email_opts.add_argument(
+        "--templates-path",
+        action="store",
+        type=str,
+        dest="email_templates_path",
+        help=(
+            "Load templates from specify directory "
+            f'(default: {get_default_opt_value(config, default_config, "templates_path")})'
+        ),
+        default=get_default_opt_value(config, default_config, "templates_path"),
+    )
+
 
 def init_email_client(options, **kwargs):
     """Initialize email client from calling script options"""
@@ -239,6 +253,8 @@ def init_email_client(options, **kwargs):
         catch_all_addr=options.email_catch_all,
         just_try=options.just_try if hasattr(options, "just_try") else False,
         encoding=options.email_encoding,
+        templates_path=options.email_templates_path,
+        initialize=True,
         **kwargs,
     )